Global patterns in efficiency of particulate organic carbon export and transfer to the deep ocean
Global patterns in efficiency of particulate organic carbon export and transfer to the deep ocean
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DOI：
10.1029/2011gb004099
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发表时间：
2012-03-23
影响因子：
5.2
通讯作者：
Madsen, Esben
中科院分区：
文献类型：
--
作者：
Henson, Stephanie A.;Sanders, Richard;Madsen, Esben
海洋的生物碳泵是全球碳循环的关键组成部分。初级生产固定的碳中只有一小部分出口到深海，但这一通量设定了碳在长时间尺度上与大气进一步接触时被隔离的效率。在这里，我们考察了颗粒输出效率(PEef)和转移效率(T-ef)的全球模式，前者是指从表层海洋输出的初级产品的比例，后者是指出口到深海的有机物的比例。前人的研究发现，T-Eff与从沉积物圈闭中恢复的深海方解石通量呈正相关，这意味着碳酸钙压载可能在调节T-Ef中发挥重要作用。另一种解释是，这种相关性不是因果关系，因为主要生物矿物相为方解石的地区往往是亚热带系统，假设这些系统产生高度抗退化的下沉集合体。我们试图通过研究T-Eff与上层海洋输出的生物矿物相之间的关系，而不是那些收集在深层圈闭中的生物矿物相之间的关系，来区分这些关于T-Eff控制的替代假说。根据卫星数据得出的全球尺度估计表明，与早先的研究一致，PEJeff在高纬度高，在低纬度低，但T-Eff在高纬度低，在低纬度高。然而，与以前研究中观察到的深层生物矿物通量的关系相反，我们发现T-Eff与上层海洋的蛋白石出口通量呈强烈的负相关，而与碳酸钙的出口通量无关。我们假设，控制T-Eff中观察到的空间格局的潜在因素是生态系统功能，特别是发生在上层海洋的循环程度，而不是用于压载的碳酸钙的可用性。
The ocean's biological carbon pump is a key component of the global carbon cycle. Only a small fraction of the carbon fixed by primary production is exported to the deep ocean, yet this flux sets to first order the efficiency with which carbon is sequestered out of further contact with the atmosphere on long time scales. Here we examine global patterns in particle export efficiency (PEeff), the proportion of primary production that is exported from the surface ocean, and transfer efficiency (T-eff), the fraction of exported organic matter that reaches the deep ocean. Previous studies have found a positive correlation between T-eff and deep ocean calcite fluxes recovered from sediment traps, implying that ballasting by calcium carbonate may play an important role in regulating T-eff. An alternative explanation is that this correlation is not causative, as regions where the dominant biomineral phase is calcite tend to be subtropical systems, which are hypothesized to produce sinking aggregates highly resistant to degradation. We attempt to distinguish between these alternative hypotheses on the control of T-eff by examining the relationship between T-eff and biomineral phases exported from the upper ocean, rather than those collected in deep traps. Global scale estimates derived from satellite data show, in keeping with earlier studies, that PEeff is high at high latitudes and low at low latitudes, but that T-eff is low at high latitudes and high at low latitudes. However, in contrast to the relationship observed for deep biomineral fluxes in previous studies, we find that T-eff is strongly negatively correlated with opal export flux from the upper ocean, but uncorrelated with calcium carbonate export flux. We hypothesize that the underlying factor governing the spatial patterns observed in T-eff is ecosystem function, specifically the degree of recycling occurring in the upper ocean, rather than the availability of calcium carbonate for ballasting.