A BBC report yesterday noted that a controversial German-Indian experiment in the Southern hemisphere ocean found that a scaled up algae seeding project on 330 sq km did not lead to the increased carbon sequestration that the researchers had expected from earlier, smaller experiments.
The idea was relatively straightforward, though the implications of full scale deployment of the strategy alarmed some critics. Here is how it was to work: seeding iron filings into the ocean would stimulate phytoplankton (algae), which would extract CO2 from the atmosphere, then die and settle to the ocean bottom, where that carbon would become tied up in sediments and remain sequestered for long periods, reducing the concentration of CO2 in the atmosphere.
Based on those earlier experiments, at least one commerical company is planning much larger -- up to 40,000 sq km -- experiments using funds from the global carbon offsets market. As one critic cited in the BBC article (from Greenpeace) noted: "if we're going to be pursing this as a climate mitigation strategy, then we're looking at a state of the world where we rely on manipulating the ocean on a truly huge scale." Manipulation is about dumping and treating, whereas finessing is about fine tuning existing systems for optimality. These are, at the heart, two very different approaches.
Now, recognition of the need to actually remove historical CO2 from the atmosphere was one of the reasons that prompted me to start this blog, and doing so via plants seems to me the best, most natural way to do so. But this "seeding" strikes me as too much of a silver (iron?) bullet approach. It doesn't really recognize the complexity of interaction in natural systems, and long term, recognition, acceptance and finessing of those systems (to which we belong) is the only answer that is going to stick -- and it is going to involve lifestyle and consumption changes, too --- du-uh!
What really gets me about this kind of idea is the silver bullet mentality, the Oh-Mi-God, just buy the right lottery tickey, Hail Mary approach.
So what actually happened? They spread six tons of iron filings. There was a burst of algal growth. The algae were eaten by copepods (I'll spare you the recitation of the food chain but it is -- not surprisingly -- as complex and interesting as that in the soil), which were eaten by amphipods, etc, etc, and so the desired "desposition" didn't happen.
Oh, well.
BTW, there are a lot of "whatever-e-pods" in the ocean food chain, species after species of mini-crustaceans -- some with barely a shell to deserve the term -- that are the heart of that food chain, the base of that food pyramid (of which, again, we are at the top...don't forget that) and these many diverse species have a real dependence on the pH of the ocean, which is changing as it absorbs more CO2 directly (chemically) and is becoming more acidic. I will try to come back to this post to link to some of that stuff in a day or so....
Here's a link to BBC report: http://news.bbc.co.uk/2/hi/science/nature/7959570.stm