Scientists are testing whether using plankton as carbon dioxide absorbers will aid in reducing climate change. Plankton are unicellular algae that survive on the surface of the ocean and are the basis for all oceanic life. Plankton naturally absorb carbon dioxide from the atmosphere and when they die, the algae sinks to the ocean floor. Therefore, the ocean floor is where much of the stored carbon remains, much like in the crop dumping scenario discussed previously.
Scientists wish to use algae as a “biological carbon pump” by inducing their growth with iron. The scientists refer to adding iron to the ocean as “seeding” the plankton in order to increase the amount of algae growth. Ocean areas already rich in nutrients are prime breeding ground for algae and the addition of iron would potentially increase carbon dioxide absorption.
Scientists believe that by fertilizing ocean water with iron it will aid in algae growth and therefore carbon absorption. A natural experiment performed, called the Crozex experiment, tested iron-rich waters in the Crozet Islands in the Southern Ocean for carbon levels. The team of scientists compared the iron-rich waters near the islands with waters not rich in iron for carbon level distinctions. The resulting data concluded that sediment and seawater samples from just below algae blooms in iron-rich waters were 2-3 times richer in carbon than waters low in iron.
An artificial fertilization experiment called Lohafex is currently testing the effects that adding iron to patches of the ocean will have on algae blooms and carbon absorption. The test will be carried on in the Scotia Sea, east of Argentina from January 7th to March 17th of this year. The team of 48 scientists will be fertilizing a patch of the ocean and studying the effects for at least 45 days. The team will be seeding the ocean patch, approximately 300 square kilometers, with 6 tons of iron sulphate. There are doubts that artificial iron seeding will ever be as effective as the natural iron that ignites algae blooms and this study is hoping to prove otherwise.
There is much concern over the 6 tons of iron sulphate being added to the ocean, which is why the experiment was suspended initially. Environmental groups are concerned that the additional iron, unnatural to the balance of the oceanic life, will cause ecosystem damage.