The Green Geek

Ocean plankton absorbing less CO2 than expected

Phytoplankton, the tiny plants that float in our oceans, apparently aren’t removing as much carbon dioxide from the atmosphere as expected. Generally the amount of CO2 uptake is calculated based on colour readings of the blooms; the greener the bloom the more carbon dioxide being absorbed. This no longer seems to be the case, as recent studies imply there may be as much as 2.5 Billion tons less carbon dioxide being absorbed each year than previously thought.

Peter Strutton of Oregon State University and colleagues studied phytoplankton fluorescence in the tropical Pacific using data from 12 years and 58,000 kilometres of ship transects and found that the phytoplankton are making far less chlorophyll than expected. They reason that in nutrient-poor waters like the tropical Pacific, phytoplankton are starved of nitrates and iron. Because of this they produce a pigment-protein complex that is not chlorophyll but shows up just as green in satellite images.

This may actually be a good thing, because it implies that ocean alage blooms are still a relatively untapped resource for storing carbon dioxide. I’ve written previously on seeding the oceans to promote algae blooms, it now appears that this same process could be used on existing blooms to bring their CO2 absorbing levels up to what is expected. The addition of nutrients to algae blooms is a relatively simple and inexpensive process, and has the potential to sequester much of the excess carbon dioxide in our atmosphere.

via New Scientist