European eels are born and die in the North Atlantic Ocean, but spend most of their lives in rivers or estuaries across Europe and North Africa. In between, they traverse thousands of miles of ocean, and scientists have long suspected that these critically endangered fish use magnetism to help guide them. A study in Science Advances shows, for the first time, that European eels might link magnetic cues with the tides to navigate. Studying juveniles during the crucial stage when they move toward land from open ocean, the authors found that eels faced different directions based on whether the tide was flowing in or out. Changing orientation might help eels take advantage of tides to travel from the ocean to the coast, and into fresh water, more efficiently. It remains unclear, however, how eels use magnetism in other life stages.
Record-breaking heat tied to climate change
Last year, a remarkable April heat wave shattered all-time temperature records across Southeast Asia, prompting public health concerns and making international headlines. Now, scientists believe the event was driven by the combined influence of a strong El Niño event and human-caused climate change. A new study in Nature Communications finds that the 2016 extreme can be attributed about 49 percent to the influence of a severe El Niño event, which began in 2015 and lingered into the following year, with global warming accounting for another 29 percent, and the rest attributed to unknown factors. The researchers note that the impact of global warming is catching up and may even become stronger than that of El Niño in the future. April is typically the hottest month of the year in Southeast Asia, but over the past century its temperatures have been growing even more extreme.
Melting ice in glacier warped Earth’s crust
NASA scientists detected a pulse of melting ice and water traveling through a major glacier in Greenland that was so big that it warped the solid Earth — a surge equivalent in mass to 18,000 Empire State Buildings. The wave — which occurred during the 2012 record melt year — traveled nearly 15 miles through the Rink Glacier in western Greenland over four months before reaching the sea, the researchers said. “It’s a gigantic mass,” said Eric Larour, one of the study’s authors and a researcher at NASA’s Jet Propulsion Laboratory. “It is able to bend the bedrock around it.” Such a “wave” has never before been detected in a Greenland or Antarctic glacier. The total amount of mass carried in the wave — in the form of either water, ice, or some combination of both — was 1.67 billion tons per month, or 6.68 billion tons overall over four months, the study, in Geophysical Research Letters, found.