Author, teacher and bioregionalist, Stephanie Mills offers our readers another in her series of essays on natural resource experts and their work in Northern Michigan. In this engaging profile, Nature Change readers get to know citizen scientist and research diver, Carol Linteau.
Carol Linteau, a retired public servant, is confronting an ecological upheaval by volunteering a special skill: she’s an underwater citizen scientist. Some people know from a very early age what they want to be. As a child Carol Linteau watched undersea shows on TV. She was captivated by Jacques Cousteau, the news about Sea Lab, and the entrancing possibility of being an aquanaut. “Even as a kid I loved to open my eyes under water,” she told me. “I loved seeing and learning about all the plants and animals there.” She was determined to be a scuba diver. The vagaries of higher education landed her on dry ground for many years, though. Linteau had a long varied career in Lansing, holding an array of policy, research, and administrative positions in state government, helping to shape Michigan’s environmental policy.
Even while she was busy at the capitol, as soon as she could afford it, Linteau acquired Scuba certification and competence, which requires extensive training to master a complex set of rules and skills—unaccustomed relationships of depth and pressure, breath and stamina—and learning to use sophisticated equipment. Now she could dive in Michigan’s lakes, straits, and rivers as well as in saltier waters in sunnier climes.
Linteau doesn’t come across as a powerhouse, but her professional and avocational resumes attest her uncommonly brave, enthusiastic, intelligent character. She’s a SCUBA and dive safety instructor with several national diving organizations, and a VIP (Volunteer-in-Parks) research diver for the National Park Service and the National Marine Sanctuaries. Although we met in a conference room in early December, it was easy to picture her teaching anywhere. She’s got a knack for clear explanation, sharing her knowledge and experience complete with illustrations. She took to the white board to sketch, something she also does as an avocational nautical archaeologist. That equable salient communication skill must have been crucial in Lansing especially doing what she called “the most difficult job I think I’ve had,” which was serving as legislative director for Michigan’s Department of Environmental Quality.
Having done a boatload of public service, in retirement Linteau’s now able to engage directly and unequivocally with her concern for the life and health of the waters. As a citizen scientist, she participates in the studies that, in situations of fact-based governance, inform environmental policies. “I find the frontline research very satisfying,” she says, “because in Lansing you are so far removed from where the creatures actually are living and what is happening in the field.”
Linteau encounters inconceivable number of aquatic creatures lately. In 2016 Sleeping Bear Dunes National Lakeshore asked her to dive in Good Harbor Bay for a research project on the ecological impacts of the irruption of zebra and quagga (dreissenid) mussels in Lake Michigan. The advent of these alien mollusks is no longer news, but seen personally its sheer magnitude beggars the imagination. When adaptable prolific organisms arrive in habitat devoid of their predators, they can, as the dreissenids have, reproduce in numbers followed by long strings of zeroes.
Mussels are soft-bodied, hard-shelled aquatic creatures with multiphase life cycles. The presence of native species ordinarily indicates the health of their watery habitat in streams, lakes, or at the edge of the sea. They eat by siphoning in plankton—tiny aquatic organisms. Zebras are astounding siphoners, passing up to a liter of water a day through their thimble-sized bodies. Unlike the diverse native mussels, which have complex life stages involving egg brooding and developmental sojourns with suitable fish, zebra mussels reproduce by releasing torrents of eggs or sperm to the water column. Some of those gametes will meet, fertilization will occur, and the resulting larvae, called veligers, will drift and grow until they attach to just about any hard surface, including other mussels. The larvae of their cousins the quagga mussels aren’t even that choosy. Not needing any firm purchase, they have spread yet more widely and deeply through the lakes.
While quadrillions of generalist Caspian mussels revolutionize the lower Lakes’ ecosystems, nineteen of Michigan’s forty-five freshwater mussel species are state listed as endangered, threatened, or of special concern. Linteau said she used to be able to see native mussels more easily but now they’ve become a rare sight. She’s spent time in the tannin-infused St. Croix River National Scenic Riverway hanging on to a heavy contraption that allows divers to “crawl” on the bottom to monitor and compare different stretches of the rushing river for the presence of native mussels and for invasive mussel contamination. To avoid becoming invasive species vectors themselves, she said the divers found themselves sitting after hours in the chlorinated hotel pool in all their diving gear to be decontaminated.
Most of what divers take to the Great Lakes to see is not biotic, but historic: The contents of Davy Jones’s Locker. Lake Michigan is oligotrophic—young, clear, and relative to the ancient salty oceans, not abounding in biodiversity. The inland seas’ cold temperatures, chemistry, and the absence of wood-boring organisms mean many hundreds of early shipwrecks are well preserved.
“When I first started diving in the Great Lakes,” said Linteau, “I could see the wood and the way the ships were constructed.” This helped identify the vessel, its era, and evolving purposes. Formerly she could see the scarf joints within the hull planks and clearly read the names of those vessels sunken for nearly a century. But the wrecks are now shrouded by a couple of inches of zebra mussels and by cladophora algae blooms. The multitudinous mussels’ supersiphoning produces what divers call “great viz”–crystal-clear water. It’s great for underwater sightseeing, but not for the aquatic organisms that depend on the plankton that formerly dimmed the lakes. “Great viz” admits sunlight deeper and promotes algae growth.
Diving in the Straits of Mackinac, off Beaver Island, and near Pyramid Point, Linteau has watched the transformation of Lake Michigan. “You used to see lots of bare sand and rocks,” she said, “and now you see zebra mussels and cladophora.” Although that algae is native, when it’s in excess, mucky anaerobic dead algae accumulations in lake bottom holes host botulinum bacteria. The toxin they produce in these conditions gets concentrated on up the food chain, killing thousands of the avian predators at the top: mergansers, bald eagles, great blue herons, loons, and plovers—another nudge towards the sixth great extinction.
Linteau’s career addressing key environmental concerns framed her public service in retirement. She’s just glad to be exploring the underwater world and to be contributing in essential ways to the University of Wisconsin and NPS research being conducted in Good Harbor Bay, and to NPS diving elsewhere, like the Channel Islands National Park and National Marine Sanctuary off Ventura, California and Isle Royale National Park in Lake Superior. Hers is not the Lloyd Bridges-style knife fight with a bad guy or chomped-by-a-giant-clam underwater exploit. Rather it’s spending an hour submerged in Good Harbor Bay in a carefully plotted area using spackling blades to scrape mussels and whatever else is clinging to the rocks there, then sending them up to the research vessel where infinitely patient scientists catalog and count every last organism found. This is how data is amassed, hypotheses tested. With her diving prowess, Linteau helps chronicle the mussel invasion: “I can touch it, I can count it, across miles and miles and acres and acres.”
Linteau has watched the changes happening year to year but the question, she says, is “not only how do we stop these critters from coming,” but by studying the current biology, trying to figure out what can be done that won’t worsen things, as previous well-meant interventions in the lakes’ ecology have done.
Although it wouldn’t be her style, Linteau could say “I told you so,” for in her days in Lansing she was among the proponents of stricter control of international freighters’ ballast flushing, which brought these pesky dreissenids to America’s inland waters. The lower lakes’ invasion by the mussels grew apace as Linteau’s policy career unfolded. There was every reason for precaution. The Lakes already had experienced many biological invasions. Her experiences of the late alewife die-off that buried the beaches around southwest Lake Michigan, including New Buffalo, her home in the early 70s also may have lingered in memory.
These days Carol Linteau is honored that her volunteer research “can help the public understand why science needs to inform public policy.” She’s happiest “putting my diving skills to work for environmental protection and public research.”
Diving retains its wonder for her. “It’s flying,” she said, so different from earthbound physicality. “You’re weightless. You’re in a world that very few people experience. Things sound different, they feel different. There’s mystery below the surface of water.”