Extraction of a coral core in Thailand | Photo: Yvonne Sawall, ZMT

Our oceans absorb large amounts of the greenhouse gas CO2 from the Earth's atmosphere. This process, known as ocean acidification (OA), has consequences for calcifying organisms such as corals to fully build their functional skeletons and thus severely impacts tropical coral reef ecosystems and fisheries.

The project will investigate the development and the effects of OA in the tropics since scientific knowledge so far has been very limited due to the lack of long-term pH measurements and proxy reconstructions in the tropical oceans. By analysing boron isotopes in long-lived corals, the project will determine seawater pH values in various tropical regions of the Atlantic, Pacific and Indian Oceans. Boron is a natural component of seawater and its isotopes are sensitive to changes in ocean pH. Corals take in this seawater to form their calcareous skeleton. Thus, any change in pH can be detected in the boron isotopes incorporated in the coral skeleton.

By determining the pH over the most recent few hundred years, the project will assess the global development of OA through the rates of pH change as well as the carbonate chemistry of our tropical oceans before and after the Industrial Revolution.

The project results can provide sound information for policymakers and stakeholders who are committed to mitigating the increase in atmospheric CO2 and its negative consequences.

The OASIS project is funded by the Federal Ministry of Education and Research (BMBF) under the "Make our Planet Great Again – German Research Initiative", grant number 57429626, implemented by the German Academic Exchange Service (DAAD).


Project Partner (Germany)


International Project Partners

Centre for Marine Environmental Sciences at the University of Bremen (MARUM), Bremen


Lamont-Doherty Earth Observatory (LDEO), Palisades, New York (USA)

IRD France Nord, Paris (France)

IRD Centre Noumea (New Caldeonia)

Scripps Institution of Oceanography, San Diego, California (USA)

Indiana State University, Terre Haute, Indiana (USA)

University of Puerto Rico, Mayagüez (Puerto Rico)