A new estimate of biodiversity on Earth

by University of Chicago Press Journals, August 30, 2017 in ScienceDaily

To date, about 1.5 million species have been formally described in the scientific literature, most of them insects. Proportionally, bacteria comprise less than 1% of all described species.

In a new paper published in The Quarterly Review of Biology (September 2017), researchers from the University of Arizona have estimated that there are roughly 2 billion living species on Earth, over a thousand times more than the current number of described species.

The onset of widespread marine red beds and the evolution of ferruginous oceans

by Haijun Song et al., August 2017, in Nature

Banded iron formations were a prevalent feature of marine sedimentation ~3.8–1.8 billion years ago and they provide key evidence for ferruginous oceans. The disappearance of banded iron formations at ~1.8 billion years ago was traditionally taken as evidence for the demise of ferruginous oceans, but recent geochemical studies show that ferruginous conditions persisted throughout the later Precambrian, and were even a feature of Phanerozoic ocean anoxic events.

Soil carbon debt of 12,000 years of human land use

by J. Sanderman et al., July 2017 in PNAS

Human appropriation of land for agriculture has greatly altered the terrestrial carbon balance, creating a large but uncertain car- bon debt in soils. Estimating the size and spatial distribution of soil organic carbon (SOC) loss due to land use and land cover change has been difficult but is a critical step in understand- ing whether SOC sequestration can be an effective climate mitigation strategy.

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Volcanic eruptions drove ancient global warming event

by Marcus Gutjah et al., August 30,  2017 in PhysOrg

A natural global warming event that took place 56 million years ago was triggered almost entirely by volcanic eruptions that occurred as Greenland separated from Europe during the opening of the North Atlantic Ocean,

The amount of carbon released during this time was vast—more than 30 times larger than all the fossil fuels burned to date and equivalent to all the current conventional and unconventional fossil fuel reserves we could feasibly ever extract.” Ridgwell said.

An unexpected finding was that enhanced organic matter burial was important in ultimately sequestering the released carbon and accelerating the recovery of the Earth’s ecosystem without massive extinctions.

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