Research aims to learn more about sinkhole
ALPENA — Scientists say the pristine nature of the Middle Island sinkhole continues to provide fruitful research.
Researchers from University of Michigan and Max Planck Institute for Microbiology in Germany, worked with divers from the Thunder Bay National Marine Sanctuary to continue their studies of the sinkholes. When not at the sinkhole the scientists had labs and equipment setup at Alpena Community College.
U of M Postdoctoral Fellow Judith Klatt said the project was a continuation of a study that began in 2009.
“We are at Middle Island’s sinkhole because the microbial mats formed, dominated by blue green algae. It is a very pristine isolated place. This bacteria, they’re not exposed to the lake water column, but instead exposed to low oxygen groundwater with a little bit of sulfur. It’s an isolated world within the Lake Huron ecosystem,” Klatt said.
Within this environment they find an ecosystem dominated by bacteria, she said.
“There are no fish or large animals of any kind. That makes it special because it’s ancient ecosystems,” Klatt said. “An early earth before the evolution of larger animals. This represents for us an ancient ocean ecosystem. What we’re most interested in is how much oxygen do these ecosystems produce. One of the big unresolved questions in science is how did our planet become oxygenated.”
Researchers know roughly the timeline of these changes but they don’t know the driving factors behind it, she said. The biological source of oxygen in the form of bacteria largely controlled the pattern of earth’s oxygen.
“We know fairly little about all of these things, which is why we’re looking at these ecosystems,” she said. “We cannot go back billions of years. Our goal is to understand the controls of oxygen production. So what we do is measure oxygen in these microbial mats. They look like biofilms.
“To most people they look very unattractive to us they’re very beautiful. They’re just a couple of millimeters thick, so they’re very thin. We use special tools that can actually measure these films local production of oxygen. We have already found some spots within the sinkhole where there’s none. Even though it’s covered in phototrophs they should be doing photosynthesis but they don’t do oxygen. Instead they perform an ancient type of photosynthesis that is connected to sulfur.”
Max Planck microbiologist Dr. Arjun Chennu said they also measure chemical substances in the vicinity of the bacterial cells.
“The hard part of what field microbiology is to try and find out what the cells are experiencing as opposed to the bulk measurements of the water column or of the sediment structure, trying to get down to the scale of the cells. That’s what microsciences are really good at doing,” Chenu said.
Some of the equipment used included an underwater photography lab and a deep sea profiler.
“What we have here is a deep sea profiler. There is an electronic cylinder with microsensors below it they go slowly into the mat. Then they measure the concentrations of sulfite, oxygen, temperature those kinds of things. Each sensor measures something different. The black one measures sulfite which is crucial for understanding genetic photosynthesis,” Max Planck microbiologist Dr. Dirk de Beer said.
Because the research continues and it’s a big project Klatt acknowledged the help they receive from the sanctuary.
“We’re always working with all these years is the sanctuary and the divers. They’ve been an amazing support today. We have all this equipment and the weather forecast was bad. They’ve helped us so much and are so experience,” Klatt said.
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