Under the leadership of Professor Dr. Sylvia Sander from GEOMAR, a group of leading marine scientists has prepared a position paper on deep-sea research and management. The report offers recommendations for the more sustainable exploration and management of this sensitive habitat . The authors argue that decisions regarding the use and protection of the deep sea are impossible without sound knowledge of ecosystem processes and biodiversity. They call for targeted research to close knowledge gaps. The report is addressed to policymakers, scientists, and international organizations and will be presented today in an online webinar.
Where does the deep sea begin? The definition is not uniform in science or in law. For their joint analysis of the current state of deep-sea research, the members of the "Deep Sea and Ocean Health" working group of the European Marine Board (EMB) agreed on a depth of 200 meters or more. Below this depth, hardly any sunlight penetrates the water, and the habitat changes dramatically. According to this definition, the deep sea makes up around 90 percent of the volume of the ocean. Its importance for ecosystems and biodiversity is therefore immense. But pressure is currently growing on these habitats on our planet, some of which are still relatively untouched: human activities such as oil extraction, fishing and potential mining on the seabed are threatening deep-sea ecosystems, and climate change is also having a negative impact.
The working group of eleven scientists has now presented its analysis on the topic of deep sea and ocean health, along with ten recommendations. Led by Prof. Dr. Sylvia Sander, Professor of Marine Mineral Resources at the GEOMAR Helmholtz Centre for Ocean Research, and Dr. Christian Tamburini of the Mediterranean Institute of Oceanography (MIO), they compiled the report, which will be presented today by the EMB in a webinar. Among other things, the document underscores the need for significant investment in deep-sea research to close knowledge gaps and provide information for scientifically sound decisions, for example, on deep-sea mining.
"The ocean is an interconnected system that extends from the coast to the deepest depths," emphasizes Sylvia Sander, "and of course the deep sea cannot be viewed in isolation from the photic – the light-filled – zone or the seafloor." Therefore, deep-sea research, use and protection are inextricably linked to ocean health.
Ten recommendations for sustainable deep-sea protection and better cooperation:
1. Effective regulation of human activities
2. Establishment of an international committee for deep-sea sustainability
3. Development of standardized methods for environmental impact assessment
4. Promoting transdisciplinary research programs
5. Investing in long-term deep-sea monitoring projects
6. Deepening the understanding of global deep-sea processes through large-scale, interdisciplinary long-term research projects
7. Research funding in areas such as genome sequencing and biogeochemical processes
8. Building global capacities for deep-sea research
9. Technology transfer to underrepresented regions
10. Implementation of the FAIR principles for deep-sea data
The possibility of life existing in the dark, cold depths of the ocean, where extremely high pressure prevails, was doubted until the end of the 19th century, when the first organisms living there were discovered with the beginning of deep-sea exploration. Today, research shows that the deep sea harbors a great diversity of life forms . Complex ecosystems exist on continental slopes, in abyssal plains, and at hydrothermal vents, the so-called black smokers, about which little is yet known.
An estimated 90 percent of all organisms in the deep sea have not yet been described, and their functions within the ecosystem are unknown. There are also major gaps in physical oceanography, for example in the modeling of deep-sea currents, which are crucial for the transport of nutrients and pollutants. In geochemistry, it is unclear how biogeochemical cycles in the deep sea are influenced by human interventions such as deep-sea mining. For example, little is known about how sediment plumes created by the extraction of manganese nodules spread and what long-term consequences they would have for the communities on the seafloor. Finally, there are also technical challenges: many modern sensors and monitoring systems are insufficiently developed for extreme depths, making it difficult to record important parameters. These knowledge gaps must be urgently closed to enable scientifically sound decisions for deep-sea management, the scientists warn.
What we do know for certain, however, is that the ocean, the largest part of which is the deep sea, stores large quantities of CO₂ and heat, thus contributing to mitigating climate change; it plays a key role in the global carbon cycle and, as the "lungs of the planet," produces more than 50 percent of the oxygen. Disruptions to these functions could have serious global consequences. To ensure the preservation of these ecosystem services, sound conservation measures and sustainable use strategies are urgently needed.
The impacts of human activity are affecting the deep sea in many ways. Changes that are irreversible on human timescales, such as global warming, acidification, and oxygen depletion, threaten these sensitive habitats. At the same time, the overexploitation of fish stocks and non-renewable resources such as oil, gas, and minerals endangers biodiversity and ecosystem functions.
Scientists agree that 2025 is a crucial year to take action for ocean health: It is crucial to effectively address climate change now to achieve the targeted net-zero emissions by 2050. Sylvia Sander: "Climate change is one of the most worrying threats to our livelihoods and life on Earth. Combined with the loss of biodiversity, it could lead to significant and irreversible disruptions to the entire ocean, including the deep sea and parts of the Earth covered by snow and ice, in the near future."
The working group stresses that Europe should take a leading role in the international protection and sustainable management of the deep sea, particularly within the framework of existing international agreements.
"The EU could play an important role in international efforts to better regulate deep-sea activities," says Sylvia Sander. "This requires the establishment of scientific committees for deep-sea protection and the development of standardized impact assessments."
The researchers also call for secure funding for transdisciplinary research and long-term monitoring. Sylvia Sander: "We need a better understanding of the ocean's health in order to protect and sustainably use the deep sea – where are changes evident?" This requires more research and technology. "We also need to provide more support to underrepresented nations in deep-sea research and recognize science as a human right. Only then can we ensure the health of the ocean and the planet for future generations."
Background: European Marine Board
The European Marine Board (EMB) is an association of 38 organizations from 19 European countries committed to marine research. It was founded in 1995 to strengthen cooperation in European marine science and develop joint research strategies. The EMB serves as an interface between science and policy, supports knowledge exchange, and provides recommendations to national authorities and the European Commission to advance marine research in Europe. Members include leading oceanographic institutes, research funders, and universities with a marine focus.
original publication
Sander, SG, Tamburini, C., Gollner, S., Guilloux, B., Pape, E., Hoving, HJ, Leroux, R., Rovere, M., Semedo, M., Danovaro, R., Narayanaswamy, BE (2025) Deep Sea Research and Management Needs.
Muñiz Piniella, A., Kellett, P., Alexander, B., Rodriguez Perez, A., Bayo Ruiz, F., Teodosio, MC, Heymans, JJ [Eds.] Future Science Brief N°. 12 of the European Marine Board, Ostend, Belgium.
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