Limno in the Lab – Scientists Sorting Snails

Ellen Hamann collecting snails from a quadrat in Lake Tanganyika.
Ellen Hamann collecting snails from a quadrat in Lake Tanganyika. Photo: Vanessa Constant

Field season is, of course, where the best photo ops and a lot of the fun of being a research scientist happens. If you’re a loyal reader of this blog, you’ll remember a handful of lively dispatches from the CFL’s Ellen Hamann as she worked this summer with the McIntyre lab on the Tanzania shoreline of Lake Tanganyika. (If you’re not a loyal reader, this is worth a read).
Now, Ellen has traded in the wetsuit and underwater camera for good ol’ pen and paper, as she helps tally the haul from Lake T.
A box full of snail specimens brought back from Africa.
A box full of snail specimens brought back from Africa. Photo: A. Hinterthuer

The collection of snail specimens Ellen and Pete brought back from Tanzania was so massive that, earlier this winter, they called in outside help in the form of two world-renowned experts from the zoology department of London’s Natural History Museum. Elllinor Michel and Jon Todd flew in from the UK to help ID the nearly 12,000 snails Ellen and Pete pulled up from the bottom of Lake Tanganyika outside of both the port town of Kigoma and the forested shores of Mahale Mountains National Park, which the team first visited this summer.
McIntyre began working on Lake Tanganyika as an undergraduate student, when Ellinor served as his mentor. “Because of the training I’ve had from her in the past,” he says, “we did okay on taxonomy of the snails from the area [around Kigoma] where we worked for the past fourteen years. But we were pretty clueless about anything we got from this new region. So we’re just making the first baby steps to figuring out what’s [near Mahale] and it only took, what, 10 or 15 years to figure out what was down in the other area?”
While Ellen records the data, Ellinor and John ID and sort snails.
While Ellen records the data, Ellinor and Jon ID and sort snails. Photo: A. Hinterthuer

Ellinor says Tanganyika is one of the most ancient extant lakes in the world, estimated at 15 million years old. “That’s the amount of time that it’s been working on being a lake,” she clarifies, “it started out as a swampy area, but it’s probably been in place as a super deep isolated body of freshwater for a good 6 million years and potentially longer than that.” For perspective, that’s 1,000 times longer than the Great Lakes have been around. And that means aquatic organisms in Lake Tanganyika have been adapting and evolving for a long, long time. The result is a daunting collection of specimens representing a staggering diversity of species.
A pile of unsorted snails await Jon and Ellinor's attention. Photo: A. Hinterthuer
A pile of unsorted snails await Jon and Ellinor’s attention. Photo: E. Hamann

Now some of that diversity is in Hasler Lab, being sorted by genus and species, and giving the researchers a better idea of the community composition of snails in Lake Tanganyika.  More important, these snails will help the team understand how that composition is affected by habitat. Comparing what snails thrive in the heavily sedimented waters off of the developed shoreline near Kigoma to the several dozen species of snails that call the more “pristine” waters around Mahale Mountain National Park home, the McIntyre lab will be able to generate some hard data on how Africa’s great lake is faring in its 15 millionth year of existence.
A single small bag of snails collected in a one meter by one meter section of lake floor contained dozens of specimens and eight different species.
A single small bag of snails collected in a one meter by one meter section of lake floor contained dozens of specimens and eight different species. Photo: E. Hamann

And, should any of this research wind up in the pages of a scientific journal, thanks to Ellinor and Jon, everyone can rest assured that, as Ellinor says, “we’re all talking about the same thing.”
 

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