Nature Geoscience 4, 766–770 (2011) doi:10.1038/ngeo1297

Published online 23 October 2011

Wei-Jun Cai and his colleagues analyze to regions that highly influenced by nutrients contained river: the northern Gulf of Mexico and the East China Sea. At the two sites, they look to support that eutrophication can increase the susceptibility of coastal waters to ocean acidification.

Both the northern Gulf of Mexico and East China Sea are shallow shelf environments that receive immense loads of nutrients, organic carbon, and inorganic carbon from two of the world’s largest rivers: the Mississippi River and Changjiang River. These two rivers were observed to contain massive loads of nitrates.

After assessing collected data in the two regions, Wei-Jun saw a widespread development of hypoxia, areas of low pH, high dissolved inorganic carbon, and low carbonate saturation state. Wei-Jun showed that eutrophication in the two bodies of water associated with the development of hypoxia and the acidification of subsurface waters.

Gustavo Adolfo Paredes analyses in his dissertation the degradation and recovery of coral reefs.  He specifically looked into the types of conservation techniques used to protect coral reefs.  Marine reserves were found to be the main type of conservation by reducing the impacts of human activities to the ecosystem, especially in relation to fishing.  However, there are is not a plethora of reserves in the Caribbean. A major problem that Paredes discovered was the lack of enforcement in these reserves.  He found that those reserves fully protected showed a trackable amount of positive change.  He also found that the protection efforts occurring were not well known throughout local communities inhibiting their abilities to contribute to the protection of the coral reefs.  Paredes concluded that larger marine reserves need to be designated, more regulations on fisheries need to be implemented, and pollution controls near reserves should be increased as well.

Under lead author Andrea J. Fassbender, researchers studied the transportation of subsurface waters containing high carbon dioxide levels in the California Current System to the surface of the ocean near shorelines.  Specifically, they studied an event of upwelling near coastal northern California.  As the water traveled toward shore, subsurface respiration added dissolved inorganic carbon along its path, making the water undersaturated in terms of Aragonite.  In the mixed layer, levels of pCO(2) decreased due to the addition of DIC, addition of alkalinity, and gas exchange.  The contribution of each process depended on the distance of the area from land.  According analysis of the results, when waters arrive at the surface of the ocean gas exchange and biological productivity reduce ocean acidification over time, but respiration processes along the path followed by the upwelling tend to increase the acidification of the upwelling waters.

Continental Shelf Research 31, 1180-1192 (2011)