[L&O Featured Article]Vol 47, Issue 3 (May 2002)

[lo-feature-admin@aslo.org]

The featured article in the May 2002 issue of L&O is:

MacIntyre, Sally, Jos=E9 R. Romero, and George W. Kling. 2002. Spatial-
temporal variability in surface layer deepening and lateral advection in 
an embayment of Lake Victoria, East Africa. Limnol. Oceanogr. 47: 656-
671. It can be read online or downloaded by clicking here. 

          http://aslo.org/lo/toc/vol_47/issue_3/0656.pdf

Instructions for reading PDF files are located on the ASLO web page: 

          http://aslo.org/help/loonline.html 

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Introductory comments by Stephen Monismith (the Associate Editor for this 
paper)

A few years back, while working on my thesis, I was perusing volumes of a 
scientific journal published early in the last century and chanced upon 
an article by the great aquatic scientist Edward A. Birge that caught my 
interest. In this article, Birge lamented the fact that while temperate 
lakes had received considerable attention by the limnological community, 
almost no work had been done on tropical lakes.  A survey of several 
decades of Limnology and Oceanography suggests that this imbalance of 
effort has continued to the present. Thus, the article in the current 
issue by MacIntyre et al. about a subembayment of Lake Victoria in Africa 
represents an important and noteworthy contribution to the science of 
limnology by revealing details of how the thermal structure of a tropical 
lake evolves diurnally. 

The strength of this paper is the way it uses important recent advances 
in our understanding of lake physics (e.g., Imberger and Patterson 1990; 
MacIntyre 1996; Wells and Sherman 2001) to  explain the complex 
interaction between those physical processes that act primarily in the 
vertical direction (local wind mixing and solar radiation) with those 
that arise from imhomogeneity in the meteorological forcing or lake 
bathymetry and that act to exchange water horizontally, e.g., between 
shallow literal regions and the interior of the lake. The paper offers 
readers the first measurements of a diurnally varying surface energy 
budget for a tropical lake. It also includes measurements of the internal 
wave climatology of the lake, something known to play a central role in 
vertical mixing in the hypolimnion, and documents the persistent 
formation of fronts. Most importantly, it shows the extreme horizontal 
variability in thermal structure that "...create a diversity of habitats 
for phytoplankton as well as sites with different rates of biological and 
chemical activity=85." However, as has been observed in temperate lakes, 
horizontal temperature gradients always lead ultimately to horizontal 
flows and re-establishment of the nearly one dimensional vertical varying 
thermal structure that we think of as describing the physical structure 
of lakes. All in all, besides its contribution to tropical limnology, 
this featured paper offers L&O readers a sophisticated overview of 
current thinking in physical limnology.

References

Imberger, J., and J. C. Patterson. 1990. Physical limnology. Adv. Appl. 
Mech. 27: 303-475.

MacIntyre, S. 1996. Turbulent eddies and their implications for 
phytoplankton within the euphotic zone of Lake Biwa. Jpn. J. Limnol. 57: 
395-410.

Wells, M. G., and B. Sherman. 2001. Stratification produced by surface 
cooling in lakes with significant shallow regions. Limnol. Oceanogr. 46: 
1747-1759.