Most ecosystems are viewed as driven by photosynthesis deriving from plants within the system's boundaries. Lakes in particular are textbook examples of how algae and aquatic plants support food webs including fish. Yet, plant production is often a poor predictor of fish and invertebrate production. Ecologists have long known that lakes receive significant inputs of organic matter from their watersheds. Recent work demonstrates that this terrestrial organic matter is potentially available, suggesting terrestrial organic matter may be significant in supporting lake food webs including top carnivores. This project will address this question by a series of whole lake additions of a stable isotope of carbon which will produce a strong contrast in isotopic composition between terrestrially-fixed carbon and carbon fixed by aquatic plants. Through a combination of stable isotope addition experiments and computer modeling, this research will provide an ecosystem-level test of the importance of the connections between terrestrial organic matter and aquatic food webs.
Abstract
00-75111 Hodgson
Collaborative Research: Alternative carbon sources for lake food webs
Most ecosystems are viewed as driven by photosynthesis deriving from plants within the system's boundaries. Lakes in particular are textbook examples of how algae and aquatic plants support food webs including fish. Yet, plant production is often a poor predictor of fish and invertebrate production. Ecologists have long known that lakes receive significant inputs of organic matter from their watersheds. Recent work demonstrates that this terrestrial organic matter is potentially available, suggesting terrestrial organic matter may be significant in supporting lake food webs including top carnivores. This project will address this question by a series of whole lake additions of a stable isotope of carbon which will produce a strong contrast in isotopic composition between terrestrially-fixed carbon and carbon fixed by aquatic plants. Through a combination of stable isotope addition experiments and computer modeling, this research will provide an ecosystem-level test of the importance of the connections between terrestrial organic matter and aquatic food webs.
