Wang Ziyu, Fang Chen, Yang Chenghao, Zhang Guoyin, Sun Dong
Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resource, Hangzhou 310012, China.
College of Oceanography, Hohai University, Nanjing 210024, China.
Sci Total Environ. 2024 Jan 1;906:167460. doi: 10.1016/j.scitotenv.2023.167460. Epub 2023 Oct 3.
The export of particulate organic matter (POM) to deep-sea is crucial for deep-sea ecosystems. However, in situ measurements of large-scale POM export flux are scarce in the tropical and subtropical western Pacific, leading to reliance on biogeochemical models or sediment trap data from a few stations. To address this gap, the underwater vision profiler was used to measure particulate density and to calculate particulate organic carbon (POC) fluxes along the Kyushu-Palau Ridge (KPR) in the Philippine Sea. The results revealed a significant latitudinal gradient of POC fluxes: 37 % of the POC output from 200 m depth was preserved to 2000 m in the Western Pacific Warm Pool and up to 51 % was preserved in the North Pacific Subtropical Gyre. The near-bottom POC fluxes north of 25°N (1.64 ± 0.80 mg m d) were significantly higher than the average near-bottom value of the entire transect (0.60 ± 0.43 mg m d). Multiple linear regression analysis showed that the chlorophyll concentration had a significant positive effect on the POC fluxes at all depths, except near the bottom, while local factors such as mesoscale eddies and the interaction effect between the topography and current velocity only had significant effects on the POC fluxes at depths of >2000 m. Particle size spectrum analysis revealed that particles ranging from 64 to 323 μm in size exerted a dominant influence on the increase in the POC fluxes in the near-bottom layers situated north of 25°N. These findings indicated that the spatial heterogeneity of POC fluxes in the western Pacific was governed not only by upper ocean primary productivity but also by mesoscale processes, current velocity, and topography. These results provided crucial fundamental information for cartography of the distribution and simulation of the dynamics of deep-sea organisms along the KPR in the Philippine Sea.
颗粒有机物质（POM）向深海的输出对深海生态系统至关重要。然而，在热带和亚热带西太平洋，大规模POM输出通量的原位测量数据稀缺，这导致人们依赖生物地球化学模型或少数站点的沉积物捕获器数据。为了填补这一空白，利用水下视觉剖面仪测量颗粒密度，并计算菲律宾海九州-帕劳海岭（KPR）沿线的颗粒有机碳（POC）通量。结果显示，POC通量存在显著的纬度梯度：在西太平洋暖池，200米深度处输出的POC中有37%在2000米深度得以保存，而在北太平洋亚热带环流中这一比例高达51%。北纬25°以北的近底层POC通量（1.64±0.80毫克·米⁻²·天⁻¹）显著高于整个断面的近底层平均值（0.60±0.43毫克·米⁻²·天⁻¹）。多元线性回归分析表明，叶绿素浓度对除近底层外所有深度的POC通量均有显著正效应，而中尺度涡旋等局部因素以及地形与流速的相互作用效应仅对深度大于2000米处的POC通量有显著影响。粒径谱分析显示，粒径在64至323微米之间的颗粒对北纬25°以北近底层POC通量的增加起主导作用。这些发现表明，西太平洋POC通量的空间异质性不仅受海洋上层初级生产力控制，还受中尺度过程、流速和地形影响。这些结果为绘制菲律宾海KPR沿线深海生物分布及动力学模拟提供了关键基础信息。
