Sink Holes in Lake Huron

The Middle Island sinkhole is open to Lake Huron, creating a gradient of biological activity. A nine-metre boat is also visible in this aerial photo for sense of scale. ((Scott Kendall/Bopi Biddanda/Grand Valley State University))Twenty metres below the surface of Lake Huron, scientists have discovered peculiar sinkholes where a bizarre ecosystem at odds with the rest of the lake flourishes.

The huge lake's freshwater fish shun the dense, salty, oxygen-deprived waters of these sinkholes off northeastern Michigan.
Instead, brilliant purple mats of cyanobacteria — cousins of microbes found at the bottom of permanently ice-covered lakes in Antarctica — and pallid, floating, ponytail-like microbes thrive.

Groundwater from beneath the lake is dissolving minerals from the ancient seabed and carrying them into the lake to form these exotic, extreme environments, says aquatic ecologist Bopaiah Biddanda of Michigan's Grand Valley State University, a leader of the team studying the sinkhole ecosystems.
"These are almost primordial Earth conditions, with high sulphur and low oxygen like in the ancient oceans that covered the Earth three billion years ago," Biddanda told CBC News.
"It gives us a window into the past and who knows what value it will hold."
The researchers describe this little-known underwater habitat in this week's issue of Eos, published by the American Geophysical Union.
Although above-ground sinkholes in the area were discovered decades ago, the submerged sinkholes were only recently uncovered.

Discovered 8 years ago

In 2001, researchers with the Connecticut-based Institute for Exploration stumbled across them during an underwater archeological survey for shipwrecks in Michigan's Thunder Bay National Marine Sanctuary.
Scientists began to explore these sinkholes a couple of years later, finding some just 20 metres below the surface and others extending 100 metres down, where the sun never shines.
But their findings have trickled in over the last few years because of the logistical problems in exploring lakebed sinkholes.
"Finding these little spots in a huge lake — you can't even compare it to looking for a needle in a haystack," said Biddanda.
The most recent findings show an ecosystem that has more in common with Antarctic lakes and deep-sea, hydrothermal vents than it does with a freshwater lake.
"We were amazed to find these brilliant cyanobacteria mats," said Biddanda. DNA sequencing of the purple mats show they are closely related to mats found in the ice-covered, oxygen-poor Antarctic lakes.
Biddanda suspects similar ecosystems once existed all around the Earth but largely disappeared as the planet's atmosphere became increasingly oxygen-rich.
The team, including researchers from the U.S. National Oceanic and Atmospheric Administration, suspects similar sinkholes exist under the other Great Lakes because, with the exception of Lake Superior, the lakebeds are all composed of limestone, with ancient aquifers running beneath.
The researchers will continue to study the sinkholes this summer, keeping a sharp eye out for the possible discovery of never-before-seen organisms and biochemical processes.

Smitty the Mastodont

Mastodont Bones Found

In l985, the gigantic bones of a mastodont were found in
 Grandville, a city in West Michigan. A family digging the

foundation of a new house reported the find to Dr. Richard

Flanders, an anthropologist at Grand Valley State University

and Dr. Flanders along with his anthropology students began

the task of digging up the skeleton of the Ice Age animal

very carefully so that none of the bones would be lost or

destroyed in the process.

After all the bones had been carefully reassembled, they

could learn a great deal about Smitty, a name the students

gave to the ancient animal. Smitty weighed as much as a

school bus and his huge tusks were supported by a very

powerful neck.

Some parts of Smitty were missing, the brain and the

legs. They wondered if Smitty might have been hunted and

then killed by paleo indians because these would have been

the choice cuts of meat. Professor Flanders took some of the

bones to a butcher for his opinion. Flanders suspected that

the animal had been butchered for its meat. The butcher told

him that it looked to him as if the bones had been butchered

in the same way butchers still cut meat today.

The place where Smitty was found also led Dr. Flanders

and his students to believe that the mastodont had been

driven into a pit by a number of hunters and their dogs where

he could be killed with stone weapons.

Although the mastodonts and their larger relatives the

mammoths were numerous at the end of the Ice Age and

quite a few of their bones have been found in the Great

Lakes basin, they disappeared from the face of the Earth

along with the other mega sized animals.   

 

Great Lakes Water Levels are Down

The Great Lakes water levels are down.  With so much water it does not seem possible that people in the Great Lakes basin need to conserve water, and yet it is becoming necessary.

 According to Alan Steinman, PhD and director of Grand Valley State University’s Annis Water Resources Institute in Muskegon, dredging in the St. Clair River by the U.S. Army Corps of Engineers has lowered water levels by a couple of inches. Dredging opened the drain to cause the lake water to run out to the Atlantic at a faster pace.  Other causes of lower water is evaporation—a hot summer—little rain and snow and little or no ice cover in the winter.  Global warming is causing great changes in the Great Lakes.  Lower water levels dry up wetlands around the lakes.  These areas are nurseries for fish and birds and serve to filter out pollutants.  Boaters may find themselves high and dry. 

So for those living in the Great Lakes watersheds, don’t waste water.  Think of ways to conserve.

Read more about the Great Lakes in The Dynamic Great Lakes.  The book will provide you with basic facts about Great Lakes and how they function.  The book is available on Amazon’s Kindle and in paperback.  Also available from Barnes and Noble and many other places where books are sold.

Sinkholes on the bottom of Lake Huron

Research Vessels on the Great Lakes

GLERL research vessel, "Shenehon", Great Lakes, NOAA Great Lakes Environmental Research Lab (GLERL)

While researching my book, The Dynamic Great Lakes, I went out on Lake Michigan with groups of students and research scientists to see the work they were doing. Pictured is a NOAA research vessel. I worked with professors from Grand Valley State University where I was teaching at the time.

Since my book is interdisciplinary, I also consulted experts in areas such as geology, fish biology, limnology and naturalists. I am not an expert, but I consulted a lot of experts while exploring the Great Lakes and their many wonders.