As little as 20 meters (66 feet) below the surface of Lake Huron, the third largest of North America's Great Lakes, peculiar geological formations--sinkholes made by water dissolving parts of an ancient underlying seabed--harbor bizarre ecosystems where the fish typical of the huge freshwater lake are rarely to be seen.
Instead, brilliant purple mats of cyanobacteria--cousins of microbes found at the bottoms of permanently ice-covered lakes in Antarctica--and pallid, floating ponytails of other microbial life thrive in the dense, salty water that's hostile to most familiar, larger forms of life because it lacks oxygen.
Groundwater from beneath Lake Huron is dissolving minerals from the defunct seabed and carrying them into the lake to form these exotic, extreme environments, says Bopaiah A. Biddanda of Grand Valley State University, in Muskegon, Mich., one of the leaders of a scientific team studying the sinkhole ecosystems. Those ecosystems are in a class not only with Antarctic lakes, but also with deep-sea, hydrothermal vents and cold seeps.
"You have this pristine fresh water lake that has what amounts to materials from 400 million years ago ... being pushed out into the lake," says team co-leader Steven A. Ruberg of the Great Lakes Environmental Research Laboratory of the National Oceanic and Atmospheric Administration (NOAA).The researchers describe this little-known underwater habitat and their ongoing investigations of it in the current issue of Eos, the newspaper of the Earth and Space Sciences, published weekly by the American Geophysical Union (AGU).
AGU is the world's largest organization of Earth and space scientists.
The scientists report that some deep sinkholes act as catch basins for dead and decaying plant and animal matter and collect a soft black sludge of sediment topped by a bacterial film. In the oxygen-depleted water, cyanobacteria carry out photosynthesis using sulfur compounds rather than water and give off hydrogen sulfide, the gas associated with rotting eggs. Where the sinkholes are deeper still and light fails, microorganisms use chemical means rather than photosynthesis to metabolize the sulfurous nutrients.
Biddanda, Ruberg, and their team are probing the origins of ancient minerals flowing in from beneath this fresh inland sea, striving to understand how long ago the minerals were deposited that are now entering the lake and how fast the salty brew containing them is arriving. The scientists also plan to chart transitions from light, oxygen-rich, fresh water near the lake's surface to dark, anoxic, salty soup down inside the sinkholes.
The sinkhole research--funded by the National Science Foundation and NOAA's Office of Ocean Exploration and Research--may shed light on how similar microbial communities can arise in environments as disparate as Antarctic lakes, deep-sea vents, and freshwater-lake sinkholes, the scientists say. Biddanda adds, "it might also lead to the discovery of novel organisms and previously unknown biochemical processes, furthering our exploration of life on Earth."
Peter Weiss | American Geophysical Union
Further reports about: > Antarctic Predators > Antarctic lakes > Deep-sea > Earth's magnetic field > Great lake's sinkholes > Lake Baikal > Oxygen > Science TV > chemical process > cold seeps > cousins of microbes > cyanobacteria > exotic ecosystems > extreme conditions > hydrothermal vents > oxygen-depleted water > peculiar geological formations--sinkholes
World's first solar fuels reactor for night passes test
21.02.2018 | SolarPACES
Geophysicists and atmospheric scientists partner to track typhoons' seismic footprints
16.02.2018 | Princeton University
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences