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What can studying the metabolism of bacteria that inhabit nine streams in the New Jersey Pine Barrens, Chester County's rolling hills, and the mountains of Costa Rica tell us about global warming?
Right now nobody knows for sure, but the Stroud Center's Senior Research Scientist Lou Kaplan thinks that one day the answer could be, "Plenty."
In search of the answer to that and other questions, Kaplan assembled an interdisciplinary team of scientists from across the country to study the structure of organic molecules and the species composition of bacteria in streams. They are now at about the halfway point of a three year, $1.4-million grant from the National Science Foundation.
Using a variety of cutting-edge techniques, Kaplan, Patrick Hatcher of Ohio State University, David Stahl of the University of Washington, Robert Findlay of Miami University of Ohio, and Margaret Palmer of the University of Maryland are trying to determine if different species of bacteria from different biological areas (or biomes) perform similar functions in breaking down organic matter that enters a stream. The implications of their search for what they call "functional redundancy" are enormous, because the ability of bacteria and other microorganisms to degrade organic molecules is a critical aspect of ecosystem function. Simply put, it is how nature purifies water.
As humans turn more and more from chemical to biological filtration systems to purify their drinking water, treat their wastewater, and decontaminate their groundwater, they need a better understanding of how the organisms actually function. Kaplan's team is investigating such questions as: Do different species of bacteria in different biomes perform the same function? If so, can species from one biome be put to work in another? What determines if an organic molecule or compound is biodegradable? Because bacteria appear to work in consortia to break down organic matter in water, what is involved in the complex process of transferring them from one biome to another?
Kaplan's team is studying one primary (and two secondary streams) in three very different regions: McDonald's Branch in the Pine Barrens; White Clay Creek in Chester County; and Rio Tempisquito in Costa Rica.
McDonald's Branch runs through a white cedar bog on New Jersey's coastal plain. As a result, its water has high acidity, low amounts of dissolved oxygen and high levels of organic carbon. White Clay Creek, in the hills and deciduous woodlands that characterize the Pennsylvania Piedmont, has extremely high levels of nitrogen, due primarily to the intensive farming practices on the surrounding land. Finally, Rio Tempisquito is found in a tropical evergreen forest in the Costa Rican mountains. Despite being surrounded by lush forests, the river has some of the lowest concentrations of dissolved organic compounds measured anywhere in the world.
By studying how each river's microorganisms fare when transported to such different biomes, the scientists hope to better understand how the metabolizing functions work. This should shed new light on our efforts to clean up our water. In the search for knowledge about how ecosystems process organic carbon, Kaplan also hopes to gain new insights into the origins and fates of the organic pools in the earth's oceans. Produced by the organic matter that flows through our rivers, these pools of dissolved carbon have a significant aggregate impact on global carbon cycles, which are believed to be a significant source of global warming.
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A section of the Rio Tempesquito in Costa Rica. |
