The effects of ocean acidification on fishes



by LORENZO CIOTTI

The effects of ocean acidification on fishes

The effects of ocean acidification on fishes - history and future outlook, study published in the Journal of fish biology, made a review on the issue. The researchers explained: "The effects of increased levels of carbon dioxide (CO2 ) on the Earth's temperature have been known since the end of the 19th century.

It was long believed that the oceans' buffering capacity would counteract any effects of dissolved CO2 in marine environments, but during recent decades, many studies have reported detrimental effects of ocean acidification on aquatic organisms.

The most prominent effects can be found within the field of behavioral ecology, e.g., complete reversal of predator avoidance behavior in CO2 -exposed coral reef fish. Some of the studies have been very influential, receiving hundreds of citations over recent years.The results have also been conveyed to policymakers and publicized in prominent media outlets for the general public.Those extreme effects of ocean acidification on fish behavior have, however, spurred controversy, given that more than a century of research suggests that there are few or no negative effects of elevated CO2 on fish physiology.

This is due to sophisticated acid-base regulatory mechanisms that should enable their resilience to near-future increases in CO2. In addition, an extreme "decline effect" has recently been shown in the literature regarding ocean acidification and fish behavior, and independent research groups have been unable to replicate some of the most profound effects.

Here, the author presents a brief historical overview on the effects of elevated CO2 and ocean acidification on fishes. This historical recap is warranted because earlier work, prior to a recent (c. 10 year) explosion in interest, is often overlooked in today's ocean acidification studies, despite its value to the field.

Based on the historical data and the current knowledge status, the author suggests future strategies with the aim to improve research rigor and clarify the understanding of the effects of ocean acidification on fishes." Due to the acidification of the oceans, marine fauna is seriously endangered.

The lowering of the marine pH creates the phenomenon of coral bleaching; the calcium carbonate that makes up the shells, molluscs, crustaceans and even coral decreases in relation to the increase in acidity, thus losing the algae that live above the surface of the organism, leading it to death.

Although many organisms suffer from this increasing acidification, some photosynthetic organisms benefit from it. One case is represented by diatoms; i.e. microscopic algae belonging to the phytoplankton. For these organisms, the increase of CO2 in water increases their ability to carry out their photosynthesis processes. These processes can be carried out if in the presence of certain environmental conditions.