The deposition of organic material in sediments on the ocean floor plays a critical role in the global carbon cycle. However, the question of whether this material is more similar to marine algae or the microorganisms that decompose the algae remains unresolved. A recent study by a team of researchers fed organic material labeled with 13C carbon to microbial communities in the laboratory to observe its processing over 400 days. The team found that the microbial communities can be stimulated by the addition of lipids and proteins, leading to the decomposition of both fresh and old organic carbon. This finding is important as increased input of fresh organic matter due to human-made and climate-induced environmental changes could impact the carbon cycle and the feedback with the climate system.
The study, led by Prof Jack Middelburg from Utrecht University, is the first to link the degradation of labile organic matter to the growth of microbes and its consequences on the composition of organic matter eventually buried in marine sediment. The researchers were surprised to find that the addition of fresh organic matter had a significant and long-lasting effect on the degradation of old, supposedly refractory organic matter. This research provides crucial insights into the connection between organic matter deposition events, the long-term preservation of organic carbon, and the various research units focusing on the ocean floor in the Cluster of Excellence “The Ocean Floor — Earth’s Unexplored Interface” at MARUM.
The input of fresh organic matter into the seafloor is expected to increase due to climate-related changes in the environment. This could have direct impacts on the microorganisms living on and in the ocean floor, as well as on the carbon cycle and its feedback with the climate system, which are still not fully understood. MARUM, a research center focused on the role of the ocean and seabed in the Earth system, aims to produce fundamental scientific knowledge through unbiased research for the benefit of society and the marine environment. They publish quality-assured scientific data, inform the public about new discoveries in the marine environment, and provide practical knowledge through engagement with society. MARUM also collaborates with companies and industrial partners in a manner that aligns with their goal of protecting the marine environment.
The dynamics of the oceans and the seabed have significant impacts on the Earth system through interactions of geological, physical, biological, and chemical processes. These interactions influence climate, the global carbon cycle, and the development of unique biological systems. MARUM’s research is aligned with the sustainability goals of the United Nations, emphasizing the importance of understanding the role of the ocean and seafloor in the Earth system. By conducting fundamental and transparent research, MARUM aims to contribute to a better understanding of the marine environment and its interconnectedness with the broader Earth system. Through collaboration with various stakeholders, MARUM seeks to protect the marine environment and promote sustainable practices for the benefit of both society and the planet.
