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Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
30 April 2025 / Kiel. Prof. Dr Ying Cui from Montclair State University in the USA is currently a guest researcher at the GEOMAR Helmholtz Centre for Ocean Research Kiel, supported by a Humboldt Research Fellowship for Experienced Researchers. During her six-month stay, the geoscientist is using Earth system models to investigate how warmer climates in the geological past affected oxygen levels in the ocean — and what this can tell us about the future. Her host is Prof. Dr Andreas Oschlies, head of the Biogeochemical Modelling Research Unit.
Looking into the Earth’s deep past can help us better understand the future — and that includes climate. This is the focus of Prof Dr Ying Cui, a geochemist from Montclair State University in the USA and currently a visiting scientist at GEOMAR. With support from the Alexander von Humboldt Foundation, she is spending six months in Kiel to collaborate with Prof Dr Andreas Oschlies and his team, aiming to unravel the links between climate, the ocean, and oxygen levels.
The Past as a Key to the Future
Prof Cui’s research focuses on periods in Earth’s history greenhouse gases were released in massive quantities over geologically short timescales — often associated with global warming events and mass extinctions. At GEOMAR, she is particularly interested in the Miocene epoch, which ended about 5.3 million years ago, when global temperatures were approximately two to three degrees Celcius warmer than today.
“Our hypothesis is that warmer climates lead to oxygen loss in the ocean, because less oxygen can dissolve in warmer water,” says Cui. But oxygen levels are not driven by temperature alone — ocean circulation also plays a crucial role. And millions of years ago, ocean currents looked very different from today. “There was no land bridge between North and South America yet, so the waters of the Atlantic and Pacific could still mix,” Cui explains. All these factors have to be taken into account to answer the central question: how did the loss of oxygen impact marine life?
Into the Depths: A Focus on the North Atlantic
To investigate this, Cui’s work focuses on the North Atlantic between 50 and 70 degrees north, east of Greenland — a region known for its nutrient-rich waters. “The North Atlantic is not only one of the most productive regions of the ocean, but also a key area for the global carbon and oxygen balance,” says Cui. “Changes in these processes can have major impacts on marine ecosystems and the global climate.”
During the international IODP Expedition 395 aboard the JOIDES Resolution drilling vessel, Cui collected deep-sea sediment cores from this region. These cores, essentially a geological diary, contain records of ocean and climate development spanning millions of years and provide valuable insights into past climate extremes. She is now using these data to drive the UVic Earth system model — a tool that simulates physical, chemical and biological processes in the ocean. The three-dimensional simulations make visible how warmer climates may have altered nutrient cycles and oxygen levels in productive ocean regions such as the North Atlantic.
Fossil Data as a Key to Better Climate Models
“Ying Cui’s research complements our work perfectly,” says her host, Prof. Dr Andreas Oschlies, head of the Biogeochemical Modelling Research Unit at GEOMAR. “One of the major uncertainties in marine biogeochemical models is their sensitivity to short-term climate fluctuations. By studying past climates, we can understand these processes under very different conditions and improve our models accordingly”. Fossil records, he adds, can help us make more reliable projections of future climate scenarios.
Background: Humboldt Research Fellowship for Experienced Researchers
The Humboldt Research Fellowship supports highly qualified researchers from abroad for a long-term research stay (6 to 18 months) in Germany. Fellows develop and carry out a research project of their own choice in cooperation with a German research institution.
http://www.geomar.de/n9865 Images for Download
https://www.geomar.de/en/research/fb2/fb2-bm/overview Biogeochemical Modelling Research Unit at GEOMAR
https://www.humboldt-foundation.de/en/ Alexander von Humboldt Foundation
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