BLOOMINGTON, Ind. -- Of all the things that might control the onset of disease epidemics in Michigan lakes, the shape of the lakes' bottoms might seem unlikely. But that is precisely the case, and a new BioScience report by scientists from Indiana University Bloomington and four other institutions explains why.
"In the paper, we go through several explanations for what is going on," said IU Bloomington biologist Spencer Hall, the report's lead author. "We are looking at the zooplankton that is infected, the fish and other creatures, the ecology, the limnology, and even the physics. Of all those explanations, the shape of the lake basins was the most powerful factor."
Also contributing to the report were scientists from the University of Illinois at Urbana-Champaign, the National Science Foundation, the University of California at Santa Barbara, and the Georgia Institute of Technology.
"This paper is a synthesis of research on a model system for the study of disease ecology," said Alan Tessier, coauthor and program director in the NSF's Division of Environmental Biology. "It combines limnological, epidemiological, ecological and evolutionary perspectives to address a general question about the occurrence of epidemics in nature. It illustrates the value of interdisciplinary approaches to understanding the emergence of patterns in systems of complex biotic and abiotic interactions."
The disease in question is caused by a fungus that infects Daphnia dentifera, the water flea that plays a critical "grazer" role in many freshwater lakes of the American Midwest. Recent research by Illinois biologist Carla Cceres, Hall and others shows the epidemics usually start in late summer or early fall.
The fungus slowly consumes the tiny crustacean's blood (hemolymph) and produces spores that fill all that remains. For the fungal spores to make it to the next potential host, the Daphnia host's exoskeleton must be
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