Role of zooplankton in determining the efficiency of the biological carbon pump
Role of zooplankton in determining the efficiency of the biological carbon pump
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DOI：
10.5194/bg-14-177-2017
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发表时间：
2017-01-12
期刊：
影响因子：
4.9
通讯作者：
Sanders, Richard
中科院分区：
文献类型：
--
作者：
Cavan, Emma L.;Henson, Stephanie A.;Sanders, Richard
海洋生物碳泵的效率（BCPeff -这里是粒子输出和转移效率的乘积）在CO2的海气分配中起着关键作用。尽管它在全球碳循环中的重要性，控制BCPeff的生物过程知之甚少。我们调查的潜在作用，浮游动物在生物碳泵使用原位观测和模式输出。观测和模拟估计的快速，缓慢和总下沉通量从三个海洋站点：南大洋，北大西洋温带，赤道太平洋氧气最低区（OMZ）的大西洋部门。我们发现，观察到的颗粒出口效率是负相关的初级生产可能是由于浮游动物放牧，直接对比模型估计。该模型和观测结果显示，在大洋中水层浮游动物处理颗粒被认为是低的OMZ网站的矿化系数和BCPeff的最强协议。由于该模型具有有限的代表性的浮游动物介导的生态化过程，我们建议，这些结果指向浮游动物在设置BCPeff的重要性，包括颗粒放牧和破碎，昼夜垂直迁移的影响。我们认为，改善浮游动物过程的参数化可能会增加生物碳泵的生物地球化学模型估计的保真度。未来的气候变化，如有机开放区的扩大，可能会降低浮游动物在全球生物碳泵中的作用，从而提高其效率。
The efficiency of the ocean's biological carbon pump (BCPeff - here the product of particle export and transfer efficiencies) plays a key role in the air-sea partitioning of CO2. Despite its importance in the global carbon cycle, the biological processes that control BCPeff are poorly known. We investigate the potential role that zooplankton play in the biological carbon pump using both in situ observations and model output. Observed and modelled estimates of fast, slow, and total sinking fluxes are presented from three oceanic sites: the Atlantic sector of the Southern Ocean, the temperate North Atlantic, and the equatorial Pacific oxygen minimum zone (OMZ). We find that observed particle export efficiency is inversely related to primary production likely due to zooplankton grazing, in direct contrast to the model estimates. The model and observations show strongest agreement in remineralization coefficients and BCPeff at the OMZ site where zooplankton processing of particles in the mesopelagic zone is thought to be low. As the model has limited representation of zooplankton-mediated remineralization processes, we suggest that these results point to the importance of zooplankton in setting BCPeff, including particle grazing and fragmentation, and the effect of diel vertical migration. We suggest that improving parameterizations of zooplankton processes may increase the fidelity of bio-geochemical model estimates of the biological carbon pump. Future changes in climate such as the expansion of OMZs may decrease the role of zooplankton in the biological carbon pump globally, hence increasing its efficiency.