Sunday, February 23, 2014

Shocking news about mass extinctions and the oceans

First of all you need to remember your history of the Earth.

"The end-Permian mass extinction, which occurred 252 million years ago, was the biggest die-off in the planet's history, and the largest of the five mass extinctions seen in the fossil record. The cataclysm killed as much as 95 percent of all species on Earth." Charles Q. Choi, LiveScience Contributor.

Scientists have just discovered some amazing information about the consequences of this mass extinction on the oceans. "... global oceans in the extinction's aftermath were a bit like a ship manned by a skeleton crew — all stations were operational, but manned by relatively few species." Moreover, "At the level of presence or absence of modes of life, there was virtually no change in the long run."

William Foster, a paleontologist at Plymouth University in England and his colleague Richard Twitchett outlined their findings in the journal Nature Geoscience. "Functional diversity of marine ecosystems after the Late Permian mass extinction event." 23 February 2014, (see Abstract of the article below)

These are very important finding. They provides a window into the challenges the oceans currently face. The research on previous climate change and its effects on the oceans is relevant because past climate change may provide vital clues about the stressors affecting our ocean ecosystems. Moreover, this research reminds us that even without any humans natural factors including catastrophic impacts on planet Earth have caused great devastation.


The Late Permian mass extinction event about 252 million years ago was the most severe biotic crisis of the past 500 million years and occurred during an episode of global warming. The loss of around two-thirds of marine genera is thought to have had substantial ecological effects, but the overall impacts on the functioning of marine ecosystems and the pattern of marine recovery are uncertain. Here we analyse the fossil occurrences of all known benthic marine invertebrate genera from the Permian and Triassic periods, and assign each to a functional group based on their inferred lifestyle. We show that despite the selective extinction of 62–74% of these genera, all but one functional group persisted through the crisis, indicating that there was no significant loss of functional diversity at the global scale. In addition, only one new mode of life originated in the extinction aftermath. We suggest that Early Triassic marine ecosystems were not as ecologically depauperate as widely assumed. Functional diversity was, however, reduced in particular regions and habitats, such as tropical reefs; at these smaller scales, recovery varied spatially and temporally, probably driven by migration of surviving groups. We find that marine ecosystems did not return to their pre-extinction state, and by the Middle Triassic greater functional evenness is recorded, resulting from the radiation of previously subordinate groups such as motile, epifaunal grazers.  Courtesy Nature Geoscience

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