08.12.2023/Kiel. Marine organisms play a crucial role in the global carbon cycle. Phytoplankton absorb carbon dioxide from the atmosphere and sequester it in organic matter that sinks to the deep ocean where it can be stored for long periods of time. Until now, this process – the biological carbon pump – was thought to be particularly efficient in oxygen-poor areas. A new study by researchers at the GEOMAR Helmholtz Centre for Ocean Research Kiel suggests that the influence of certain zooplankton species on the biological carbon pump has been underestimated. The scientists have published their findings in the journal Communications Earth & Environment.