What is the role of tropical rivers and streams in the global carbon cycle as carbon dioxide levels in Earth’s atmosphere continue to rise? Chip Small, UGA Ecology Ph.D. ’10 and Catherine Pringle, distinguished research professor in the Odum School, organized a workshop to bring together scientists who study tropical rivers and streams around the world to explore that question. The workshop, “Carbon cycling in tropical streams,” took place at the Organization for Tropical Studies (OTS) La Selva Biological Station, Costa Rica, from April 15-17.
“Concern about climate change from rising levels of carbon dioxide in Earth’s atmosphere due to the burning fossil of fuels has led scientists to intensively study the natural carbon cycle – the exchange of carbon throughout the biosphere (the global zone of air, soil, and water that is capable of supporting life) – in an attempt to understand how the biosphere will respond,” said Small. “While much of this study has focused on terrestrial ecosystems, rivers and streams play an important, but often overlooked, role, transporting large amounts of dissolved carbon away from local watersheds.”
Pringle explained that tropical streams and rivers in particular appear to be especially important, due to warmer temperatures which result in higher rates of carbon processing by microbes, but relatively few studies have focused on carbon in tropical streams. Other factors also make understanding the role of tropical streams and rivers crucial. “Many nations in the tropics have rapidly developing economies,” she said, “and carbon dynamics in tropical streams and rivers are expected to be disproportionately affected by pressure from urbanization and land-use change, compounded by the effects of climate change.”
The workshop, funded by a Research Coordination Network Grant to OTS from the National Science Foundation, brought together twenty-two researchers with experience studying carbon in various tropical aquatic ecosystems including large rivers (the Amazon, Mekong, and Congo) and smaller streams in Central and South America, southeast Asia, and Africa. Researchers were from institutions including the Woods Hole Research Center, the Stroud Water Research Center, the University of Washington School of Oceanography, and the University of California-Davis.
Small and Pringle hope the results of the workshop will offer a better understanding of how carbon is transported and processed in tropical streams and rivers, and how expected global changes may alter these processes. Results will be reported in a synthesis paper that will be submitted to the journal BioScience later this year and will be followed up by a special session at the Annual Meetings of the American Society for Limnology and Oceanography held in San Juan, Puerto Rico in February 2011.