Pollution makes crustaceans adapt rapidly

September 29, 1999

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 Plön, 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.

In Hairston's Cornell laboratory, researchers already had learned how to awaken 300-year-old crustacean eggs. Working at Lake Constance, the biologists needed to go back only 37 years, beginning with Daphnia eggs that were deposited on the lake bottom in 1962, to trace the clever crustaceans' evolution. They hatched Daphnia eggs that piled up year after year in sediments, then reared the crustaceans to adulthood in the laboratory and offered them cyanobacteria from the lake. Cyanobacteria produce high concentrations of the hepatotoxin, microcystin-LR.

Daphnia with 1960s genes -- before Lake Constance became so polluted and cyanobacteria were so plentiful -- couldn't stomach the modern meal. But by the late 1970s -- just a decade later -- Daphnia had become much more adept at living on a diet laced with the toxic algae. And Daphnia hatched from eggs deposited between the 1980s and the 1990s were found to retain this ability.

DNA tests of Daphnia grown from eggs that were deposited over the years revealed that crustaceans that couldn't cope easily with cyanobacteria were virtually eliminated from the population; all that remain today are cyanobacteria eaters, even though the toxic bacteria still aren't particularly nutritious.

"Strong natural selection can lead to rapid changes in organisms, which can, in turn, influence ecosystem processes," the biologists concluded in their article.

Other authors of the Nature report, titled "Dormant eggs record rapid evolution," are Lawrence J. Weider, Max Planck Institute for Limnology; Ursula Gaedke, Limnology Institute, Universiy of Constance; Cami L. Holtmeier, David M. Post and Jennifer A. Fox, graduate students in ecology and evolutionary biology at Cornell; Janet M. Fischer, postdoctoral fellow at Cornell; and Carla E. Caceres, a former graduate student in Hairston's laboratory and now a biologist at the Illinois Natural History Survey's Center for Aquatic Ecology. At Cornell, Hairston (pronounced "HAHRS-ton") is the Frank H.T. Rhodes Professor of Environmental Science.

The Lake Constance study was funded by grants from the U.S. National Science Foundation and the German Academic Exchange Service.
Related World Wide Web sites: The following sites provide additional information on this news release. Some might not be part of the Cornell University community, and Cornell has no control over their content or availability.

-- Cornell Ecology/Hairston Lab: http://www.es.cornell.ed u/hairston/hairston.html

-- Max-Planck-Institut für Limnologie: http://www.mpil-ploen.mpg.de/

Cornell University

Related Evolution Articles from Brightsurf:

Seeing evolution happening before your eyes
Researchers from the European Molecular Biology Laboratory in Heidelberg established an automated pipeline to create mutations in genomic enhancers that let them watch evolution unfold before their eyes.

A timeline on the evolution of reptiles
A statistical analysis of that vast database is helping scientists better understand the evolution of these cold-blooded vertebrates by contradicting a widely held theory that major transitions in evolution always happened in big, quick (geologically speaking) bursts, triggered by major environmental shifts.

Looking at evolution's genealogy from home
Evolution leaves its traces in particular in genomes. A team headed by Dr.

How boundaries become bridges in evolution
The mechanisms that make organisms locally fit and those responsible for change are distinct and occur sequentially in evolution.

Genome evolution goes digital
Dr. Alan Herbert from InsideOutBio describes ground-breaking research in a paper published online by Royal Society Open Science.

Paleontology: Experiments in evolution
A new find from Patagonia sheds light on the evolution of large predatory dinosaurs.

A window into evolution
The C4 cycle supercharges photosynthesis and evolved independently more than 62 times.

Is evolution predictable?
An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: how do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again?

Predicting evolution
A new method of 're-barcoding' DNA allows scientists to track rapid evolution in yeast.

Insect evolution: Insect evolution
Scientists at Ludwig-Maximilians-Universitaet (LMU) in Munich have shown that the incidence of midge and fly larvae in amber is far higher than previously thought.

Read More: Evolution News and Evolution Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.