Life strategy of Antarctic silverfish promote large carbon export in Terra Nova Bay, Ross Sea

TL;DR

Antarctic silverfish contribute significantly to carbon export in the Ross Sea through their eggs and feces, impacting the Southern Ocean's carbon cycle.

Contribution

This study quantifies the role of Antarctic silverfish in carbon flux, revealing their spawning strategy modulates carbon export.

Findings

Eggs and feces of Antarctic silverfish account for 41% of annual POC flux in the Ross Sea.

The variability in carbon flux is influenced by the spawning strategy of the species.

A potential decrease in silverfish biomass could impact Southern Ocean biogeochemical cycles.

Abstract

Antarctic silverfish Pleuragramma antarcticum is the most abundant pelagic fish in the High Antarctic shelf waters of the Southern Ocean, where it plays a pivotal role in the trophic web as the major link between lower and higher trophic levels. Despite the ecological importance of this species, knowledge about its role in the biogeochemical cycle is poor. We determine the seasonal contribution of Antarctic silverfish to carbon flux in terms of faeces and eggs, from samples collected in the Ross Sea. We find that eggs and faeces production generate a flux accounting for 41% of annual POC flux and that the variability of this flux is modulated by spawning strategy. This study shows the important role of this organism as a vector for carbon flux. Since Antarctic silverfish are strongly dependent on sea-ice, they might be especially sensitive to climatic changes. Our results suggest that a potential decrease in the biomass of this organism is likely to impact marine biogeochemical cycles, and this should be factored in when assessing Southern Ocean carbon budget.

A study focused on the Ross Sea found that sinking of Antarctic silverfish eggs and faeces promotes the biological carbon pump contributing to a large amount of the annual carbon export.

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