Wisconsin Sea Grant Frogs: Cool Science
Why Study Frogs?
We interviewed Bill Karasov, a UW-Madison Professor
and Wisconsin Sea Grant researcher interested in wildlife toxicology (the
study of how toxins in the environment
Q: What is an example of the kind of research
studies your students work on?
A: Graduate student Robin Jung is checking tadpoles
inside an enclosure that she placed in a wetland along Green Bay, Wisconsin.
As an experiment, Robin collected eggs of frogs and put
them in enclosures placed in wetlands that are either relatively clean
or relatively contaminated. Do you think that eggs and tadpoles do better
in less contaminated environments?
Q: Why study frogs?
A: The eggs, larvae and adults are food for many
fish, birds and mammals. When amphibians are contaminated, they pass toxins
along to their predators.
When amphibians disappear, this can affect those other animals.
And, like the miners' canaries, a decline in amphibians is like a red
flag, warning us that something is wrong with the environment that we
all share. Finally, many of us have an ethical sense that we should protect
life on earth as best we can.
A special note to you, our readers: How can I help?
Do you want to help scientists learn more about disappearing frogs? If
you find a deformed frog, be sure to write down the exact location of
where you found it, make
a copy of this form from the North American Reporting Center for Amphibian
Malformations and send it to Bob Hay, Cold Blooded Species Manager, Wisconsin
Department of Natural Resources, 101 S. Webster St., Madison, WI 53707-7921
Q: What research projects
are you working on now?
A: I am interested in wildlife toxicology, the study
of how toxins in the environment affect wildlife. We
are studying whether frogs living in a contaminated ecosystem lay eggs
that will hatch normally into tadpoles that grow and mature normally.
We are especially interested in whether the sex organs (gonads)
of frogs that metamorphose from tadpoles
growing in the contaminated ecosystem are normal. This is because some
contaminants in the environment are thought to disrupt sexual development.
In the laboratory we are testing some of these chemicals for their effects
Q: How do you conduct your research?
A: We study leopard frogs
(Rana pipiens), green frogs (Rana clamitans), and American
toads (Bufo americanus). We picked them because they are common enough
in the ecosystem that we can reliably find them to study, and we know
that if we collect some we are not harming their populations.
We collect eggs of these frogs and put them in enclosures
placed in wetlands that are either relatively clean or relatively contaminated.
This way we can study what happens right in the natural environment. We
also collect eggs and adults and bring them to the laboratory where we
expose them to known amounts of certain chemicals. We make many measurements
on them, such as how many hatch, how fast they grow, how long it takes
them to metamorphose (turn from tadpoles
to frogs), how much chemical ends up in their bodies, whether their organs
are normal, and how some enzymes in their bodies react to the chemicals.
Q: What tools and technology do you use?
A: We use microscopes to look closely at tissues,
centrifuges to separate and isolate specific parts of cells of tissues,
spectrophotometers to measure amounts of contaminants or levels of enzymes
in tissues, chromatography to measure amounts of certain chemicals or
proteins, and computers to analyze all the data.
Q: What advice would you give a student interested
in your field?
A: This is a really interesting and exciting field
for those who love biology and are concerned about protecting wildlife
and the environment.
If you want to help advance knowledge about wildlife toxicology
it is best if you study both natural history and fundamentals of modern
biology and its techniques. You should like studying new things, because
we are always learning more and more through science, and even professional
scientists have to keep learning to keep up!
copyright 2001 University
of Wisconsin Sea Grant Institute