Taxonomy term

news

Humans accidentally created new rivers in Europe

Meandering rivers that flow through and transport sediment to deltas often split off from their main courses and flow in different directions. This process, called avulsion, happens naturally when a river overflows its banks and the floodwaters carve out a new course for the river to follow. But humans can also trigger avulsions by changing the shape of the landscape, and in a new study, scientists report that people have been doing this for a very long time.

15 Feb 2019

Free swimmers came back first after Great Dying

About 252 million years ago, at the boundary between the Permian and Triassic periods, the vast majority of marine and terrestrial life died out in the most devastating extinction event in Earth’s history. Earth’s ecosystems eventually recovered, but not in the way — or as quickly as — scientists thought. In a new study looking at how marine species reemerged in the Triassic, researchers report a surprising trend of recovery from the top of the food chain down.

14 Feb 2019

Archaeologists hit pay dirt in medieval latrines

Archaeologists digging in Lübeck, Germany, unearthed an unusual source of information about past dietary habits in the city: parasite eggs recovered from 700-year-old latrines.

12 Feb 2019

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

Mediterranean heritage sites threatened by rising seas

The Mediterranean region has been a cultural center for centuries, giving rise to numerous locales designated as UNESCO World Heritage sites. A new study looking at the effects of rising sea levels on treasures like the Venetian Lagoon, the Old City of Dubrovnik and the ruins of Carthage indicates that most UNESCO sites on the Mediterranean Sea are at risk of storm surge and coastal erosion as well as inundation in the coming decades.

07 Feb 2019

Mighty Mekong cut by monsoon, not tectonics

The rivers draining the Tibetan Plateau are some of the largest, longest and most deeply incised waterways in the world. For decades, most geologists assumed that these river canyons were cut as the plateau was uplifted following the initial collision of the Indian subcontinent with Asia. However, recent studies have found that the plateau was already elevated by 40 million years ago — roughly 20 million years before the deep canyons formed. 

06 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

Deep drilling reveals how impact crater's hidden ring formed

When the 15-kilometer-wide Chicxulub meteorite slammed into what is now Mexico’s Yucatán Peninsula 66 million years ago, it was moving at more than 20 kilometers per second. The impact blasted a hole 200 kilometers wide and more than 30 kilometers deep in Earth’s surface. The forces involved in such impacts are colossal — many orders of magnitude greater than the largest human-made explosions — and scientists have traditionally relied on models to explain what happens in the moments after impact. But in a new study looking at shocked rocks retrieved from the depths of the buried Chicxulub Crater, scientists have determined how the crater’s “peak ring” formed in mere minutes.

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

Melting glaciers shift Earth's axis

A perfectly round desk globe spins evenly on a fixed axis, but that’s not the case with Earth, which wobbles as the position of its spin axis — the imaginary line running between the North and South poles — slowly drifts over time. In a new study in Earth and Planetary Science Letters, scientists suggest that there are three main reasons for the movement of Earth’s spin axis, called polar motion.

28 Jan 2019

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