Bates College geology professor Mike Retelle is part of a team of scientists studying climate change through clams that live a long, long time.

Think 300 to 500 years long.

The project, which won a three-year National Science Foundation grant last month, measures water temperature changes over time by examining the growth rings in clams’ shells.

He’s doing a lot of traveling to Norway and packing very warm socks.

Name: Mike Retelle

Age: 61

Lives: Monmouth

Please describe your project a bit: We (my colleagues and our students) are studying the record of marine climate recorded in clam shell growth in northern Norway. Our field site in northernmost Norway is along the northern extent of the North Atlantic Drift (Gulf Stream), which has migrated north beyond mainland Norway during warm climatic periods (perhaps during medieval times) and pushed south by polar waters during cold periods like the Little Ice Age. The study will give us an opportunity to see how marine currents are involved in influencing climatic transitions over the last 1,000 years or so. The key to this is the clams. Their growth is seen in distinct annual bands (in the shells) and is a function of food and water temp, so we can count back and measure lines and resolve the chemistry of the annual layers back through time to reconstruct marine climate. My colleague Will Ambrose calls them “trees of the sea,” since it’s a process similar to reconstructing climate from tree rings.

What’s your role? I’ll be surveying beaches above present sea level that go back to around 6,000 years before present. Then we can target beaches for sampling clams beyond those modern ones in the bays and on the modern beach.

How big is a 500-year-old clam? And how do they get so old? That’s a better question for a biologist, but clams grow like other organisms, fast at first, then slow down as they age. A 500-year-old clam isn’t too much bigger than one that’s a 100 or 200, but they generally have thick shells. The growth rings get very narrow when they get older. The species we’re working with is the ocean quahog (Arctica islandica) and my guess is that they can grow old because they aren’t commercially harvested like they are on the eastern seaboard.

Farthest distance you’ve traveled by plane for research: That’s a three-way tossup. Right out of college, I worked as a geologist on the Alaska pipeline and they shipped me to the north slope beyond the Brooks Range. After that, as a grad student and post-doc I worked on the north coast of Ellesmere Island in the Canadian arctic sampling arctic lakes and mapping geology at 82 degrees north. That required a long flight in a small plane. Now, on top of the clam project on the north coast of mainland Norway, I’m working in Spitsbergen, which is about two-and-a-half hours north of the mainland on a glacier monitoring project. They’ve all been great experiences.

Farthest distance you’ve traveled by boat for research: I guess that would be an oceanographic cruise in Baffin Bay in October 1990 on a Canadian ship, CSS Hudson. That ship was about 90 meters long. We were recovering marine sediment cores in front of retreating glaciers on Baffin Island. We also spent some time in the open North Atlantic north of Labrador and a lot of people on the ship were green from sea sickness.

You’ve logged a lot of time in the arctic — what are the must-have supplies you pack?  SmartWool socks, good boots, lots of fleece, polypro and Gore-Tex layers, chocolate, Jameson’s Irish whiskey (medicinal purposes) and I’m never bored, so books are for bad weather days: Dan Brown, Tom Clancy, Richard Russo.

Ever seen signs of a yeti? No, but my field assistant and I were on Ellesmere Island and hiking back to camp after a few days out mapping and, in an exhausted state, thought we saw a big herd of polar bears as we were walking into the sun. It turned out to be a herd of arctic hares . . . we haven’t told many people about that.

What’s your dietary relationship like with seafood? Do you eat clams? My mom worked in a fish market when I was a kid and I love seafood. This past field season we had cod and clams almost daily and in every way possible (fried, baked, in casseroles and in chowders). The people we live with in northern Norway run a commercial cod fishing operation, so we enjoy the catch of the day and we also get a chance to fish after work.

kskelton@sunjournal.com

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