Lakes beneath glaciers could enrich the oceans near Antarctica and Greenland

New research has found that water beneath glaciers in Antarctica and Greenland flows into nearby oceans, carrying elements that could affect how life grows and thrives.

The study, published today in the Proceedings of the National Academy of Sciences, found that subglacial lakes in Antarctica and streams emerging from under the Greenland ice sheet contain trace elements including iron, which has long been considered a nutrient. necessary to feed phytoplankton, microscopic algae that act as a counterweight to global warming by extracting carbon dioxide from the atmosphere.

“This is probably the first attempt to simultaneously examine the entire suite of nutrients and micronutrients in subglacial lakes,” said Berry Lyons, lead co-researcher on the study, professor of earth sciences and distinguished academic at Ohio State University.

Scientists have known since about 2007 that there are lakes that drain under glaciers in Antarctica and that those lakes are natural phenomena, not caused by climate change. But this study shows that the water contained in subglacial lakes could affect the surrounding oceans, something that hadn’t previously been known.

To understand the contents of the lakes and running water that form beneath the glaciers, the teams drilled through the ice sheet in West Antarctica to the lake below and sampled the meltwater flowing from beneath the glacier. Leverett in Greenland. The lake they drilled in Antarctica, Subglacial Lake Mercer, is named after the late John Mercer, an Ohio State glaciologist and first senior Ohio State researcher Byrd Polar and the Climate Center. The lake is about 500 miles from the South Pole; the glacier above is often just over a kilometer.

The equipment that entered the lakes had to be thoroughly sanitized, so as not to introduce materials from the outside world into the subglacial environment.

After drilling, the researchers dropped the equipment into the lakes and brought water samples to the surface to measure the chemical and biological composition of the water there.

In addition to iron, many other elements were also significantly higher than in rivers, the primary source of these elements in the ocean. These findings suggest that runoff from subglacial lakes and melting ice sheets could play an important role in how ocean life grows, especially how life grows in the Southern Ocean near Antarctica, the researchers say. Patterns of ocean life up to this point have generally not viewed subglacial runoff as contributing to ocean life and chemistry; these results indicate that it could play a larger role than scientists had thought.

This study shows that runoff from beneath glaciers in Antarctica and Greenland includes important nutrients for phytoplankton and is a previously unknown input that can counteract the greenhouse gases that are warming Earth’s atmosphere. Concentrations of these chemicals were higher in the water under the Antarctic ice sheets than they were under the Greenland ice sheets, the study found.

The Southern Ocean doesn’t have enough iron to feed large phytoplankton blooms, said Chris Gardner, a researcher at the Ohio State Byrd Center and co-author of the study. But it is possible that runoff from subglacial lakes brings significant amounts of iron to the Southern Ocean which can feed phytoplankton.

“The growth of phytoplankton in the Southern Ocean is limited because iron is not available,” Gardner said. “The addition of iron could potentially induce phytoplankton bloom which would extract carbon dioxide from the air and could be a negative feedback for climate change. We have to study it further to know. “

The experiments that allowed researchers to understand more about the contents of the subglacial lake in Antarctica involved scientists and logistics experts from around the world. The work was led by researchers from Florida State University and Montana State University, and the work in Greenland was done by researchers from the University of Bristol in the UK. The work on Antarctica was funded by the National Science Foundation’s Subglacial Antarctic Lakes Scientific Access (SALSA) project, led by researchers from Montana State University.