Earth’s ocean floor covers about 71 percent of the planet, making it a giant yet poorly explored area of exchange between the surface and subsurface. To better understand this part of the planet, researchers launched The Ocean Floor – Earth’s Uncharted Interface, a seven-year project to investigate the unique habitats the ocean floor provides, its role in carbon and nutrient cycling, and its implications for controlling the global climate.
Kai-Uwe Hinrichs (MARUM – Center for Marine Environmental Sciences at the University of Bremen, Germany), a Co-chair of the DCO Deep Life Scientific Steering Committee, co-leads the project, which encompasses three units, each with a different focus on ocean-floor function.
The “Receiver” unit will study processes that determine how much organic matter reaches the ocean floor and how those processes relate to global biogeochemical cycles. The “Reactor” unit will quantify chemical, biological, and geological reactions occurring within the ocean floor, and their implications for the limits of deep life. They will also investigate the microbial habitats and energy sources created by water-rock reactions and how these processes interact with geodynamics. The “Recorder” unit will delve into the ocean floor as an archive of data from past climate conditions. Specifically, they will focus on periods when Earth was 2 to 4 degrees Celsius warmer than today. These periods are an analog for future climate change scenarios and can show us how oceanic ecosystems responded to previous episodes of warming.
DCO contributed enormously to the momentum needed to initiate this project, said Hinrichs, in particular for the Reactor unit, which focuses on several aspects of the deep carbon cycle and its implications for microbial life. “It was an enormous advantage being a member of the DCO network and having participated in many meetings. It was so clear what are the important questions,” said Hinrichs, who also serves on the DCO Executive Committee. He points to the T-Limit of the Deep Biosphere off Muroto project, an initiative to drill more than a kilometer into the ocean floor to discover the upper temperature limit of life, as being especially helpful in launching the current project.
The researchers will receive the equivalent of more than $8 million annually, funded by the Excellence Strategy, put forth by the German Government. The grant began in 2019 and will continue until 2025, at which point the researchers can apply to renew for another seven years. Hinrichs is excited that the long lifespan of the grant will enable the group to tackle difficult problems and do more in-depth, riskier research than is possible with shorter grant cycles.
The funding primarily will support the training of early career researchers and the technology needed to access the ocean floor, such as their drilling platform MeBo, underwater vehicles, and deep sampling instruments. The team already has 20 research cruises planned, and half of those will focus on deep life and water-rock reactions beneath the seafloor.
The Ocean Floor project is open to guest researchers and its organizers welcome new collaborations. To facilitate international collaborations, interested scientists can apply for a fellowship through the nearby Hanse Institute of Advanced Studies, which funds sabbatical trips for scientists interested in Earth or Energy research, among other themes.
DCO researchers named in the proposal as international collaborators include Uli Harms (GFZ Potsdam, Germany), Fumio Inagaki (JAMSTEC, Japan), Mark Lever (ETH Zürich, Switzerland), Beth Orcutt (Bigelow Laboratory for Ocean Sciences, USA), Shuhei Ono (Massachusetts Institute of Technology, USA), Victoria Orphan (California Institute of Technology, USA), and Andreas Teske (University of North Carolina at Chapel Hill, USA). Additionally, Wolfgang Bach, Gerhard Bohrmann, Verena Heuer, Marta Perez-Gussinye, Lars Wörmer (all at MARUM, Germany), Antje Boetius, Nicole Dubilier, Gunter Wegener (all at Max Planck Institute for Marine Microbiology, University of Bremen), and Thorsten Dittmar (University of Oldenburg, Germany), are local researchers involved in the project with close thematic connections to the DCO.
Main image: MARUM has an established infrastructure for exploring the ocean floor, including research vessels, drilling equipment, and sampling devices. Credit: MARUM – Center for Marine Environmental Sciences, University of Bremen