River

Antarctica Is Covered in Rivers, Lakes, and Waterfalls. That Might Not Be Good.

The floating ice shelves that buttress Antarctica are less icy than we thought, it turns out. They’re filled with flowing water. New research published in the scientific journal Nature maps the extensive network of meltwater from Antarctica’s ice sheets and found that, contrary to previous understanding, lakes and rivers—even waterfalls—created by melting have been common for at least seven decades.

Two new papers analyze satellite imagery of Antarctica dating back to 1973 and aerial photography dating back to 1947 for evidence of meltwater. Warming oceans melt ice shelves around from the bottom up, while warming air temperatures melt them from the top down, creating pools and rivers of liquid water on the continent’s surface.

Researchers found that over the last 70 years, a system of meltwater drainage has transported water from the continent of Antarctica across the floating ice shelves that surround it, traveling up to 75 miles and creating ponds up to 50 miles long.

This isn’t great news for the stability of the ice shelf. Water is heavy, and the weight can cause the ice below these lakes to crack. As…

‘River piracy’ on a high glacier lets one waterway rob another

Kluane Lake
HIGH-WATER ROBBERY The melting of Kaskawulsh Glacier in northwestern Canada diverted water flow from one river into another, plummeting water levels in the waterway that once fed Kluane Lake (shown).

The diversion of headwaters from one stream into another

Ahoy! There be liquid booty on the move in the high mountains. Since May 2016, a channel carved through one of northwestern Canada’s largest glaciers has allowed one river to pillage water from another, new observations reveal. This phenomenon, almost certainly the result of climate change, is the first modern record…

Young eels use magnetic ‘sixth sense’ to navigate

juvenile European eel
EEL GPS Juvenile European eels may use Earth’s magnetic field to help them cross the Atlantic Ocean to reach freshwater rivers in Europe, including these seen in the U.K.’s Bristol Channel.

Earth’s magnetic field helps eels go with the flow.

The Gulf Stream fast-tracks young European eels from their birthplace in the Sargasso Sea to the European rivers where they grow up. Eels can sense changes in Earth’s magnetic field to find those highways in a featureless expanse of ocean — even if it means swimming away from their ultimate destination at first, researchers report in the April 13 Current Biology.

European eels (Anguilla anguilla) mate and lay eggs in the salty waters of the Sargasso Sea, a seaweed-rich region in the North Atlantic Ocean. But the fish spend most of their adult lives living in freshwater rivers and estuaries in Europe and North Africa.

Exactly how eels make their journey from seawater to freshwater has baffled scientists for more than a century, says Nathan Putman, a biologist with the National Oceanic and Atmospheric Administration in Miami.

The critters are hard to track. “They’re elusive,” says study coauthor Lewis Naisbett-Jones, a biologist now at the University of North Carolina at Chapel Hill. “They migrate at night and at depth. The only reason we know they spawn in the Sargasso Sea is because that’s where the smallest larvae have been collected.”

Some other marine animals, like sea turtles and salmon, tune in to subtle changes in Earth’s magnetic field to help them migrate long distances. To test whether eels might have the same ability, Putman and his colleagues placed young European eels in a 3,000-liter tank of saltwater surrounded by copper wires. Running electric current through the wires simulated the magnetic…