Sinking particle fluxes and biological carbon pump efficiency in the Labrador Sea during a <i>Phaeocystis</i> bloom decline

Roca-Martí, Montserrat; Healey, Madeline; McBride, Colleen E.; Sipler, Rachel; Devred, Emmanuel; Cisternas-Novoa, Carolina; Romanelli, Elisa; Ohashi, Kyoko; Kienast, Stephanie S.

doi:10.5194/bg-23-6229-2026

Articles | Volume 23, issue 17

https://doi.org/10.5194/bg-23-6229-2026

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

https://doi.org/10.5194/bg-23-6229-2026

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

Articles | Volume 23, issue 17

Research article

|

11 Sep 2026

Research article |

| 11 Sep 2026

Sinking particle fluxes and biological carbon pump efficiency in the Labrador Sea during a Phaeocystis bloom decline

Montserrat Roca-Martí, Madeline Healey, Colleen E. McBride, Rachel Sipler, Emmanuel Devred, Carolina Cisternas-Novoa, Elisa Romanelli, Kyoko Ohashi, and Stephanie S. Kienast

Supplement

https://doi.org/10.5194/bg-23-6229-2026-supplement

Data sets

Particulate Th-234, organic carbon, organic nitrogen and biogenic silica concentrations in size-fractionated particles in the Labrador Sea in spring 2022 M. Roca‐Martí et al. https://doi.org/10.1594/PANGAEA.983961

Total (dissolved + particulate) Th-234 and U-238 activities in seawater in the Labrador Sea in spring 2022 M. Roca‐Martí et al. https://doi.org/10.1594/PANGAEA.983957

Download

Article (3936 KB)
Full-text XML

Short summary

We studied a historically large spring phytoplankton bloom in the Labrador Sea to quantify how much carbon reaches the deep ocean. Despite high productivity, only a small fraction of organic carbon sank below the ocean's productive layer, suggesting a limited role of the dominant phytoplankton species (Phaeocystis) in carbon export. Our findings highlight the need for long-term observations to better assess the ocean’s role in carbon sequestration.