Aquatic Oil Pollution ? many-sided problem, until oil use is stopped

Torstai 18.7.2019 klo 11:44 - Mikko Nikinmaa

 

With oil spills, the usual picture in the news is a bird covered with oil. The contaminated bird loses its ability to regulate temperature in water and slowly dies because of heat loss. Although this is a significant problem during oil spills, it is probably not the most important one. As the most important one I would place the effect of oil contamination on mainly unicellular marine algae. Marine algae account for almost half of global photosynthesis, thus being the most important carbon dioxide sinks of the world. Largely because of oil pollution, it has been estimated that the algal carbon dioxide sink has decreased by 20 %. This negative effect is greater than would be caused, if deforestation of Amazon rain forest would increase manyfold. Oil pollution also influences fish. Effects are largely age-dependent and associated mainly with cardiac function. It appears that the toxicity of oil increases with increasing pressure. This is significant, as oil is drilled at deeper depths than earlier. In addition, dispersants, changing oil to small droplets, which are dispersed in the water column, increase the toxicity of oil spill to fish and other aquatic organisms, mostly by increasing the surface area of oil in contact with the (respiratory) surface of organisms. As a consequence, the uptake of toxic components of oil, and thereby their toxic effects, are increased. In contrast, the dispersants in the concentrations used appear to cause little toxicity. It is quite clear that as long as oil is used in significant amounts in fuels and energy production, the problems persist. Further, the socalled biofuels or biodiesels are exactly as bad for aquatic life as fossil oil. Therefore, in terms of combatting climate change, using biofuel is exactly the same as using fossil oil, if the use of fossil fuel is coupled with forestation.

Kommentoi kirjoitusta. Avainsanat: aquatic toxicology, oil spill, water pollution, fish kills