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Hot but not bothered: Warm soils favor microbes with small genomes

Centralia, Pa., sits above rich subterranean coal seams, which made the town a mining center for about a century. In 1962, the seams were accidentally ignited by burning garbage, turning the coal from a commodity into a liability. Driven away by fire-associated hazards and particulate air pollution, all but a few human residents have long since abandoned the town. However, a new study reveals that the same isn’t true for all forms of life: A diverse population of microbial life resides in Centralia’s hot soils. These heat-tolerant microbes are offering scientists novel insights into the composition and character of soil microbial communities and resilience in response to dramatic ecosystem change.

08 Feb 2019

"Cradle of Humankind" fossils can now be dated

Robyn Pickering was taught as an undergraduate about a collection of limestone caves in northern South Africa known collectively as the Cradle of Humankind for the trove of early hominin fossils discovered there. She learned that, unlike hominin fossils unearthed in East Africa, whose ages have been constrained by dating the surrounding layers of volcanic ash, the fossils in the Cradle — including well-preserved specimens of Australopithecus africanus and the recently discovered Homo naledi, among others — were impossible to date independently. Now, Pickering, an isotope geochemist at the University of Cape Town, and her colleagues have figured out a way to date the South African fossils after all. In a recent study published in Nature, the researchers report ages for flowstones — horizontal deposits of calcium carbonate that form natural cements on cave floors — across eight caves in the Cradle of Humankind. The flowstones sandwich fossil-bearing sediment layers, allowing age ranges for the fossils to be determined.

05 Feb 2019

Thirsty mantle: Subduction zones swallow more water than thought

For all the water stored in oceans, ice and other reservoirs at Earth’s surface, there’s likely even more in the planet’s interior, where it plays important roles in many geological processes, including the formation of magma and the lubrication of earthquake-producing fault zones. Uncovering just how much water is inside Earth — and the extent to which it moves back and forth between the surface and subsurface — has long been a challenge for scientists interested in understanding the planet’s water cycle. A new study peering beneath the Mariana Trench in the Western Pacific has revealed that some subduction zones might pull significantly more water into Earth’s interior than previously thought.

30 Jan 2019

Sulfides in thawing permafrost responsible for carbon dioxide release

After warming the bench since the Pleistocene, a key player in the Arctic carbon cycle is getting back in the game thanks to thawing permafrost. In a new study, researchers report that rising temperatures are freeing sulfide minerals previously bound within Arctic permafrost. These minerals are contributing to stream acidification and accelerated weathering of carbonates — and thus to the release of carbon dioxide into the atmosphere — at least in one part of northern Canada.

03 Dec 2018

Ocean tide size linked to supercontinent cycle

Daily tides are driven primarily by Earth’s rotation and the gravitational force of the moon on oceans. However, in a new study in Geophysical Research Letters, researchers suggest that tidal magnitudes are also influenced, on longer timescales, by the size and shape of the ocean basins, and are therefore driven by plate tectonics.

07 Sep 2018

Sea-level rise could cut off wastewater service to millions in U.S.

Scientists report in a recent study that with just 30 centimeters of sea-level rise, roughly 4 million people in the U.S. could lose access to municipal wastewater services — services that allow three-quarters of America to run the tap and flush the toilet. And with even higher seas, the number goes up.

21 Jun 2018

"Dam levels critical" in Cape Town

At first glance, a visitor to Cape Town might not notice the extent of the parched conditions — people still go about their business, amid the same kind of hustle and bustle you would find in other major cities. But looking closer, there are signs that something is not right. People standing in buckets to conserve water during showers is one such sign, and bottled water flying off grocery store shelves is another.

13 Jun 2018

Cape Town faces a waterless future

The city of Cape Town, South Africa, is bone dry. In 2017, after two straight years of drought, a third drought year offered more of the same.. This past January, city leaders announced that they would shut off the taps to the municipal water supply in April because that was when “Day Zero” — the day when the water supply would run dry — was predicted to occur. Day Zero has since been pushed back to sometime in 2019, but, for 4 million Capetonians, living under the specter of a day without water is the new normal, and signs of that reality litter the city. Sometimes literally.

22 May 2018

When more humidity means less water

Scientists have long assumed that temperature is the main control on melting of winter snowpacks across the mountainous western United States. In a recent study, however, scientists suggest that regional humidity may have a larger impact than temperature.

16 May 2018

El Nino "flavors" affect California rainfall

Twenty years ago, the 1997–98 El Niño surpassed the 1982–83 event to become the strongest El Niño ever recorded, contributing to famine and drought in Southeast Asia, devastating floods in Southern California, and other natural disasters. By many metrics, the 2015–16 El Niño bested both to claim the title of the strongest El Niño on record. This most recent event, nicknamed the “Godzilla El Niño,” did contribute to extreme weather in parts of the world, including disastrous fires in Indonesia and the longest, global coral-bleaching event on record. However, it did not have the anticipated effect on California, which, at the time, was in the midst of a severe multi-year drought. In a recent study, researchers suggest the 2015–16 El Niño was the wrong “flavor” to bring heavy precipitation to the state.

13 May 2018

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