November 5, 2007 7:21 AM PST

'Ocean seeding' plans to capture carbon in oceans draw fire

Posted by Martin LaMonica

In some of the most ambitious efforts by green tech start-ups, a handful of businesses have emerged with plans to capture large amounts of carbon dioxide by stimulating the growth of ocean plankton.

On Monday, a group of watchdog environmental bodies, including Greenpeace and the ETC Group voiced their opposition to a project proposal from Australia-based Ocean Nourishment.

The company is said to be planning on "seeding" the Sulu Sea between the Philippines and Borneo with a nitrogen nutrient called urea, which would be pumped into the ocean from a special plant.

A plankton bloom. Good to capture carbon dioxide?

(Credit: Planktos)

The idea behind these geo-engineering projects is to drop large amounts of food into the ocean, which acts as a fertilizer to grow plankton. During metabolism, the plankton should be able to consume large amounts of carbon dioxide, a greenhouse gas linked to global warming.

Other clean tech companies pursuing similar approaches include Planktos which is using iron as a fertilizer. It intends to fund the business by selling carbon credits, represented by the carbon dioxide sequestered by plankton growth.

Another company, called Climos, last month issued a call to create a code of ethics for ocean carbon experiments, which includes a permitting process and oversight over the environmental impact of these practices.

"Clearly, a market has emerged that can fund carbon mitigation activity. However, important questions of effectiveness, environmental impact and corporate conduct in all ocean fertilization projects need to be addressed as these projects move forward," Margaret Leinen, Climos' chief science officer, said in a statement.