High Temporal Variability of Total Organic Carbon in the Deep Northeastern Pacific
High Temporal Variability of Total Organic Carbon in the Deep Northeastern Pacific
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DOI：
10.3389/feart.2020.00080
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发表时间：
2020-03-27
影响因子：
2.9
通讯作者：
Hansell, Dennis A.
中科院分区：
文献类型：
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作者：
Lopez, Chelsi N.;Robert, Marie;Hansell, Dennis A.
研究了东北太平洋深海区总有机碳（TOC）的季际和年际变化特征。在2017年和2018年沿P线样带从整个较深水柱（>250 m）季节性采集样本，并在2018年春季采集溶解有机碳（DOC）的一次分布。深度大于1000 m的TOC浓度在季节内（浓度差异类似于2-6 μ mol kg(-1)）和跨季节（浓度差异类似于2-12 μ mol kg(-1)）都观察到高度异质性，这与上覆水域的荧光变化相一致。这些观测结果表明，从上层海洋下沉的生物颗粒季节性地向深海输送可观测到的TOC。正如2018年春季TOC和DOC分布的差异所表明的那样，这些颗粒的存在似乎也对DOC池有所贡献。季节TOC净积累和去除率在不同年份之间存在差异：2017年和2018年分别为0.5和2.1 μ mol kg（-1）天（-1）（积累）和0.6和2.1 μ mol kg（-1）天（-1）（去除）。速率估计表明，有机碳进入深海的速率与水华后的去除速率大致相同，表明了季节性产生的有机碳的有效去除。在浮游植物丰度较高的支持下，2018年春季凝胶状浮游动物丰度较高，在季节性水华期间增加了有机碳向深海区的输出，导致深海局部TOC浓度高达148 μ mol kg（-1）。这些结果表明，与低营养系统不同，高纬度深海TOC浓度具有高度变异性。
The interseasonal and interannual variability of total organic carbon (TOC) was assessed in the deep northeastern Pacific Ocean, an area characterized by high primary production and organic matter export. Samples were collected from throughout the deeper water column (>250 m) seasonally in 2017 and 2018 along the Line P transect, as well as one distribution of dissolved organic carbon (DOC) in spring 2018. High heterogeneity was observed in TOC concentrations at depths greater than 1,000 m, both within seasons (concentration differences of similar to 2-6 mu mol kg(-1)) and across seasons (similar to 2-12 mu mol kg(-1)), coinciding with changes in fluorescence in the overlying waters. Such observations suggest that biogenic particles sinking from the upper ocean are seasonally delivering observable TOC to depth. The presence of these particles also appeared to contribute to the DOC pool, as suggested by differences in the TOC and DOC distributions in spring 2018. Seasonal TOC net accumulation and removal rates differed between the years: 0.5 and 2.1 mu mol kg(-1) day(-1) (accumulation) and 0.6 and 2.1 mu mol kg(-1) day(-1) (removal) for 2017 and 2018, respectively. The rate estimates indicated that introduction of organic carbon to the bathypelagic occurred at approximately the same rate as removal post-bloom, demonstrating the efficient removal of seasonally produced organic carbon. High abundances of gelatinous zooplankton in spring 2018, supported by higher abundances of phytoplankton, enhanced the export of organic carbon to the bathypelagic zone during the seasonal bloom, resulting in localized TOC concentrations up to 148 mu mol kg(-1) in the bathypelagic. These results indicate high variability in bathypelagic TOC concentrations at high latitude, unlike oligotrophic systems.