Mollusks, corals, carbon, and volcanoes

May 30th, 2012 by Michon Scott
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Paleozoic, Mesozoic, and Cenozoic. These are the major eras in the history of life on Earth, and the transition from one period to another has been marked by a major turnover in fossils — one assemblage of organisms going extinct and being replaced by another.

Today paleontologists agree that the biggest extinction in the fossil record occurred at the transition between the Paleozoic and Mesozoic, about 250 million years ago. During this Permo-Triassic extinction, perhaps as much as 70 percent of the plant, reptilian, amphibian, and insect species died on land. In the ocean, the consequences were even more devastating; up to 96 percent of Earth’s marine species went extinct.

The cause of such a catastrophic loss of life has been the subject of ongoing study. One proposed explanation is an asteroid strike like the one blamed for dinosaur extinction 65 million years ago. Another explanation involves the oxygen level in the ocean. Marine organisms need oxygen just as terrestrial organisms do, and some scientists have speculated that oxygen-poor water welled up from the ocean depths and suffocated marine life. Another hypothesis is large-scale volcanism. Studies published in November 2011 and May 2012 argue that volcanism does the best job of explaining all the evidence in the geologic record. And it not only explains the ancient mass extinction, but also hints at future threats to ocean life.

Although weathered by 250 million years of erosion, the Siberian Traps remain unmistakable today. Photo by Jon Ranson, NASA.

The volcanic hypothesis centers around the Siberian Traps, flat-topped volcanic mountains in Russia. The massive eruption that produced these mountains occurred 250 million years ago, about the same time as the Permo-Triassic extinction. The eruption was one of the biggest volcanic events in the last 500 million years, and it matches up with not only the timing of the extinction, but with the kinds of animals that were hit hardest.

Volcanoes release carbon dioxide, and the Siberian Traps eruptions would have emitted huge quantities of it, while also producing it indirectly. The basalts released by the eruptions flowed over sedimentary rock rich in organic material. Geologic studies of the Siberian Traps have revealed gas explosion structures along the margins of the flood basalts, which geologists have interpreted as evidence of sudden, violent carbon releases from sedimentary rocks under pressure by lava.

Besides raising atmospheric temperatures with heat-trapping gas, the newly released carbon dioxide would also have affected the ocean. Carbon dioxide dissolves in seawater to create carbonic acid, increasing ocean acidity. The carbonic acid reacts with carbonate ions, leaving less carbonate for marine life to use for shells or skeletons. Animals with such shells or skeletons suffer, but they don’t all suffer equally. Mollusks and marine arthropods have what biologists refer to as “buffered physiology,” which means they have closed circulation systems and/or gas-exchanging features (such as gills) to buffer their internal tissues from changes in ocean chemistry. Other animals such as sponges, coralssea urchins, and sea lilies do not; their tissues are directly exposed to seawater. What the Permo-Triassic extinction studies found was that the poorly buffered organisms experienced greater rates of extinction and took longer to rebound.

Likely to be among the biggest losers in ocean chemistry changes, corals have few mechanisms to protect their internal tissues from increasing acidity. Image courtesy NOAA Ocean Explorer.

Carbon dioxide alone did not cause the catastrophic extinction 250 million years ago. Other factors, including higher temperatures and lower oxygen levels in the water, also pressured marine life. But carbon dioxide likely played an outsized role.

No one can predict when volcanic activity as widespread and destructive and the Siberian Traps eruptions might occur again. But we do know that rising carbon dioxide levels in the atmosphere pose a threat to marine life today. While volcanoes currently release 130 to 380 million metric tons of carbon dioxide each year, human burning of fossil fuels releases about 30 billion tons of it. That’s anywhere from 100 to 300 times as much greenhouse gas that can increase ocean acidity.

Today’s ocean contains a sizable reservoir of fine-grained calcium carbonate sediment that acts as a counterweight to rising ocean acidity. Geologists surmise that such a reservoir probably didn’t exist in the Permo-Triassic ocean. Moreover, today’s marine organisms descended from the survivors of high acidity episodes over the last 250 million years, so they may be better able to withstand ocean chemistry changes. Nevertheless, rising ocean acidity could spell trouble for marine organisms such as corals. A 2011 study of volcanic carbon dioxide seeps in Papua New Guinea found that ocean acidification and temperature stress reduced coral diversity and abundance. As before, poorly buffered marine life could suffer.

For more information on carbon dioxide and ocean acidification, please see the Earth Observatory features The Carbon Cycle and The Ocean’s Carbon Balance.

References

Clapham, M.E., Payne, J.L. (2011) Acidification, anoxia, and extinction: A multiple logistic regression analysis of extinction selectivity during the Middle and Late Permian. Geology. 39(11), 1059-1062.

Fabricius, K. E., Langdon, C., Uthicke, S. Humphrey, C. Noonan, S., De’ath, G. Okazaki, R. Muehllehner, N. Glas, M.S., Lough, J.M. (2011) Losers and winners in coral reefs acclimatized to elevated carbon dioxide concentrations. Nature Climate Change. 1, 165-169.

Kerr, R.A. (1997) Life’s winners keep their poise in tough times. Science. 278(5342), 1403.

Mitchell, A. (2012, April 30) Life in the sea found its fate in a paroxysm of extinction. The New York Times.

Payne, J.L., Clapham, M.E. (2012) End-Permian mass extinction in the oceans: an ancient analog for the twenty-first century? Earth and Planetary Sciences. 40, 89-111.

PBS Evolution. (2001) Permian-Triassic extinction.

7 Responses to “Mollusks, corals, carbon, and volcanoes”

  1. aldo ferretti says:

    unfortunately i am too old to get blasted into space, but whatever i get from you via e-mail is fascinating

  2. Attila Bruncsak says:

    At the end of that period the level of carbon dioxide has decreased to normal both in the oceans and the atmosphere and the life had the chance to florish a new. I wonder if the same increase of carbon-dioxide would happen again (independently of being natural or man-made reason) there is one signifcant difference: the radiation of the sun is bigger now than 250 millions year ago. There is a chance that the same size (or slightly bigger) of deviation could not let the earth to return to its previous meta-stable status (which can be shortly desribed by the mixtture of two phase of water, ice and fluid) but to venus-like meta-stable status when the oceans are evaporated to the atmosphere, all the carbon dioxide are realesed from the calcium carbonates.

  3. A. Andrew says:

    Human burning of fossil fuels releases about 30 billion tons of carbon dioxide a year. That’s anywhere from 100 to 300 times as much greenhouse gas generated by natural events. All these facts and still lots of people are not even willing to admit that humans are the main reason for getting our universe closer and closer to disaster.

  4. Eric Pritchard says:

    Surely the normal result of volcanic activity is cooling, not heating. Volcanoes release large amounts of sulphur dioxide into the atmosphere which reflects solar radiation, hence the effect of Toba 75,000 years ago (ice age with the human race almost reduced to extinction) and Tambora (year without a summer, 1816), not to mention the effect of the Laki fissure eruptions on the agriculture of Europe. The other point is that increasing the temperature of the oceans reduces their ability to absorb carbon dioxide so they become less acidic. We could from that postulate a cooling effect from the Traps, which would affect surface life, and also increase the oceans ability to absorb carbon dioxide. This would make the oceans more acidic (poisoning the marine life) and further accentuate the cooling effect of the sulphur dioxide by reducing the atmospheric greenhouse effect, making conditions even worse on land.

  5. JOSEPH WILDHAGEN says:

    Volcanic activity associated with the Hawaiian hot spot is the greatest now in the entire history of the Hawaiian archipelago, and the Pacific rim of fire seems to be awakening as in the irregular occurance of Earth’s magnetic reversal. Global Warming has been a political excuse to impose a new concept of global taxation, and exposed frequent tampering with data has destroyed the credibility of politically conformed pseudoscience. In fact Earth has been in an unusually long period of warm since the Younger Dryas stadial, glaciers have been melting for over 12,000 years (not just the last 100 years), and it was not due to Fred Flintstone cooking fish on an open wood fire. A global extinction event seems to really be occuring, and the politicalization of science is masking the real causes, including chem trails, the deliberate poisoning of the environment; the planned use of extremely poisonous dispersant chemicals for the Gulf Oil Spill a year ago, which has destroyed the immune systems of fish and other life; the poisoning of domestic water systems with Sodium Fluoride and associated toxins (developed in NAZI Germany to dumb down the population, falsely claiming dental benefits), which in turn poisons the environment with toxic gray and black water down stream. The globalist rich (Bilderbergers) believe that a global extinction event is acceptable, survivable (in their underground reserves with vast food and seed collections), and desireable (stated objective reduce world’s population to half a billion, under their domination). It is sad that real science cannot be retained with humanitarian policy to establish a sustainable harmonious environment on Earth, instead of a violent self justified “whomever dies with the most toys wins” mentality. The gift of the large mammals for food during the last ice age will not be available this time, only canablism remains as an option as overfishing, habitat reduction, and genetically engineered poisoning of the natural flora destroys the delicate balance of ecosystems.

  6. katesisco says:

    While I see what J Wild sees, I would also like to have a more complete record of history and prehistory. Did you know that the only place on Earth carbon disulfide occurs naturally (man made PVC) is on the lips of active volcanos? It is a vicious dna mutagen. Mother Nature is entirely capable of eliminating life without human intervention.
    And Yes, our interglacial is unusually long and warm. To what do we owe this?
    Consider: if Earth has experienced periodic heating (expansion) and contraction (disappation of heat) events, it would show a catastrophic gelogic record such as Earth does. If this combination produced our life (intelligence is entirely local) then perhaps this life was able to alter the catastrophic periods to less than catastrophic. Is it odd that we have the amazing pyramids that are as old as our strange long-term warm? Instead of an E that blew itself apart due to a heated core, we would have a safety valve that minimized and maximized short term events to long term less dangerous.
    And this volcanism is now seen as producing the small-cluster monoatomic elements. Since volcanos produce greater bursts of energy than produced on the surface of the sun, one might well consider that this is the source of the altered elements. Science says our surface is depleted of silicon compared to the inner material so it appears this energy produced by volcanos is capable of mutating elements. The small-cluster gold, rhodium, pladium, platium, etc. that mimic ceramic are undetectable because their valances, while not filled, do not combine as in analytic chemistry. Are they the source of missing matter and energy?

  7. karen gravina says:

    I live in Hull,MA and I’m wondering what is going on in the ocean. I’ve noticed over recent years more and more bleached out ripped up red,orange coral on the beach after fall and winter storms. This summer a huge deposit of tiny clams with paper thin shells washed ashore in July,2012 and they are continuing to wash ashore and are piling up on the beach. I haven’t seen this happen before. This has continued through this month with more and more clams in Jan, 2013.

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