ITHACA, N.Y. -- When the going gets toxic, the hungry get clever -- very quickly -- say biologists from Cornell University and Germany's Max Planck Institute for Limnology whose study of tough times in a German lake has shown that rapid evolution can influence the environmental effects of pollution.
The discovery, reported in the Sept. 30 issue of the journal Nature, shows that environmental degradation can be reduced when the affected animals evolve quickly, according to Cornell biologist Nelson G. Hairston Jr.
"It appears that ecological events that we think of as occurring relatively quickly -- such as nutrient enrichment of a lake -- can be influenced by the rapid evolution of the animals that are affected," says Hairston, a professor of environmental science. "If these little crustaceans hadn't changed with the times, their kind might not have survived." Hairston co-authored the Nature report with Winfried Lampert, director of the Max Planck Institute for Limnology in Pln, Germany.
In less than 30 years, as Germany's Lake Constance suffered environmental degradation from phosphorus pollution, populations of tiny crustaceans called Daphnia found more and more toxic cyanobacteria (also called "blue-green algae") mixed with their favorite food, a more edible type of algae. So the crustaceans adapted to handle a less nutritious food that would have seriously stunted the growth of their ancestors, and they became one of the important, natural controls for toxic cyanobacteria in the lake.
The research, carried out at the Germany institute, documented the crustaceans' express-style evolution by hatching a series of dormant Daphnia eggs that were found, level by level, in lake-bottom sediments in a state of "diapause." Diapausing animals, such as certain insects and crustaceans, can suspend their growth and development for years or even centuries during periods of unfavorable conditions.