Tag Archives: timothy lyons

Research in the news: The rise of oxygen on Earth

Yale’s Noah J. Planavsky and collaborators have published a Nature review article titled “The rise of oxygen in Earth’s early ocean and atmosphere.”

Published online Feb. 19, the review surveys and assesses research about the emergence of significant oxygen concentrations and suggests that this happened hundreds of millions of years before the “great oxygenation event” of 2.3 billion years ago. In between, oxygen levels appear to have fluctuated considerably, according to the authors. (more…)

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Global Extinction: Gradual Doom as Bad as Abrupt

*In “The Great Dying” 250 million years ago, the end came slowly*

The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life–and it killed in stages–according to a newly published report.

It shows that mass extinctions need not be sudden events.

Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. (more…)

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Widespread Ancient Ocean “Dead Zones” Challenged Early Life

*Persistent lack of oxygen in Earth’s oceans affected animal evolution*

The oceans became oxygen-rich as they are today about 600 million years ago, during Earth’s Late Ediacaran Period. Before that, most scientists believed until recently, the ancient oceans were relatively oxygen-poor for the preceding four billion years.

Now biogeochemists at the University of California-Riverside (UCR) have found evidence that the oceans went back to being “anoxic,” or oxygen-poor, around 499 million years ago, soon after the first appearance of animals on the planet. (more…)

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