02-27-2009, 03:09 PM
by Jeff Alexander | Muskegon Chronicle
Thursday February 26, 2009, 7:22 AM
Bopaiah A. BiddandaA scientist at Grand Valley State University's Annis Water Resources Institute in Muskegon has discovered biologically-rich sinkholes on the bottom of Lake Huron that are similar to deep sea vents on ocean bottoms.
The sinkholes, formed by salty groundwater seeping into the lake and dissolving the ancient underlying seabed, are found offshore of Alpena in about 65 feet of water, said GVSU scientist Bopaiah A. Biddanda. He co-authored an article about the sinkholes in the current edition of Eos, the journal of the American Geophysical Union.
Biddanda said the sinkholes are home to "bizarre" ecosystems dominated by brilliant purple mats of cyanobacteria, or blue-green algae, but largely devoid of fish.
"Groundwater from beneath Lake Huron is dissolving minerals from the defunct seabed and carrying them into the lake to form these exotic, extreme environments," Biddanda said. "Those ecosystems are in a class not only with Antarctic lakes, but also with deep-sea, hydrothermal vents and cold seeps."
The sinkholes, some of which are larger than a football field, are similar to Karst sinkholes on land. Biddanda said this is the first time that scientists have documented such sinkholes in the Great Lakes.
The Lake Huron sinkholes are dominated by brilliant purple mats of cyanobacteria -- cousins of microbes found on the bottom of permanently ice-covered lakes in Antarctica -- and pallid, floating pony-tails of other microbial life, according to the journal article.
The saltwater venting out of the sinkholes is hostile to most life forms because it lacks oxygen, the scientists said in the article.
"You have this pristine fresh water lake that has what amounts to materials from 400 million years ago ... being pushed out into the lake," said Steven A. Ruberg, a scientist at the National Oceanic and Atmospheric Administration's Great Lakes lab who co-leads the sinkhole project with Biddanda.
Archaeologists studying shipwrecks in the Thunder Bay National Marine Sanctuary in 2001 inadvertently discovered that Lake Huron's water in that area had unusually high levels of electrical conductivity. Biddanda and Ruberg were called in to study the situation and discovered the sinkholes.
Biddanda said there are likely more sinkholes under the other Great Lakes.
http://www.mlive.com/news/muskegon/index...ist_d.html
Thursday February 26, 2009, 7:22 AM
Bopaiah A. BiddandaA scientist at Grand Valley State University's Annis Water Resources Institute in Muskegon has discovered biologically-rich sinkholes on the bottom of Lake Huron that are similar to deep sea vents on ocean bottoms.
The sinkholes, formed by salty groundwater seeping into the lake and dissolving the ancient underlying seabed, are found offshore of Alpena in about 65 feet of water, said GVSU scientist Bopaiah A. Biddanda. He co-authored an article about the sinkholes in the current edition of Eos, the journal of the American Geophysical Union.
Biddanda said the sinkholes are home to "bizarre" ecosystems dominated by brilliant purple mats of cyanobacteria, or blue-green algae, but largely devoid of fish.
"Groundwater from beneath Lake Huron is dissolving minerals from the defunct seabed and carrying them into the lake to form these exotic, extreme environments," Biddanda said. "Those ecosystems are in a class not only with Antarctic lakes, but also with deep-sea, hydrothermal vents and cold seeps."
The sinkholes, some of which are larger than a football field, are similar to Karst sinkholes on land. Biddanda said this is the first time that scientists have documented such sinkholes in the Great Lakes.
The Lake Huron sinkholes are dominated by brilliant purple mats of cyanobacteria -- cousins of microbes found on the bottom of permanently ice-covered lakes in Antarctica -- and pallid, floating pony-tails of other microbial life, according to the journal article.
The saltwater venting out of the sinkholes is hostile to most life forms because it lacks oxygen, the scientists said in the article.
"You have this pristine fresh water lake that has what amounts to materials from 400 million years ago ... being pushed out into the lake," said Steven A. Ruberg, a scientist at the National Oceanic and Atmospheric Administration's Great Lakes lab who co-leads the sinkhole project with Biddanda.
Archaeologists studying shipwrecks in the Thunder Bay National Marine Sanctuary in 2001 inadvertently discovered that Lake Huron's water in that area had unusually high levels of electrical conductivity. Biddanda and Ruberg were called in to study the situation and discovered the sinkholes.
Biddanda said there are likely more sinkholes under the other Great Lakes.
http://www.mlive.com/news/muskegon/index...ist_d.html