Bentho-pelagic coupling is the exchange of energy, nutrients, carbon, and organisms between the open water (pelagic zone) and the seafloor (benthic zone). These connections help sustain deep-sea ecosystems, recycle nutrients, and support the movement and storage of carbon in the ocean.

This connection works like a two-way street:

• Downward pathways: Organic matter travels down from the sunlit surface to the deep sea. This happens when gravity pulls down sinking particles like marine snow and dead jellyfish, when ocean currents naturally push water downward, and when deep-diving marine animals travel to the depths to feed.
• Upward pathways: Energy and nutrients travel back up to the upper ocean. This is driven by deep-water turbulence and underwater "benthic storms" that stir up sediments from the seabed, as well as by the upward swimming of tiny marine larvae and the seasonal migrations of small open-ocean organisms.

OceanSOS investigates how climate change and human activities may alter bentho-pelagic coupling, affecting ocean food webs and the biological carbon pump.

Sources:

• Henry, L.-A., et al. (2026). Mesoscale eddies in the subpolar North Atlantic: Their ecological importance and conservation significance. Progress in Oceanography, 246, Article 103760. https://doi.org/10.1016/j.pocean.2026.103760

Around a quarter of the carbon dioxide released into the atmosphere each year is absorbed by the ocean. Tiny marine organisms that photosynthesise sunlight at the surface of the ocean, called phytoplankton, help move some of this carbon from the ocean surface into deeper waters where it can remain stored for decades or even centuries. This natural process, known as the biological carbon pump, is one of Earth's most important climate regulation systems. OceanSOS is investigating how emerging human activities and climate change could alter this process and what that means for marine ecosystems and the global climate.

The Biological Carbon Pump (BCP) is a natural process in which marine organisms capture carbon from the atmosphere and transport it into the deep ocean, where it can be stored for centuries to millennia. Tiny phytoplankton absorb carbon at the sea surface through photosynthesis, while sinking organic matter, marine snow, the marine food chain, and the movement of animals transfer carbon through the water column to the seafloor. This process plays a vital role in regulating Earth's climate by reducing the amount of carbon dioxide in the atmosphere. OceanSOS studies how climate change and human activities may affect the BCP and its ability to store carbon in the future.

Sources:

• Wilson et al., (2022), ‘The Biological Carbon Pump in CMIP6 Models: 21st Century Trends and Uncertainties’, Proceedings of the National Academy of Sciences. 119, e2204369119, https://doi.org/10.1016/j.pocean.2026.103760.
• Woods Hole Oceanographic Institution. (n.d.). Biological carbon pump: How the ocean stores CO2. Ocean Learning Hub. https://www.whoi.edu/ocean-learning-hub/ocean-topics/how-the-ocean-works/cycles/biological-carbon-pump/

Around a quarter of the carbon dioxide released into the atmosphere each year is absorbed by the ocean. Tiny marine organisms that photosynthesise sunlight at the surface of the ocean, called phytoplankton, help move some of this carbon from the ocean surface into deeper waters where it can remain stored for decades or even centuries. This natural process, known as the biological carbon pump, is one of Earth's most important climate regulation systems. OceanSOS is investigating how emerging human activities and climate change could alter this process and what that means for marine ecosystems and the global climate.

The Biological Carbon Pump (BCP) is a natural process in which marine organisms capture carbon from the atmosphere and transport it into the deep ocean, where it can be stored for centuries to millennia. Tiny phytoplankton absorb carbon at the sea surface through photosynthesis, while sinking organic matter, marine snow, the marine food chain, and the movement of animals transfer carbon through the water column to the seafloor. This process plays a vital role in regulating Earth's climate by reducing the amount of carbon dioxide in the atmosphere. OceanSOS studies how climate change and human activities may affect the BCP and its ability to store carbon in the future.

Sources:

• Wilson et al., (2022), ‘The Biological Carbon Pump in CMIP6 Models: 21st Century Trends and Uncertainties’, Proceedings of the National Academy of Sciences. 119, e2204369119, https://doi.org/10.1016/j.pocean.2026.103760.
• Woods Hole Oceanographic Institution. (n.d.). Biological carbon pump: How the ocean stores CO2. Ocean Learning Hub. https://www.whoi.edu/ocean-learning-hub/ocean-topics/how-the-ocean-works/cycles/biological-carbon-pump/

The Planetary Boundaries Safe Operating Space (PB SOS) framework defines the environmental limits within which humanity can safely operate while maintaining a stable, resilient Earth system. For each of the planet's critical biophysical systems, the framework identifies control variables — measurable, scientifically defined guardrails that track the planet’s health and warn when human pressures risk triggering irreversible, non-linear ecological tipping points.

In OceanSOS, this global concept is adapted for the marine environment by developing regional Safe Operating Spaces that establish localised thresholds for human activity. This adaptation is highly critical, as global tracking indicates that vital marine guardrails — most notably ocean acidification — have now breached their safe operating zones. By combining localised scientific data, models, and expert knowledge, the framework translates abstract global limits into concrete indicators for precautionary, evidence-based ocean management, helping decision-makers protect marine ecosystems before catastrophic damage occurs.

Sources:

• Rockström, J., Steffen, W., Noone, K., Persson, Å., Chapin III, F. S., Lambin, E., ... & Foley, J. (2009). Planetary boundaries: exploring the safe operating space for humanity. Ecology and society, 14(2).