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GLIN==> Fw: Did You Know? ...New Diatom discovered in Lake Superior

----- Original Message ----- From: <Wendy_W_Smith@nps.gov>
Sent: Friday, December 16, 2005 12:37 PM
Subject: Did You Know? ...New Diatom discovered in Lake Superior

Did You Know? …New Diatom discovered in Lake Superior

In this day and age when new invasive species are being identified left and
right, it’s refreshing to hear that new endemic species are being
discovered as well! A tiny diatom, endemic only to Lake Superior and Lake
Nipigon, was recently discovered by researchers Rebecca Bixby of the
University of Georgia, Mark Edlund of the Science Museum of Minnesota and
Eugene Stoermer from the University of Michigan. The three described the
new diatom, called Hannaea superiorensis, in the November issue of the
journal of Diatom Research. The new species of photosynthetic algae was
once grouped with other diatoms found in cold, pristine rivers and streams
around the world, yet it is clearly different. For one thing, Hannaea
superiorensis is boomerang-shaped, and is nearly twice the length of the
other diatoms in its genus.

You might expect to identify new endemic species in the far reaches of
tropical rainforests, and other less explored parts of the world, but it is
really quite exciting to make a new discovery of this sort right here in
the Midwest.

Diatoms are microscopic algae that live as single cells or in small
colonies. Their cell walls are composed of silica. The newly identified
species grows amongst other microscopic organisms in a brownish slime on
the submerged rocks along the Lake Superior shoreline. Edlund, an
associate scientist at the Science Museum of Minnesota’s St. Croix
Watershed Research Station, first collected this new species of diatom in
1992 from the harbor side of the Coast Guard breakwall in Grand Marais, MN.
Recent studies have revealed that it is in good abundance all across the
lake. Healthy populations of Hannaea superiorensis are found on the North
Shore, around Isle Royale, the Keweenaw Peninsula, and in northern and
eastern Lake Superior. The diatom prefers the high energy,
well-oxygenated, cold waters of Lake Superior's wave zone. "It's not
rare, and it appears to be doing well," Edlund said. "But whenever you have
a species that's endemic to one area, it's important because, if you lose
it there, it's extinct."

Currently, scientists recognize around 25,000 diatom species, and
interestingly, many are used in research. Each species responds
differently to both pollution and environmental conditions, so diatoms are
often used as indicators of water quality. Because their cell walls are
composed of silica, they are also found in the fossil record. According to
Edlund, "Scientists studying diatoms in sediments are using the fossil
record to measure the historical impacts of land use and water-level
management on lakes and rivers within the National Parks. They are also
integrating the sediment record with modern communities and monitoring to
develop diatoms as biomonitors of ecosystem health.”

By discovering a diatom unique to Lake Superior and Lake Nipigon, Edlund
and his fellow researchers may well have found a sensitive harbinger to
detect ecological change in many of the Western Great Lakes Parks.

The genus Hannaea is named for G Dallas Hanna, a pioneering American diatomist. The word superiorensis is a Latinization of the new species' home, Lake Superior.

Note:  A high resolution photo of Hannaea superiorensis is available at
http://ugaphoto.alumni.uga.edu/special/bixby-diatom.jpg  Photo credit:
Mark Edlund.

For more information, see reference:  Bixby, R.J., Edlund, M.B. and
Stoermer, E.F. (2005) Hannaea superiorensis sp. nov., an endemic diatom
from the Laurentian Great Lakes.  Diatom Research 20(2): 227-240.
(published 02 November 2005)

"Did You Know?" is a weekly e-mail bulletin featuring research findings
that could prove useful to interpreters, educators, and research managers
in the Great Lakes region. It is distributed by the Great Lakes Research
and Education Center. If you decide you do not want to receive future "Did
You Know?" bulletins, simply e-mail me at Wendy_W_Smith@nps.gov and ask to
be removed from the "Did You Know?" list.

Wendy W. Smith
Education Coordinator
Great Lakes Research and Education Center
Indiana Dunes National Lakeshore
1100 N. Mineral Springs Rd.
Porter, IN 46304

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