Climate – Biogeochemical Interactions in the Tropical Ocean

The animation illustrates the schematic formation of an oxygen minimum zone (here shown in magenta) at the eastern continental boundaries in the tropics. In the upwelling areas of the oceans, an interplay of physics and biology causes oxygen deficiency. Here, nutrient-rich deep water reaches the surface. The abundance of nutrients and plankton at the surface leads to high oxygen consumption in deeper zones. Only weak currents occur there, which transport relatively oxygen-poor water. This has resulted in large oxygen minimum zones.

It is obvious to everyone that humans cannot breathe under water without aids. However, it is less well known that breathing can also become a problem for marine life: In some regions, oxygen is naturally present in very small concentrations in the sea, and this has a significant impact on living conditions in these regions. These are not small, hidden corners of the oceans, but rather considerable areas of the world ocean: the so-called oxygen minimum zones extend over large areas of the tropical seas.

Collaborative Research Center 754  / Sonderforschungsbereich 754

"Climate-Biogeochemistry Interactions in the Tropical Ocean"

The Collaborative Research Center (SFB 754) addresses the relatively newly recognized threat of ocean deoxygenation, its possible impact on tropical oxygen minimum zones and implications for the global climate-biogeochemistry system. The overall goal of the SFB 754 is to improve understanding of the coupling of tropical climate variability and circulation with the ocean's oxygen and nutrient balance, to quantitatively evaluate the nature of oxygen-sensitive tipping points, as well as to assess consequences for the Ocean's future. 

The key questions of the SFB 754 are:


• How does subsurface dissolved oxygen in the tropical ocean respond to variability in ocean circulation and ventilation?

• What are the sensitivities and feedbacks linking low or variable oxygen levels and key nutrient source and sink mechanisms? In the benthos? In the water column?

• What are the magnitudes and time scales of past, present and likely future variations in oceanic oxygen and nutrient levels? On the regional scale? On the global scale?

Changes in ocean's oxygen and nutrient concentrations controlled by climate. 

The Collaborative Research Centre 754 (SFB 754) "Climate-Biogeochemistry Interactions in the Tropical Ocean" is funded by the German Research Foundation (DFG) since 2008. This project involves scientists from the Christian-Albrechts University Kiel (CAU), GEOMAR Helmholtz Center for Ocean Research Kiel and the Max-Planck-Institute Bremen.


Click here for downloading the SFB754 Flyer.


Prof. Andreas Oschlies            
Tel: +49 431 600 1936
Fax:  +49 431 600 4469
Scientific Secretary:            
Dr. Lothar Stramma
Tel: +49 31 600 4103
Fax: +49 431 600 4102
Scientific Coordination:
Dr. Christiane Schelten
Tel: +49 431 600 4242
Fax. +49 431 600 4202