Latitudinal gradient and influencing factors of deep-sea particle export along the Kyushu-Palau Ridge in the Philippine Sea

Ziyu Wang; Chen Fang; Chenghao Yang; Guoyin Zhang; Dong Sun

doi:10.1016/j.scitotenv.2023.167460

Latitudinal gradient and influencing factors of deep-sea particle export along the Kyushu-Palau Ridge in the Philippine Sea

Sci Total Environ. 2024 Jan 1:906:167460. doi: 10.1016/j.scitotenv.2023.167460. Epub 2023 Oct 3.

Authors

Ziyu Wang¹, Chen Fang², Chenghao Yang³, Guoyin Zhang⁴, Dong Sun⁵

Affiliations

¹ Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resource, Hangzhou 310012, China.
² College of Oceanography, Hohai University, Nanjing 210024, China.
³ State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China.
⁴ Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China.
⁵ Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resource, Hangzhou 310012, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China. Electronic address: sund@sio.org.cn.

PMID: 37797769
DOI: 10.1016/j.scitotenv.2023.167460

Abstract

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^-2 d^-1) were significantly higher than the average near-bottom value of the entire transect (0.60 ± 0.43 mg m^-2 d^-1). 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.

Keywords: Benthic community; Habitat classification; Mesoscale eddy; POC flux; Resuspension; Warm pool.