Editor’s note: Full-length version of story.
Calanus finmarchicus are succulent little butterballs. Simply scrumptious to a whole host of marine animals.
No bigger than grains of rice, the translucent crustaceans that look like a cross between a crayfish and a flea gorge on spring phytoplankton blooms and microzooplankton in the ocean to bulk up with energy-rich lipids. It’s those lipid reserves that make the planktonic copepods particularly delectable — and power-packed.
In the northern Atlantic Ocean, C. finmarchicus is the primary prey for a range of species — fueling schools of herring and powering pods of endangered northern right whales. This and other Calanus species are such vital intermediary links in the marine food web that changes in their populations could profoundly affect the health of marine animals — from leaner fish of lesser value to fewer whale calves — and the structure of the pelagic ecosystem in northern oceans.
That’s why Andrew Pershing and Jeffrey Runge study them. The two research scientists, who hold joint appointments with the University of Maine and the Gulf of Maine Research Institute, consider C. finmarchicus a linchpin whose role must be better understood in the face of growing ecosystem variability and environmental change.
“Arguably copepods are the most abundant multicellular animals in the world, yet most people don’t know much about them,” says Runge, a biological oceanographer. “Calanus finmarchicus is among the most predominant of the copepods in the North Atlantic, including the Gulf of Maine. If its special capacity to produce large amounts of lipids were substantially reduced here, what would be the impact on species like herring, sand lance, mackerel, and the rest of the system? It could have implications for the region’s fisheries in the future.”
Runge studies ocean ecosystem productivity. He focuses on the physical and biological factors that can affect zooplankton production — from variable ocean currents and temperatures to the growth and survival of fish larvae.
Pershing focuses on what causes changes in the Gulf of Maine ecosystem over time. He uses satellite and other data to develop computer models of marine ecosystems that can reconstruct and forecast population dynamics in C. finmarchicus and other key species.
For both scientists, the implications of climate changes on C. finmarchicus, such as warmer water temperatures and acidification, loom large.
“There are huge changes going on in the marine environment,” says Pershing. “Some of them are natural. We’ve always had changes in the climate. But then on top of that, we’re adding this new signal of global warming and climate change. What effect that’s going to have on ocean ecosystems is really important, both for understanding fisheries and the way humans interact with these systems, and for understanding the ocean’s ability to take carbon out of the atmosphere and lock it away. The big question for me is really all about change: how things shift from one year to the next and what drives that.”