A group of scientists aboard the Coast Guard icebreaker Healy are heading to the Arctic to study an important ecosystem downstream of drill sites in the Chukchi Sea.
Hanna Shoal is a shallow, 30-mile long shelf off the coast of northwest Alaska. It’s one of the Chukchi Sea’s most biologically productive spots and an important feeding area for walrus and bowhead whales. It’s also just downstream of a number of oil and gas leases – including one of Shell’s exploratory drill sites.
“And so anything that goes in the water at the drill sites may end up in this very productive region,” says Carin Ashjian, a senior scientist at the Woods Hole Oceanographic Institute.
Ashjian is one of a dozen researchers participating in a 5-year, $5.6 million dollar study of Hanna Shoal. The Bureau of Ocean Energy Management [BOEM] is footing the bill for the work. BOEM oceanographer Heather Crowley says the data will help inform future policy decisions about the region.
“As they decide on where the energy policy for the outer continental shelf goes in the future, where to potentially sell leases, and for approval of future development and production plans proposed by industry.”
Hanna Shoal has been studied before, but never comprehensively. The team aboard the Healy is planning to look at all aspects of the area’s ecosystem, from the worms that live in the seafloor sediments to the krill in the water column and the currents that push everything around. Lead scientist Ken Dunton says his goal is to understand how that all fits together.
“Not only to understand who’s related to who, who’s eating who, who’s hunting whom, but in the end, how are toxins, whether they be heavy metals or polyaromatic hydrocarbons, going to be transferred through the food web to the highest trophic levels.”
The highest trophic levels being the whales and walrus. Dunton says scientists have a hard time understanding how the Deepwater Horizon oil spill in the Gulf of Mexico changed the food web because they didn’t have baseline data.
“They’re reporting all kinds of interesting responses by the community, but did some of those conditions exist previously? We don’t know,” Dunton says.
Collecting data about Hanna Shoal now, before drilling starts in earnest, should make it easier to understand its impacts later. But there’s a complicating factor: sea ice retreat.
Declining annual sea ice is changing Hanna Shoal’s ecosystem, even as the group tries to establish a baseline. Dunton says that will ultimately need to factor into any model of how human activities are impacting Hanna Shoal.
“Scientists, as nerdy as we are, we have quite a task in front of us, and that’s why we bring to bear young minds, grad students, post docs, to figure out how to separate these two confounding developments.”
The Healy team will spend two weeks sampling on and near Hanna Shoal and then will leave instruments behind to continue monitoring until the ship returns again next summer.
