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.

中文翻译：

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“沉没”——浮游动物尸体对亚南极南大洋颗粒有机碳通量的贡献

浮游动物尸体是生物引力泵的一个重要但尚未得到充分研究的途径。为了了解它们对亚南极地区碳通量下降的贡献，我们分析了桡足类Neocalanus胴体的碳含量、微生物再矿化率和下沉速度。此外，还分析了胴体通量对不同死亡率、微生物周转率和下沉速度的敏感性，并与来自沉积物陷阱的碳通量测量值进行了比较。微生物分解速率（在 0.02 和 0.16 d ^-1之间）与海洋雪的分解速率相当，突出了尸体作为微生物热点的重要性。高下沉速度（730 ± 182 m d ^-1) 表明流向深海的颗粒有机碳通量是巨大的。胴体通量对下沉速度的变化很敏感，但对微生物分解速率的波动似乎不太敏感。需要对浮游动物死亡率和影响尸体通过水柱下沉的因素进行更多研究，以量化尸体介导的碳输出，并将其纳入海洋生态系统和生物地球化学模型。