Ocean & Climate
The ocean is a major player in the Earth’s climate. It holds the largest reservoir of active carbon and thereby largely determines atmospheric carbon dioxide levels. Ocean circulation transports heat and salt from low to high latitudes and drives vertical mixing of carbon, nutrients and oxygen between the upper and deep ocean. The vast ocean floor has accumulated sinking material for millions of years and hence its sediments offer long records that capture Earth’s climate variability. Together, these lines of research combine to improve our understanding of the dynamic link between our ocean and climate on successive time scales as well as human interference with the ocean.
Ocean as CO2 and heat sink
The ocean absorbs annually about 25% of anthropogenic produced CO2. Planktonic organisms are key in this process by taking up dissolved inorganic carbon for photosynthesis and calcification, thereby removing carbon from the ocean’s surface. To predict our future climate accurately, it is essential to understand how the ocean absorbs, transports, and stores heat through dynamic processes like circulation and mixing.
Acidification of the ocean results from increasing atmospheric CO2 and will affect calcifying marine organisms from tiny pelagic coccolithophores to reef-building corals. How these organisms are impacted is the focus of our lab experiments with modern calcifying organisms and investigation of fossil life forms from past high-CO2 periods. This will help to determine the feedback that calcifying organisms have on atmospheric CO2.
Ocean circulation and climate
Ocean currents act much like a conveyer belt. They are important for the transport of heat, nutrients, and dissolved gases such as CO2. Warming of the ocean and input of freshwater from Arctic Sea-ice and melting polar icecaps are affecting the ocean circulation. Sustained observations of basin-wide transports provide insight into the changing circulation and help to validate and improve climate models.
Past climate records
Major transitions in Earth’s climate system leave strong marks in the sedimentary record. More detail on those climate changes and the link with the ocean can be obtained by analysis of geochemical, biological, and physical parameters in sediment archives. Paleoceanographic reconstructions based on these parameters help to understand the climate system and tipping points therein under anthropogenic pressure, such as the effect of CO2 on global temperatures.
Ocean circulation and climate
Ocean currents and deep convection are important for the transport of heat, nutrients, and dissolved gases such as CO2, as well as the exchange with the deep ocean. Warming of the ocean and input of freshwater from Arctic Sea-ice and melting polar icecaps are affecting ocean circulation. Sustained observations of basin-wide transports provide insight into the changing circulation and help to validate and improve climate models.
Seagoing instruments that are deployed in and on the open ocean are often tailor made. Most instruments are adapted, designed, developed and tested in close collaboration between scientists of the department of Ocean Systems and the technicians of the National Marine research Facilities (NMF). Their joint experience and expertise and the seagoing equipment itself is also available to the marine and maritime research community.