Shallow particulate organic carbon regeneration in the South Pacific Ocean
Shallow particulate organic carbon regeneration in the South Pacific Ocean
复制标题
南太平洋浅层颗粒有机碳再生
DOI：
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发表时间：
2019
影响因子：
11.1
通讯作者：
R. Edwards
中科院分区：
文献类型：
--
作者：
F. Pavia;F. Pavia;R. Anderson;R. Anderson;P. Lam;B. Cael;Sebastián M. Vivancos;Sebastián M. Vivancos;M. Fleisher;Yanbin Lu;Pu Zhang;Hai Cheng;Hai Cheng;R. Edwards
意义 阳光照射下的海洋表层浮游生物进行光合作用，将溶解的二氧化碳固定为颗粒有机碳 (POC)。这种 POC 下沉并进行呼吸，将二氧化碳释放到与大气隔离的地下水中。这种再生发生的深度尺度强烈影响大气中的二氧化碳，但迄今为止的估计很少且难以解释。我们使用一种新的地球化学方法以前所未有的分辨率确定南太平洋的 POC 再生深度尺度，在缺氧区域和贫营养环流环境中发现浅层再生。我们的结果表明，由于环流扩张和对扩大缺氧区域的两个相反的反馈，未来海洋碳储存量减少，其对海洋碳储存的净影响需要未来的研究。海洋表层产生的颗粒有机碳（POC）通过水柱下沉并在深处呼吸，成为深海中固碳的主要载体。大气中的二氧化碳水平对呼吸作用将 POC 转化回无机碳的长度（深度）非常敏感，因为较浅的水域与大气的交换速度比较深的水域更快。然而，对这种碳再生长度尺度及其时空变异性的估计是有限的，阻碍了表征其对环境条件的敏感性的能力。在这里，我们基于放射性钍同位素 230Th 的标准化，展示了热带南太平洋东部 GEOTRACES GP16 样带的 POC 通量高垂直和空间分辨率的分区剖面。我们发现贫营养南太平洋环流的碳再生长度尺度比之前的估计更浅，表明向深海的碳转移效率较低。秘鲁海岸附近的低氧水域中碳再生受到强烈抑制。规范马丁曲线幂律不足以捕捉低氧站的 POC 通量分布。相反，我们使用指数函数拟合这些剖面，并在深度保留通量，发现浅层再生但 POC 封存量低于 1,000 m。再生长度尺度和深度处的 POC 通量都密切跟踪氧浓度接近零的深度。我们的研究结果表明，由于贫营养环流的扩大，气候变暖将导致海洋碳储存减少，但低氧水域扩张对海洋碳储存的相反影响将需要建模和未来的工作来解决。
Significance Plankton in the sunlit surface ocean photosynthesize, fixing dissolved CO2 into particulate organic carbon (POC). This POC sinks and is respired, releasing CO2 into subsurface waters that are sequestered from the atmosphere. The depth scale over which this regeneration happens strongly affects atmospheric CO2, but estimates to date have been sparse and challenging to interpret. We use a new geochemical method to determine POC regeneration depth scales at unprecedented resolution in the South Pacific Ocean, finding shallow regeneration in both oxygen-deficient zone and oligotrophic gyre settings. Our results imply decreased future ocean carbon storage due to gyre expansion and two opposing feedbacks to expanding oxygen-deficient zones, the net effects of which on ocean carbon storage require future research. Particulate organic carbon (POC) produced in the surface ocean sinks through the water column and is respired at depth, acting as a primary vector sequestering carbon in the abyssal ocean. Atmospheric carbon dioxide levels are sensitive to the length (depth) scale over which respiration converts POC back to inorganic carbon, because shallower waters exchange with the atmosphere more rapidly than deeper ones. However, estimates of this carbon regeneration length scale and its spatiotemporal variability are limited, hindering the ability to characterize its sensitivity to environmental conditions. Here, we present a zonal section of POC fluxes at high vertical and spatial resolution from the GEOTRACES GP16 transect in the eastern tropical South Pacific, based on normalization to the radiogenic thorium isotope 230Th. We find shallower carbon regeneration length scales than previous estimates for the oligotrophic South Pacific gyre, indicating less efficient carbon transfer to the deep ocean. Carbon regeneration is strongly inhibited within suboxic waters near the Peru coast. Canonical Martin curve power laws inadequately capture POC flux profiles at suboxic stations. We instead fit these profiles using an exponential function with flux preserved at depth, finding shallow regeneration but high POC sequestration below 1,000 m. Both regeneration length scales and POC flux at depth closely track the depths at which oxygen concentrations approach zero. Our findings imply that climate warming will result in reduced ocean carbon storage due to expanding oligotrophic gyres, but opposing effects on ocean carbon storage from expanding suboxic waters will require modeling and future work to disentangle.
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影响因子：
5.2
作者：
Guidi, Lionel;Legendre, Louis;Henson, Stephanie A.
通讯作者：
Henson, Stephanie A.
影响因子：
56.9
作者：
Stramma, Lothar;Johnson, Gregory C.;Mohrholz, Volker
通讯作者：
Mohrholz, Volker
影响因子：
5.2
作者：
Henson, Stephanie A.;Sanders, Richard;Madsen, Esben
通讯作者：
Madsen, Esben
受多种放射性核素约束的北大西洋颗粒元素通量
影响因子：
5.2
作者：
Hayes, Christopher T.;Black, Erin E.;Anderson, Robert F.;Baskaran, Mark;Buesseler, Ken O.;Charette, Matthew A.;Cheng, Hai;Cochran, J. Kirk;Edwards, R. Lawrence;Fitzgerald, Patrick
通讯作者：
Fitzgerald, Patrick