The sediment biogeochemistry of phosphorus (P) and biogenic silica (BSi) in the southern South China Sea shelf (SSCS) is inadequate understood. Here, we examine the spatial distributions of P species and BSi in surface sediments across the Sunda Shelf and explore their relationships with satellite data of sea surface chlorophyll-a (Chla), suspended particulate matter (SPM), particulate organic carbon, particulate inorganic carbon, primary production (PP), and phytoplankton functional types. The total sediment P (TSP), in the range from 283.94 to 579.94 μg/g dry sediment, was dominated by inorganic P with higher levels in stations outside the Lupar and Saribas estuaries. The TSP was composed of seven different P species including Ca-IP and Ca-OP (58%), Detr-P (15%), Exch-P (11%), Fe-IP (10%), Ref-P (4%) and Ads-IP (2%) based on a sequential extraction method. The concentrations of various sediment P species were found significantly correlated with satellite climatological SPM, diatom biomass, and monthly climatological pico-PP revealing the importance of biological production for the sediment P storage, whereas the sediment BSi concentration showed no correlations with any of the above satellite products. An elevated R2 value in the regression of BSi with the in-situ depth-integrated Chla points to the need of developing satellite algorithms with vertical profiles from space. Finally, we argue that future studies of the SSCS sediment biogeochemistry may be benefited from data of hyperspectral and geostationary satellites.

中文翻译：

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南海巽他陆架沉积生物地球化学梯度及其与卫星观测的相关性


对南海南部陆架（SSCS）沉积物中磷（P）和生物硅（BSi）的生物地球化学了解还不够。在这里，我们研究了巽他陆架表面沉积物中 P 物种和 BSi 的空间分布，并探讨了它们与海面叶绿素-a (Chla)、悬浮颗粒物 (SPM)、颗粒有机碳、颗粒无机碳卫星数据的关系、初级生产（PP）和浮游植物功能类型。沉积物总磷 (TSP) 范围为 283.94 至 579.94 微克/克干沉积物，以无机磷为主，卢帕河口和萨里巴斯河口以外的站含量较高。 TSP 由七种不同的磷组成，包括 Ca-IP 和 Ca-OP (58%)、Detr-P (15%)、Exch-P (11%)、Fe-IP (10%)、Ref-P ( 4%）和 Ads-IP (2%) 基于顺序提取方法。发现各种沉积物 P 物种的浓度与卫星气候 SPM、硅藻生物量和每月气候 pico-PP 显着相关，揭示了生物生产对沉积物 P 储存的重要性，而沉积物 BSi 浓度与上述任何一项都没有相关性卫星产品。 BSi 与原位深度集成 Chla 回归中 R2 值升高表明需要开发具有太空垂直剖面的卫星算法。最后，我们认为未来 SSCS 沉积物生物地球化学的研究可能会受益于高光谱和地球静止卫星的数据。