Ocean fertilization not the answer

Fertilizing the ocean may not slow down global warming. The controversial process of dumping urea or iron into the ocean to induce an algae bloom in order to remove CO2 from the atmosphere may not be effective, according to new research published in the Journal of Geophysical Research.

“With big blooms you don’t have enhanced sequestration, you actually have diminished sequestration,” said Michael Lutz, lead author of the study. He believes one of the things that is happening is that the fish and zooplankton are eating the fresh nutrient rich algae.

Fish and zooplankton will eat whatever they can find, Lutz said. And they are often accustomed to eating recycled food, but given the choice, will eat the fresh algae. “Which would you rather eat, a fresh sandwich or one that’s been sitting around for days?”

Another factor is that the algae, once combined with the CO2 from the atmosphere, have to sink to effectively hold on to the carbon. The study found that this critical sinking step was not occurring in induced algae blooms.

This finding is important because some scientists have thought that this method of “fertilization” could help solve global warming by pulling CO2 from the atmosphere. An Australian company has been eyeing the possibility of dumping 500 tons of urea into the Pacific Ocean. However, urea from fertilizer runoff has often been associated with toxic algal blooms—not carbon capture.

Environmentalists oppose the method saying it is a drastic measure that will have unintended consequences and could do more harm than good. This new research may very well vindicate them.

For more on ocean fertilization check out Peter Sergo’s story Greening-up the Ocean.