Fishdunnit! Mystery solved( VIRGINIA KEY Fla. -- An internationa...)

VIRGINIA KEY, Fla. -- An international team of scientists has solved a mystery that has puzzled marine chemists for decades. They have discovered that fish contribute a significant fraction of the oceans' calcium carbonate production, which affects the delicate pH balance of seawater. The study gives a conservative estimate of three to 15 percent of marine calcium carbonate being produced by fish, but the researchers believe it could be up to three times higher.

Published January 16th in Science, their findings highlight how little is known about some aspects of the marine carbon cycle, which is undergoing rapid change as a result of global CO2 emissions.

Until now, scientists believed that the oceans' calcium carbonate, which dissolves in deep waters making seawater more alkaline, came from marine plankton. The recent findings published in Science explain how up to 15 percent of these carbonates are, in fact, excreted by fish that continuously drink calcium-rich seawater. The ocean becomes more alkaline at much shallower depths than prior knowledge of carbonate chemistry would suggest which has puzzled oceanographers for decades. The new findings of fish-produced calcium carbonate provides an explanation: fish produce more soluble forms of calcium carbonate, which probably dissolve more rapidly, before they sink into the deep ocean.

Corresponding authors Drs. Frank Millero and Martin Grosell at the University of Miami's Rosenstiel School of Marine and Atmospheric Science and Dr. Rod Wilson of the University of Exeter note that given current concerns about the acidification of our seas through global CO2 emissions, it is more important than ever that we understand how the pH balance of the sea is maintained. Although we know that fish carbonates differ considerably in their chemical make-up, the team has really only just scratched the surface regarding their chemical nature and ultimate fate in the ocean. Scientists
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