Ocean acidification and pollution coexist to exert combined effects on the functions and services of
marine ecosystems. Ocean acidification can increase the biotoxicity of heavy metals by altering their
speciation and bioavailability. Marine pollutants, such as heavy metals and oils, could decrease the
photosynthesis rate and increase the respiration rate of marine organisms as a result of biotoxicity and
eutrophication, facilitating ocean acidification to varying degrees. Here we review the complex interactions
between ocean acidification and pollution in the context of linkage of multiple stressors to marine
ecosystems. The synthesized information shows that pollution-affected respiration acidifies coastal
oceans more than the uptake of anthropogenic carbon dioxide. Coastal regions are more vulnerable to
the negative impact of ocean acidification due to large influxes of pollutants from terrestrial ecosystems.
Ocean acidification and pollution facilitate each other, and thus coastal environmental protection from
pollution has a large potential for mitigating acidification risk.