Some weeks ago, the journal Biogeosciences published an article entitled Over-calcified forms of the coccolithophore Emiliania huxleyi in high-CO2 waters are not preadapted to ocean acidification, co-authored by Dr. Peter von Dassow and candidate for Doctor of ecology Francisco Díaz, members of IMO and the Department of Ecology at the Pontifical Catholic University of Chile.
Asked to talk about this article, Díaz explained that their main conclusions have to do with the fact that “one of the ocean’s most important organisms producing calcium carbonate, the coccolithophore Emiliania huxleyi, seems to have reached the limit of its adaptive capacity to ocean acidification.”
He added that “although coccolithophores are really tiny, with sizes varying between 3 and 20 microns, they are important, mainly because they precipitate calcium carbonate in the form of calcite, which they use to form their coccospheres (see article image). Therefore, being widely spread in the upper ocean except for the poles, this worldwide calcium carbonate production represents a large fraction of the total inorganic carbon flow exported into the depths. Additionally, the presence of these coccosperes in fecal pellets, for example, increases the sinking velocity of particulate organic matter (also known as ballast effect).”
This piece of research is directly related to the current ocean acidification (anthropogenic CO2 absorption in saltwater producing a reduction in pH values), which “will slow down the calcification rate for these organisms more and more and will subsequently reduce the flow of calcite (directly) along with the amount organic matter (indirectly, as a result of the ballast effect) exported into the depths. This could result in a reduction of net CO2 sequestration from the atmosphere and ocean into the depths both on an ecological and geological scale (we’re talking about negative feedback),” as Francisco Díaz said, adding that “this ecological function, which consists in precipitating calcium carbonate and sequestering organic as well as inorganic carbon into the depths, is what we’re trying to understand and protect in our lab.”
If you would like to know more about this topic, please visit the following link: biogeosciences
