Two Oklahoma researchers are studying a type of plankton in Minnesota lakes they say could offer clues about how plants and animals adapt to changes in their environments caused by human activity.
Larry Weider, a biology professor at the University of Oklahoma, and Punidan Jeyasingh, a zoology professor at Oklahoma State University, will work with a Minnesota researcher to look at daphnia, a small freshwater crustacean that lays eggs that can lie dormant on lake bottoms for decades or even centuries.
The project, which is funded by a $229,267 grant from the National Science Foundation, is a continuation of years of work Weider and Jeyasingh have conducted.
The project will allow researchers to get a better look at how daphnia changed as the area around the lakes became more heavily populated and industrialized, Weider said. During the project, researchers will take soil samples from Minnesota lake beds and separate each sample by time period, he said.
Researchers will then hatch daphnia eggs they find in the soil, giving them daphnia specimens that date to times before European settlement, when the area was more sparsely populated by American Indian groups, Weider said.
Researchers can then look at genetic markers to see how daphnia adapted to cope with changes to the lakes where they lived, including changes brought about by agriculture and industry.
In particular, researchers are interested to see what happened to daphnia when phosphorous levels in the lakes began to increase because of chemical fertilizer runoff, Jeyasingh said. Phosphorous is critical for the plankton to survive, but it was relatively scarce before agriculture began to change the chemical content of the lakes.
Based on previous research, Jeyasingh said he expects to see more modern daphnia make less efficient use of phosphorous than the samples from centuries ago as phosphorous became more plentiful.
A good way to think about it is to imagine $100 bills fell from the sky every day, Jeyasingh said. Cash would be easier to find, so people would be less worried about how they spent it.
“Nobody is going to be budgeting their money as well as they do now,” he said.
Looking at how daphnia evolved as their ecosystem changed could give researchers a better idea of how human activity affects organisms more broadly.
The impact of humans on ecosystems themselves has been well researched, Jeyasingh said. But how the organisms in those ecosystems adapt to their new surroundings isn't as well understood, he said.
Understanding those adaptations is important, he said, because when an ecosystem like a wetland is changed or contaminated, researchers can restore that ecosystem to some extent. But they can't undo the changes organisms have undergone to deal with the new ecosystem.
“Not many people are looking at the evolutionary implications of global change,” Jeyasingh said. “You can't just restore an ecosystem after it's damaged by going to Lowe's and getting a bunch of trees and planting them.”