Hot, Sour & Breathless – Ocean Under Stress: How is the Biggest Ecosystem on Earth Faring?

This brief provides a guide of three interacting stressors facing the ocean: acidification, warming, and deoxygenation. In the future many parts of the ocean are likely to experience more than one of these environmental stressors at the same time, since they are driven by the same underlying process – increases in atmospheric CO2 and other greenhouse gases. These “hot spots” will not only be warmer, but are also likely to be more stratified, have increased acidity and contain less oxygen, increasing the stress on marine life in ways that may be more than the simple addition of each.

Acting together these stressors could more rapidly threaten biogeochemical cycles, ecosystems and the goods and services the ocean provides to society, thereby increasing the risk to human food security and industries depending on productive marine ecosystems. Furthermore, changes in the exchange of gases between the atmosphere and ocean will impact on climate change.