Particulate Organic Matter Distributions in the Water Column of the Chukchi Sea During Late Summer
Particulate Organic Matter Distributions in the Water Column of the Chukchi Sea During Late Summer
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DOI：
10.1029/2021jc017664
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发表时间：
2021-09-01
影响因子：
3.6
通讯作者：
Welch, Kylie A.
中科院分区：
文献类型：
--
作者：
Goni, Miguel A.;Juranek, Lauren W.;Welch, Kylie A.
2016年9月和2017年8月完成了两次海洋学巡航，以调查楚科奇大陆架东北部的颗粒有机物（POM）分布。这两个时期的特点是高度分层的条件下，与区域水团的分布，影响POM分布的主要对比。总的来说，表层沃茨的特点是叶绿素荧光低（Chl Fl < 0.8 mg m（-3））和粒子束衰减（c（p）< 0.3 m（-1））值，以及低浓度的颗粒有机碳（POC < 8 mmol m（-3））、叶绿素和脱镁叶绿素（Chl + Pheo < 0.8 mg m（-3））和悬浮颗粒物（SPM类似于2 g m（-3））。在密度跃层以下的中等深度测量的Chl Fl和Chl + Pheo（类似于2 mg m（-3））值定义了次表层叶绿素最大值（SCM），其表现出中等POC（类似于10 mmol m（-3）），c（p）（类似于0.4 m（-1））和SPM（类似于3 g m（-3））。相比之下，密度跃层以下较深的沃茨的特征是Chl Fl和Chl + Pheo低（类似于0.7 mg m（-3）），c（p）高（>1.5 m（-1））和SPM高（>8 g m（-3）），POC高（>10 mmol m（-3））。从表面和SCM区域的水柱的POM组成与活跃的浮游植物来源的贡献是一致的，而从底部沃茨的样品的特点是高的Pheo/（叶绿素+ Pheo）的比率（>0.4），指示改变浮游植物碎屑。在两次巡航中，在表层和中层沃茨都观察到POM的明显对比。在2016年9月巡航期间，在一段时间的顺向风之后，在中层沃茨中测量了叶绿素和POC的增加，在2017年8月巡航期间，在一段时间的顺向风之后，在表层沃茨中测量了与生产力提高一致的叶绿素和POC的增加。
Two oceanographic cruises were completed in September 2016 and August 2017 to investigate the distribution of particulate organic matter (POM) across the northeast Chukchi Shelf. Both periods were characterized by highly stratified conditions, with major contrasts in the distribution of regional water masses that impacted POM distributions. Overall, surface waters were characterized by low chlorophyll fluorescence (Chl Fl < 0.8 mg m(-3)) and particle beam attenuation (c(p) < 0.3 m(-1)) values, and low concentrations of particulate organic carbon (POC < 8 mmol m(-3)), chlorophyll and pheophytin (Chl + Pheo < 0.8 mg m(-3)), and suspended particulate matter (SPM similar to 2 g m(-3)). Elevated Chl Fl and Chl + Pheo (similar to 2 mg m(-3)) values measured at mid-depths below the pycnocline defined the subsurface chlorophyll maxima (SCM), which exhibited moderate POC (similar to 10 mmol m(-3)), c(p) (similar to 0.4 m(-1)) and SPM (similar to 3 g m(-3)). In contrast, deeper waters below the pycnocline were characterized by low Chl Fl and Chl + Pheo (similar to 0.7 mg m(-3)), high c(p) (>1.5 m(-1)) and SPM (>8 g m(-3)) and elevated POC (>10 mmol m(-3)). POM compositions from surface and SCM regions of the water column were consistent with contributions from active phytoplankton sources whereas samples from bottom waters were characterized by high Pheo/(Chl + Pheo) ratios (>0.4) indicative of altered phytoplankton detritus. Marked contrasts in POM were observed in both surface and middepth waters during both cruises. Increases in chlorophyll and POC consistent with enhanced productivity were measured in middepth waters during the September 2016 cruise following a period of downwelling-favorable winds, and in surface waters during the August 2017 cruise following a period of upwelling-favorable winds.