IS THERE ANY BAD SEQUESTRATION?:

Fertilizing the ocean with iron could help reduce atmospheric carbon dioxide levels, according to newly released findings of a research cruise. Why? In a word, diatoms.

A hunger for iron rules the microscopic sea life of the Southern Ocean surrounding ice-covered Antarctica. Cut off from most continental dirt and dust, the plankton, diatoms and other life that make up the broad bottom of the food chain there can't get enough iron to grow. And that's why some scientists think that artificially fertilizing such waters with the metal could promote blooms that suck CO2 out of the air. Then, when these microscopic creatures die, they would sink to the bottom of the ocean and take the carbon with them.

Such blooms occur naturally, of course, so the first part of the hypothesis is not controversial. What remained questionable until now is whether such blooms in fact sequestered much carbon or if it was being quickly recycled back into the atmosphere. The problem for scientists is that oceanic waters tend to mix, which makes monitoring and delineating an experiment in the ocean challenging.

The solution, devised by biological oceanographer Victor Smetacek of the Alfred Wegener Institute for Polar and Marine Research in Germany and his colleagues, was to use an eddy. Such swirling currents can be remarkably self-contained. In fact, the new research to be published in Nature on July 19 shows that less than 10 percent of the eddy's waters mixed with the surrounding ocean.

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