mass extinction – Geobites

September 22, 2022September 23, 2022

Getting to Grips With the Sixth Mass Extinction

Featured Image: It is well-understood that the Earth’s biodiversity is in severe decline. However, it is less clear if this decline can now be called a mass extinction. Public domain image via. The Wilderness Society.

Paper: The Sixth Mass Extinction: fact, fiction, or speculation?

Authors: Robert H Cowie, Philippe Bouchet & Benoît Fontaine

Human-driven emissions and land use changes have impacted Earth’s biosphere greatly, causing global extinction rates to climb fast. However, does the current undeniable biodiversity crisis meet the requirements to be called a mass extinction?

September 14, 2022September 14, 2022

Chicxulub’s small sibling

Featuring image: 66 million years ago, a giant meteorite impact ended the age of the dinosaurs. Artist impression of the impact. Painting by Donald E. Davis, Public Domain (C0)

Paper: The Nadir Crater offshore West Africa: A candidate Cretaceous-Paleogene impact structure

Authors: U. Nicholson, V. J. Bray, S. P. S. Gulick, B. Aduomahor

The appearance of a flaming, 10 km wide meteorite over the Gulf of Mexico must have been striking, literally. But could the meteorite, which killed the dinosaurs, have had a small sibling or even a whole family of smaller space rocks hurtling towards Earth?

The massive meteorite impact at Chicxulub in the Gulf of Mexico ended the era of the dinosaurs 66 million years ago. Now, only a few thousand km apart from it, researchers might have found another, smaller crater of a similar age. And it might show that the Chicxulub meteorite was not alone but part of a cluster of meteorites, bombarding the Earth at the end of the Cretaceous period.

August 31, 2022August 31, 2022

The rise of Sponges

Featuring image: Venus flower basket glass sponges (Euplectella aspergillum) in the Gulf of Mexico. NOAA Okeanos Explorer Program – Gulf of Mexico 2012 Expedition, CC-BY-2.0

Paper: Palaeoecological Implications of Lower-Middle Triassic Stromatolites and Microbe-Metazoan Build-Ups in the Germanic Basin: Insights into the Aftermath of the Permian–Triassic Crisis

Authors: Y. Pei, H. Hagdorn, T. Voigt, J.-P. Duda, J. Reitner

The Permian-Triassic crisis was the greatest mass extinction in Earth’s history. But an unlikely animal might have benefited from this cataclysm: the sponge.

Microbial mats like stromatolites represent the lithified remains of different slimy accumulations of microorganisms. While there are many different types, Pei and co-workers investigated a special type of microbial mats with a very different internal structure, called microbial-metazoan build-up, mainly consisting of sponges. By comparing these fossil structures to common stromatolites from the Permian-Triassic boundary, the researcher team could show that sponges profited from the mass extinction with the aid of bacteria.

April 26, 2022April 26, 2022

Earth’s darkest hour

Featured image: This is a Trilobite fossil from Volkhov river, Russia. Trilobites were marine arthropods which went extinct at the end of Permian period. CC BY-SA 3.0 via Wikimedia commons

Paper: Bioindicators of severe ocean acidification are absent from the end-Permian mass extinction.

Authors: William J. Foster, J.A. Hirtz, C. Farrell, M. Reistrofer, R. J.Twitchett, R. C. Martindale

What if I told you that an extinction event occurred In Earth’s history that dwarfs the demise of dinosaurs? This turbulent period dawned 252 million years ago, during the Late Permian period. The largest volcanic eruptions in the history of our planet began in now what is known as Siberia. The eruptions spewed out millions of cubic kilometers of lava, enough to bury an area the size of United States under a mile thick layer of rock!

February 25, 2022September 26, 2022

What caused the end-Triassic Mass Extinction in the Oceans?

Feature Image: Outcrop of volcanic rock associated with the Central Atlantic Magmatic Province. This Large Igneous Province has a strong correlation to the onset of a mass extinction ~200 million years ago, however, an exact mechanism for the extinction has been difficult to determine. CC BY-SA 4.0, via Wikimedia Commons

Paper: Two-pronged kill mechanism at the end-Triassic mass extinction

Authors: Calum P. Fox; Jessica H. Whiteside; Paul E. Olsen; Xingquian Cui; Roger E. Summons; Kliti Grice

Journal: Geology

A recent study by Calum Fox and colleagues sheds light on what caused one of the “big five” mass extinctions on Earth since complex life emerged ~540 million years ago. They found that repeated pulses of volcanic activity were responsible for the extinction in two main ways: ocean poisoning caused by gaseous hydrogen sulfide (H₂S) rising through the water column (known as euxinia) and ocean acidification.