Krill defecation at depth reduces carbon flux attenuation in the Weddell Sea euphotic zone

Atherden, Florence; Rowlands, Emily; Flint, Gareth; Fielding, Sophie; Schmidt, Katrin; Fileman, Elaine; Richter, Maren; Wilkinson, Bethany; Atkinson, Angus; Manno, Clara

doi:10.5194/os-22-2621-2026

Articles | Volume 22, issue 4

https://doi.org/10.5194/os-22-2621-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

Processes influencing carbon cycling on the Antarctic continental...

https://doi.org/10.5194/os-22-2621-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 22, issue 4

Research article

|

28 Aug 2026

Research article |

| 28 Aug 2026

Krill defecation at depth reduces carbon flux attenuation in the Weddell Sea euphotic zone

Florence Atherden, Emily Rowlands, Gareth Flint, Sophie Fielding, Katrin Schmidt, Elaine Fileman, Maren Richter, Bethany Wilkinson, Angus Atkinson, and Clara Manno

Supplement

https://doi.org/10.5194/os-22-2621-2026-supplement

Data sets

POC and PON flux data from the western Weddell Sea (Feburary 2024) during the PICCOLO research cruise SD035 Florence Atherden et al. https://doi.org/10.5285/47f15a7a-de57-dc68-e063-7086abc0ccb7

Faecal pellet volume flux, size and shape data, and krill egg flux sampled using a drifting sediment trap from the western Weddell Sea (Feburary 2024) during the PICCOLO research cruise SD035 Florence Atherden et al. https://doi.org/10.5285/4aa06690-48e3-0212-e063-7086abc0af43

Chlorophyll-a samples collected in the Southern Ocean on cruise SD035 in January-March 2024 as part of PICCOLO. Bethany Wilkinson https://doi.org/10.5285/4f7aed48-816a-d8cf-e063-7086abc055b4

CTD data near floating sediment trap deployments on the western Weddell Sea continental shelf during early 2024 Maren Richter et al. https://doi.org/10.5281/zenodo.20849254

Short summary

The Southern Ocean influences global climate, in part, through biological production of carbon-rich particles which trap atmospheric CO₂ in the deep ocean. Our study highlights that krill defecating at 50–100 m and injecting carbon-rich pellets effectively counteracts the "typical" scenario where the quantity of particles rapidly decreases from the surface, ultimately increasing how much atmospheric carbon is stored. These processes are of global benefit, but vulnerable in a changing climate.