Sunday, February 20, 2011

Ocean Rainfall & Acidification: scientists study the process at sea

Acidification is one of the great challenges facing our oceans. It is the process whereby the ocean water's pH level, it's level of acidity, increases to a point that impacts various marine species, particularly those who build shells. Acidification disrupts the calcium carbonate building process for various types of shellfish, shells, and corals.

What is driving acidification is airborne pollutants from the burning of fossil fuels. CO2 enters the atmosphere and then, transported by winds, is deposited at sea. Scientists are trying to learn more about this transportation process - in essence, the A-to-B process, from your car's tailpipe or energy factory to the ocean.

Scientists from the University of Miami Rosenstiel School of Marine & Atmospheric Science are pouring over the results of a two-year study wherein they observed the process of rainfall at sea to determine how much pollution is entering the ocean by this method. Rainfall is considered one of the primary means of transporting airborne pollutants to sea. But to what degree? How much returns to earth; how much remains airborne; and where is it falling?

Rainfall collectors on land can provide one sort of perspective, but we've all seen how weather patterns can change when they move from land to sea or vice versa. So, the scientists set up collectors at sea off the coast of Bermuda and the nearby Sargasso Sea. They wanted to measure a compound commonly found in the atmosphere: Beryllium-7. Comparing those measurements with Beryllium levels in the atmosphere, the scientists could make estimates as to the amount of rainfall in remote ocean areas. They hope that their methods can be utilized on a global level.

"Over vast areas of the oceans the only rainfall data available are those made by using conventional rain collectors placed on islands," said Joseph Prospero, professor of marine and atmospheric chemistry at the UM Rosenstiel School. "However, rainfall on the island is not necessarily representative of that which falls in the surrounding ocean.

The effects of acidification have been documented and that has lead to it being named one of the major threats to the oceans and all that live within. But to better understand how to deal with it, scientists continue to analyze and understand the process. It is often through that work from which solutions are derived.

Read more in Science Daily.

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