Tiny crustaceans endure extremes

Researcher joins WSU to study how organisms cope with living in challenging environments

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Tiny crustaceans endure extremes

TEVA MAYER | The Daily Evergreen

TEVA MAYER | The Daily Evergreen

TEVA MAYER | The Daily Evergreen

TEVA MAYER, Evergreen managing editor

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Aquariums gurgle inside closed labs as Wes Dowd navigates the marine science wing of Heald Hall.

Dowd, an associate professor of environmental animal physiology, will spend the next three years studying copepods, microscopic crustaceans that live in intertidal pools. He will research how their unique biochemistry allows them to tolerate and live in their changing habitat.

His voice echoes as he makes his way down a hall lined with metal doors and enters his lab.

“The cool things about these guys,” he says, pointing to rows of small glass containers housing hundreds of tiny copepods, “is that they do their whole life cycle so fast. Understanding the effects of the variation over the course of a whole individual’s life can be completed in the amount of time that a graduate student or an undergraduate is actually here.”

They already have some idea of how the organisms cope with their highly variable habitat, Dowd says. He offers the example of osmolytes, compounds in the copepods’ bodies that protect against salt and heat stress by maintaining the structure of proteins and membranes.

The idea for the study came during one of Dowd’s field seasons at Hopkins Marine Station in Monterey Bay, California. His past research in intertidal zone ecology and his summers in the field led him to the splash pools of the upper shoreline, where he became aware of the copepod system.

Splash pools, he explains, are small puddles of salt water high on the shore, where they are rarely exposed to the ocean’s tides and spray. The copepods spend their entire lives in these pools, subject to extreme spectra of temperature, salinity, pH levels and oxygen concentrations.

“They have incredible tolerance,” he says, holding up one of the jars of spasming copepods. “All these ideas were building in my head of what a neat system it would be.  Other people have done a lot of genetics, and some physiology, but not in this way.”

Dowd’s childhood in Virginia, close to the Chesapeake Bay, gave him access to the ocean and marine life. He recalls feeling driven from a young age to understand how things work.

“I actually had a book when I was a kid called ‘The Way Things Work’,” he says.  “I was really interested in kind of taking things apart, and physiology is as close as you can get to that and the life sciences.”

During college, he found himself on a pre-med track, headed for a career as an orthopedic surgeon.  It wasn’t until he was a junior that he realized he did not like working in hospitals. After taking a summer course at a marine lab, he says, it clicked that he could spend the rest of his life doing similar work. Nevertheless, he graduated and enrolled in an environmental science and policy program.

“I was there for two weeks — this doesn’t sound like a great model for how you should do it,” he laughs. “I started this program and I was just incredibly bored with it after about two weeks, so I sort of shopped around and took a course in fish biology and fishery science.”

The project he conducted through the class landed him a position in a lab as a graduate student.

“I jumped ship, switched to a different program and was all of a sudden studying animal physiology [with] sharks in Virginia,” he says. But while sharks are charismatic and shark research can land a spot on the Discovery Channel, studying them would not allow the lab research he wanted to pursue.

He soon found himself in Antarctica, as a post-doc student at Stanford, where he studied the heat-stress tolerance of fish that had evolved to withstand sub-freezing water temperatures.

“I haven’t actually finished the project,” he says with a laugh. “Science is like that … life happens and you start other projects. Things are always there and you do the ones that seem the most important at the time.”

Research on the intertidal zone — specifically, how physiology allows for variation in body temperatures between individual mussels and neighboring mussel patches — took priority as Dowd moved on to teach at Loyola Marymount University. His interest, fueled by the variation between organisms and environmental factors in these shoreline microhabitats, never ceased.

“Physiologists for a long time have been concerned in the laboratory with reducing variance and reducing error,” he explains, “but in nature that’s the most important thing, the variation. So that’s what we’ve been trying to kind of tease apart.”

His fascination is evident as he holds a tiny glass tube up to the light of his lab, looking for a copepod.

“So that’s a female with an egg mass,” he says, pointing out the swimming crustacean and the dark mass of eggs she will carry until they are ready to hatch.

Dowd came to WSU with copepod research in mind, citing the university’s concentration of qualified professors and departments as a reason he committed to the move from Los Angeles.

“It’s really got the whole mix of expertise that I’ve been trying to draw on over my whole career all in one place,” he says, evident in his recruitment of electrical engineering students for the construction of the computer that will control the variables in the copepod study.

He adds that the drive to the Washington coast isn’t a hindrance — his commute to the shore while at LMU was the same length.

Kat Anderson, a University of British Columbia postdoctoral researcher, has helped Dowd get the copepod research up and running. Anderson says her interest in intertidal environment variability grew during her thesis research.

“I realized we don’t have a good sense yet about how animals respond to fluctuation,” she says, moving aside a mug with an octopus tentacle as its handle, to pull up graphs of temperature and carbon dioxide cycles in tide pools. She explains that an understanding of how organisms deal with variability now could help predict how they will react to future environmental changes.

Her current task in the Dowd lab is to develop a way to keep the copepods in isolated chambers, hooked up to a larger aquarium with carefully controlled temperature, salinity, pH and oxygen to mimic natural, daily cycles.

The chamber, she explains, would be enough space for a female copepod to start reproducing. Analyzing a copepod’s reproductive behavior is a good proxy for overall fitness.

“We can get an idea of her reproductive output, how long she lives for,” Anderson says, “and then we can also take her out and measure things like her activity levels and her respiration rates.”

Down the hall from the copepod lab, Dowd sits in an office crowded with physiology and biology textbooks.

“Once you figure out all the problems, then it’s just data collection,” he says. “The fun and difficult part is figuring out how to do all these things in the first place.”