Biogeochemistry in Coastal Seas

Aquatic Nutrient Cycles

The status of aquatic ecosystems is in general determined by the availability of essential nutrients like nitrogen, phosphorus and silicic acid, and by the oxygen content of the water. River-Sea systems and coastal seas are amongst the most productive of the world’s ecosystems, but excessive nutrient inputs (e.g., from traffic, agriculture and industrial sources) may lead to unwanted algal growth (eutrophication) and declining oxygen concentrations in coastal zones.

Healthy river-sea ecosystems are able to remove excess nutrients by microbial processes before they reach the coastal ocean. In historically impacted systems, the natural attenuation capacity is weakened, and they receive additional (legacy) nutrients from sediments that were deposited years ago.

Marine biologists and geoscientists of the Department "Aquatic nutrient cycles” jointly investigate nutrients and oxygen dynamics in the coastal ocean, quantify the fluxes, and asses their impact on ecosystem functions. For this, we apply novel underwater observation technology and stable isotope techniques.