Nicolas Barrier

Abstract Although the role of marine macrofauna in the ocean carbon cycle is increasingly understood, the cumulative impacts of fisheries and climate change on this pathway remain overlooked. Here, using a marine ecosystem model, we estimate that each degree of warming reduces macrofauna biomass and carbon export by 4.2% and 2.46%, respectively. Under a high emission scenario (SSP 5–8.5), this translates to a 13.5% ± 6.6% decline in export by 2100, relative to the 1990s.

1 Introduction Anthropogenic climate change is expected to significantly impact the abundance and spatial distribution of pelagic communities of high trophic level organisms (HTL) (Lefort et al., 2015; Lotze et al., 2019; Tittensor et al., 2021).

Abstract Offshore pelagic ecosystems are composed of vertically and functionally distinct epipelagic, migrant and resident mesopelagic communities. While this vertical structure plays a key role in carbon sequestration and in supporting important fisheries, there is still no consensus on the respective contribution of the environmental factors (light, oxygen) and processes controlling it at both global and regional scale.