Ocean acidification

Research shows that oceans worldwide absorb about a quarter of the carbon dioxide (CO₂)  ons arising from human activities (burning of fossil fuels and land-use change). This uptake of CO₂ results in chemical changes in seawater. One chemical change is an increase in the acidity of seawater, known as ocean acidification (PDF). In the North Sea, there is large seasonal variability in ocean acidity (see trends & projections).

It is difficult to determine exactly to what extent ocean acidific ation affects marine ecosystems and species, as ocean processes are closely interconnected. Impacts are usually the result of a combination of change s and pressures (such as noise, plastics, and resource extraction), rather than acidification alone. Research shows that ocean acidification, together with other processes such as the rate of ocean warming , can negatively affect marine species by weakening skeletons, lowering survival rates, and influencing reproduction, behaviour, and physiology. How strongly these effects are present in the North Sea remains unclear.