Student Adam Marko inspects tubs of tadpoles.

Swamp Things

Professor, student take to the bogs to study the effects of pesticides of wetland creatures

It’s just after midnight, and Pitt Professor of Biological Sciences Rick Relyea and his research team, including sophomore ecology and evolution major Adam Marko, can hear the love in the air—a “ribbit” here and a “click” there—which means it’s time to stroll into action.

Call it an amphibian Lover’s Lane, if you will, but Relyea and his team know what they’re getting into as they pull on green rubber waders that should keep them dry to their armpits.

Actually, it’s a swamp, part of a 130-acre farm along Pymatuning Lake that has been converted into a field station called the Pymatuning Lab of Ecology for Pitt’s Department of Biological Sciences. On this particular night, the researchers follow the sounds and dip nets into the murky water in hopes of catching these amorous creatures.

Their quest: mating frogs.

Of course, they find the water, filled with the sulfurous scent of the lake, freezing cold and the mosquitoes unrelenting. The mud—lots of it—manages to slosh over the top of waders and into their shoes. But Marko says he wouldn’t have it any other way.

After all, Marko, who has been trudging through swamps for fun since early childhood, and the rest of the team are embarking on a serious, research-driven egg hunt, which begins with finding the actual frogs. During mating, the females release tiny eggs into the water, which the males then fertilize externally.

But finding the eggs on their own proves next to impossible, so, instead, the researchers find the frogs, place them in tubs, and then collect all the eggs in the tub before releasing the frogs the next day.

Of predators and pesticides

For the researchers, this egg-gathering exercise represents only the beginning of a series of experiments that takes on a much more serious tone back in the lab. That’s where they await the eggs’ transformation into tadpoles, which become the beginning of research that explores the effects of pesticides.

In one experiment, Marko tested Relyea’s hypothesis that pesticides become much more deadly when animals smell predators. He placed five species of tadpoles in 80 tubs of water, alongside newts (which he fed every other day) that were placed in screened cages. Then he added low concentrations of pesticides. He began with 10 tadpoles in each tub, and every morning he would examine the tubs, with clipboard in hand, counting to see how many were alive in each tub.

The question: Do these pesticides become more lethal when the amphibians smell predators? The answer turned out to be that, in some species, pesticides become two to four times more deadly.

Rick Relyea

Swamps, not sports

Relyea hired Marko at the end of his freshman year through a Pitt work-study program called UROP, or Undergraduate Research Opportunity Program. Relyea says Marko was hired on the basis of his exceptional grades, mature attitude toward research, ability to easily relate to Relyea’s research, and love of the outdoors.

Marko admits that he has been wading in swamps for years. While other kids were out playing sports, Marko could be found at a nearby swamp peeking under rocks for interesting animals. Some things apparently never change, according to those who work with him in Relyea’s lab. His claim to fame so far is having trapped a muskrat, along with giant black bugs called Dytiscid beetles, which are about three inches long.

“They’re kind of rare, but they’re neat to see,” Marko said. “It’s hard to believe there’s an insect that big swimming in Pennsylvania.”

Marko came to Pitt largely because of the Pymatuning lab field station, which includes hundreds of small ponds and wading pools, and because Pitt’s Department of Biological Sciences offers an ecology and evolution subfield. Marko says he set his sights on biology after attending his first Envirothon, a continent-wide written ecology competition, while in ninth grade. Marko’s team always made it to the state level.

Said Relyea of the hands-on research experience he gives his students: “I try to teach by example. I’ve been involved with about 25 undergraduates in the last four years. I hope it’s working.”

As far as Marko is concerned, the experience—especially the field station—is working well … except for one small problem.

“There are mosquitoes everywhere,” he lamented. “You can hear them while you’re trying to sleep. And there’s no way of getting around it, so you have to wear a lot of clothing. I try to keep on a long sleeve shirt and pants, but you get so hot because it’s humid. But it’s only for two weeks, so it’s not so bad.” • AP