This is a two year appointment with the U.S. Geological Survey through the Mendenhall Research Fellowship program. The focus of this research opportunity is understanding organic and inorganic carbon cycling and transport in fluvial aquatic ecosystems. The primary objectives are to: 1) identify and quantify drivers of riverine carbon fluxes; and, 2) present an integrated assessment of major C inputs and losses in one or more stream or river ecosystems. Within these broad objectives, the postdoctoral researcher will have wide latitude to pose specific research questions, define approaches, and adapt or develop new methodologies. Candidates for this position are expected to possess a Ph.D. and to present a detailed research proposal (maximum 8 pages) by the opportunity closing date (September 20, 2013). The U.S. Federal Government gives strong preference to U.S. citizens. We strongly encourage candidates to review material at the USGS Mendenhall Program website and to contact the research advisors prior to submitting a proposal. Kimberly Wickland, firstname.lastname@example.org.; Edward Stets, email@example.com.; Robert Striegl, firstname.lastname@example.org.; George Aiken, email@example.com.