A new look at ocean carbon remineralization for estimating deepwater sequestration
A new look at ocean carbon remineralization for estimating deepwater sequestration
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DOI：
10.1002/2014gb005063
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发表时间：
2015-07-01
影响因子：
5.2
通讯作者：
Henson, Stephanie A.
中科院分区：
文献类型：
--
作者：
Guidi, Lionel;Legendre, Louis;Henson, Stephanie A.
生物碳泵通过向下转移有机物质（主要是颗粒），在深层沃茨中进行碳封存。这一机制在很大程度上取决于表层沃茨中海洋浮游生物吸收CO2以及随后颗粒有机碳通过水柱下沉。大部分的下沉POC是在其向下过境的过程中，和温和的变化，在大气CO2浓度的反馈，但鲜为人知的是全球变化，在大气CO2浓度。在这里，我们评估这种变化的基础上，现代水下粒子成像结合现场POC通量数据，并讨论了潜在的变化来源。我们发现了一个显着的关系，浮游植物组合的大小结构和矿化。我们获得了地球化学省的地球化学化的第一个区域化估计值，这些估计值的范围在通常使用的全球统一地球化学化值的-50%和+100%之间。我们将区域化的值应用于卫星估算的上层海洋POC输出，以计算区域化和全海洋的深层碳通量和固存。在2000米处，全球有机碳固存的结果值为0.33PgCyr（-1），在永久密度跃层顶部深度处为0.72PgCyr（-1），这比基于均匀矿化和固定固存深度的常用方法所得到的值高出3倍。这些结果强调，应使用可变的矿化和封存深度来模拟海洋碳封存和对大气的反馈。
The biological carbon pump causes carbon sequestration in deep waters by downward transfer of organic matter, mostly as particles. This mechanism depends to a great extent on the uptake of CO2 by marine plankton in surface waters and subsequent sinking of particulate organic carbon (POC) through the water column. Most of the sinking POC is remineralized during its downward transit, and modest changes in remineralization have substantial feedback on atmospheric CO2 concentrations, but little is known about global variability in remineralization. Here we assess this variability based on modern underwater particle imaging combined with field POC flux data and discuss the potential sources of variations. We show a significant relationship between remineralization and the size structure of the phytoplankton assemblage. We obtain the first regionalized estimates of remineralization in biogeochemical provinces, where these estimates range between -50 and +100% of the commonly used globally uniform remineralization value. We apply the regionalized values to satellite-derived estimates of upper ocean POC export to calculate regionalized and ocean-wide deep carbon fluxes and sequestration. The resulting value of global organic carbon sequestration at 2000m is 0.33PgCyr(-1), and 0.72PgCyr(-1) at the depth of the top of the permanent pycnocline, which is up to 3 times higher than the value resulting from the commonly used approach based on uniform remineralization and constant sequestration depth. These results stress that variable remineralization and sequestration depth should be used to model ocean carbon sequestration and feedback on the atmosphere.