OOS 53 - Global Browning of Inland Waters: Implications of Changing Terrestrial Dissolved Organic Carbon Concentrations for Aquatic Ecosystems

Friday, August 10, 2012: 8:00 AM-11:30 AM
B113, Oregon Convention Center
Christopher T. Solomon, McGill University & University of Montreal
Brian C. Weidel, US Geological Survey; and Stuart E. Jones, University of Notre Dame
Stuart E. Jones, University of Notre Dame
Inputs of terrestrial-derived dissolved organic carbon (DOC) play a fundamental role in structuring the physics, biogeochemistry, carbon balance, and food webs of aquatic ecosystems. Data from across the northern hemisphere show that loads of DOC have increased in recent decades. While the drivers of these changes have been debated, the pattern is clear and is expected to continue. Existing theory and data suggest that changing DOC loads may reconfigure aquatic ecosystem structure and function, with important consequences for carbon balances, recreational fisheries, and other ecosystem services. Yet it is only in the past few years that ecologists have really begun to grapple with understanding these changes. This organized session will bring together a diverse set of perspectives on this emerging environmental issue. Our goal is to bring together some of the best hydrologists, biogeochemists, microbial ecologists, and food web ecologists working on these ideas, to facilitate an exchange of ideas, perspectives, and emerging findings. The central question of this session will be: How will changing terrestrial DOC inputs affect aquatic ecosystems? We will begin the session with talks from experts on DOC loads, who will contextualize the session by describing their evolving understanding of how DOC loads have changed and will continue to change. Next, several talks will consider the effects of changing DOC loads on physical and biogeochemical processes in streams and lakes. A final set of talks will consider potential food web effects of changing DOC loads, from both theoretical and empirical perspectives and at several levels of biological organization. We anticipate that these diverse perspectives will initiate a dialogue amongst attending scientists about how direct and indirect influences of terrestrial carbon will combine to determine aquatic ecosystem services under elevated terrestrial carbon supply. This session focuses on an emerging issue that touches on the interests of a broad swath of ESA’s membership. Aquatic ecologists will be interested because terrestrial-aquatic linkages are becoming an organizing theme in limnology. These linkages are a prominent example of cross-habitat subsidies, which are of interest to food web ecologists in many biomes these days. Some of the most interesting potential effects of changing DOC loads will be mediated by shifts in the behavioral ecology of fishes and other consumers. Because changing DOC loads will alter regional carbon balances, biogeochemists and climate scientists will be interested as well. Bringing together the perspectives of these diverse sub-disciplines is a major goal of this session.
8:20 AM
 Why are small lakes brown? A framework for assessing watershed carbon loading and in-lake processing for a northern lake district
Ishi Buffam, University of Cincinnati; Paul C. Hanson, University of Wisconsin; Monica G. Turner, University of Wisconsin, Madison; Stephen R. Carpenter, University of Wisconsin - Madison
9:00 AM
 Controls of lake water color on stratification, mixing, and seasonal water temperatures in small temperate lakes
Jordan S. Read, University of Wisconsin-Madison; Kevin C. Rose, Miami University; Paul C. Hanson, University of Wisconsin
9:20 AM
 Dissolved organic material as a resource subsidy for phytoplankton in lake ecosystems
Jasmine E. Saros, University of Maine; Craig E. Williamson, Miami University; Carrie E.H. Kissman, St. Norbert College; Kevin C. Rose, Miami University
9:40 AM
9:50 AM
 Direct and indirect effects of organic matter sources on denitrification in Florida rivers
Megan L. Fork, Florida International University; James B. Heffernan, Duke University
10:10 AM
 Dissolved organic matter dynamics in high-elevation lakes: Effects on bacterial ecology and ecosystem metabolism
Steven Sadro, University of California, Santa Barbara; Craig E. Nelson, University of California, Santa Barbara
10:30 AM
 Implications of changing terrestrial organic carbon export on lake productivity: Merging process and habitat specific responses to an integrated ecosystem level understanding
Jan Karlsson, Umeå University; Ann-Kristin Bergström, Umeå University; Pär Byström, Umeå University; Cristian Gudasz, Umeå University; Catherine Hein, Umeå University
10:50 AM
 Implications of dissolved organic carbon on fish feeding and predator prey interactions
Brian C. Weidel, US Geological Survey; Jake Zwart, Calvin College; Stuart E. Jones, University of Notre Dame; Christopher T. Solomon, McGill University & University of Montreal
11:10 AM
 Subsidy or subtraction? Whole-lake experiments, surveys, and models to test the effects of terrestrial DOC on aquatic food webs
Christopher T. Solomon, McGill University & University of Montreal; Stuart E. Jones, University of Notre Dame; Brian C. Weidel, US Geological Survey; Patrick T. Kelly, University of Notre Dame
See more of: Organized Oral Session