Special Sessions for ASLO 2005 Summer Meeting

SS01 Ecosystem Engineers in the Benthic Boundary Layer
Organizers: Luca A. van Duren, Netherlands Institute of Ecology, (l.vanduren@nioo.knaw.nl) and Joseph D. Ackerman, University of Guelph, (ackerman@uoguelph.ca)

Benthic plants and animals influence their hydrodynamic environment by extracting horizontal momentum from the flow and introducing turbulence into the near-bed region. This occurs either passively, when biogenic structures act as roughness elements, or actively, through the action of the suspension feeders (e.g., pumping, exhalant siphons). In the former, biomechanical properties, especially stiffness, have a large impact on the interaction of the biogenic structures with flow and sediments. In the latter, changes in behaviour (e.g. pumping rates of bivalves) have an impact on the exchange processes near the sediment-water interface. Collectively, these relatively small-scale hydrodynamic processes can affect ecosystems. This session therefore encourages papers that examine the role of organisms as ecosystem engineers in the benthic environment. Papers that couple the physical and biological environments in freshwater and marine systems are encouraged at the level of individual organisms, small aggregates of organisms, as well as the larger scale of ecosystems.

SS02 Ecology of Gelatinous Zooplankton
Organizers: Francesc Pages, Institut de Ciencies del Mar (CSIC), (fpages@cmima.csic.es) and Jennifer E. Purcell, Western Washington University, (purcelj@cc.wwu.edu)

The gelatinous zooplankton have received increased attention from the global scientific community in recent years, in part due to dramatic blooms of native and introduced species, and their obvious importance in the plankton food web. This group includes filter-feeding pelagic tunicates (e.g., appendicularians, salps), and predators that feed with tentacles (scyphomedusae, hydromedusae, siphonophores, ctenophores) or lobes (some ctenophores). We seek to bring together scientists from many countries to explore recent advances in our understanding of the importance of these abundant consumers. Topics of special focus in this session will be their importance in the food web, population dynamics, and relationships to environmental change.

SS03 Trace Metal Cycling in Aquatic Environments
Organizers: Antonio Tovar-Sanchez, CSIC- Univ. Illes Balears, SPAIN, (antonio.tovar@uib.es) and Sergio A. Sañudo-Wilhelmy, Stony Brook University, NY, USA, (ssanudo@notes.cc.sunysb.edu)

While trace metals are ubiquitous in aquatic systems, we are still learning how external and internal forcing functions influence their biogeochemical cycling. This session will provide a forum for presentations that contribute to the understanding of the biotic and abiotic processes regulating these cycles. Participation is encouraged by scientists investigating natural and anthropogenic sources, fate and transport of trace metals in rivers, lakes, coastal and oceanic waters. Both empirical and modeling studies are welcome. This session will also aim to identify critical research needs for better understanding of metal cycles in aquatic systems.

SS04 Climate Change in Ocean and Marginal Sea Ecosystems: Observation, Modeling, and Experiments
Organizers: Evaristo Vázquez-Domínguez, ICM-CMIMA (CSIC), (evazquez@icm.csic.es) and Victoria Coles, University of Maryland Center for Environmental Science, Horn Point Laboratory, (vcoles@hpl.umces.edu)

We propose a special session for the 2005 ASLO summer meeting highlighting the effects of anthropogenic climate change on open ocean and marginal sea ecosystems. Discriminating between the ecological effects of anthropogenically induced climate variability, natural decadal climate variability, and global changes associated with anthropogenic influences distinct from climate, remains a challenge. However, it seems clear that most IPCC models predict a global surface air temperature warming of between 2 and 5ºC for this century if the concentration of CO2 is doubled. These effects are spatially heterogeneous, and regionally, particularly in the northern hemisphere, the increases may be even greater. Observations of glacial retreat, reductions in sea ice cover, and increasing sea level all corroborate an increase in the warming trend. There is greater uncertainty about changes to rainfall, frequency of storm events, surface ocean pH, and other factors that influence the physical conditions of the upper ocean, however these effects are likely to also influence ecosystem response. Because these studies are largely projected into the next century using numerical models with well-known deficiencies, which generally do not include potential ecosystem feedbacks, the challenge for the coming decade is to generate observations, experiments, and model refinements to improve these forecasts, and ultimately to guide mitigation efforts.

Our biosphere is composed of a complex network of systems, and to understand the effects of climate change on this network, we must understand not only the changes in the interacting components, but also, the new pathways which may be formed under conditions different from those observed today. Indeed, this is especially important for the aquatic systems that cover 71% of the earth surface and are the main reservoir of easily available inorganic carbon. Beyond this study of passive response to external change, we must also improve our understanding of the feedbacks between ocean ecosystems, the carbon system, and climate. We propose that this session include; the study of recent climate variability to understand its effects on biogeochemical cycles and on the ecosystem; model studies of the effects of climate change and variability on ecosystems and potential feedbacks to the climate system; and mechanistic experiments focused on food web response to climate changes under controlled conditions. This diverse range of studies will provide a mechanism for cross-fertilization of different branches of investigation.

SS05 Biogeochemistry of Tropical Rivers
Organizers: Michael McClain, Florida International University, (michael.mcclain@fiu.edu) and Jay Brandes, The University of Texas at Austin, (brandes@utmsi.utexas.edu)

We would like to hold a special session focusing on the biogeochemistry of tropical river systems. There are a wide variety of ongoing studies on these rivers, covering a diversity of subjects from basic examinations of carbon and inorganic matter inputs and transport, nutrient cycling, to more complex studies of deforestation and global change impacts, pollution and water use issues. This session provide a much-needed opportunity for researchers to discuss the current state of tropical river studies.

SS06 Fate and Effects of Terrestrial DOM in Aquatic Ecosystems
Organizers: Jan Karlsson, Climate Impact Research Centre, Umeå University, (jan.karlsson@eg.umu.se) and Morten Søndergaard, Freshwater Biological Laboratory, University of Copenhagen, (msondergaard@bi.ku.dk)

Rivers, lakes and coastal ecosystems receive large quantities of allochthonous DOM with consequences for ecosystem function and activity. Important properties of DOM are its specific absorption of UV- and PAR radiation and its function as a carrier of nutrients and chemical energy. Due to the absorption properties of DOM, and specifically the absorption by coloured compounds, it competes with primary producers for light and at the same time protects aquatic communities against high UV radiation. The bound nutrients are made available by interactions between photochemical reactions and direct microbial utilisation. The chemical energy is utilized by heterotrophic bacteria and may support a substantial portion of secondary production. Research over the past decade has dramatically increased our understanding of the quantity of terrestrial DOM export and how it can affect the biota. However, much is still to be learned about the effects and behaviour of specific DOM compounds, e.g. differences in quality and quantity linked to climate gradients and land use, competition between heterotrophic bacteria and primary producers for the bound nutrients, degradation kinetics, and the importance for ecosystem energy support and metabolism. We invite you to contribute to this special session with focus on the fate of terrestrial DOM (DOC, DON and DOP) in rivers, lakes and coastal waters, and how the physical and chemical properties affect these ecosystems and their biota. Results presenting new methods and approaches are also welcome.

SS07 Applied Ecosystem-level Research to Reverse Coral Reef Degradation
Organizers: Michael J. Dowgiallo, NOAA/Center for Sponsored Coastal Ocean Research, (michael.dowgiallo@noaa.gov) and Felix A. Martinez, NOAA/Center for Sponsored Coastal Ocean Research, (felix.martinez@noaa.gov)

Coral reefs, one of the most complex marine ecosystems, remain poorly understood and are under intense pressure from anthropogenic disturbance against the background of environmental variability. This has influenced scientists and resource managers to focus on addressing the suite of stressors that affect coral reef ecosystem health. However, the need to devise management strategies has been hampered by the lack of understanding of how coral reef ecosystems function under pristine conditions much less when disturbed. The approach of combining basic research with applied objectives presents an alternative for providing insight on coral reef ecosystem function that also informs resource managers when designing and evaluating management strategies to stop and ultimately reverse coral reef degradation due to human impact. The purpose of this special session is to provide an international forum for scientists and resource managers to 1) provide examples of basic and applied research activities that have management implications; and, 2) share views and evaluate the success of such an approach.

SS08 Carbon and Carbonate Fluxes in the Coastal Ocean
Organizers: Fred T. Mackenzie, Department of Oceanography University of Hawai'i at Manoa, USA, (fredm@soest.hawaii.edu) and Jean-Pierre Gattuso, Laboratoire d'Oceanographie de Villefranche, CNRS-Université de Paris 6, Fr, (gattuso@obs-vlfr.fr)

The role of the coastal ocean in the global carbon and carbonate cycles is disproportionately high considering its relatively small surface area (7% of the surface of the ocean). For example, it contributes 14-30% of the oceanic primary production and about 50% of the marine calcification. The aim of this session is to examine the factors explaining such high rates of activity and update global estimates of processes such as primary, production, respiration, calcification, air-sea CO2 fluxes, inputs from land and atmosphere, and outputs to the open ocean. Presentations based on process studies, modelling and data synthesis are welcome. This session is a tribute to the late Professor Roland Wollast, a leader and visionary, one of the leading scientists who helped to recognize the critical importance of the coastal ocean in the global biogeochemical cycles.

SS09 Interactive Effects of Multiple Stressors on Aquatic Ecosystems
Organizer: Rolf Vinebrooke, University of Alberta, (rolf@ualberta.ca)

Additive and non-additive interactions among anthropogenic stressors are the key drivers of current changes in aquatic ecosystem functioning. However, our understanding of the ecological impacts on stressors is largely derived from findings of single- stressor studies, which cannot be used to predict the effects of non-additive antagonistic or synergistic interactions among stressors. Nevertheless, most stressors do not operate independently, but rather in combination with other stressors to adversely affect aquatic biodiversity and ecosystem function. The purpose of this session is to bring together aquatic ecologists who are developing and testing hypotheses that examine how major human stressors, such as climate warming, chemical pollution, invasive species, and land-use, interact to affect freshwater and marine ecosystems at the levels of physiology, population, community, and function.

SS10 Coastal Pollution: From Molecular Biology Based Genome Sensing to Real Time Ocean Sensing
Organizers: Sunny Jiang, University of California, Irvine, (sjiang@uci.edu) and Stanley Grant, University of California, Irvine, (sbgrant@uci.edu)

Rapid human development in the coastal region has put tremendous pressure on coastal water quality and nearshore ecosystems with consequent impacts on human health and the coastal economy. To characterize and mitigate this problem, tools are necessary for rapid identification of the source, severity, fate and transport of pollutants in coastal regions. Recently, multi-dimensional tools, from molecular biology based genome sensing to large-scale real-time ocean sensing programs, have been developed and applied to investigate coastal pollution issues. This session calls for research papers on all aspects of coastal pollution investigation. The topics include, but are not limited to, microbial pathogen and indicator dynamics, pollution source identification, fate and transport (governed by microbial ecological and oceanographical processes), real-time sensing programs, ocean observing programs, computational modeling of pollutants and health effects, and integration of biology, physics and ocean/atmosphere science for coastal pollution investigation.”

SS11 Biodiversity, Biogeochemistry and Trophic Interactions: The Braid of Pelagic Microbial Ecology
Organizers: Farooq Azam, Scripps Institution of Oceanoraphy, (fazam@ucsd.edu) and Fereidoun Rassoulzadegan, Laboratoire d'Oceanographie de Villefranche (LOV), Université de Paris VI (, (rassoul@obs-vlfr.fr)

While research into the pelagic ecosystem often focus on system properties such as biodiversity, biogeochemistry, and food web structure, these phenomena are presumably closely linked and emerge from a common set of basic mechanisms. Insight into the linkages between biodiversity, biogeochemistry and trophic networks should bring us closer to a deeper understanding of these underlying principles, as well as how they link to the different emergent properties at the system level. Contributions to this session may range from adaptive mechanisms at the gene and organism levels optimizing competitive or defense strategies, on specific sets of trophic interactions, to responses at the food web level to changes in environmental conditions.

SS12 Quantifying Bioturbation and Bio-irrigation: A ‘Camino’ Beneath the Sediment-water Interface
Organizers: Filip J. R. Meysman, Netherlands Institute of Ecology, (f.meysman@nioo.knaw.nl) and Jack J. Middelburg, Netherlands Institute of Ecology, (j.middelburg@nioo.knaw.nl)

Individual organisms as well as their concerted action have a major impact on sediment texture, heterogeneity and particle and solute transport. Solute transport is enhanced in and near tubes, burrows and burrow networks through passive or active flushing. Particle mixing occurs due to animal movement as well as due to feeding and defecation. A quantitative understanding of bio-irrigation and bioturbation depends on development of theory and models, detailed combined tracer-animal data sets and new, improved experimental approaches. This session welcomes contributions addressing all aspects of bio-irrigation and bioturbation whether observational, theoretical or experimental. Papers integrating field or experimental data with models are in particular welcome.

SS13 Stable Isotopes in Ecology and Biogeochemistry
Organizers: Eric Boschker, Netherlands Institute of Ecology, (e.boschker@nioo.knaw.nl) and Jack J. Middelburg, Netherlands Institute of Ecology, (j.middelburg@nioo.knaw.nl)

Stable isotopes have shown to be powerful tools in a wide range of applications in aquatic sciences. Natural abundance isotope ratios have proven to be useful in unraveling food-webs and tracing organic matter and nutrient sources. Stable isotopes have also been used extensively as tracers for rate measurements (e.g., primary production, nitrogen cycling). More recent applications involve the use of stable isotopes in unconfined, field experiments and combination of stable isotope with biomarkers to link microbial identity with activity or to integrate microbial components in food web studies. This session welcomes contributions from systems along the aquatic continuum. Natural abundance, tracer application as well deliberate in situ addition studies are invited.

SS14 Nutrient Return Pathways to the Upper Ocean and Their Climate Sensitivity on Decadal to Centennial Time Scales
Organizers: Andreas Oschlies, School of Ocean and Earth Science, University of Southampton, (andreas.oschlies@soc.soton.ac.uk) and Jorge L Sarmiento, AOS Program, Princeton University, (jls@princeton.edu)

Data from large-scale surveys and process studies as well as results from ecosystem-circulation models now begin to reveal details of the complex three-dimensional pathways that return nutrients from thermocline and deeper waters back to the ocean surface. Recent studies have revealed the potential of various mode and intermediate water masses to modulate nutrient supply on decadal to centennial time scales. However, the mechanisms that control the nutrient and associated carbon fluxes and their climate sensitivity are not yet well understood. Processes that may be relevant range from upwelling and subsequent modification of nutrient-rich deep water masses, large-scale balances of mode-water formation and destruction, and eddy-mediated transports, to local enhancements of diapycnal mixing. We invite contributions from both data and model based studies that help to identify the relevant pathways along which nutrients are carried back to the ocean surface, to quantify the associated transport rates and transition times, and to determine their sensitivity to climate change.

SS15 Food Webs End-to-end, Including the Ecosystem Approach to Living Marine Resources
Organizers: Richard B. Rivkin, Memorial University of Newfoundland, Canada, (rrivkin@mun.ca) and Louis Legendre, Villefranche Oceanography Laboratory, France, (legendre@obs-vlfr.fr)

The management and sustainable use of living marine resources depends on the quantitative understanding of (a) the recruitment, growth and mortality of species, (b) the channelling of energy and organic matter through the autotrophic and heterotrophic components of the food web to the marine resources and (c) the flux and recycling of elements from the food web back to primary producers and downward to the deep ocean. The ecosystem-scale consideration of living marine resources is necessary to developing quantitative approaches to complex ecosystems. The characterization, analysis and modelling of marine pelagic ecosystems is generally conducted along three distinct approaches, i.e. pelagic ecosystems, biogeochemistry and ecosystem approach to marine resources. This Special Session will bring together the three communities, to compare and exchange concepts and results from field work, laboratory experiments and modelling exercises, with the goal of fostering integrative approaches to marine pelagic ecosystems and living resources.

SS16 Environmental Effects on Reproduction of Marine Invertebrates
Organizers: Catharina J.M. Philippart, Royal Netherlands Institute for Sea Research, (katja@nioz.nl), Peter M. J. Herman, Netherlands Institute of Ecology, (P.Herman@nioo.knaw.nl), and Steve J. Hawkins, Marine Biological Association of the UK, (sjha@mba.ac.uk)

The recruitment of sessile marine benthic invertebrates with pelagic larvae is the end result of a complex reproductive cycle, which starts with gametogenesis and spawning in adults, and continues with fertilization, growth and development in the pelagic larval phase, followed by settlement, post-settlement growth and development (and sometimes resettlement), to eventually deliver juveniles with a reasonable probability to recruit into the adult population. Density-dependent and density-independent mortality during these complex recruitment processes critically influence such population phenomena as age-class strength, population fluctuations correlated with life history, and uncorrelated densities of recruits and adults. As an example, settlement rate is influenced by the number of propagules arriving, the site-specific hydrodynamic conditions, behavioral factors and activities of the resident benthic assemblage.

During the previous century, marine systems have experienced drastic changes in external forcing, such as in the rates of supply of organic matter and nutrients, and in climatic conditions. When environmental conditions change, a transformation in behavior, physiology or morphology of marine organisms during early development might incur a selective advantage. New environmental conditions may not only affect the intensity, timing and temporal extent of spawning and settlement, but also the morphology of the larvae and settlers. Shell shape, for example, can be structured by the degree of wave-exposure, the overcrowding posing physical compression on individuals, food availability and the nature of substrate. Morphological flexibility of feeding structures has been proved to exist in the larvae of distantly related phyla, such as molluscs and echinoderms. However, the relatively high connectivity of marine systems facilitates dispersal of pelagic propagules of sessile benthic marine organisms and may counteract evolutionary adaptation to changed conditions.

The aim of this symposium session is to further and fuller understand the effects of changing environmental conditions on the recruitment of marine invertebrates. Contributions covering the research on the direct and indirect effects of environmental conditions on the reproductive cycle of marine invertebrates and the consequences for their dispersal, settlement success and survival are welcomed. Understanding factors that affect the reproduction of marine organisms is necessary to better resolve questions with regard to spatio-temporal patterns in biodiversity and ecosystem functioning, and to potential effects of eutrophication and global warming on marine ecosystems.

SS17 Viruses, Microbial Diversity and Ecosystem Function
Organizers: Steven W Wilhelm, University of Tennessee, (wilhelm@utk.edu), Markus G. Weinbauer, Laboratoire d'Océanographie de Villefranche, (Markus.Weinbauer@obs-vlfr.fr), and Curtis A. Suttle, University of British Columbia, (csuttle.eos.ubc.ca)

Viruses are major players that shape the diversity of planktonic communities and influence biogeochemical cycles through horizontal gene transfer (including virus genes) and selective mortality of hosts. Molecular techniques including clone libraries, community fingerprinting approaches and large-scale shot-gun sequencing (meta-genomics) have demonstrated the enormous diversity of virus communities. Through cell mortality and the release of lysis products (the viral shunt), these communities strongly affect ecosystem functions such as carbon and nutrient cycling, primary and secondary production and respiration. This session invites papers that address virus infection and diversity (including virus host systems), and how they influence the linkage(s) between microbial diversity and ecosystem functioning. Papers on the effect(s) of viruses on functional diversity and activity are also encouraged. Such studies are essential to develop an understanding of the role of virus infection on ecosystem stability and efficiency.

SS18 The Consequences of Biodiversity in Aquatic Habitats
Organizers: Per Jonsson, Tjärnö Marine Biological Laboratory, Gothenburg University, Sweden, (per.jonsson@tmbl.gu.se) and Helmut Hillebrand, University of Cologne, Institute for Botany, Aquatic Ecology, Cologne, Germ, (helmut.hillebrand@uni-koeln.de)

Understanding the consequences of biodiversity for the functioning of ecosystems has become a major task in the face of the recent global decline in biodiversity. Does biodiversity affect the rates of processes in aquatic ecosystems such as production rates or consumption rates? Does biodiversity increase or weaken the stability of aquatic communities? What are the mechanisms underlying biodiversity effects? These questions have raised considerable interest and transformed into a highly successful research agenda. However, the main evidence in this context comes from terrestrial communities. The special features of aquatic habitats inhibit the direct transfer of these results, and warrant a strong aquatic research initiative on the role of diversity in aquatic habitats. Recently, a variety of projects have been started in North America and Europe extending the knowledge on biodiversity consequences. These projects address a variety of novel questions: 1) how does genetic versus morphological diversity affect ecosystem functioning? 2) does diversity present an insurance against the multitude of stressors potentially affecting aquatic communities? 3) does the openness of aquatic communities to dispersal affect the relation between diversity and ecosystem functioning? 4) how does the diversity of one trophic level propagate through other compartments of aquatic food webs. These highly relevant topics will attract a large group of potential contributors and a large audience. The special session will therefore unite experimental ecologists from both freshwater and marine sciences, and theoretical ecologists.

SS19 Ecosystem Level Approach in Environmental Assessments of Maricultures
Organizers: Kenny Black, Scottish Association of Marine Sciences, (Kenny.Black@sams.ac.uk) and Marianne Holmer, Institute of Biology, University of Southern Denmark, (holmer@biology.sdu.dk)

Due to the on-going declines of natural fish stocks and the growing demand for marine products aquaculture is expected to maintain or even increase the rate of expansion in the coastal zones throughout the world. Although the industry is beneficial for the society, the environmental issues are often of concern to the public. The issues raised have been extending from the effects of waste products, such as particulates, chemicals and medicines on the environment, to transmission of genes and interactions with local fisheries. The knowledge on environmental issues has grown significantly during the past decade in many regions, but there are still gaps, in particular in the tropics and in countries where the industry has been introduced recently. Most environmental studies have been done at single farm level, whereas an integrated approach on ecosystem level has only seldom been applied. The local effects are thus well-documented whereas positive or negative effects on ecosystem level remain unexplored despite the fact that there is a large difference in sensitivity and assimilations capacity in different ecosystems. It is therefore difficult to transfer knowledge between different global regions, such as from temperate to tropical or from eutrophic to oligotrophic sites. The aim of this special session is to bring together groups working within the area of environmental issues of maricultures and to fill the gaps of knowledge and to provide ideas towards an integrated ecosystem approach for environmental assessments of maricultures in the future.

SS20 Diazotrophy in the Ocean: Rates, Causes and Consequences
Organizers: Aubert Le Bouteiller, IRD, (Aubert.Le-Bouteiller@noumea.ird.nc) and Cecile Dupouy, IRD, (dupouy@noumea.ird.nc)

Over the past decade, data of dinitrogen-fixation rates by diazotrophs have produced greatly increased estimates of N2-fixation in oceanic waters, implying that nitrogen fixation is quantitatively significant in the global nitrogen cycle. Moreover, biogeochemical studies and modelling have demonstrated the important role of N2-fixing organisms in the biological pump, ocean/atmosphere CO2 exchanges and climate regulation. Recently, an intensive multidisciplinary research program comprising nine cruises in the SW Pacific produced new data of cyanobacteria pigments, in situ C and N2-fixation rates, phosphate uptake, sedimentation and bacterial production. The evidence of Trichodesmium influence on satellite radiances allows a better understanding of spatial and temporal distributions of these organisms. This session is devoted to a presentation of last results dealing with the importance of diazotrophy in the ocean, including remote sensing approach and modelling, and to a discussion about the different biogeochemical processes linked to N2-fixation in the oligotrophic ocean, with a special focus on its fate.

SS21 Functional Diversity of the Microzooplankton
Organizers: Albert Calbet, Institut de Ciències del Mar-CMIMA (CSIC), (acalbet@icm.csic.es) and Michael R. Landry, Scripps Institution of Oceanography, (mlandry@ucsd.edu)

Recent research has revealed that microzooplankton (principally heterotrophic protists) play a pivotal role in shaping the structure of marine ecosystems, as primary grazers of marine phytoplankton, as major secondary producers, and as important contributors to bulk respiration and remineralization in the ocean’s euphotic zones. These insights come primarily from techniques that measure microzooplankton-associated processes and impacts at the integrated or net community level. However, at a point in time where phytoplankton ecologists and microbiologists are embracing the notion of ‘functional groups’ and seeking to distinguish and depict their characteristics in empirical and modeling studies, and where mesozooplankton ecologists aim at incorporating the ontogenetic, behavioral and energetic complexities of dominant species in individual-based models, we have little information about the importance of functional biodiversity and behaviorally driven interactions among microzooplankton or the extent of their species or group- specific activities within the food web. As a first step toward achieving a more robust and useful realization of microzooplankton functional roles in the dynamics of marine systems, we invite contributions that contemplate the significance of their diversity and varying impacts in plankton communities and ecosystems, as well as advanced techniques for their study in ocean research programs.

SS22 Polar Shelf-basin Exchange: Physical Forcing, Biogeochemical Fluxes and Food Web Dynamics
Organizers: Jackie Grebmeier, University of Tennessee, (jgrebmei@utk.edu) and Louis Fortier, University of Quebec, Canada, (louis.fortier@bio.ulaval.ca)

Implementing the plans for the International Polar Year (2007-2008), which is based on a suite of national and international initiatives that bring together synoptic sets of multidisciplinary observations, obtains key data sets necessary to understand factors controlling change, establishes a legacy of observational networks and launches internationally coordinated multidisciplinary expeditions into new scientific frontiers, entails rigorous examination of the present status quo of polar research. On our pilgrimage into some of last unexplored regions of the ocean, the engirdling polar shelves have to be crossed and knowledge obtained here used as a proxy for those regions still to be investigated. Scenarios of future climatic development, in essence based upon global circulation models, predict significant warming in the Arctic, but far less so in Antarctica. Changes in the marginal ice zone extent, ice thickness and changes in the extent and eventual disappearance of polynyas (or establishment of new ones), will result in significant alterations of the C flux, biodiversity and changes of mans live conditions. How these changes will influence the polar shelf-basin exchange of biogenic matter is the main focus of this session. Based on these considerations, we pose three comprehensive questions: (1) How will physical forcing and biological alterations affect the dissolution and biological C pump on and off the shelves fringing the Polar Ocean and Antarctica? (2) What are the food web dynamics and the C flux in the various polar shelf regions? (3) How do the shelves 'work' to produce and concentrate food, and how will such mechanisms be altered under scenarios of climate variability?

To address these questions we invite contributions focusing on the physical oceanography, ice cover, primary production, pelagic food web dynamics, pelagic-benthic coupling and benthic mineralization of Polar shelf regions, with the aim to sum up the present state-of-the art, contribute to a pan-polar understanding of C cycling and climate change and get ready for the implementation of one of the greatest challenges in oceanographic research, i.e. the IPY.

SS23 The Urban Coast: A Growing World-Wide Trend
Organizers: Russell Moll, California Sea Grant, (rmoll@ucsd.edu) and Linda Duguay, University of Southern California Sea Grant, (duguay@usc.edu)

The human population of the world is increasingly becoming urban and drawn to coastal cities. As of 1998, about 3.2 billion people, or more than half of the population of the planet inhabit a thin strip along the coast just 120 miles wide. The juxtaposition of large population centers to the coast is posing new and challenging problems with regard to maintaining high quality coastal aquatic environments. The rate of human migration to already crowded coasts is ever increasing and the associated issues of this continued demographic shift are becoming more urgent. By 2050, 80% of the human population is expected to live in urban centers and anticipated growth will add another 4 billion residents to the more than 3 billion already in such settings. An additional factor in the impact of major cities on coastal environments is the level of development and the increasing size of the world's major cities. The focus of this session is on the suite of problems that are unique to the urban coast. Topics such as urban water quality, non-point pollution from runoff, aquatic invasive species, increasing size and concentrations of large ports and harbors, and the overall effect of urbanization on human health are among the issues that will be addressed in this session. Contributions are sought that highlight problems in the coastal aquatic environment that are unique to or accentuated by the urban setting.

SS24 Biodiversity and Ecosystem Function, Contrasting Human-altered With Pristine Streams
Organizers: Francesc Sabater, Department of Ecology, Universitat de Barcelona, (fsabater@ub.edu), Tom J. Battin, Department of Limnology, IECB, University of Vienna, (tomba@pflaphy.pph.univie.ac.at), and Eugenia Marti, Centre d'Estudis Avançats de Blanes (CSIC), (eugenia@ceab.cisc.es)

While most of our knowledge on stream ecology originates from pristine ecosystems, society cannot ignore that streams have experienced multiple alterations from human activity over the past decades. Humans have reduced habitat structure, altered hydrological regime and increased nutrient inputs through diffuse and point pathways. Ultimately, this has resulted in reduced stream ecosystem integrity and services. Recently growing societal awareness (EC Water Framework Directive, USA Water Act) has significantly promoted research on human altered streams. However, most of this research is devoted to biotic indexes and less to ecosystem function. This session will bring together research on biodiversity and ecosystem function from human altered stream and contrast this with knowledge from pristine streams. Researchers studying human impacts on organic matter processing, nutrient dynamics, metabolism, community structure, and trophic interactions are welcome to participate. The session aims at establishing the state-of-the-art of human altered stream ecology, transferring knowledge from pristine streams, identifying major gaps and future needs. Ultimately this should enhance exchange of perspectives on a transnational environmental issue and strengthen collaboration among scientific communities.

SS25 Identification and Quantification of Major Feed-backs of Ocean Biology to Climate Change
Organizers: Dieter Wolf-Gladrow, AWI, (dwolf@awi-bremerhaven.de) and Marion Gehlen, LSCE, (gehlen@cea.fr)

Anthropogenic driven climate change implies a change in forcing to which ocean biology will respond. The response of ocean biology will in turn feed back on the initial forcing to either reinforce (positive feed-back) or dampen it (negative feed-back). Climate forcing includes global warming, changing atmospheric composition (CO2), changing inputs of nutrients, modifications in hydrological cycle etc. These changes will impact on ocean physics (circulation, stratification), chemistry (acidification, nutrient availability, water column oxygenation) and ocean biology. The response of ocean biology will operate through changes in ecosystem structure (for instance, reduction of calcifiers under high pCO2). Effects on marine biota will translate to changes in the strength of the biological C pumps and modifications in air-ea exchanges of climatically active gases (CO2, DMS, N2O), thereby closing the feed-back loop. We invite contributions from field, laboratory and integrative modeling studies aiming at the identification and quantification of major feed-backs between ocean biology and ongoing/future climate change. While field observations and laboratory studies might address parts of a feed-back loop, modeling studies should aim at a complete integration of the latter.

SS26 Respiration in Aquatic Ecosystems: Current Understanding and Future Directions
Organizers: Peter J. Le B. Williams, University of Bangor, UK, (pljw@bangor.ac.uk) and Paul A. del Giorgio, Dépt des sciences biologiques, Université du Québec à Montréal, Canada, (del_giorgio.paul@uqam.ca)

Respiration in aquatic ecosystems remains perhaps the largest gap in our understanding of the global carbon cycle, and as such, has received increasing attention in recent years. The increased focus on aquatic respiration has led in some case to the questioning of current paradigms, and more generally to a change in our conceptual and practical approach to assessing carbon dynamics and metabolism in aquatic ecosystems. This session aims at promoting a synthesis and discussion of the major accomplishments in the field in recent years, as well as of the major unresolved discrepancies and gaps in our current understanding of aquatic respiration. We would like to encourage presentations that focus on large-scale patterns and processes related to respiration in the major aquatic ecosystems of the biosphere, covering freshwater and marine wetlands, oceans, estuaries, lakes and rivers and through the net productivity of individual systems, the connections between them. Research that specifically attempts to incorporate respiration into models of carbon and energy flow is also encouraged.

SS27 Biomineralized Tissues in Marine and Freshwater Organisms
Organizers: Beatriz Morales-Nin, CSIC/UIB-IMEDEA, (beatriz.morales@uib.es) and Erlend Moksness, Institute of Marine Research, Flødevigen Marine Research Station, (moksness@imr.no)

The biomineralized tissues are key players in the organisms as structural components as well as ionic reservoirs of fundamental elements such as Calcium. Moreover, calcified structures such as otoliths and statoliths form part of the sensorial system and represent a part of the organisms interaction with the environment. The formation of these tissues is related to the environmental conditions as well as to the organism metabolism. Certain biominerals are not reabsorved during the organism life and can last for a long time after the death, thus having the potential to act as registers of both the organism and the environmental conditions. In molluscs, corals and fish the biomineralized tissues have been extensively studied for age determination. Recently their microchemical composition has been employed for paleostudies, to identify natal habitats, and to explore ecological traits. However, many questions remain unresolved concerning the present situation (biomineral fluxes, growth rates) and the future in the context of global change. How is the increase acidification going to affect the calcium budget at the sea? How is this going to affect the organisms? The developments in several research fields such as stoichhiometry, modelling, environmental and biological studies, make a session on biomineralization in the context of global change a timely issue.

SS28 Copper: A Micronutrient or Toxic Element in the Environment?
Organizers: Maria T. Maldonado, University of British Columbia, (mmaldonado@eos.ubc.ca) and James W. Moffett, Woods Hole Oceanographic Institution, (jmoffett@whoi.edu)

Copper has long been recognized as an important contaminant in natural waters and is the focus of increasing regulatory scrutiny. Yet, it is also a critical element required for many metalloenzymes that catalyze biogeochemically important reactions such as denitrification. Given that its bioavailability is governed by its complexation chemistry in natural waters, which is highly variable, it is important to determine the conditions when it is beneficial versus harmful. We seek to bring together researchers studying copper from biogeochemical, physiological, toxicological and molecular perspectives, since the processes involved in toxicity and micronutrient limitation share many common

SS29 Atmospheric Deposition of Nutrients, Organic Carbon and Pollutants as a Driver of Marine and Limnic Ecosystems
Organizers: Steven J. Eisenreich, Joint Research Centre, Ispra, (steven.eisenreich@jrc.it) and Jordi Dachs, IIQAB-CSIC, (jdmqam@cid.csic.es)

Atmospheric deposition can contribute important inputs of nutrients, carbon and pollutants to aquatic ecosystems. During the last decades, research has shown the importance of atmospheric inputs of N, P and Fe in oligotrophic regions and in areas with high aerosol concentrations. However, much effort is needed to clearly determine the role of these inputs in ecosystems dynamics and productivity. On the other hand, atmospheric deposition is a key entry route of stressors, such as pollutants, to marine and limnic ecosystems. In fact, atmosphere-water exchange controls the dynamics of most pollutants (organic and inorganic) in aquatic ecosystems, and thus their potential impact. Recently, it has also been suggested that atmospheric inputs of organic carbon may be important to balance the marine carbon cycle and for the aquatic metabolic balance. Besides all these lines of evidence of the important role that atmospheric drivers have on aquatic ecosystems, the field is in its infancy. The proposed special session aims to address the multiple interactions between atmospheric inputs of materials (carbon, nutrients, pollutants, etc) and the functioning of marine and limnic ecosystems.

SS30 Nitrate Uptake By Phytoplankton in Nutrient-rich Areas
Organizers: Patricia Glibert, University of Maryland, (glibert@hpl.umces.edu) and Yves Collos, University of Montpellier, France, (collos@univ-montp2.fr)

Many earlier studies of nitrate uptake by phytoplankton considered that uptake was saturated near 10-20 µmol N/liter. A few recent studies have shown that this is not always the case and multiphasic uptake systems do exist in some unicellular algae and operate in a range of concentrations that are important in the cureent context of eutrophication in coastal waters. This introduces serious bases that are not taken into account by present models of new production. Other phenomena that are related to nitrate uptake are nitrite and ammonium excretion during nitrate assimilation. We invite contributions on these topics as an effort to reach more accurate estimates of net nitrate uptake in eutrophic areas.

SS31 Coupled Oceanographic Processes in Estuaries and River Dominated Margins
Organizers: Pere Puig, Institut de Ciències del Mar, CSIC and Miguel A. Goñi, Department of Geological Sciences, University of South Carolina, (goni@geol.sc.edu)

Estuaries and river dominated ocean margins are extremely dynamic environments that are especially sensitive to anthropogenic activities and climate change. New multidisciplinary research initiatives are exploring the interconnections between physical forcing (e.g., waves and currents) and geological (e.g., sediment transport and deposition), chemical (e.g., carbon turnover and burial), and biological processes (e.g., primary and secondary production, species compositions) in these environments. This session invites presentations investigating the coupling of physical, geological, biogeochemical and ecological processes in estuaries and river dominated margins. Interdisciplinary research from both field studies and modeling efforts will be considered and are appropriate for this session.

SS32 Diversity Among Components of the Microbial Loop
Organizer: John Dolan, Marine Microbial Ecology Group, Lab Oceanogr Villefranche, (dolan@obs-vlfr.fr)

This session will be devoted to exploring patterns of diversity in planktonic microbes with the goal of establishing commonalities and differences. Free-living microbes have been described as having global distributions. The amount of genetic diversity among both prokaryotic and eukaryotic planktonic microbes (femto, pico and nano- sized organisms) presently being described should then soon reach a plateau? This is far from clear. Distinct patterns may exist for autotrophic prokaryotes compared to autotrophic eukaryotes. Contributions will ideally involve a variety of microbes from viruses (relations between bacterial and viral diversity) to Pico-autotrophs (prokaryotes & eukaryotes) to bacteriovores and herbivores.

SS33 Estuaries as Biogeochemical Reactors
Organizers: Kenneth Mopper, Old Dominion University, (kmopper@odu.edu) and Elizabeth C. Minor, Old Dominion University, (eminor@odu.edu)

Estuaries, in addition to being sites of significant autochthonous production, are also sites of significant reworking of nitrogen, phosphorous, trace metal, and organic carbon moieties ultimately derived from terrestrial and anthropogenic sources. The combination of these processes leads to considerable alteration of riverine inputs before export to the coastal ocean. This special session focuses upon processes within the estuarine “biogeochemical reactor” including microbial and photochemical reactions, and physicochemical processes such as flocculation, aggregation and disaggregation.

SS34 Plate Tectonics and Chemotrophy at Deep-sea Vents
Organizers: F. Grant Ferris, University of Toronto, Ontario, Canada, (grant.ferris@utoronto.ca) and Danielle Fortin, University of Ottawa, Ontario, Canada, (dfortin@uottawa.ca)

Plate tectonics give rise to tens of thousands of kilometers of mid-ocean ridges and back-arc basins around the world. The intense hydrothermal activity present in such areas sustains a rich geochemical supply of nutrients that nourish some of the most unique ecosystems on Earth. Primary production arises solely from microbial chemotrophy, which not only represents possibly one of the earliest metabolic pathway on the planet, but also contributes significantly to global cycling of mineral forming elements. This special symposium will address new inter-disciplinary cutting-edge research in microbial geochemistry of mid-ocean ridges and back-arc basins. It will specifically focus on the role of microorganisms in metal cycling resulting from mineral dissolution, precipitation and sorption reactions, and on reactions kinetics and microbial diversity.

SS35 Alternative Pathways of Nitrogen Removal From the Sea
Organizers: Stefan Hulth, Department of Chemistry, Göteborg University, (stefan.hulth@chem.gu.se), Nils Risgaard-Petersen, National Environmental Research Institute, (nri@dmu.dk), and Tage Dalsgaard, National Environmental Research Institute, (tda@dmu.dk)

The biologically mediated reduction of NO3- or NO2- (NOx-) to N2 through denitrification is generally considered to be the major process responsible for removal of nitrogen from the sea. Until recently, it was believed that denitrification was based solely on the reduction of NOx- to N2 in an oxygen-free environment by facultatively aerobic bacteria with an organotrophic metabolism. This classical view has recently been challenged by the discovery of alternative pathways of combined nitrogen transformations. These alternative pathways include the anaerobic oxidation of NH4+ to NO3- or N2 with manganese oxides and the ANAMMOX process i.e. the anaerobic oxidation of NH4+ to N2 with NO2-. Both ANAMMOX and the anaerobic oxidation of NH4+ with manganese oxides have long been overlooked in biogeochemical N-cycling. However, especially within the last few years, field studies have shown that for instance the ANAMMOX process is a significant alternative to conventional denitrification in both sediments and anoxic water columns. Yet we are only beginning to understand the quantitative importance of these processes, their regulation and their underlying microbiology in aquatic systems. This session will focus on ANAMMOX and anaerobic NH4+ oxidation with manganese oxides. State-of-the-art knowledge about the biogeography of these processes, their regulation and microbiology plus their impact on our ability to measure aquatic N2 production will be addressed.

SS36 Non-extremophilic Archaea in Aquatic Environments
Organizers: Lydie Herfort, Royal Netherlands Institute for Sea Research (NIOZ), (Herfort@nioz.nl) and Randall E. Hicks, University of Minnesota-Duluth, (rhicks@imap.d.umn.edu)

For decades Archaea were thought to only dwell in extreme environments inhospitable for Eukarya and Bacteria, but new approaches such as ribosomal RNA surveys or archaeal lipid analysis have clearly established that they are abundant in the water column of both marine and freshwater environments. Yet very little is known about these pelagic Archaea, mainly because so far cultivation has been unsuccessful. Recently, however, important results have emerged from studies that use cultivation-independent approaches and from work carried out on the only cultured non-extremophyle Archaea, Cenarchaeum symbiosum, a symbiont of the marine sponge Axinella mexicana. This session encourages the presentation of results from studies in the marine and freshwater environments that will further our understanding of the physiology, biochemistry and ecology of non-extremophilic Archaea.

SS37 Size Structure of Plankton Communities
Organizers: Xabier Irigoien, AZTI, (xirigoien@pas.azti.es), Roger Harris, Plymouth Marine Laboratory, (r.harris@pml.ac.uk), and Angel Lopez-Urrutia, Instituto Español de Oceanografía, (alop@gi.ieo.es)

Size plays a major role in ecology at most scales. Size effects range from those of body size on biological rates and times to the effects of community size spectra on energy flow in aquatic ecosystems. Important new findings concerning the basis of allometric relationships have been published recently These provide the theoretical foundation for practical applications and the establishment of a metabolic theory of ecology. Since the first descriptions of plankton size spectra by Sheldon et al, the slope of the log-log relation between individual biomass and abundance in aquatic ecosystems has been shown to be around -1. Sheldon himself suggested an allometric explanation for this pattern. Hence, size spectra distribution and allometry share many common aspects. In this session we invite contributions on theoretical and practical aspects of both size spectra distribution and allometric relationships. Papers on the widest range of aquatic ecosystems, including size structured modelling as well as possible connections between both theories are particularly encouraged.

SS38 Microbial Plankton Ecology and Biogeochemical Fluxes in the Subtropical Gyres
Organizers: Emilio Marañón, Universidad de Vigo, (em@uvigo.es) and Ricardo Letelier, Oregon State University, (letelier@coas.oregonstate.edu)

The oligotrophic subtropical regions of the open ocean support extensive ecosystems which, due to their vast size, are of global biogeochemical importance. Once termed 'marine deserts', these regions are now known to account for a significant fraction of global marine primary production and carbon export into the deep ocean. Over the past 15 years, on-going programs that look at the temporal and spatial variability of upper ocean biogeochemistry and ecology (e.g. HOT, BATS, AMT) have greatly advanced our understanding on the composition, structure and functioning of the microbial community in these subtropical gyres. Recent advances in molecular tools have been used to determine the high diversity in both prokaryotic and eukaryotic assemblages, and to detect novel metabolic pathways in the upper layers of these regions. Far from being steady-state systems, marine ecosystems in subtropical oligotrophic environments display a considerable amount of variability in biological rates over a wide range of temporal and spatial scales. At the local scale, episodes of enhanced primary and export production can be caused by several mechanisms, including eddy- or internal-wave induced nutrient pumping, summer water-column stratification, and atmospheric dust deposition. During these events, complex interactions within the food web, including trophic cascades, can alter significantly biogeochemical fluxes and the fate of organic matter. Interannual and long-term variability in upper ocean biogeochemistry of the subtropical gyres has been linked to climate-related changes of the coupled ocean-atmosphere system. In the context of climate change, there is a pressing need to understand how these vast marine ecosystems will respond to long-term changes in the frequency and intensity of physical perturbations. Thanks to the sustained progress of different observational programs, it is already possible to attempt comparative studies of the composition and activity of pelagic microbial assemblages in different subtropical provinces, which should be more revealing than the detailed study of a particular environment. The proposed session will invite contributions reporting on the results of observational, experimental and modelling studies on the microbial ecology and biogeochemistry of the subtropical gyres. Addressed topics will include, among others, plankton diversity, trophic interactions, physical-biological coupling, nutrient control of biological rates, community metabolism, biological coupling of elemental fluxes, and the role of atmospheric inputs and climate-induced variability in modulating the biogeochemical role of the microbial pelagic assemblage. The ultimate aim will be to integrate different perspectives and approaches into a coherent view of the structure and functioning of the planktonic compartment in the subtropical gyres, as a previous step to address the response of these ecosystems to on-going and predicted processes of global change.

SS39 Ecological Thresholds of Sustainability in Aquatic Ecosystems
Organizers: Michael F. Piehler, University of North Carolina at Chapel Hill, (mpiehler@email.unc.edu), Hans Paerl, University of North Carolina at Chapel Hill, (hans_paerl@unc.edu), and Daniel Conley, National Environmental Research Institute, Denmark, (dco@dmu.dk)

It is becoming increasingly clear that ecosystems do not always respond to gradual changes in forcing variables in a smooth way, but can respond with abrupt, discontinuous shifts to an alternative state as the ecosystem exceeds a threshold in one or more of its key variables or processes. Identification of ecological thresholds of sustainability could clearly assist in the management of aquatic ecosystems by identifying the level of pressure imposed on a given resource while maintaining acceptable levels of environmental quality or ecological condition. Whenever these thresholds are exceeded, the resources, services or functions affected may suddenly shift status, adopting attributes that cannot be easily reverted to levels below the thresholds. The levels of the indicators at which such state shifts occur are termed points of no return. These changes in ecological thresholds and points of no return invokes the existence of non-linear behavior such that alternative mathematical formulations must be used to address the changes that occur in the quality, property or functioning of the ecosystem. This session will focus on ecological thresholds in aquatic ecosystems and will explore some of the various aspects of thresholds research including the development of links between pressures and thresholds to achieve sustainability in aquatic ecosystems.

SS40 Nutrient Transformations Along the Land-ocean Continuum in the Context of Global Change
Organizers: Caroline Slomp, Faculty of Geosciences, Utrecht University, the Netherlands, (slomp@geo.uu.nl), Ragueneau Olivier, UMR CNRS 6539, Institut Universitaire Européen de la Mer, France, (olivier.ragueneau@univ-brest.fr), and Phillip Ford, CSIRO, Australia, (Phillip.Ford@csiro.au)

Nutrient cycles in the coastal ocean over the past century are profoundly being affected by human-induced changes. These are occurring worldwide and include modified river inputs of nutrients through river manipulation, fertilizer application, waste water discharge or biological invasions. On a short-term, this can greatly affect the ecology of the coastal ocean. On the long-term, this may impact the marine carbon cycle in the open ocean. This session welcomes all contributions focussing on changes in nutrient cycling at the land-ocean interface and the consequences for the ecology and biogeochemistry of the coastal ocean. Both experimental and modeling studies are welcome. Contributions focusing on the links between terrestrial processes and deliveries, and marine nutrient cycling are particularly encouraged, as well as those dealing with the cycling of several biogenic elements (e.g. Si, N, P) or those studying the responses of the coastal zone to more than one anthropogenic perturbation.

SS41 Lipids in Trophic Interactions
Organizers: Michael Arts, National Water Research Institute Environment Canada, (Michael.Arts@ec.gc.ca) and Eric von Elert, University of Konstanz, (eric.vonelert@uni-konstanz.de)

The flow of energy and material in aquatic food webs is substantially determined by the quality of the dietary carbon. There is increasing evidence of a requirement for specific lipids, (e.g. particular fatty acids or sterols), of different functional groups in food webs ranging from protozoan to herbivorous invertebrates to fish. Such requirements are becoming more and more obvious for planktonic and benthic species in both marine and freshwater systems. Changing abiotic factors (e.g. temperature and UV) and biotic factors (e.g. exotic invaders) may greatly affect the availability and/or composition of dietary lipids thereby influencing trophic interactions. The purpose of this session is to bring together researchers interested in the role that dietary lipids have on growth, production, energy transfer efficiency and competition within and amongst trophic levels.

SS42 Hydrology-related Downstream-effects on Lakes
Organizers: Alfred Wüest, Limnological Research Center, Switzerland, (Wuest@eawag.ch), S. Geoffrey Schladow, Director, Tahoe Environmental Research Center, (Gschladow@ucdavis.edu), and Kenneth I. Ashley, Aquatic Ecosystem Science Section, Fisheries Centre, University of British , (Ken.Ashley@gems5.gov.bc.ca)

Many lakes and reservoirs are situated downstream of major hydrological disturbances. Examples include upstream reservoirs and dams, large-scale river diversions and flow alterations, clear-felled watersheds, or encroaching urbanization. Alterations of the stream, groundwater and direct runoff regimes and specifically timing and magnitude of hydro-peaking discharges not only affect the habitats for fish and macro-zoobenthos, but have also physical and biogeochemical effects. Water temperature changes, as a result of reservoir and dam operations, can negatively affect downstream fish diversity (cool/warm water fishery) and habitat suitability. Dam-induced nutrient retention results in downstream “cultural” oligotrophication. Changes in the sediment discharge patterns alter the light regime, and hence primary productivity. Presentations that focus on downstream effects, particularly resulting from the altered hydrology, hydraulics, biogeochemical cycling and resulting trophic interactions in the modified catchment, are specifically welcomed.

SS43 Eutrophication and Harmful Algal Blooms
Organizers: Edna Graneli, University of Kalmar, (Edna.Graneli@hik.se) and Patricia M. Glibert, Univ. of Maryland Center for Environmental Science, (glibert@hpl.umces.edu)

Eutrophication is now recognized as one of the factors contributing to the proliferation of harmful algal blooms (HABs). In the past decade several advances have been made in our understanding of the relationship between nutrients and HABs. For example, much has been learned about the global extent of eutrophication and about the diverse physiological mechanisms that HABs employ to obtain their nutrients. In this session contributions that highlight progress in our understanding of global eutrophication, physiological ecology of HABs with respect to nutrients, new methodologies and approaches for measuring nutrients and their relationship to HABs, studies on HABs in comparative eutrophic systems, and models that address the relationship between nutrients and HABs are encouraged.

SS44 Interactive Effects of DOM Properties and Mineral Nutrients on Bacterial Composition and Activity
Organizers: Isabel Reche, Universidad de Granada, (IRECHE@UGR.es) and Stuart Findlay, Inst. of Ecosystem Studies, Millbrook, NY USA, (findlays@ecostudies.org)

Microbial ecology has undergone technological advances allowing description of community composition in diverse aquatic ecosystems. Given the information on taxonomic distribution and diverse measures of metabolic activity, the field is now poised to ask questions about what system characteristics or processes control diversity, activity or the abundance of particular taxa. We propose a special session focussed on the capacity for organic substrates and inorganic nutrients to act as predictors of community structure and metabolism. Invited speakers representing particular ecosystem types (e.g. streams, lakes, estuaries, coastal waters) will address the potential ability of these solutes to cause changes in which taxa are present, similarity among communities, metabolic processes and capacity for growth. This broad view should reveal whether attributes of solute dynamics, composition or quantities can organize the rapidly increasing data available on bacterial community structure and function in aquatic ecosystems.

SS45 Understanding the Plumbing of the Biosphere: Theory and Observations in Aquatic Systems (Homage to Ramon Margalef)
Organizers: Marta Estrada, Institut de Ciències del Mar, CMIMA (CSIC), Barcelona, Spain, (marta@icm.csic.es) and Dolors Planas, Université de Québec à Montreal, Montreal, Canada, (planas.dolores@uqam.ca)

Ramon Margalef was one of the great ecologists of our time and a world expert in both limnology and oceanography. He had the ability to integrate concepts and ideas from different fields with insight from his naturalistic knowledge, to propose a coherent framework of unifying principles for the interpretation of ecological observations. Before modern sensors and computing power helped to highlight the importance of physical-biological interactions, Margalef saw the aquatic medium as an environment structured by turbulent motions at different scales (a manifestation of the external or auxiliary energy introduced by wind and currents), which interacted with organism adaptations. One of the most inspiring conceptual models in phytoplankton ecology has been his classification of phytoplankton life-forms as a function of available nutrients and external energy. In one of his early publications, Margalef proposed the use of expressions derived from information theory to quantify ecological diversity. The significance of diversity in planktonic systems and its relationships with connectivity and ecosystem structure and function were a recurring topic throughout his scientific career. Other subjects in which he made outstanding contributions were the characterization of ecological succession on the basis of global parameters of the ecosystem such as the production to biomass ratio, the role of external energy in biological production, and the contacts between ecological succession and evolution. He was also a pioneer in adopting an integrative view of biogeochemistry. Margalef insisted on considering man as an integral part of the biosphere, rather than as a bystander, and emphasized the need of interpreting the relationships among human societies within a general ecological context. Margalef combined his intellectual capacity with a high human quality. He was generous in sharing ideas and had a fine sense of humour. He was also an enthusiastic teacher that communicated his love for nature to students and coworkers.

This special session is a tribute to the scientific legacy of Ramon Margalef and aims to feature contributions that will emphasize integration of theory and observation or provide opportunity for discussion on subjects that had been Margalef’s favorites, such as (but not limited to) the relationships between diversity and ecosystem structure and function, the interactions between physics and biology and how these shape succession and selection of life forms, and the ecological role of boundaries and spatial organization in general.

SS46 Allelopathy in Aquatic Systems
Organizers: Catherine Legrand, Marine Science division, Dept. of Biology and Environmental Science, Univer, (catherine.legrand@hik.se) and Karin Rengefors, Limnology, Dept. of Ecology, Lund University, Sweden, (Karin.Rengefors@limnol.lu.se)

It is well established that chemical interactions are a component of competition in terrestrial systems, but they are still largely unknown in aquatic systems. In recent years, there has been increasing evidence that allelochemicals are produced by aquatic plants, algae, bacteria, and fungi. These allelochemicals influence algal growth, water chemical characteristics, nutrient dynamics, life cycles, and microbial ecology. Allelopathy is also part of plant and microbial interactions, may structure plant and microbial communities, changes competition patterns, and leads to co-evolution of organisms. The understanding of and knowledge about allelopathy in aquatic systems is still limited and this session will bring together a diverse group of biologists, ecologists, and chemists who have used various approaches to examine the role/importance of allelopathy in aquatic systems. Submissions are encouraged that examines the role, the chemical nature, and the mode of action of allelochemicals in aquatic ecology, as well as evolutionary aspects of the chemical warfare among aquatic plants and microbes.

SS47 Autotrophic and Heterotrophic Relationships in Streams and Rivers
Organizers: Bill Sobczak, College of the Holy Cross, (wsobczak@holycross.edu) and Sergi Sabater, University of Girona, (sergi.sabater@udg.es)

Algal biomass and productivity in fluvial ecosystems affects the relevance of heterotrophic components coexisting in fluvial and downstream ecosystems. At the same time, bacterial processing of organic matter may influence rates of primary production. These mutual bacterial and algal relationships affect the efficiency of river ecosystems in transforming organic matter, and are likely influenced by the terrestrial-aquatic linkages existing in the ecosystem. The trophic significance of these interactions may be different in streams and rivers with watersheds of varying size, land-use and hydrological modifications. This symposium will aim to define the relevance of algal and bacterial interactions at a wide range of spatial scales and watershed disturbances.

SS48 Biogeochemistry, Ecology, and Hydrodynamics of Tidal Flat Systems
Organizers: Jack Middelburg, Netherlands Institute of Ecology (NIOO-KNAW), (j.middelburg@nioo.knaw.nl) and Meinhard Simon, ICBM, University of Oldenburg, (m.simon@icbm.de)

Tidal flat regions at the land sea interface are one of the most productive aquatic ecosystems and significant sinks of organic matter in coastal regions. They are affected by terrestrial as well as marine inputs of dissolved and particulate inorganic and organic matter. They exhibit pronounced tidal currents and the specific hydrodynamic properties lead to rhythmic settling and resuspension of particulate inorganic as well as organic matter. The sediment is characterized by biofilms of autotrophic and heterotrophic microbes and anoxic processes govern the system already closely below the surface. Usually, particulate organic matter is accumulated and microbial processes dominate cycling of matter and elements and energy fluxes. During the recent past tidal flat systems have been investigated by quite a few research groups with respect to various aspects of biogeochemical and microbial processes in the sediment and water column and hydrodynamics, including modelling approaches. We would like to bring together the interesting results of these recent studies in a session to assess state of the art knowledge and to identify aspects for future work. Therefore we encourage active researchers in this field to submit contributions.

SS49 An Ocean Literacy Campaign
Organizers: Michiko Martin, National Oceanic and Atmospheric Administration, (michiko.martin@noaa.gov) and Francesca Cava, National Geographic Society, (francesca.cava@noaa.gov)

It was most recently recognized by the Preliminary Report of the U.S.Commission on Ocean Policy that “to successfully address complex ocean- and coastal-related issues, balance the use and conservation of marine resources, and realize future benefits from the ocean, an interested, engaged public will be needed.” The Commission identified ocean education as a key component of the strategy to promote lifelong learning that leads to an informed public. A technologically advanced world requires scientifically and environmentally literate public. An educated public can keep pace with technological advances as well as environmental issues of great complexity and scale. This special session will bring together researchers leading the effort to increase ocean literacy through ocean education. Presentations that focus on efforts that integrate K-12 teachers and students in scientific research are especially encouraged. Papers will also be encouraged that identify new scientific discoveries that have not made it into text books and how to make this information and data available to teachers and classrooms.

SS50 Ecology of Aquatic Pathogens in a Changing Environment
Organizers: Alexandra Z Worden, Marine Biology and Fisheries Division, Rosenstiel School of Marine and Atmo, (aworden@rsmas.miami.edu) and Stefan Bertilsson, Department of Limnology, Evolutionary Biology Centre, Uppsala University, S, (stebe@ebc.uu.se)

Microbial pathogens represent a severe threat to the sustainable use of aquatic resources for drinking water, food and recreation. Recently, several studies have shown that global change and local environmental disturbances can alter the spread and persistence of such aquatic health hazards. However to date the underlying mechanisms and the magnitude of these impacts are poorly known for most pathogens. This session focuses on the impact of biotic and abiotic environmental factors on dynamics of pathogenic microorganisms in freshwaters and coastal ecosystems. The overall goal is to provide a forum for integrating different approaches to understanding persistence, growth and spread of such microbes in aquatic environments. Thus a range of topics are welcomed, including both experimental studies and field-surveys of how pathogenic bacteria, microeukaryotes and viruses respond to diverse environmental factors. Mechanisms of population control, such as predation, dispersal and growth requirements for both organic substrates and nutrients are appropriate to the session, Studies of in situ dynamics and physiological responses to environmental parameters are also appropriate Furthermore, we encourage submission of contributions in which predictive population models and novel molecular tools for parallel detection and quantification of microbial pathogens are used as “early warning systems.” Thus critical areas of research necessary for understanding pathogens in the aquatic environment will be brought together: research on the mechanisms by which they are controlled or proliferate and modelling as well as detection efforts for safer and more efficient management of risks factors associated with microbial pathogens and in natural aquatic systems.

SS51 Exchange Processes in Upwelling Systems
Organizers: M. Kosro, Oregon State University, (kosro@coas.oregonstate.edu) and E. D. Barton, IIM, CSIC, (e.d.barton@iim.csic.es)

Upwelling sytems exchange water, biota, particles, and dissolved material vertically between sub-surface and surface layers, and horizontally between continental shelf and open ocean. Some exchanges are widespread and general, like Ekman transport; others are localised and specific, like subduction at fronts or upwelling around capes. All have profound implications for biogeochemical and biological processes, whether these refer, for example, to nutrient cycling, carbon budget, or dispersion or retention of larvae and eggs. Recent advances in numerical modelling down to the mesoscale, in direct observations of vertical exchanges through tracer studies, in study of bottom boundary exchanges, and in the biogeochemistry of the water column justify a general session on upwelling systems. Studies in the different upwelling zones around the oceans (including of course the Iberian system) merit exposure in a common meeting where progress may be assessed and ideas for future developments propounded. Leading players in the various disciplines and regions will be able to present their vision of the state of the art.

SS52 Comparative Ecosystem Studies of Harmful Algal Blooms
Organizers: Grant C Pitcher, Marine and Coastal Management, Cape Town, South Africa, (gpitcher@deat.gov.za), Patrick Gentien, CREMA, L'Houmeau, France, (Patrick.Gentien@ifremer.fr), and Alan Cembella, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, German, (acembella@awi-bremerhaven.de)

Harmful Algal Blooms (HABs) cause world-wide problems with significant economic, social and human health consequences. A present challenge is to improve the prediction of HABs by determining the ecological and oceanographic mechanisms underlying their population dynamics through integration of biological, chemical and physical studies supported by enhanced observation and modeling techniques. The international programme Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB) has been established to foster international co-operative research on HABs in ecosystem types sharing common features, comparing the key species involved and the oceanic processes that influence their population dynamics. Comparative studies of this nature allow patterns of correspondence, consistency and reproducibility to be resolved; harmful species from similar habitat types may be grouped, and the extent to which these species respond in a similar way, in systems that share similar characteristics, allow the oceanographic processes that influence HAB population dynamics and community interactions to be established. Equally important will be the identification of similar systems that do not have the same functional HAB species or groupings; or do not respond in a consistent way to the processes that characterize these systems. Understanding the response of harmful algae to perturbations within similar systems also assists in prediction, and identification of divergences from predicted responses will also be informative. Invited speakers will address comparative studies of HABs in upwelling systems, fjords and coastal embayments, and stratified systems.

SS53 Polar Aquatic Ecosystems and Environmental Change
Organizers: Warwick F. Vincent, Laval University, (warwick.vincent@bio.ulaval.ca), Carles Pedrós-Alió, Institut de Ciències del Mar, (cpedros@cmima.csic.es), and John C. Priscu, Montana State University, (jpriscu@montana.edu)

Global circulation models predict that the Arctic and Antarctic regions will experience accelerated climate change over the course of this century. This session will focus on new insights into the structure and functioning of marine and freshwater ecosystems in the north and south polar regions, and their sentinel roles as early indicators of global change. Contributions are welcome on high latitude lakes, ponds, rivers, ice habitats and polar seas, with emphasis on microbial community structure, biodiversity, ecosystem processes and responses to environmental forcing.

SS54 Production of the Odours Geosmin and MIB in Freshwater
Organizers: Niels O. G. Jorgensen, Dept. of Ecology, Royal Veterinary & Agricultural University, Copenhagen, D, (nogj@kvl.dk) and Michele Burford, Centre for Riverine Landscapes, Griffith University, Brisbane, Australia, (m.burford@griffith.edu.au)

The taste and odour compounds geosmin and methylisoborneol (MIB) reduce the quality of surface water as a source of drinking water. Due to the increasing global water consumption, the odours constitute a growing problem to the water supply in many cities. In addition, the odours cause damage to fish in freshwater aquacultures as the compounds accumulate in fish and lower their value as consumer food. Geosmin and MIB are produced by several species of cyanobacteria, but recent studies indicate that actinomycete bacteria may also be responsible for the odour production in freshwater. The present knowledge on mechanisms controlling the production of geosmin and MIB in cyanobacteria and actinomycetes is limited and sporadic. Therefore, The taste and odour compounds geosmin and methylisoborneol (MIB) reduce the quality of surface water as a source of drinking water. Due to the increasing global water consumption, the odours constitute a growing problem to the water supply in many cities. In addition, the odours cause damage to fish in freshwater aquacultures as the compounds accumulate in fish and lower their value as consumer food. Geosmin and MIB are produced by several species of cyanobacteria, but recent studies indicate that actinomycete bacteria may also be responsible for the odour production in freshwater. The present knowledge on mechanisms controlling the production of geosmin and MIB in cyanobacteria and actinomycetes is limited and sporadic. Therefore, in this symposium we wish to focus on ecological, physiological and molecular tools for characterizing odour production in freshwater cyanobacteria and actinomycetes.

SS55 Parasitism in the Plankton
Organizers: Alf Skovgaard, Institut de Ciènces del Mar, Barcelona, Spain, (skovgaard@icm.csic.es) and D. Wayne Coats, Smithsonian Environmental Research Center, MD, (coatsw@si.edu)

Organisms in plankton communities, i.e. phytoplankton, microzooplankton and mesozooplankton, are hosts for a wide variety of parasites. Most recent research has considered marine, parasitic dinoflagellates, freshwater microsporidians, and freshwater fungi, suggesting that these types of parasites may be most common and ecologically important. However, several other taxonomic groups, including ciliates, myxosporidians, perkinsids, apicomplexans, and ellobiopsids, are known to infect phyto- or zooplankton. In general, the functional biology, pathology, and epizootiology of these parasite/host associations are not well understood, but examples show that parasites are sometimes important in regulating populations of planktonic organisms. Parasitism must, thus, be taken into account as a regulating factor in concert with food supply, grazing, food quality, behavioural interactions, etc. The fact that planktonic parasites, or their hosts, are often difficult or impossible to culture sets certain limits for experimental and morphological studies. Recent molecular methods have, however, proven valuable for resolving the taxonomy and phylogeny of several groups of planktonic parasites that were not well resolved using traditional morphological studies.

This session will encourage contributions on ecology, distribution, and functional biology of planktonic parasites in marine and freshwater environments, including papers addressing taxonomy and phylogeny of hosts and parasites. One of our goals is to bring together scientific expertise freshwater and marine parasites to stimulate cross-fertilization of ideas.

SS56 Coastal Sand Ecosystem Dynamics
Organizers: Perran Cook, Max Planck Institute, (pcook@mpi-bremen.de) and Markus Huettel, Florida State University, (mhuettel@ocean.fsu.edu)

Sediment transport, low concentrations of organic matter and nutrients, and deep oxygen penetration characterize the sands that blanket a large fraction of the shallow continental shelf. Despite the mechanical stress caused by bed load transport and the low standing stock of organic substrates, these sediments often exhibit high mineralization rates and benthic primary production rates that can match those of the overlying water column. The relatively high permeability of the sands permits rapid pore water and particle exchange. Thus, the dynamics of uptake, metabolism, and release of organic matter are fundamentally different from those in fine-grained cohesive marine deposits. The biological and biogeochemical dynamics of this ecosystem are further complicated by the fluctuating inputs of nutrients through atmosphere, rivers, groundwater and anthropogenic activities. In the shallow coastal zone, variations in temperature, fresh water, nutrient and contaminant input are not buffered very well and cause dramatic changes in the ecosystem over short time periods. Coastal resource exploitation affects the sandy shelf ecosystem on different spatial and temporal scales, and a rapid increase of these activities can be expected. The consequences of global climate change will be most pronounced in the shallow coastal zone affecting, amongst others, water level, currents and waves, sediment transport, and primary production and, thus, profoundly influence this ecosystem. In this session we will focus on processes and observations in coastal sandy ecosystems with emphasis on the biogeochemical cycling of matter, water column and benthic biology/microbiology, processes and dynamics of the sedimentary environment, and the influences of hydrodynamics, external input and anthropogenic activities.

SS57 Eutrophication, Macroalgal Blooms and Coastal Ecosystem Services
Organizers: Just Cebrian, Dulphin Island Sea Lab, (jcebrian@disl.org) and Nuria Marba, Consejo Superior de Investigaciones Científicas, Spain, (nuria.marba@uib.es)

Increased anthropogenic nutrient and carbon loading into coastal ecosystems is often conducive to the appearance of extensive and pervasive macroalgal blooms in the receiving systems. Consequently, much attention has been devoted recently to evaluating the effects of eutrophication-induced macroalgal blooms on the structure, metabolism and dynamics of coastal ecosystems. Nevertheless, our understanding of how macroalgal blooms alter the services and benefits offered by these ecosystems, such as, for instance, the trophic support of fisheries, the provision of habitat for organisms, and the filtering of land-derived nutrients, is little developed. Results to date suggest opposing trends, with some studies pointing to increased, but others indicating decreased, secondary production and nutrient accumulation with macroalgal blooms. This session seeks papers that investigate how macroalgal blooms influence the critical components and processes that determine the services and benefits that coastal ecosystems offer to the biosphere and humankind. The goals are twofold: (1) to increase our knowledge of the diversity of impacts that macroalgal blooms may have on these services, and (2) to improve our understanding of the mechanisms that regulate those impacts.

SS58 Global or Coastal Observations with Ships of Opportunity
Organizers: Friedhelm Schroeder, GKSS Research Centre, (friedhelm.schroeder@gkss.de), David Hydes, SOC, (dhj@soc.soton.ac.uk), and Franciscus Colin, GKSS Research Centre, Inst. f. Coastal Research, (franciscus.colijn@gkss.de)

Within GOOS (Global Ocean Observation System) ships of opportunity are used to do regular observations. These can have the character of regular observations on oceanic transects to observe long term changes or the measurement of water quality parameters in coastal and shelf seas. In the latter case these observations maybe part of regular monitoring tasks by governmental or environmental agencies. The development of a wide variety of sensors has enbaled us to measure many parameters at a high temporal and spatial scale. An extension of the spatial scale can be reached by coupling these shipborne observations with remotes sensing. Data gathered are available for operational services, for environmental assessments and modelling. Specific problems such as coastal eutrophication can be used to show the power of the observational strategy. In the symposium different technical developments for measuring systems of ships of opportunity and applications to different problems (oceanography, eutrophication, water quality etc.) will be discussed. In addition, a link to remote sensing and modelling will be established.

SS59 Seamount and Island Oceanography
Organizers: Rui Miguel A. Caldeira, Center for Macaronesian Studies, University of Madeira, (rui.caldeira@uma.pt) and Manfred Kaufman, Center for Macaronesian Studies, University of Madeira, (mkbiomar@uma.pt)

Small islands and seamounts often rise 4000m above the seafloor with diverse bathymetry; their influence to the prevailing currents creates unique distribution patterns of biogeochemical variables, including plankton and nekton organisms. The sustainability of high biomass levels often depends upon an enhanced primary production supported by upwelling of deep nutrient-rich water; this effect also known as “island-mass-effect” has had some attention from the scientific community, and yet the full scope of its dynamics are not completely understood. In recent years however, small islands and seamounts received carefull attention in light of an increase in the fishery activities diverting from overexploited continental coastal areas. In this symposium we propose to discuss research themes relevant to small island and seamount oceanography,particularly those focusing on multidisciplinary studies i.e. biological-physical-chemical interactions of marine ecosystems.

SS60 Hydrology, Geochemistry and Ecology of Monsoonal Catchments
Organizers: Robert Wasson, Charles Darwin University (Darwin, Northern Territory, Australia), (Robert.Wasson@cdu.edu.au) and Miles Furnas, Australian Institute of Marine Science, (mfurnas@aims.gov.au)

The catchments and associated freshwater systems of eastern Africa, southern Asia, southeast Asia, east Asia and northern Australia are profoundly influenced by the monsoonal climatology of the region. Rainfall and flow regimes in monsoonal catchments and river systems are strongly seasonal, usually without the large temperature fluctuations characteristic of high-latitude river systems. The broad monsoonal region supports a large proportion (ca. 40%) of the world’s human population and associated agricultural land use, and delivers a significant proportion of the freshwater, sediment and solutes (including nutrients) from land sources to the ocean. Monsoonal catchments are geographically and ecologically diverse, varying widely in the extent of human modification. All are characterised by seasonal, often episodic flow regimes that present significant challenges for measurement of key fluxes and processes, and for the management of water, fishery and other resources. A considerable amount of work has been undertaken in recent years on watersheds and rivers of the monsoonal region. Contributions will illustrate the diversity of characteristics and dynamics of monsoonal catchments and river , emphasizing common features of and approaches to dealing with monsoonal river systems, particularly in how knowledge gained in better studied systems can be used to better understand the many poorly or unstudied rivers and catchments of the region.

SS61 Linkage Between Pico, Nano-plankton and Biogeochemical Cycle in the Ocean
Organizers: Yoshimi Suzuki, Department of Biology and Geosciences, Shizuoka University, (seysuzu@ipc.shizuoka.ac.jp), Loic Charpy, IRD, (lcharpy@com.univ-mrs.fr), and Beatriz E. Casareto, Laboratory of Aquatic Science, (casaretobe@aol.com)

For a long time, oceanographers have studied the likage between foodweb and biogeochemical cycles in the ocean. Until now main species of phytoplankton were diatom and coccolithophorids in the organic matter and nutrient dynamics. However, pico, nano-plankton plays more important role than previously thought in biomass production and biogeochemical cycles. In this session, we would like to discuss recent results including topics about temporal and spacial variation of pico, nano- plankton, interaction between pico- nanoplankton and organic carbon, nutrients consumption, new production throuhout N2 fixation, export fluxes. Studies on field observations, laboratory experiments, and model in the open ocean, coastal ocean, coral reef, mangrove and seagrass communites will be discussed.

SS62 Pelagic Infochemistry
Organizers: Susan B. Watson, National Water Research Institute, Environment Canada, (swatson@ucalgary.ca), Georg Pohnert, Max Planck Institute for Chemical Ecology, Department of Bioorganic Chemist, (pohnert@ice.mpg.de), and Michael Steinke, School of Environmental Sciences, University of East Anglia, (M.Steinke@uea.ac.uk)

Infochemicals are important signalling compounds in terrestrial and benthic ecosystems. Aside from a few examples, relatively little is known about the chemical ecology of pelagic organisms. This special session will explore the relevance of infochemicals in the pelagic ecology of freshwater and marine habitats. The role of chemical signalling in aquatic environments is likely to be important and studies in this area may provide information on species competition, bloom development seasonal succession and the structuring of food-webs. Submissions are encouraged on topics such as the pelagic infochemistry of trophic interactions and sexual reproduction, intra- and interspecific cell-to-cell signalling, biosynthesis and signalling pathways of infochemicals, evolution of pelagic signalling and the chemical “arms race”. Due to the multi-disciplinary nature of infochemistry research, this session will be of interest to investigators in aquatic biochemistry, molecular biology, ecology, biogeochemistry, limnology and oceanography.

SS63 Chemical Characterization of Dissolved Organic Matter in Aquatic Systems
Organizers: Georgina Spyres, Institute of Marine & Coastal Sciences, Rutgers University, USA, (spyres@imcs.rutgers.edu) and Alexandra Gogou, Hellenic Centre for Marine Research, Athens, Greece, (agogou@ath.hcmr.gr)

Dissolved Organic Matter is composed of a great variety of molecules ranging from simple hydrocarbons to complex polymers that are exchanged and transformed biogeochemically in aquatic systems. The cycling of these components plays a key role in global carbon and nitrogen fluxes and is intrinsically linked to the cycling of nutrients and trace metals. In the last decade, there has been increasing evidence linking the chemical character of DOM and its production, transformation and removal in aquatic ecosystems. However, to date, less than 20% of the DOM pool has been chemically characterized at the compound level. The chemical analysis of isolated fractions from the DOM pool is currently the most commonly adopted approach for compound class and specific compound information. Methodologies such as gas and liquid chromatography combined with mass spectrometry (MS) and other spectroscopic techniques are used for compound class and specific compound information. Furthermore, novel applications of other state-of-the-art techniques (e.g., electrospray ionization mass spectrometry) have significantly enhanced our ability to detect and identify specific organic compounds in water samples. This session invites presentations of analytical studies that examine the chemical composition of DOM and help to demonstrate its role in biogeochemical cycling in both freshwater and marine environments.

SS65 Human Incentives and Valuation of Aquatic Ecosystems and Their Services
Organizers: Niels Vestergaard, University of Southern Denmark, (nv@sam.sdu.dk) and Eva Roth, University of Southern Denmark, (er@sam.sdu.dk)

What is the economical value of aquatic ecosystems and how can it be found? How does people react to different management regimes? Is the value needed to perform proper management? Understanding of aquatic ecosystems and their services has become an important contemporary problem in science and policy making. The purpose of this special session is to explore the main contemporary themes. Several new topics and approaches will be discussed.

SS66 Ocean & Ice - Atmosphere Interactions Through the Emission of Trace Gases
Organizers: Patricia A. Matrai, Bigelow Laboratory for Ocean Sciences, (PMatrai@bigelow.org) and Rafel Simó, Institut de Ciències del Mar, CSIC, (rsimo@icm.csic.es)

The oceanic biosphere plays a crucial role in the regulation of the composition of the atmosphere through the exhalation and uptake of volatile substances. Marine biota is not only a major agent for carbon dioxide sequestration in the long term, but it is also the source of many trace gases that balance the global cycle of a number of major elements, and contribute to the performance of the atmosphere as a reactor, transporter, radiation reflector and heat accumulator. Biogenic trace gases are, therefore, essential vectors in the biosphere-climate feedback gears that characterize the functioning of the Earth System. In this session, we intend to address all aspects of trace gas (DMS and other S gases, halocarbons, N2O and other N gases, CH4, LMW hydrocarbons, etc.) science, from the way they are produced and cycled in the water column to their atmospheric effects, through air-sea exchange and their response to physicochemical forcing. Emphasis will be given to the biological and chemical controls of trace gas net production in the water column, comprehensive modeling, and large-scale effects on biogeochemical cycles and atmospheric chemistry. Contributions on trace gas emissions from oceanic ice and its snow cover are encouraged.

SS67 Aquatic Pilgrimages: Non-Indigenous Species Invasions in Aquatic Ecosystems
Organizers: Henry Vanderploeg, GLERL/NOAA, (Henry.Vanderploeg@noaa.gov), Thomas Nalepa, GLERL/NOAA, (Thomas.Nalepa@noaa.gov), and Beatrix Beisner, University of Quebec at Montreal, (beisner.beatrix@uqam.ca)

Long-range assisted migration of species is having a profound impact in freshwater, estuarine, and marine ecosystems world-wide. Much attention has been paid to invasions and impacts in the Great Lakes region and North American estuarine waters, yet non-indigenous species are also having important impacts elsewhere. In one sense, invasions and impacts are a local phenomenon as species from outside a particular region have major impacts on a focal ecosystem. On the other hand, invasions are of global interest, both because they may lead to a homogenization of community structure across local systems, and because a number of local communities may be invaded by species from different donor regions. In either case, resulting impacts may be unique, cumulative, or broadly uniform. It is towards a general theory of both potential local and cross-system effects that this session will work. The responses of aquatic communities to invasion can provide insight into not only specific invader impacts but provide “natural” experiments that can be used to uncover general ecological mechanisms. We propose to examine invasion dynamics and impacts in diverse systems world-wide. With this session, we hope to further work towards a set of global generalizations on what constitutes a successful invader and an invasible system, while also determining when peculiarities of ecosystems or species must be taken into account. In order to accomplish this, we welcome presentations of experimental and observational studies from aquatic communities (e.g. plankton, benthos, fish), but are also looking for presentations on new theoretical ideas and modeling approaches.

SS68 Pharmaceuticals in the Aquatic Environment
Organizers: Miquel Lurling, Wageningen University, Aquatic Ecology & Water Quality Management Group, (miquel.lurling@wur.nl) and Marieke de Lange, Wageningen University, Aquatic Ecology & Water Quality Management Group, (marieke.delange@wur.nl)

The occurrence of pharmaceuticals and other personal care products is investigated worldwide. However, little is known about fate and dynamics of pharmaceuticals: do they break down easily, where do they end up in the aquatic system, do they sorb to suspended matter and sediment or do they remain soluble. Next big question is what threat do these pharmaceuticals pose for biota? First results show that even at low surface water concentrations pharmaceuticals do have a negative effect on organisms, ranging from phytoplankton, macrophytes to macroinvertebrates. These negative effects are expected to have implications for ecosystem functioning. These effects occur worldwide at low concentrations and chronic exposure. It is a hidden threat to ecosystems, and should be of interest to limnologists, not only to ecotoxicologists.

Contributions covering the following 4 themes would be welcome: 1) sources, occurrence and concentrations of pharmaceuticals and other personal care products in surface waters, 2) fate and dynamics in the aquatic system, 3) effects on biota (on all levels and processes: e.g. individual, population, community, ecosystem, trophic interactions) and 4) implications for policy makers.

SS69 Ecosystem Dynamics in Pulsing Littoral Zones: Lakes and Rivers
Organizers: Karl-Otto Rothhaupt, University of Konstanz, Limnological Institute, (Karl.Rothhaupt@uni-konstanz.de) and Matthias Wantzen, University of Konstanz, Limnological Institute, (wantzen@mpil-ploen.mpg.de)

Water level fluctuations are widely accepted as important drivers for ecosystem dynamics in littoral zones of rivers, e.g. by shaping the physical and chemical setting of the habitat, by intensifying aquatic-terrestrial linkages and organic matter dynamics, and by setting the stage for sequential use of littoral habitats during the flood cycle. Hydraulic engineering has reduced these important functions not only in rivers but also in lakes. Few lakes have remained which still have a pulsing hydrology. For example, most prealpine lakes have been regulated for several centuries and fixed positions of the peri-, epi- and eulittoral zones are generally taken as "normal" in most northern countries. On the other hand, studies from systems that still undergo natural water level fluctuations can provide insights into undisturbed processes both for basic research and for ecosystem rehabilitation. This special session aims to summarize the current state of the art and to investigate how hydrological pulses influence the littoral biota and ecosystem functions in lakes and rivers.

SS70 Advances in the Development of Biological Indicators for Assessment of Aquatic Ecosystem Health
Organizers: Dorte Krause Jensen, National Environmental Research Institute, Denmark, (dkj@dmu.dk), Anna-Stiina Heiskanen, EC-Joint Research Centre, Institute for Environment and Sustainability, (anna-stiina.heiskanen@jrc.it), and Anne Lyche Solheim, Norwegian Institute for Water Research, (anne.lyche@niva.no)

The sustainable management of aquatic environment requires ecological status assessment based on monitoring of the structure and functioning of aquatic ecosystems. Assessment of water quality has traditionally been mainly based on chemical aspects but current legislation like the European Water Framework Directive (WFD) and the U.S. Clean Water Act set ecological quality objectives, and demand water quality to be assessed using biological quality elements such as phytoplankton, fish, and benthic flora and fauna. Currently intensive research is being carried out to develop biological indicators that respond in a predictable manner to human disturbances, and allow classification of ecological quality based on functional relationships between pressures and indicators. This session will present scientific achievements in the recent developments of biological quality indicators and metrics for the assessment of the inland and marine (coastal and transitional) waters. The session seeks to identify promising biological indicators through scientific work and to illustrate how these may be used in monitoring and management of aquatic ecosystems.

SS71 Role of Algal Mortality in the Dynamics of Harmful Blooms
Organizer: Ed Buskey, University of Texas at Austin, (buskey@utmsi.utexas.edu)

There has been considerable interest the the ecology of harmful algal blooms in recent years. Much research has focused on the factors regulating the growth rates of harmful algal species. This session would focus on the role of cell mortality, through grazing losses, disease (bacterial and viral) and physical loss processes (sinking, dispersal) on the development of harmful algal blooms. As a related consideration, the role of theshold bloom levels in grazing suppression and losses to disease processes could also be considered.

SS72 Assessing and Modelling Eutrophication
Organizer: Alice Newton, Universidade do Algarve, (anewton@ualg.pt)

Eutrophication is affecting all types of aquatic environments, freshwater, estuarine and coastal. This problem has grown from local to regional and is now global. Assessing the causes and evaluting the extent of the eutrophication is a priority for the management of these important resources. Modelling is useful for understanding the scale and consequences of eutrophication and also for running scenarios for predicting the response of the system. A range of models will be considered: from complex descriptions of a particular system to simpler approaches, which provide comparative indicators for a range of systems. The ways in which information may be exchanged between models and scaling issues will be addressed.

SS73 Coupling of Physical, Chemical and Biological Processes in Plankton Dynamics: A Quantitative Multidisciplinary Perspective
Organizers: Yvan Lagaduec, Caren, Umrs CNRS Ecobio, Université de Rennes, (yvan.lagadeuc@univ-rennes1.fr), Jef Huisman, Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, Un, (jef.huisman@science.uva.nl), and Myriam Bormans, CSIRO Land and Water, (Myriam.Bormans@csiro.au)

Human induced changes in catchments combined with climate variability have altered the structure and succession of plankton in fresh and coastal waters in a way which is difficult to assess and predict quantitatively. Over the past decades many of the signs of unhealthy impacts of flow and land use changes (eutrophication, sediment inputs, algal blooms) are becoming more apparent. Population increases, mainly in coastal areas are likely to exacerbate these effects. A combination of physical, chemical and biological approaches offers the best chance to understand the complex interactions on a variety of scales and to better manage these systems. This session welcomes contributions, which explore aspects of these interactions. We encourage presentations on experimental and modeling studies in both freshwater and coastal systems to increase cross-fertilization of techniques, models and approaches.

SS74 Biogeochemistry of Methane and Carbon Dioxide at High Concentrations
Organizers: George W. Kling, University of Michigan, (gwk@umich.edu) and Bernhard Wehrli, EAWAG / ETH, (wehrli@eawag.ch)

Research on methane in aquatic systems has recently focused on topics such as the biogeochemical cycling of methane production and oxidation in lakes, methane emissions from lakes and reservoirs to the atmosphere and their contribution to the global radiative forcing, and the fascinating occurrence of gas seeps and methane hydrates in Lake Baikal, Black Sea and other continental and coastal waters. Elevated concentrations of carbon dioxide are usually found in lakes in volcanic regions, where CO2 is emitted from the subsurface. In the case of Lakes Nyos and Monoun in Cameroon, accumulated CO2 was suddenly released from these lakes with catastrophic consequences. Finally, in Lake Kivu both gases, methane and carbon dioxide, play an important role, as the elevated methane concentrations could potentially trigger a CO2 eruption from this lake. Presentations which contribute to the understanding of the biogeochemical cycling and physical transport of gases in lakes and coastal seas including the sediment to water, water to atmosphere and bubble-related fluxes as well as related transformation processes are encouraged.

SS75 Advances at the Interface of Theoretical and Empirical Plankton Ecology
Organizers: Chris Klausmeier, Georgia Institute of Technology, (christopher.klausmeier@biology.gatech.edu) and Elena Litchman, Georgia Institute of Technology, (Elena.litchman@biology.gatech.edu)

Given their small size, short generation times, and relative simplicity, plankton are ideal systems to test existing ecological theory in the laboratory and the field. In turn, plankton have inspired a large body of ecological theory. Recent advances at the interface of theoretical and empirical plankton ecology include experimental tests of predator-prey theory, field tests of resource-competition theory, expansion of the theory of ecological stoichiometry, and the discovery of chaos in resource-competition interactions. We welcome empirical talks that address theoretical questions, theoretical talks that are based in reality, or talks that combine theoretical and empirical approaches. We also seek talks from all levels from the physiological to the ecosystem, especially those that cross these scales.

SS76 The Microbial World as an Effective Model System in Ecology
Organizers: Thierry Bouvier, CNRS-University of Montpellier II, (tbouvier@univ-montp2.fr) and Thomas Pommier, Kalmar University, (thomas.pommier@hik.se)

Understanding the structure and functions of diversity in the ecosystem is a common interest shared by general and microbial ecologists. Although the microbial world provides an effective model system to address fundamental ecological questions, general ecology and microbial ecology grew into two parallel stems. However, studies merging ecological theories, microbial laboratory-based model and/or field experiments are becoming more common and start to bridge the gap between the two disciplines. From this perspective, this session encourages contributions unifying different approaches from both disciplines through the study of the aquatic microbial world and address questions relative to diversity (evolution, distribution and variability) and the ecological mechanisms and theories that govern their patterns.

SS77 Stoichiometric Aspects of Ecology and Evolution in Aquatic Ecosystems
Organizers: Dag O. Hessen, Dept. Biology, University of Oslo, (d.o.hessen@bio.uio.no) and Tom Andersen, Dept. Biology, University of Oslo, (tom.andersen@bio.uio.no)

Ecological stoichiometry (ES) is the study of the balance of energy and multiple chemical elements in ecological interactions. This field has many intellectual roots like the seminal works of Liebig, Lotka and Redfield, but most proximally it has emerged from studies of trophic interactions in freshwater plankton. It has in recent years expanded it ranges, and appears to be a useful concept for understanding effects at cellular level such regulation of growth in response of elemental ratios, as well as providing additional insights in the coupling of biogeochemical cycling of key elements like C, N and P at the ecosystem level. At the individual level, stoichiometric principles clearly have some important evolutionary implications. The field of ES has been rapidly expanding field with the aquatic sciences, and we thus find it timely to arrange a special session to highlight recent advances within the topic of ES, bringing together marine and freshwater scientists, theoretical as well as empirical works and finally merging evolutionary aspects and ecology.

SS78 Radionuclide Tracers: Contributions to Our Understanding of Freshwater, Estuarine and Marine Processes
Organizers: Joseph Smoak, University of South Florida St. Petersburg Environmental Science, Policy an, (smoak@stpt.usf.edu) and Ashanti J. Pyrtle, University of South Florida College of Marine Science, (apyrtle@marine.usf.edu)

Radionuclide tracers have been successfully applied in examining processes within aquatic systems as well as aquatic system interactions with other environments. This session will highlight recent advancements in and applications of radiometric techniques used to investigate a wide-range of aquatic processes. We invite contributions on both natural and artificial tracer studies of complex aquatic systems and surrounding environments. Such environments include surface, subsurface, groundwater, estuarine, marine, and freshwater systems. Presentations focused on interactions between these environments, as well as those that consider exchanges at terrestrial, air and/or particle interfaces, are particularly encouraged.

SS79 Algal and Bacterial Cell Death: Incidence, Mechanisms and Consequences
Organizers: Ilana Berman-Frank, Bar Ilan University, (irfrank@mail.biu.ac.il), Tom Berman, Kinneret Limnological Laboratory, (berman@amiad.org.il), Kay Bidle, Institute of Marine and Coastal Sciences, Rutgers University, (bidle@imcs.rutgers.edu), and Susana Agusti, IMEDEA, CSIC-UIB, (sagusti@uib.es)

Microplankton evolved in the Archaen oceans more than 2.5 billion years ago and, in time, came to have pivotal roles in regulating aquatic food webs, biogeochemical cycles, and Earth’s climate. In order to maintain biogeochemical cycles throughout billions of years of Earth’s history, microplankton must not only grow, but also die. Over the past century of discovery of aquatic biogeochemical cycles, a misconception emerged that phytoplankton are immortal: unless eaten by heterotrophic zooplankton, or sinking irreversibly into the deep ocean, it has been assumed that the cells grow indefinitely, primarily by binary fission. New discoveries and growing empirical evidence on the rates and mechanisms of phytoplankton and bacterial cell death illustrate key loss processes across aquatic systems. It has become increasingly apparent that phytoplankton are not immortal; upon encountering adverse environmental conditions, they often die spontaneously. Indeed, substantial cell death by lysis has been documented in field populations, with some estimates exceeding 50% of phytoplankton growth. These observations highlight important loss processes independent of grazing by heterotrophs must exist and might explain how an average of ~50% of global primary production is consumed by bacteria. In parallel, evidence of high mortality has emerged as a consequence of an improved understanding of the role of viruses and pathogens in aquatic ecosystems. It is clear that the population dynamics of bacteria and phytoplankton, the most abundant components of pelagic communities, are dependent on the balance between growth and losses. Indeed, now recognized as a key loss component of aquatic microorganisms, cell death processes may explain their abundance and community structure equally as well as resource availability. Yet, the environmental conditions and cellular mechanisms that illicit and execute microplankton cell death remain poorly investigated. This lack of understanding precludes our capability to predict microplankton cell death in nature and, thereby, to incorporate this important process in models of ecosystem structure and nutrient fluxes in pelagic ecosystems. This session provides a platform to present new findings on the environmental and physiological triggers of cell death in bacteria and phytoplankton, the cellular mechanisms responsible, and its ecological consequences. This session aims to bring together phytoplankton and microbial ecologists, physiologists, molecular biologists, evolutionary biologists and biogeochemists in an imaginative, interdisciplinary and vibrant area of science. We invite papers with field, lab and theoretical backdrop in order to exhibit the spectrum of approaches used in this field.

SS80 Impacts of Climate Change and Other Drivers of Change on Freshwater Ecosystems
Organizers: Charles R. Goldman, University of California, (crgoldman@ucdavis.edu), Martin Dokulil, Institute for Limnology, Austrian Academy of Sciences, Austria, (martin.dokulil@oeaw.ac.at), Martin Kernan, Environmental Change Research Centre, University College London, (mkernan@geog.ucl.ac.uk), and Rick Battarbee, Environmental Change Research Centre, University College London, (rbattarb@geog.ucl.ac.uk)

Freshwater ecosystems, already under stress from land-use change and pollution, now face additional pressures from climate change, directly and through interaction with other drivers of change. There is a pressing need to understand and manage the ecological consequences of these interactions. The proposed special session will focus on the key drivers of aquatic ecosystem change (land-use, nutrients, acid deposition and toxic substances) and how these interact with global, especially climate, change. We will consider lakes, rivers, wetlands and groundwater. A tutorial session will review the current state of research. It is anticipated that subsequent papers will examine the effects of climate change and its interactions with other drivers and methods for disentangling these across a range of ecosystem types. We are keen to ensure that research on climate change effects on aquatic ecosystems being undertaken across the globe are represented through oral and poster presentations.

SS81 Single-cell Analyses in Aquatic Microbes: Patterns, Controls, and Linkages Between Biogeochemical Function and Microbial Diversity
Organizers: Josep M. Gasol, Institut de Ciéncias del Mar - MCIMA, CSIC, (pepgasol@icm.csic.es), Barry F. Sherr, Oregon State University, (sherrb@coas.oregonstate.edu), and Gerhard J. Herndl, NIOZ, The Netherlands, (herndl@nioz.nl)

Identifying the role that particular microbes play in biogeochemical cycles relies on the simultaneous assessment of their phylogenetic identity and ecological function. Over the last few years various single-cell techniques have been developed for the phylogenetic identification of microbes and for the evaluation of their contribution to the cycling of C, P, and S. Various combinations of these techniques now allow us to open the microbial black boxes and to identify groups of microbes that are functionally important components of ecosystems. This enables us to gain insights into the dynamics and regulation mechanisms in the microbial food web and thereby advancing from a description of microbial processes to a mechanistic understanding of the functioning of microbial communities, allowing for the resolution of the spatial and temporal scales of in situ cell-specific microbial activity, and for the differential response of microbial groups to changing environmental conditions.

We invite contributions that make use of single-cell analyses, such as flow cytometry cell sorting, microautoradiography, confocal microscopy, bacterial enzyme activities and fluorescence in situ hybridization, to answer ecological questions relevant to the identification, physiological status and ecological function of important microbial groups in aquatic systems.

Recognizing the land-to-ocean path of the medieval Santiago's Way and the meeting's motto ‘A pilgrimage through global aquatic sciences’, we encourage contributions from investigators working in all aquatic environments, from lakes to the oceans and from the benthos to the plankton.

SS82 Benthic Biofilms in Freshwater and Marine Systems
Organizers: Anna M. Romaní, University of Girona, Institute of Aquatic Ecology, (anna.romani@udg.es), Helene Cyr, University of Toronto, (helene@zoo.utoronto.ca), and Graham Underwood, University of Essex, (gjcu@essex.ac.uk)

Many aquatic microorganisms live in attached communities (biofilms) embedded in a polysaccharide matrix and contribute substantially to the energy flow (production and loss of organic matter) and sediment-water interactions (e.g. stabilization of sediments, exchanges of nutrients and contaminants, refuge for pathogens). Microbial consortia living within benthic biofilms (algae, bacteria, fungi, protozoa) are in close contact to each other and are organized by antagonistic and/or synergistic relationships. These species-rich communities also respond to human disturbances and are important indicators in environmental assessment programs. The main goal of this Special Session is to bring together researchers working on benthic biofilm communities in streams, lakes and shallow marine systems to compare approaches and contrast the structure and functioning of biofilms in these different ecosystems.

SS83 Spatial Processes in Marine and Freshwater Ecosystems
Organizers: W. Gary Sprules, University of Toronto at Mississauga, (gsprules@utm.utoronto.ca), Andre W. Visser, Danish Institute for Fisheries Research, (awv@dfu.min.dk), and E. Agnes Blukacz, University of Toronto at Mississauga, (ablukacz@utm.utoronto.ca)

It has long been realized that distributions of aquatic organisms ­ from fish to plankton to bacteria ­ are not uniform in space and time. These distributions are often organised into patches and aggregations with peak concentrations several times higher than mean background levels, and at scales ranging from millimetres to kilometres. How these patches are formed, maintained and exploited is thought to be a key determinant in shaping pelagic ecosystems and influencing processes from fisheries recruitment to the vertical flux of detrital material. Oftentimes, the governing dynamics have both physical (turbulence and stirring) and biological (growth, grazing and motility) components, the relative contributions of which may be strongly scale dependent. In the 50 years or so since Morrison Cassie’s seminal work on plankton patchiness, interest in spatial heterogeneity has endured, although emphasis on food web consequences has received less attention than measurement and origins of spatial pattern. A recent explosion in particle-counting technologies and analytical techniques such as wavelets and multifractals have stimulated this continuing interest. This session invites contributions that through modelling, observation or experiment examine spatial patterning in marine and freshwater ecosystems, its effects on trophic processes and its governing dynamics.

SS84 Multi-tracer Approaches Toward Understanding Particle Fluxes and Dynamics in the Sea
Organizers: Pere Masque, Institut de Ciécia I Tecnologia Ambientals, Universitat Autónoma de Barcelo, (Pere.Masque@uab.es), Stuart Wakeham, Skidaway Institute of Oceanography, (sutart@skio.peachnet.edu), Robert Armstrong, Marine Sciences Research Center, (rarmstrong@notes.cc.sunysb.edu), and Juan-Carlos Miquel, International Atomic Energy Agency - Marine Environmental Laboratory (MEL), (j.c.miquel@iaea.org)

Particulate matter plays a major role in the redistribution of carbon and other elements in the sea. Sinking particles export organic matter from the sea surface into the interior of the ocean, where it can provide energy and nutrition to heterotrophs, can be remineralized, or can be sequestered in deep water and sediments. The redistribution of organic carbon influences the depth distribution of dissolved CO2 which in turn affects the exchange of CO2 between ocean and atmosphere and the response of the ocean and global climate to environmental change. It is thus critical to understand quantitatively and mechanistically those processes involved in organic carbon remineralization. Biogeochemical investigations into the behavior of particulate matter now rely on multi-tracer approaches, combining tools in organic geochemistry, inorganic and radioisotope geochemistry, zooplankton ecology and microbiology, and statistical analysis and modeling. Current studies include DYFAMED and MedFlux in the Mediterranean; RODA and ESTOC near the Canary Islands in the Atlantic; PAP in the North Atlantic; VERTIGO and BATS near Bermuda in the Atlantic; and HOT, VERTIGO, and E-FLUX near Hawaii in the Pacific, among others. This session encourages presentations that involve multi-tracer approaches that are in use to shed new light on the mechanisms responsible for POC profiles in the ocean and that will lead to a predictive capability relating oceanic carbon cycling and global climate change.

SS85 The Implementation of Observations in the Coastal Zone: The Global Ocean Observing System
Organizers: Tom Malone, Ocean.US Office for Integrated and Sustained Ocean Observations, (t.malone@ocean.us) and Tony Knap, Bermuda Biological Station, (knap@bbsr.edu)

Coastal systems are experiencing unprecedented changes and becoming more susceptible to natural hazards, more costly to live in, and less able to support living resources. There are troubling trends in the magnitude or frequency of a broad spectrum of phenomena from global warming and sea level rise to harmful algal blooms and habitat loss. Trends such as these are related to both natural processes and increasing human demands on coastal ecosystems to support commerce, living resources, recreation, and living space and to receive, process, and dilute the effluents of human society. Informed management for sustained use of these goods and services requires the capacity to routinely and rapidly assess the state and health of marine systems, detect changes on a broad spectrum of time and space scales, and provide timely predictions of likely future states. We do not have this capacity today. The coastal module of GOOS is intended to develop this capacity through a more integrated and holistic approach to achieving six societal goals: 1) improve the safety and efficiency of marine operations; 2) more effectively control and mitigate the effects of natural hazards; 3) improve the capacity to detect and predict the effects of global climate change on coastal ecosystems; 4) reduce public health risks; 5) more effectively protect and restore healthy ecosystems; and 6) more effectively restore and sustain living marine resources.

This session is designed to take advantage of the release of the Implementation Plan for the Coastal Panel of GOOS in mid-2005. Developing a fully integrated, multi-disciplinary global system for the coastal module of GOOS is especially challenging for at least two reasons: (1) monitoring and research activities in much of the world’s coastal ocean are non-existent or primitive at best; and (2) operational capabilities for detecting and predicting changes in ecosystem health and the sustainability of living marine resources are poorly developed relative to those for marine operations, weather forecasting, and climate prediction. Meeting these challenges will require major investments in capacity building and pilot projects for the development of “end-to-end” observing capabilities, for enabling implementation in the developing world, and improving specific elements of system from observing capabilities to data management and modeling.

This session will invite and call for papers on any of the topics discussed above however they should specifically relate to implementation. Presentations on Specific Pilot projects or ongoing operational systems would be encouraged as well as presentations on data management and modeling and analysis.

SS86 Brown Trout From the Old World to the New World: Modification and Homogenization of Freshwater Ecosystems Around the Globe
Organizers: Francis Juanes, Univ. of Massachusetts, (juanes@forwild.umass.edu) and Doris Soto, Universidad Austral de Chile, Puerto Montt, Instituto de Acuicultura, (dsoto@uach.cl)

The Brown trout, Salmo trutta, is native to Europe, north Africa and Western Asia. It was introduced to North America in 1884, and is now widely stocked throughout much of Canada and the US. The species was also introduced to southern South America early in 1900, as well as to New Zealand. In most cases sport fishing was one of the major objectives for introduction. Apparently its success in the new habitats is due to its tolerance to poor-quality water. Indeed, this species seems to tolerate warmer water temperatures than other trout species. Brown trout (BT) is today one of the most cosmopolitan freshwater fish, however, we do not have large assessments on its impact, where introduced, particularly at the ecosystemic level. It is quite possible that this species have contributed to homogenization of freshwater habitats around the world. This special session is attempting to bring together brown trout studies around the world, which will allow us to compare the species role in the ecosystem. Questions such as BT role as top predator, BT modifying resource and energy allocation in streams and lakes, BT having any effects on the relevance of allochtonous vs. autochtonous resources for productivity, BT affecting biodiversity etc. Other indirect effects such as the role of BT on mercury accumulation in ecosystems could also be relevant around the globe. Therefore, we invite scientists all over the world to send provocative abstracts and to join us in this exciting special session.

SS87 The Biogeochemistry of the Tropical Atlantic Ocean
Organizers: Ajit Subramaniam, LDEO, Columbia University, New York, (ajit@ldeo.columbia.edu), Douglas Capone, University of Southern California, Los Angeles, (capone@usc.edu), and Douglas Wallace, Leibniz-Institut für Meereswissenschaften, Kiel, (dwallace@ifm-geomar.de)

The tropical Atlantic Ocean is a very dynamic system influenced by intense seasonal riverine inputs and dust deposition. Biological productivity exceeds what might otherwise be expected in an otherwise oligotrophic environment. There have been several recent interdisciplinary studies of the tropical Atlantic Ocean by European and American investigators. These studies have included new measurements and experimental studies of trace metal chemistry, diazotrophy, and carbon drawdown. They are altering our understanding of the impact of tropical rivers and aeolian dust on oceanic carbon and nitrogen cycling. We invite presentations of results from field surveys as well as modeling studies of the biogeochemistry of the tropical Atlantic Ocean in order to promote the exchange of ideas and results across disciplinary boundaries and among research groups.

SS88 Reservoirs: Limnology in the Making
Organizers: Fabio Roland, Universidade Federal de Juiz de Fora, (fabio.roland@ufjf.edu.br) and Joan Armengol, Univ. Barcelona, (jarmengol@ub.edu)

The growing number and size of reservoirs worldwide is re-shaping the distribution and role of freshwater ecosystems at a global scale. Reservoirs affect the hydrological balance of the biosphere, as well as the sedimentary budget and the fluxes of materials from land to aquatic ecosystems and, eventually, the ocean. Reservoirs also preclude the free migration of organisms upstream in watersheds. In summary, reservoirs are reshaping the distribution and role of freshwater ecosystems and deserve, therefore, a dedicated examination within the realm of aquatic sciences. Compared to the millenary age of most freshwater bodies, reservoir life spans count in decades, and the consequences of the removal of dams can be massive on the processes mentioned above. This session provides a forum to present results on the role of reservoirs on ecosystem processes at both the local and, particularly, the regional and global scales.

SS89 Global Limnology
Organizers: Yves Prairie, Université du Québec à Montréal, (prairie.yves@uqam.ca) and Jonathan Cole, Institute of Ecosystem Studies (cole@ecostudies.org)

Limnology has traditionally been dominated by research at the single ecosystem (lake, reservoir, pond, stream) level, with the occasional comparative analyses at regional scales. As a consequence, the role of freshwater aquatic ecosystems have largely remained within the boundaries of those offered by these local ecosystems, such as recreation, fishing, and local water supply. Not surprisingly then, the global role of freshwater ecosystems in the functioning of the biosphere is seldom addressed in spite of the mounting evidence that it may play a quantitatively important role in the processing of materials they receive from land.

The purpose of this special session is to bring together current estimates of the extent of freshwater resources (streams, rivers, lakes, reservoirs) and the biogeochemical role they play at the global scale.

SS90 Other

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