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'Sinking dead' - how zooplankton carcasses contribute to particulate organic carbon flux in the subantarctic Southern Ocean

journal contribution
posted on 2023-05-21, 05:14 authored by Svenja Halfter, Cavan, EL, Butterworth, P, Kerrie SwadlingKerrie Swadling, Philip BoydPhilip Boyd

Zooplankton carcasses are an important, yet understudied, pathway of the biological gravitational pump. To understand their contribution to the downward carbon flux in the subantarctic, carcasses of the copepod Neocalanus tonsus were analyzed for carbon content, microbial remineralization rates, and sinking velocities. In addition, the sensitivity of carcass flux to varying mortality, microbial turnover, and sinking velocity rates was analyzed and compared to carbon flux measurements from sediment traps. Microbial decomposition rates (between 0.02 and 0.16 d−1) were comparable to those of marine snow, highlighting the importance of carcasses as microbial hotspots. High sinking velocities (730 ± 182 m d−1) suggest that particulate organic carbon flux to the deep ocean is substantial. Carcass flux is sensitive to a change in sinking velocity but appears less sensitive to fluctuations in microbial decomposition rate. More research on zooplankton mortality and the factors that influence carcass sinking through the water column is needed to quantify the carcass-mediated carbon export and enable their inclusion in marine ecosystem and biogeochemical models.


Publication title

Limnology and Oceanography








Institute for Marine and Antarctic Studies


Amer Soc Limnology Oceanography

Place of publication

5400 Bosque Blvd, Ste 680, Waco, USA, Tx, 76710-4446

Rights statement

© 2021 The Authors. Limnology and Oceanography published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography.

Repository Status

  • Restricted

Socio-economic Objectives

Antarctic and Southern Ocean oceanic processes

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