Spiking the oceans with iron or other nutrients to stimulate algal growth and thereby combat global warming just might not be such a hot idea after all.

That at least is the suggestion coming from a Stanford University/Oregon State University study published in the Journal of Geophysical Research.

The idea – which some peg at about $100 billion – calls for ocean fertilization to increase algal blooms, which would absorb carbon dioxide as they grow. But the scientists’ research suggests that it would only reduce atmospheric CO2 if the carbon incorporated in the algae then sinks into deep water. In their research the scientists reported finding seasonal patterns in algal abundance and carbon sinking rates.

“However, the relationship between the two was surprising: less carbon was transported to deep water during a summertime bloom than during the rest of the year.”

The researchers’ conclusion at this point is that ocean fertilization schemes remove less CO2 from the atmosphere than had been expected because those schemes ignore natural processes – the “biological pump” by which atmospheric CO2 incorporated into the algae sinks.

“Very surprising” is how researcher and lead author Dr. Michael Lutz, now with the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, described the findings. “If, during natural plankton blooms, less carbon actually sinks to deep water than during the ret of the year, then it suggests that the biological pump leaks. More material is recycled in shallow water and less sinks.”

Journalists following the ocean fertilization issue need not conclude that this study alone means curtains for the ocean-engineering idea, much as some critics might like to say so. It is potentially, however, one nail in what may in the end turn out to be a coffin. Reporters wanting to follow-up on the study can begin by contacting Barbara Gonzalez at Rosenstiel at 305-421-4704 or by e-mail. And then go from there.

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