Climate change and ocean acidification

Abstract

Carbon dioxide (CO2) is the greenhouse gas which ultimately causes ocean acidification. Oceans have approximately absorbed up to 30% of the released CO2 to the atmosphere since the Industrial Revolution. The incessant increase in this gas concentration in the atmosphere and its consequent dissolution in the oceans have resulted in the decrease of several tenths of seawater pH. Scientists have intensely studied this process and its consequences for the last decade. Oceanographic cruises of data collection throughout the planet are essential for a correct evaluation of the state and consequences of ocean acidification. Similarly, laboratory studies are highly important for the evaluation of marine ecosystems. The North Atlantic Ocean stands out globally due to the high accumulation of anthropogenic CO2 (up to 25% of the total of all oceans, when it only constitutes a 15% of the total oceanic area). Other observed consequences have been the pH reduction and the consequent decrease in the organism capacity to build calcareous structures. The scarce studies carried out in the Baltic Sea have shown great capacity to buffer pH decrease. Despite them, several studies have verified the ocean acidification process and its effects on marine organisms. Overall, positive, negative, and neutral responses have been found among the effects on organisms. Several species, such as plankton, mollusks, crustaceans, and corals, seem to be dramatically affected. These findings show the necessity of an ongoing investigation in order to acquire an accurate vision of the ecosystems health in this current volatile situation