Contaminant Cycling Under Climate Change: Evidences and Scenarios

Marine ecosystems are influenced by many factors related with human activity, such as eutrophication, chemical contamination, selective overfishing, bottom trawling and blast fishing. However, various regions have shown at least some changes that were likely to be attributable to recent climate change. Although various works have pointed to repercussions of climate change on ocean processes at physical and biological levels, a few thoughts were highlighted on contaminant pathways in concert with the predicted and confirmed climate changes. Human activities released during the last century a cocktail of contaminants that are stored in soil, coastal sediments and ice. Predicted alterations under climatic changes raise pertinent questions on this topic. Are hazardous substances stored in those compartments released to cycling within the ecosystem under climate changes? To what extent are quantities injected in the ecosystems toxic to marine organisms? Does it affect ecosystem functioning? This article reviews relevant aspects of contaminant cycling under climate changes and gives examples of evidences and scenarios. The selected examples are: melting of ice in the Arctic and the already observed increase of trace metals availability in water; temperature increase and the enhanced production of methyl mercury, a potent neurotoxin; prolonged periods of UV radiation and mercury release from soils and air-exposed sediments; sea-level rise and coastal erosion and the release of metals and organic pollutants from salt marshes; heavy rainfall events and abrupt input of historical and present contaminants from agriculture fields, obsolete industrial and urbanised areas.