Ocean acidification

The main cause of ocean acidification (OA) is primary caused by the atmospheric CO2absorbed by the ocean \cite{Feely_2010}  affecting the water chemistry. The impacts of OA are not uniform across all species, some phytoplankton, algae and seagrass may also thrive with higher CO2 concentrations in the ocean, as they may increase their photosynthetic and growth rates. However, a more acidic environment will harm other marine species such as molluscs, corals and some varieties of plankton. The shells and skeletons of these animals may become less dense or strong. In the case of coral reefs this may make them more vulnerable to dissolution storm damage and slow the recovery rate \cite{Haigh_2015}.
For example, acid rain from vehicle emissions and industry cause an increase in ocean acidity, which is likely relevant, at least near urbanised regions \cite{Doney_2007}. Additions of organic carbon to the ocean, such as sewage, decomposes to dissolved inorganic carbon (DIC), and increases acidity \cite{Nagelkerken_2015}. Agricultural run-off provides nutrients which then fuel (an anthropogenic) increase in production of organic carbon in the ocean\cite{Howarth_2002}, again increasing acidity.'' To correctly measure OA DIC, pH, total alkalinity (TA), and partial pressure of CO2  (PCO2 )— must be known, in addition to temperature and salinity and to be more accurate, phosphate and silicic acid concentrations are also required  \cite{Haigh_2015}.'' OA affects the ecosystem mostly by the disruption of the food web chains. As an example, in areas like British Columbia where the class of diatom Phytoplankton (which has an higher trophic transfer) is predominant \cite{Ryther_1969}, a switch to a class with lower nutritional value would take place affecting the directly the higher trophic levels\cite{Haigh_2015}.