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It’s the diatoms that make the Great Lakes great

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21 October, 2015

Mark Edlund

Euan Reavie hosted nine diatomists at the Natural Resources Research Institute (NRRI) in Duluth, Minnesota on 12-13 October 2015.

The NRRI Great Lakes Diatom Taxonomy Workshop is periodically held to sort out the taxonomy of some of the over 3000 diatoms found in the Laurentian Great Lakes. Discussions centered on centric and araphid forms that have been encountered in plankton and sediment collections made during USEPA research cruises that have been ongoing since the 1980s. Taxa in questions were circumscribed by consensus and images to help support EPA’s long-running plankton monitoring efforts that are coordinated by NRRI. The team focused on the small fragilarioid araphids including the Staurosirella pinnata, Staurosira venter, Pseudostaurosira elliptica, P. microstriata, and P. brevistriata-inflata groups to harmonize taxonomy among analysts. Centrics were next on the agenda with discussions centered around “Cyclotellapolymorpha, krammeri, and kuetzingiana. The small Stephanodiscus species from the Great Lakes include many undescribed forms in the minutulus, parvus, medius, conspicueporus group that challenge even the best analysts, but have long been recognized by Great Lakes scientists as a special part of the flora. An unanticipated visit by Ed Theriot confirmed that Great Lakes small Stephs are in need of significant revision or description. Scope time was paired with great discussions over lunch and dinners that were delayed by power outages as fall blew into Duluth.

The group included diatomists from Minnesota (Euan Reavie, Lisa Estepp, Andy Bramburger, Elizabeth Alexson, Mark Edlund, David Burge), Wisconsin (Bob Pillsbury), Michigan (Norm Andresen), Ohio (Gerald Sgro), and Texas (Ed Theriot).