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mary caperton morton

How the Arctic became salty

The Arctic Ocean hasn’t always been as salty as other oceans. In the Eocene, between 56 million and 34 million years ago, the water surrounding the North Pole — freshened by melt from sea ice and river runoff — was cut off from the Atlantic and Pacific oceans by land bridges. At some point, plate tectonic processes opened the North Atlantic, submerging the land bridges and allowing saltwater to pour into the Arctic, but the timing and details of these events are largely unknown. New research suggests a tipping point may have been reached as one particular land bridge submerged far enough below the ocean surface.

25 Sep 2017

Titan's oddly oriented dunes may be electrostatically sculpted

Saturn’s largest moon, Titan, which has a dense, nitrogen-rich atmosphere with evidence of large amounts of frozen water at the surface, is a world apart from Earth’s moon. Among other strange phenomena, Titan has vast fields of frozen hydrocarbon particles that form 100-meter-tall dunes whose crests point east, opposite the prevailing west-blowing winds predicted by atmospheric models of Titan. In a new study in Nature Geoscience, researchers have found that these mysterious dunes may be sculpted in part by electrostatic charging of the frozen hydrocarbon grains.

01 Aug 2017

Rearranging the dinosaur family tree

Dinosaurs have long been grouped into two major clades — Ornithischia and Saurischia — largely based on the shapes of their hips. But new phylogenetic research is shaking up the dinosaur family tree, suggesting the traditional two-branch system needs reorganizing.

20 Jun 2017

Butchery or trampling? Controversy marks ancient animal bones

At some point in early human evolution, our ancestors began regularly hunting, butchering and consuming meat from large game, a protein- and fat-rich change in diet that may have helped fuel the development of a larger and more complex brain. When exactly this change took place has long been a matter of debate. Stone tools from 2.6 million years ago have offered the most solid evidence to date. But the discovery several years ago of a pair of 3.4-million-year-old animal bones in Dikika, Ethiopia, that appear to show cut marks indicative of butchery could push the date back significantly. Some researchers think the bones were marked by incidental trampling, however, not by early humans. 
 
22 Nov 2015

Setting sail on unknown seas: The past, present and future of species rafting

The 2011 Japanese tsunami set adrift tons of debris, some of it carrying live plants and animals that landed in North America more than a year later. It isn’t the first time species have traveled the globe on ersatz rafts, and it won’t be the last. But it is concerning.

24 Feb 2013

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