Preparing for a Sea Change

by Ela Schwartz

Biodiversity and Heavy Metals in the Salt Marshes

What do you envision when you hear the word “shore”? Most likely a sandy beach with splashing waves, not a salt marsh. But look through the eyes of Matthias Foellmer, Ph.D., associate professor of biology, and you’ll see that these areas are the homes of a myriad of life forms: marsh grasses stirred by breezes, mussels exposed in the low tide and migratory birds stopping by to grab a meal before continuing on their way inland. Look closer and you’ll see the many species of what Dr. Foellmer refers to as “small animal biomasses you can hardly see, like crabs, insects and spiders.”

Known as arthropods, these creatures are a specialty of Dr. Foellmer, who is leading students in research that examines the influences of humans on invertebrate populations in wetlands along the South Shore of Long Island.

He explains that what makes Long Island’s salt marshes unique is that they are “isolated and disturbed.” Suburban sprawl has decimated the swaths of salt marshes once prevalent on our coasts. The result is secluded patches where these tiny creatures cannot travel from one habitat to another. Concurrently, these patches are being damaged by pollution due to their proximity to densely populated urban/ suburban developments.

One of Dr. Foellmer’s undergraduate students, Carolyn Trietsch ’12, extensively surveyed three isolated salt marsh patches still attached to the mainland. She and Dr. Foellmer used pitfall traps, beat sheets and sweep nets to whisk insects from vegetation. In Summer 2011, Ms. Trietsch even received a stipend from Adelphi’s McDonell Fellowship to pursue this research with Dr. Foellmer. “We are still in the process of identifying these creatures in the lab,” he says. After this phase is completed, Ms. Trietsch, now a master’s candidate at Adelphi, will analyze the data. Hypotheses to explore include the possibility of differences in genetic structure in populations or identifying ones that are extinct in one patch but not in others.

Another of Dr. Foellmer’s students, Andrew Vacca, M.S. ’12, analyzed the effects of heavy metal bioaccumulation in invertebrate food webs consisting of plants, small insects and wolf spiders. “What he found is that wolf spiders heavily accumulate methylmercury, which is highly toxic,” Dr. Foellmer explains. Toxicity can lead to neurological, behavioral and reproductive impairments. Despite his own fascination with spiders, he is well aware that they don’t make the best poster children to inspire most of us to be more environmentally conscious. But what about the birds who prey upon the spiders? “The accumulation of mercury in spiders is a threat to them as well as the animals that eat them,” he says, “and other studies have shown that semi-aquatic wolf spiders are the means by which aquatic methylmercury can move up to terrestrial food webs.”

Pioneering Conservation Physiology

From tiny arthropods, we travel up the food chain to the large, marine mammals known as pinnipeds, which include the seals and sea lions studied by Heather Liwanag, Ph.D., assistant professor of biology.

Unlike smaller animals, such as the geckos Dr. Liwanag also studies, these long-lived mammals “are not going to adapt or evolve as rapidly, and a lot of them are in trouble. So we need to figure out how to keep them with us, and not just in zoos,” she says.

A whitecoat harp seal photographed by Linnea Pearson.

Dr. Liwanag is active in what she calls the “upand- coming” field of conservation physiology, which looks at how animals physiologically respond to environmental changes. “The common thread in my research is critical temperature,” she says, meaning the maximum and minimum temperatures organisms can tolerate before having to adjust their physiology.

Another question she seeks to answer is: “How fast does a seal’s fur grow back?” Why? Because researchers glue data tags to the seal’s fur, then cut the seal’s fur to remove the tag. “No one has looked at how the loss of fur may compromise the seal’s ability to insulate itself, including when it dives for food into higher pressures,” she says. Dr. Liwanag raised the funds to purchase a small hyperbaric chamber that re-creates the higher pressures that occur underwater so that she and her students can insert pelts and measure the amount of water that can penetrate the fur under pressure.

Dr. Liwanag is also collaborating with Linnea Pearson, a Ph.D. candidate at the University of Alaska Anchorage, to study insulation in harp seals from birth to adult and how this relates to environmental temperature changes. She explains that baby seals are born on the Arctic sea ice and nurse for only 12 days before they are abandoned by their mothers. They fast on the ice for another four to six weeks. “When they are first born, they have very little blubber and instead rely on thick, fluffy fur to keep warm,” Dr. Liwanag explains. “As the blubber develops, their fur changes from the thick pelage they had at birth to a thin, more streamlined…pelt like the adults have.” If there isn’t enough ice for these seals to sit on while they develop, they’ll be forced to venture into the water before they’re physiologically ready to withstand the icy temperatures.

In addition, if the waters seals inhabit become warmer and the sea ice continues to recede, these creatures may need to maintain their body temperatures by raising their metabolism, which requires them to increase food intake. If food sources are no longer plentiful, they must expend energy to forage. “So it’s a downward spiral,” she says.

In the future, Dr. Liwanag hopes to apply her research on critical temperatures to polar bears. “The ice is receding at rates not predicted in even the most liberal of climate models,” she says. “Polar bears are spending more time swimming, and we have no idea what their thermal capabilities are in water. I’m hoping to work with captive polar bears in zoos to look at lower critical temperatures in water and acquire data that will help us understand how [climate] changes are going to affect them.”

Budding Science Teachers Get Their Feet Wet

 Author and conservationist Rachel Carson wrote in A Sense of Wonder: “By suggestion and example, I believe children can be helped to hear the many voices about them. Take time to listen and talk about the voices of the earth and what they mean—the majestic voice of thunder, the winds, the sound of surf or flowing streams.”

It’s a sentiment echoed by Tracy Hogan, Ph.D., associate professor in the Ruth S. Ammon School of Education, who says graduate students enrolled in the School’s selective Science Education Advancement (SEA) program are learning how to “use the natural world as a classroom and become interpreters of the waters.”

SEA is funded by a $1.2 million National Science Foundation grant and provides generous annual stipends to participating scholars. Dr. Hogan says the program provides hands-on opportunities for students by offering two field-based or, rather, water-based summer programs.

For five days Lou Siegel, a part-time professor in Adelphi’s environmental studies program, takes students to such locales as Rockaway Beach in Queens, Jones Inlet on Long Island’s South Shore and Hempstead Bay (via kayak) to test waters, identify organisms and observe urban ecology.

The students also participate in a three-week paid internship with the Nassau County Board of Cooperative Education Services (BOCES) Summer Marine Biology Program. Adelphi students take kids in grades kindergarten through 12 on the waters of the North and South Shores, where they learn to evaluate water quality and fish and plant populations.

Dr. Hogan says, “These programs allow our graduate students to work like scientists and then think as teachers. They learn to understand the water environment around Long Island, and then how to plan a lesson or field trip to transfer their knowledge to the kids.”