The ocean floor tells us stories from times long past which are most relevant for the future – those about global warming and changes in environmental conditions. With the help of specific biomarker molecules, Professor Dr. Kai-Uwe Hinrichs’ research group decodes material cycles from epochs of the highest climate dynamics as part of “The Ocean Floor – Earth’s Uncharted Interface” Cluster of Excellence – and at the same time researches how the carbon cycle has changed and could develop in the future.

Von Merle El-Khatib

11 Jun 2024

The image on Kai-Uwe Hinrichs’ computer screen is colorful. It shows the distribution of molecules within a small section of just a few centimeters of sediment core. The molecules reflect the surface temperatures of the ocean. Red stands for warm, green for cold – the temperature fluctuations of a period of about a century are visible at a glance.

The period under investigation is the most recent epoch of Earth’s history that was warmer than today, around 125,000 years ago. Such periods form a central research focus of the University of Bremen’s “The Ocean Floor” Cluster of Excellence. With the university’s MARUM – Center for Marine Environmental Sciences, the Alfred Wegener Institute, the Helmholtz Centre for Polar and Marine Research, the Max Planck Institute for Marine Microbiology, and the Leibniz Centre for Tropical Marine Research, this project includes four institutions of the U Bremen Research Alliance. “You have to go back a long time to find carbon dioxide concentrations comparable to those predicted for the coming century,” says Hinrichs. “These epochs from the past have a model character for the dynamics and interaction of future events.”

Hinrichs and his research group developed the imaging method, which shows high-resolution climate and environmental processes in the history of the earth. In some cases, the researchers can even extract information from the ocean floor samples month by month and read them like a climate diary. “We now also decipher the fine print in the sediment, which we couldn’t do before because we lacked the necessary tools,” says Hinrichs. The carriers of the information are the molecules that originate from dead seaweed from the past and are now made visible via the new imaging method. “They tell a story,” Hinrichs explains.

Hinrichs and an international team have found microbial life even at a depth of 2.458 kilometers below the ocean crust, which is currently the record depth for the detection of microorganisms in the seafloor. Per milliliter of sediment, there are often well over one million cells that are still active even in 20 million-year-old sediments and, for example, convert the old organic material from algae and plants into methane. “The deeper you go, the slower the processes become. It’s a completely different world,” says Hinrichs.

“The synergies in Bremen, the opportunities for development, and the support from the university are outstanding,” Hinrichs emphasizes. “I’ve always enjoyed working here.” An exciting article on climate research on the ocean floor by U Bremen Research Alliance member institutions was recently published in issue 9 of the U Bremen Research Alliance's science magazine "Impact":


Merle El-Khatib
Comunication und marketing
Tel.: +49 421 218 60046

About UBRA:

The University of Bremen and twelve federal and state financed non-university research institutes cooperate within the U Bremen Research Alliance. The Alliance includes research institutes of the four major German science organizations, i.e. Fraunhofer Society, Helmholtz Association, Leibniz Association and Max Planck Society, as well as the German Research Center for Artificial Intelligence.

Prof. Dr. Kai-Uwe Hinrichs und Janina Bösche, doctoral researcher, take a look at core samples.   © Jens Lehmkühler / U Bremen Research Alliance
Molecules of marine algae in sediment samples give detailed indications of past climatic conditions.   © Jens Lehmkühler / U Bremen Research Alliance
Preparing a core sample: Janina Bösche, doctoral researcher in Prof. Dr. Kai-Uwe Hinrichs’ research group.   © Jens Lehmkühler / U Bremen Research Alliance
Destination for researchers from all over the world: The MARUM core repository archives samples from several oceans and geological eras.   © Jens Lehmkühler / U Bremen Research Alliance

Participating cooperation partners

Universität Bremen
Max Planck Institute for Marine Microbiology
Leibniz Centre for Tropical Marine Research
Alfred Wegener Institute