For 20 years, biology professor Keith Grasman has studied the effects of pollution on Great Lakes gulls, herons and terns.
Researching Great Lakes waterbirds from Calvin College on Vimeo.
On their way to the island, biology professor Keith Grasman and his team of student researchers passed a line of smokestacks towering over the channel. They reached the Saginaw Bay as a gravel barge trundled by, en route to one of the industrial sites in Bay City.
As they neared the island, Grasman slowed the boat and senior Alyssa Moore pointed out a colony of large birds nesting in the island’s dead trees. “Those are cormorants,” she said. “They remind me of The Lorax.”
The team dropped anchor and rowed ashore, hauled the rubber dinghy onto the breakwater and climbed up to the island. Several thousand birds lifted into the sky at their approach.
Nests filled with eggs and chicks were hidden under the low canopy of mustard plants, clover and stinging nettle. Bird carcasses in various states of decomposition were scattered among them. “There’s lots of death on these islands,” Grasman said.
The researchers laid their equipment at the base of the hill and ran up to where they had fenced in a group of Caspian Tern chicks they had first encountered four weeks ago. They chased the chicks around the enclosure, stuffing them into bags the size of pillow cases. When all 11 were caught, the team descended the hill, hunkered down in the shelter of a few tall bushes and set to work.
Twenty years with waterbirds
For 20 years, Grasman has studied the effects of pollution on Great Lakes colonial waterbirds, focusing on three species: Herring Gulls, Black-Crowned Night Herons and Caspian Terns. By testing these birds, he provides the data needed to guide cleanup efforts and inform government agencies, like the U.S. Fish and Wildlife Service which sponsors his work, of the magnitude of the problem.
Colonial waterbirds are exposed to pollution when they eat contaminated fish. But the gulls and terns that make their homes on the CDF are affected much more directly. Bay City’s channel conducts a high volume of cargo ships, whose deep drafts require the channel to be regularly dredged. The resulting sediment is thick with industrial chemicals like polychlorinated biphenyls (PCBs).
Considered too toxic to be brought inland, the sediment is dumped on the island.
Many of the island’s birds display symptoms of Great Lakes embryo mortality, edema and deformity syndrome (GLEMEDS), responsible for immune system deficiencies and birth defects like crossed bills.
Feisty research subjects
Crouching among the weeds, sophomore Sylvia Fuhrman and senior Will VandenHeuvel unpacked their rulers and forceps to measure each chick’s growth. To take body mass, VandenHeuvel attached a drop scale to each bag and waited for the flustered occupant to settle down. “Five-hundred-twenty g (grams) for this guy,” VandenHeuvel announced when the bag had stopped jumping.
Still two weeks from fledging, the chicks were roughly the size of submarine sandwiches, their caps speckled and gray. They bit, kicked, defecated and occasionally spat up whole fish as Fuhrman and VandenHeuvel passed them around. “Where did this come from?” Fuhrman asked when she discovered a two-inch long minnow in her lap.
After measuring each bird, Fuhrman passed it on to Moore and Grasman for blood sampling. Moore covered the chick’s body with a bag, leaving one wing exposed. Grasman then rubbed at the downy feathers to reveal the pink skin with purple veins underneath. Using a standard medical syringe, Grasman took only one percent of each chick’s body mass in blood; the percentage is important because drawing too much can be fatal.
“These little guys turn into absolutely majestic birds,” he said. Caspians, the largest terns in the world, can live up to 30 years, migrating from the Great Lakes to Central and South America every year.
Witnessing the effects of industrial pollution
One chick Grasman and Moore worked on was having difficulty with blood clotting. Grasman believes this common and potentially fatal condition is caused by the bay’s pollution. The mortality rate in the colony is high. Of the 61 terns fenced at the beginning of the study, only 20 have survived. Still, the Caspians fare better on average than the Herring Gulls.
Grasman directed VandenHeuvel to take the bird back to the enclosure. Separating it from the researchers would bring its blood pressure down, he believed. (By the end of the day, the bird had recovered.)
Once the process of measuring and taking blood samples was finished, the team returned the rest of the chicks to the enclosure and repeated the process on the second group.
Centrifuges and nitrogen tanks on the road
After more than three hours on the island, the team rowed back to the boat. They had three-and-a-half more hours waiting for them on the mainland. “This is more of the delicate side of the field work,” VandenHeuvel said.
Back at the truck, the team would spin the samples in a generator-powered centrifuge, isolating the blood’s constituent parts. The researchers would then freeze the vials in liquid nitrogen and take them back to the lab to be cultured, revealing more about the birds’ immune functions. Through cryopreservation, Grasman’s team is also able to create a physical history that can be studied in the future—“In case we come up with some fantastic tests to run on them,” Fuhrman explained.
Grasman discovered his passion for wildlife toxicology as a student at Calvin on a similar summer research project. After instructing graduate students at Wright State University in Ohio, Grasman returned to Calvin to lead his own summer researchers. “When I moved back to Calvin,” Grasman said, “I realized our undergraduates can function a lot like graduate students. … Clearly we couldn’t do the project without them.”
The team’s research has been unpredictable and demanding. Their sites ranged from the coast of Lake Erie in Monroe, Mich., to the islands around De Tour in the Upper Peninsula. Weather dictated when they departed for the field and how long they stayed; the three students were constantly on call.
For VandenHeuvel, the job description was ideal. “I want to do this job when I’m older, but in Costa Rica with the wildlife there,” he said.
The past month-and-a-half has been instructive for Fuhrman. She has yet to choose a career path, but believes the fellowship has provided insight into her options as a biologist.
Moore, who is anticipating a career in veterinary medicine, found beauty in the close contact with animals afforded to her by the fellowship: “To actually hold part of creation just made me respect it even more, and I have a tangible reason to protect it.”
As Grasman moves into his third decade leading colonial waterbird research at Calvin, he is watching global use of industrial chemicals rise in tandem with global population. Research into how those chemicals affect not only individual species but whole ecosystems is essential in his mind. That Calvin should be involved seems obvious to him: “From a big picture perspective, many people at Calvin are concerned about caring for the environment. Bird research is one way of doing that.”