A building block of life, organic carbon is essential to aquatic food webs. In lakes, aquatic plants produce organic carbon by harnessing the sun's energy (photosynthesis); some of this carbon supports the growth of fish and invertebrate populations. Scientists have long suspected that organic carbon from land is also significant to aquatic life but this idea is difficult to demonstrate. By tracing the fate of carbon through large-scale lake manipulations, Pace, Cole, and colleagues have revealed that in some water bodies the aquatic food web is significantly subsidized by terrestrial organic carbon.
That maple tree leaves many eventually become perch, and that the vegetation around a water body can have profound impacts on the animal life within the body of water-- both blur the perceived ecological boundaries between aquatic and terrestrial systems.
The impetus behind the study, which involved manipulating two Michigan lakes, was a better understanding of the aquatic food chain. Pace explains, "We wanted to reveal what many ecologists have long thought- aquatic life is partly dependent on organic matter produced in the watershed." Using a chemical tracer, Pace and his colleagues set out to quantify this assumption. "The moral of the story," Pace comments, "is, yes, fish are made from algae, but fish are also partly m
Contact: Lori M. Quillen
Institute of Ecosystem Studies