Earth Sciences

Almost 20 percent of the Earth's atmosphere is oxygen. Green plants produce it as a byproduct of photosynthesis and it, in turn, is used by most living things on the planet to keep our metabolisms running.

Yet before those photosynthesizing organisms appeared about 2.4 billion years ago, the atmosphere was mostly carbon dioxide, a lot like Mars and Venus.

The common hypothesis is that there must have been a small amount of oxygen in the early atmosphere. Where did this abiotic ("non-life") oxygen come from? Oxygen reacts quite aggressively with other compounds, so it would not persist for long without some continuous source.


When you take a shower and use soap and then lather, rinse and repeat twice with that shampoo, it gets washed off your body and goes down the drain.

Environmentalists have claimed these soaps and shampoos and washing machine detergents - surfactants - seep into groundwater, lakes and streams, where they could pose a risk to fish and frogs.

But do they? Not likely, finds a new report of the potential impact on the environment of the enormous amounts of common surfactants used day in and day out by consumers all over the world. 



Phytosaur: still got it. Credit: BFS Man, CC BY

By Stephanie Drumheller, University of Tennessee; Michelle Stocker, Virginia Tech, and Sterling Nesbitt, Virginia Tech

Ice sheets were never simple. There is no magic knob that could be turned to optimize melting rates and movement, outside environmental press releases.

A new paper in Nature this week
shows that not only is meltwater not as simple as sometimes contended, we don't even know what we don't know. Observations of moulins (vertical conduits connecting water on top of the glacier down to the bed of the ice sheet) and boreholes in Greenland show that subglacial channels ameliorate the speedup caused by water delivery to the base of the ice sheet in the short term.


Americans love their dogs, and most people clean up after their pets when they are out on a walk, but some do not: people who claim they wouldn't pour toxic chemicals or medicines onto the ground because they recognize it gets into waterways delude themselves into believing dog excrement is "natural" and will be okay in waterways.

But it isn't. Bacteria and anti-bacterial strains from dogs can make people sick from dogs just like it does humans, and we recognize that humans should not go to the bathroom on the ground near a lake.



Phreatic eruption: Mount Ontake. Credit: EPA/Ministry of Land, Infrastructure

By Rebecca Williams, University of Hull

Mount Ontake, Japan’s second-highest volcano, erupted killing at least 31 people on September 27.

Since then, there has been feverish speculation about why tourists were on an active volcano and why the eruption wasn’t predicted.

Farm runoff and urban pollution in the Hawaiian islands is causing sea turtle tumors, according to a study in PeerJ.

The paper by researchers at  Duke University, the University of Hawaii and the National Oceanic and Atmospheric Administration finds that nitrogen in the runoff ends up in algae that the turtles eat, promoting the formation of tumors on the animals' eyes, flippers and internal organs.


Planetary geologists have speculated for decades that glaciers might once have crept through Valles Marineris, the 2,000-mile-long chasm that constitutes the Grand Canyon of Mars.

Using satellite images, astronomers have identified features they say might have been carved by past glaciers as they flowed through the canyons but those claims have remained highly controversial and contested. 

Now, a joint team from Bryn Mawr College and the Freie Universitaet Berlin has identified what could be the first mineralogical evidence of past glaciers within the Valles Marineris: a layer of mixed sulfate minerals halfway up the three-mile-high cliffs of Ius Chasma at the western end of the canyon system.

Though the Intergovernmental Panel on Climate Change (IPCC) has asked climate scientists not to attribute weather conditions to climate change, a new paper is doing just that. 

A team writing in the Bulletin of the American Meteorological Society says that the atmospheric conditions associated with the unprecedented drought currently afflicting California are "very likely" linked to human-caused climate change.


There is less saline in Nordic Seas but that can't be blamed on more Arctic waters due to global warming. Instead, it is that the Gulf Stream has provided less salt.

 The Nordic Seas have freshened substantially since 1950. This has happened at the same time as there has been observed increased river runoff and net ice melting in the Arctic. The concurrence of a less saline ocean and Arctic freshwater input has given the climate research community reason for concern, but a new study finds that the source of fresher Nordic Seas since 1950 is rooted in the saline Atlantic, as opposed to Arctic freshwater that is the common inference.