Saturday, September 1, 2012

Island Creek Foundation Gala Yale on Ocean Acidification

Reminder Island Creek Foundation Gala on September 8th

On Saturday September 8, Duxbury's Island Creek Oyster Group will be hosting the annual Foundation Fundraiser, Friends for Haiti. Its shaping up to be another terrific event on the beach, with some epic food from both Boston and NYC's finest chefs, great cocktails, and great friends - all to support the Foundation's work building sustainable sources of protein in developing countries. You can check it out through clicking on this link

The current rate of ocean acidification has no precedent in 300 million years of Earth history according to the Yale Environmental Review

A story in the Yale Environmental Review highlights the rapidly growing phenomenon of ocean acidification. At least a third of all the carbon dioxide that humans have released into the atmosphere has been absorbed by the ocean. Once dissolved in seawater, CO2 forms carbonic acid, which not only lowers the pH of the ocean – that is, makes it more acidic – but also decreases the availability of Carbonate ions (CO32-) to organisms that need it to grow Calcium Carbonate (CaCO3) shells. This  is problematic for steamer clams and oysters. The impact on oyster growth is being noted in the Pacific Northwest. Laboratory studies have shown that many organisms at the base of the marine food web suffer from reduced shell formation in acidified conditions – conditions that may become typical during this century. In other words, ocean acidification threatens the very foundation of the marine ecosystem.

Scientists have been able to discern past acidification events for some time by noting a decrease in CaCO3 deposition on ancient seafloors. Recent advances in trace element and isotopic chemistry, however, have enabled them to discern past events with greater clarity than before, and to a horizon of about 300 million years.  Within that span, scientists are looking for events that are analogous to the one that is happening today.

There aren’t many. In most earlier events, the decrease in ocean pH was not accompanied by decreased availability of CO32-.  That is because these past events happened over periods of 100,000 years or more, time during which the natural weathering of terrestrial rock kept the saturation state of CaCO3 in the oceans stable despite the change in pH.  Today, acidification is happening too quickly for weathering to counterbalance it, and so this event may be unprecedented in the history of the planet.

Three past acidification events may be partially comparable to what is happening today, but further research is needed to understand their history in more detail.  In the meantime, it appears that the current acidification event is driving biogeochemical changes in the oceans that are potentially unparalleled in the history of Earth. 

One implication of this for oyster restoration is that the presence of a mass of shell may be helpful on a micro-level as the shell is an effective buffer to acid. One of oyster shell's main components its calcium carbonate which is effectively the same acid neutralizer as that in Rolaids and Tums. 

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