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Fri Oct 19, 2012, 04:41 PM

New report blames heat for ancient extinction

Source: Xinhua

Chinese, British and German scientists have discovered that the worst extinction of the Earth's history happened because the planet was simply too hot to survive.

The discovery about the end-Permian mass extinction, which wiped out the world's species 250 million years ago and was followed by a "dead zone" of five million years in which the planet welcomed no new species,came in a paper published on Friday in Science, one of world's top scientific journals.

The joint study by the China University of Geosciences in Wuhan, capital of central China's Hubei Province, the University of Leeds in Britain and the University of Erlangen-Nuremburg in Germany, shows the cause of the lengthy devastation was a temperature rise to lethal levels: around 50 to 60 degrees Celsius on land, and 40 degrees Celsius at the sea-surface.

<snip>

Professor Paul Wignall from the School of Earth and Environment at the University of Leeds, one of the study's co-authors, said: "Nobody has ever dared say that past climates attained these levels of heat. Hopefully future global warming won't get anywhere near temperatures of 250 million years ago, but if it does we have shown that it may take millions of years to recover."

<snip>

Read more: http://www.shanghaidaily.com/article/article_xinhua.asp?id=102733



Another article has this graphic:
http://io9.com/5953178/triassic-eras-extreme-heat-created-dead-zones-across-the-planet

Triassic era’s extreme heat created “dead zones” across the planet


A paleogeographic reconstruction of the Early Triassic world (Smithian substage) around 252 to 247 million years ago, showing a ‘dead zone' in the tropics. Marine reptiles (ichthyosaurs), terrestrial tetrapods and fish almost exclusively occurred in higher latitudes (>30 °N and >40 °S) with rare exceptions. Credit: Yadong Sun, University of Leeds.

<snip>

And indeed, life had no choice but to react to this heat. It's suspected that marine life swam to the polar regions to keep cool. Similarly, terrestrial animals also headed to the extreme north and south. Back then, the mega-continent Pangea existed, making Antarctica/Australia and Siberia likely areas for re-habitation.

Meanwhile, the tropical regions would have been bizarre places to visit. These areas would have been very wet, but with very few plants growing — only shrubs and ferns. These ares would have been devoid of most terrestrial creatures. And in the waters, only shellfish would have stuck around.

What happened? Essentially, the superhot Earth was caused by a breakdown in global carbon cycling. Normally, plants help regulate temperature by absorbing CO2 and burning it as dead plant matter. But without plants, the CO2 levels rose unchecked, causing a spike in temperatures. Specifically, the researchers estimate that at least 12×10^3 gigatons of isotopically depleted carbon as methane was injected into the atmosphere.

To reach this conclusion, the scientists collected data from over 15,000 conodonts (tiny teeth of eel-like fishes). By analyzing the isotopes of oxygen in these remnants, they were able to determine the temperature levels hundreds of millions of years ago. You can read the entire study at Science.


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Arrow 24 replies Author Time Post
Reply New report blames heat for ancient extinction (Original post)
bananas Oct 2012 OP
bemildred Oct 2012 #1
frogmarch Oct 2012 #2
bananas Oct 2012 #9
frogmarch Oct 2012 #21
bananas Oct 2012 #10
frogmarch Oct 2012 #22
msongs Oct 2012 #3
nichomachus Oct 2012 #4
aquart Oct 2012 #5
kentauros Oct 2012 #12
closeupready Oct 2012 #6
dipsydoodle Oct 2012 #7
Rosa Luxemburg Oct 2012 #8
jimlup Oct 2012 #11
Spitfire of ATJ Oct 2012 #13
kentauros Oct 2012 #14
Posteritatis Oct 2012 #20
kentauros Oct 2012 #23
starroute Oct 2012 #15
AverageJoe90 Oct 2012 #19
ErikJ Oct 2012 #16
Agnosticsherbet Oct 2012 #17
ErikJ Oct 2012 #18
Spitfire of ATJ Oct 2012 #24

Response to bananas (Original post)

Fri Oct 19, 2012, 04:47 PM

1. That's the one.

Thanks for posting. That's really hot.

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Response to bananas (Original post)

Fri Oct 19, 2012, 05:00 PM

2. Thank you!

I'm going to check out the link now.

Exciting study!

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Response to frogmarch (Reply #2)

Fri Oct 19, 2012, 06:12 PM

9. Unfortunately, the paper in Science is paywalled

Science has the paper and a perspective article on the paper, both paywalled.
http://www.sciencemag.org/content/338/6105/366.abstract

Science 19 October 2012:
Vol. 338 no. 6105 pp. 366-370
DOI: 10.1126/science.1224126

Report

Lethally Hot Temperatures During the Early Triassic Greenhouse

Yadong Sun1,2,*,
Michael M. Joachimski3,
Paul B. Wignall2,
Chunbo Yan1,
Yanlong Chen4,
Haishui Jiang1,
Lina Wang1,
Xulong Lai1

Abstract

Global warming is widely regarded to have played a contributing role in numerous past biotic crises. Here, we show that the end-Permian mass extinction coincided with a rapid temperature rise to exceptionally high values in the Early Triassic that were inimical to life in equatorial latitudes and suppressed ecosystem recovery. This was manifested in the loss of calcareous algae, the near-absence of fish in equatorial Tethys, and the dominance of small taxa of invertebrates during the thermal maxima. High temperatures drove most Early Triassic plants and animals out of equatorial terrestrial ecosystems and probably were a major cause of the end-Smithian crisis.

Received for publication 1 May 2012.
Accepted for publication 4 September 2012.



http://www.sciencemag.org/content/338/6105/336.summary

Science 19 October 2012:
Vol. 338 no. 6105 pp. 336-337
DOI: 10.1126/science.1228998

Perspective

Geochemistry
Life in the Early Triassic Ocean

David J. Bottjer

In the next 100 years, it is projected that Earth will move to a greenhouse climate state (1). The future ocean will not only be hotter but also more acidic and will contain extended zones with reduced oxygen (2, 3). Study of past periods of global warming helps to project what Earth and its biota will be like in this new state and what the journey to that state will entail. On page 366 in this issue, Sun et al. (4) show that beginning with the end-Permian mass extinction (∼252.6 million years ago) and continuing for the next 5 million years, Earth's oceans were extremely hot, with stressful and commonly lethal effects on ocean life.



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Response to bananas (Reply #9)

Fri Oct 19, 2012, 10:12 PM

21. Thank you. nt

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Response to frogmarch (Reply #2)

Fri Oct 19, 2012, 06:16 PM

10. io9 links to the wrong paper

The io9 article links to a paper published last July, which is also paywalled.
http://www.sciencemag.org/content/333/6041/430.abstract?sid=39695b89-79f0-4b26-83c9-ea4db742ed62

Science 22 July 2011:
Vol. 333 no. 6041 pp. 430-434
DOI: 10.1126/science.1204255

Report

Atmospheric Carbon Injection Linked to End-Triassic Mass Extinction

Micha Ruhl1,2,*,
Nina R. Bonis1,3,
Gert-Jan Reichart4,
Jaap S. Sinninghe Damsté4,5,
Wolfram M. Kürschner1,6

Abstract

The end-Triassic mass extinction (~201.4 million years ago), marked by terrestrial ecosystem turnover and up to ~50% loss in marine biodiversity, has been attributed to intensified volcanic activity during the break-up of Pangaea. Here, we present compound-specific carbon-isotope data of long-chain n-alkanes derived from waxes of land plants, showing a ~8.5 per mil negative excursion, coincident with the extinction interval. These data indicate strong carbon-13 depletion of the end-Triassic atmosphere, within only 10,000 to 20,000 years. The magnitude and rate of this carbon-cycle disruption can be explained by the injection of at least ~12 × 103 gigatons of isotopically depleted carbon as methane into the atmosphere. Concurrent vegetation changes reflect strong warming and an enhanced hydrological cycle. Hence, end-Triassic events are robustly linked to methane-derived massive carbon release and associated climate change.

Received for publication 14 February 2011.
Accepted for publication 1 June 2011.

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Response to bananas (Reply #10)

Fri Oct 19, 2012, 10:15 PM

22. sheesh! Thanks again. My company left and

I was just getting ready to read it.

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Response to bananas (Original post)

Fri Oct 19, 2012, 05:02 PM

3. so life should have evolved to meet the new conditions...ooops nt

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Response to bananas (Original post)

Fri Oct 19, 2012, 05:18 PM

4. So, basically, kind of a "do over"

Not a bad idea at all.

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Response to bananas (Original post)

Fri Oct 19, 2012, 05:28 PM

5. Going into global warming, that's just lovely.

Can we please carve all of Shakespeare into stone in at least three different forms of writing?

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