Impacts of climate change on deep-sea habitats

The UK’s territorial deep sea covers a huge geographic area and supports a wide range of environments and biological communities. The deep sea is remote, difficult and expensive to study and as result our understanding of its ecology is still very limited, with detailed studies restricted to a small number of localities. Deep-sea ecosystems carry out a range of ecosystem processes that are essential to global biogeochemical cycling (e.g. organic carbon turnover and burial). There are no long-term datasets from the UK’s deep sea showing the extent of natural biological variability over time. The lack of a natural baseline makes it difficult to predict future climate-driven changes. Deep-sea organisms are largely reliant for food on plankton sinking from surface waters. Climate-driven changes in surface ocean productivity will therefore have a major impact on deep-sea ecosystems. Studies on the Porcupine Abyssal Plain indicate that increases in the annual flux of detrital food reaching the deep-sea bed can trigger population explosions of some benthic invertebrate species. Deep-sea populations are therefore likely to be responsive to climate-driven changes in ocean primary production. Ocean acidification poses a major long-term threat to deep-sea corals and other calcifying organisms. However, at present we have very few data on which to base predictions of future impacts.