Produce Plankton, Curb Carbon

Some attempts to limit global warming are as wacky as they are creative: Backyard wind turbines, fuel made from fast- food grease, even solar-powered iPod chargers. Now, some scientists think the solution to cutting carbon emissions may be farm-fresh plankton.

Planktos, a firm dedicated to restoring ecosystems, plans to induce plankton growth in oceans to create carbon sinks, large ocean areas that produce oxygen and remove carbon dioxide from the atmosphere. The company announced it will dump tons of powdered iron in international waters west of the Galapagos Islands to spur plankton growth, with the hope of removing CO2 emissions from the atmosphere. The strategy, known as iron seeding, will take place over a two-year period with a goal of  creating six large plankton blooms.

From an article in The Australian:

Phytoplankton, the plant form of plankton, struggle to grow if there is little iron—but the extra supplies could mean that as the phytoplankton grow they will photosynthesize and absorb carbon that, when they die and sink, will be trapped on the seabed, where it will be out of the system.

Today, the Southern Ocean absorbs less greenhouse gas than it did 20 years ago. Planktos scientists believe that one way to fix that is to increase the amount of carbon sinks in the ocean.

Each decade since 1981, the ocean has soaked up between 5 percent and 30 percent less of the greenhouse gas than experts had predicted and has unloaded more carbon dioxide into the atmosphere, the international team led by Dr. Corinne Le Quere, from the University of East Anglia and British Antarctic Survey, said.


Like the rainforests, the Southern Ocean is one of the most important carbon “sinks” that together remove half of all man-made emissions of carbon dioxide. It acts like a huge sponge, trapping carbon from the atmosphere.

But the article also noted that smaller-scale iron seeding projects were unsuccessful in removing carbon from the air, and some people are skeptical that a larger project would work any better.  In fact, articles in National Geographic and The Scientist suggest that iron seeding is an ineffective and prohibitively expensive method of curbing global warming.

We here at Plenty are all for creative carbon-cutting projects, but we’re skeptical about this one. For one, some evidence suggests that iron seeding is not an efficient method to curb global warming. Furthermore, marine animals have had a rough time lately (think: lost whales, dying corals, and declining fish populations, among others). Pumping these already struggling sea-farers full of iron may not make the times any easier.  

And we’re not the only ones worrying. From a 2003 article in Nature (sorry—a paid subscription is required to access the full article):

"There is no free lunch," agrees Sallie Chisholm, a marine biologist at the Massachusetts Institute of Technology who is at the forefront of attempts to resist the iron-fertilization plans. She fears that altering natural carbon fluxes could trigger a cascade of unwanted side effects. The iron could, for example, prompt the growth of toxic algae, which could kill other marine life or change water chemistry by removing oxygen. "The oceans are a tightly linked system, one part of which cannot be changed without it resonating through the whole system," says Chisholm.

Were marine critters to cry NIMBY about iron seeding, we can’t say we’d blame them.


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