American oceanographers came to the conclusion that a radical way to protect the planet from global warming - saturating the waters of the World Ocean with iron salts - will not accelerate the growth of phytoplankton and will not force it to absorb more carbon dioxide. The press service of the Massachusetts Institute of Technology (MIT) writes about this with reference to an article in the scientific journal Proceedings of the National Academy of Sciences.
"Fertilizing" the waters of the World Ocean with iron salts is one of the most radical and, as some climatologists believe, effective plans to combat global warming. The experiments of German climatologists off the coast of Antarctica back in 2012 showed that such "seeding" should accelerate the reproduction of the smallest unicellular algae and blue-green bacteria and enhance their ability to absorb CO2.
"Our model shows that the saturation of the oceans with iron compounds will not greatly affect the total biomass of phytoplankton, since the total amount of this metal in its waters is now ideally suited to the needs of algae," commented one of its authors, MIT oceanographer Jonathan Lauderdale.
Such ideas and proposals have caused serious protests from many environmentalists and eco-activists. They fear the serious side effects of such a method, and also indicate that such a procedure will be of little effect. In addition, it can enhance toxic algae blooms that threaten the life of coastal flora and fauna, as well as those living nearby.
The ocean water cycle
Lauderdale and his colleagues tried to combine the results of numerous experiments on the "fertilization" of different parts of the oceans with iron salts and to estimate how much the biomass of phytoplankton will change throughout the Earth as a whole. In these calculations, the scientists took into account how iron ions interact with water, various organic substances and enzymes of algae and cyanobacteria themselves.
Based on similar principles, oceanographers have calculated how "seeding" with iron will affect phytoplankton, which lives in the near-surface waters of the North Atlantic and coastal regions of Antarctica, as well as in the deep waters of the seas. All these areas of the World Ocean differ from each other in the content of iron and other trace elements.
These calculations unexpectedly indicated that iron-containing fertilizers will have almost no effect on the total biomass of phytoplankton, since algae and bacteria will not be able to extract excess metal from the water without sacrificing other aspects of their growth and without interfering with the reproduction of microbes in other parts of the oceans. … This is due to the fact that in order to assimilate iron, photosynthetic organisms need certain organic molecules that can bind to this element. Moreover, there are quite a few such molecules in water.
For example, "seeding" of Antarctic coastal waters with iron can only lead to a short-term surge in the growth rate of phytoplankton. It will stop almost immediately when bacteria and algae use up all such substances, including those surpluses that normally fell into the Atlantic and other corners of the hydrosphere.
As a result, the biomass of algae and cyanobacteria in the Northern Hemisphere will decrease, which will compensate for its growth off the coast of Antarctica. Similar processes will take place in other regions of the World Ocean, which is why its "fertilization" with iron, according to Lauderdale and his colleagues, will not slow down global warming, but at the same time will cause a lot of negative environmental consequences.