The tragedies of marine towns
On monday a study by the Convention on Biological Diversity in collaboration with the UNEP World Conservation Monitoring Centre was released (->press release). The study with the title “Scientific Synthesis of the Impacts of Ocean Acidification on Marine Biodiversity” is a survey on the current results in the investigation of ocean acidity. It is thus a follow-up study to studies initiated e.g. by the global network of science academies (see IAP statement on ocean acidification ) or like the ones which led to the Monaco Declaration.
A main message of these studies and statements is that Carbondioxide i.e CO2 (a major greenhouse gas) has increasingly been taken up by the worlds oceans and thus reduced the effects caused by an increased CO2 level in the athmosphere like e.g. the greenhouse effect. This may on the first sight sound good to climate sceptics since it means that there are processes which act naturally against higher CO2 levels. Unfortunately there are now plenty of measurements which indicate that the uptake of CO2 has been slowing down in the last years, i.e. that it seems that a kind of saturation has been partially/will be reached soon. Due to this the
accumulation of CO2 in the atmosphere may accelerate rather soon.
A second main message/problem with this uptake of CO2 is ocean acidification. If CO2 reacts with water this gives carbonic acid , which dissolves mostly to HCO3- and hydrogen ions H+. Thus after CO2 has been taken up by the ocean waters it will give to a smaller amount carbonic acid H2CO3 and carbonate ions CO3^2- and for the most part bicarbonite ions HCO3-. The hydrogen ions decrease the PH level – (you may sometimes find information of PH levels on your liquid soap) that is – the PH gives an indication of the concentration of hydrogen ions H+ via the concentration of Hydronium and it is thus a measure of the acidity or basicity of a solution.
Furthermore the carbonate ions CO3^2- form together with H+ again bicarbonate HCO3-. A higher concentration of H+ (”the acidity”) thus decreases the availablity of carbonate. But carbonate is necessary for producing calcium carbonate (CaCO3) which is essential for shell formation in marines organisms such as corals, shellfish and marine plankton. In other words the increasing acidification of the oceans is harmful to a lot of marine creatures. Since this process is very fast and the fast increasing acidification is clearly measurable this will lead to a rapid change in the composition of the oceans with more or less forseeable consequences. In particular it is very likely that this will have an impact on fish consumption.