Great read. I'm impressed by the fact that it was written in so clear a layman's language. The community is indeed realizing the complexity of the physical nature of the ocean as it relates to carbon budgets. One of the interesting byproducts of increased CO2 in the oceans, is that pH decreases (ie., the oceans become more acidic)as CO2 increases. It has been shown experimentally that even a small decrease in pH would drastically affect marine organisms that secrete calcareous skeletons (shells and skeletons made of calcium carbonate) that dissolve (and are harder to form) at lower pH. In the recent issue of Nature, scientists reported for the first time observed ecological effects of increased CO2 (from local volcanic sources) on marine organisms. Their data show that with what would seem to be small changes in pH, the effect on marine life is drastic.
It turns out that the deep-time rock record may record a similar crisis following a mass extinction at the end of the Permian. A number of lines of evidence suggest that atmospheric CO2 was much higher then, most likely due to intense volcanism and ocean stratification (which in theory allows CO2 to build up in the deep ocean). This time of high CO2 was not only much warmer than the preceeding glacial interval, but also resulted in what we call a "reef gap" in the rock record--a time when animals were simply not building reefs. We know that corals existed before and after the reef gap, yet no there were no reefs (or coral fossils) for millions of years. It has been suggested that because of the increased CO2, corals and other organisms were unable to secrete their calcareous skeletons.
Scientists have reported coral bleaching, a phenomenon where, due to decreased pH, the microbial symbionts that live with corals are expelled, causing the corals to loose their color. These symbionts, called Zooxanthellae are vital for coral growth and reef formation. The coral bleaching trend occurring now may be the precursor to another "reef gap". Considering how much biodiversity is associated with coral reefs, a new "reef gap" would be bad news for marine life and those of us that depend on it.
I thought that UV light was commonly blamed for coral bleaching? (i.e. not global warming through increased CO2 release, but CFCs released in the 1930-1980 period).
In regards to the zooxanthellae, do they live on without the reef structure as individual animals, or were ancient reefs built by a completely non-related set of species?
And tying modern changes in ocean chemistry to deep time occurances sounds like a great source of grant money... particularly if you are accepting said grant money from those who wish to posit that modern CO2 changes are due to natural geochemistry changes, and not human action.
It turns out that the deep-time rock record may record a similar crisis following a mass extinction at the end of the Permian. A number of lines of evidence suggest that atmospheric CO2 was much higher then, most likely due to intense volcanism and ocean stratification (which in theory allows CO2 to build up in the deep ocean). This time of high CO2 was not only much warmer than the preceeding glacial interval, but also resulted in what we call a "reef gap" in the rock record--a time when animals were simply not building reefs. We know that corals existed before and after the reef gap, yet no there were no reefs (or coral fossils) for millions of years. It has been suggested that because of the increased CO2, corals and other organisms were unable to secrete their calcareous skeletons.
Scientists have reported coral bleaching, a phenomenon where, due to decreased pH, the microbial symbionts that live with corals are expelled, causing the corals to loose their color. These symbionts, called Zooxanthellae are vital for coral growth and reef formation. The coral bleaching trend occurring now may be the precursor to another "reef gap". Considering how much biodiversity is associated with coral reefs, a new "reef gap" would be bad news for marine life and those of us that depend on it.
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I thought that UV light was commonly blamed for coral bleaching? (i.e. not global warming through increased CO2 release, but CFCs released in the 1930-1980 period).
In regards to the zooxanthellae, do they live on without the reef structure as individual animals, or were ancient reefs built by a completely non-related set of species?
And tying modern changes in ocean chemistry to deep time occurances sounds like a great source of grant money... particularly if you are accepting said grant money from those who wish to posit that modern CO2 changes are due to natural geochemistry changes, and not human action.
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