IPCC Climate Change Ocean acidification Anthropogenic climate change is altering the living conditions in the ocean more dramatically than in the past 50 to 300 million years. The oceans are becoming warmer [...] which chemically react with constituents of seawater, making the oceans more acidic. But that’s not all: for various reasons, warming oceans store less oxygen. In other words, they gradually lose their lifeblood [...] in the seas simultaneously reduces the number of safe havens remaining to them. Increasing ocean acidification puts organisms under additional pressure. Further, these three climate impacts are mutually

factors such as warming, nutrient deficiency or ocean acidification, by focusing on one of the most sensitive areas on Earth, the subarctic and Arctic Ocean. Thereby, we contribute to the Helmholtz research [...] CO 2 is taken up by the ocean, concentrations of CO2 and bicarbonate increase while the concentration of carbonate ions and the pH decrease, also known as 'Ocean Acidification'. Just like warming, also [...] greenhouse gas, rising CO 2 causes ocean warming: temperatures of the surface waters have already increased by 1.1°C on average, while some regions like the Arctic Ocean changing fastest (IPCC 2022). The

of Southern Ocean phytoplankton to global change, in particular to ocean acidification. The availability of trace metals and light are considered key factors in controlling Southern Ocean phytoplankton [...] Polarstern expedition ANT XXVII-2. Picture: S. Trimborn (Photo: Alfred-Wegener-Institut) Southern Ocean phytoplankton are major drivers of global carbon cycling accounting for 20% of the global annual primary [...] information is available on how these environmental factors (trace metals, CO2, light) affect Southern Ocean phytoplankton. In particular research on interactive effects of these factors is still missing. The

in the polar ocean View from Rpthera Point, Western Antarctic Peninsula. Photo: S. Trimborn (Photo: Alfred-Wegener-Institut) In vast areas of the ocean, particularly in the Southern Ocean, marine primary [...] of marine ligands, their chemical structures and turnover pathways are essentially unknown. Ocean acidification, increased glacial melting and changes in aerosol deposition are likely to impact concentration [...] micronutrients in seawater and will focus on biological production and degradation of ligands in polar oceans, their molecular composition, chemical properties and responses to changing environmental conditions

Nöthig Research The Arctcic Ocean reacts more sensitive to Gloabal Change than other oceans. Sea ice strongly decraeses, temperatures rise at least twice as much, acidification and, the influence of warmer [...] mainly as part of projects such as FRAM, LTER HAUSGARTEN, PEBCAO in different regions of the Arctic Ocean. The main goal of our arctic research is to understand and follow seasonal and interannual fluctuations [...] Key aspect is to measure the changes of all parameters in relation to rise in temperature and acidification.

life in the ocean, in particular carbon, nitrogen, phosphorus and silicon, as driven by physical, biological and chemical processes. Marine biogeochemical cycles play a relevant role in ocean productivity [...] system. The elements of the biogeochemical cycles are considered essential ocean variables (EOV) as defined by the Global Ocean Observing System. In order to study biogeochemical cycles, we need to measure [...] alkalinity, which provides information about the buffer capacity of seawater, relevant to study ocean acidification. The facility is divided in three modules based on scientific topics, as follows. Nutrients:

Polar and Marine Research, have discovered in a recent study that Ocean Acidification can negatively affect diatoms of the southern polar ocean. In laboratory experiments, they observed that diatoms under [...] deep ocean. Thus, the CO 2 is removed from the global carbon cycle for a couple of thousand years. Dr. Sebastian Rokitta has explored during the past three years how the advancing Ocean Acidification affects [...] Helmholtz-PhD Awards who have been awarded for the very first time this year. Consequences of Ocean Acidification for calcareous algae (Youtube, 17.4.2013) The calcareous microalga Emiliania huxlyei is distributed

Arctic Ocean. Stratification If freshwater enters the Arctic Ocean via rivers, preci- The consequences of climate change for the Arctic Ocean pitation or melting sea ice, it alters the ocean’s surface [...] deep-sea connection between the Arctic Ocean and other oceans runs through the Fram Strait – the passage between Greenland and Spitsbergen. Warming, acidification, altered stratification of water masses [...] sensitively to ocean acidification if the water temperature rises at the same time. Here are some selected general facts and forecasts regarding the consequences of climate change in the Arctic Ocean. Warming

of the Paris Climate Agreement is not achieved. Under conditions of further warming and acidification of the ocean, Atlantic cod and its arctic relative polar cod would be forced to look for new habitats

any other oceanic region of the planet and its sea-ice cover is declining faster than models predict. Due to changes in sea-ice cover and stratification, the productivity in the Arctic Ocean may transition [...] predominantly light-controlled to being more nutrient-controlled. Also, the phenomenon of ocean acidification is most pronounced in the Arctic due to the higher solubility of CO 2 at low temperatures as [...] lower alkalinity. To elucidate potential synergistic or antagonistic interactions between ocean warming, acidification or altered light and nutrient availability, we apply multi-factorial incubation matrices