Sun Cece, Song Zhaoliang, Ran Xiangbin
Marine Ecology Research Center, First Institute of Oceanology, Ministry of Natural Resources, Qingdao 266061, China; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Shandong Provincial Key Laboratory of Fishery Resources and Ecological Environment, Qingdao, Shandong 266071, China; Shandong Changdao National Observation and Research Station for Fishery Resources, Yantai 265800, China.
Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China.
Sci Total Environ. 2024 Oct 15;947:174544. doi: 10.1016/j.scitotenv.2024.174544. Epub 2024 Jul 5.
The transportation of silicon (Si) by rivers to the sea plays a vital role as an external source of Si budget for coastal environments, impacting the carbon cycle in the ocean. Nevertheless, the transport of reactive silica (RSi) from small rivers to the coastal sea has been frequently disregarded in scientific investigations. This research focused on 24 rivers situated along the Bohai Sea (BS) Rim, encompassing small rivers (SR) and the largest river in the region, the Yellow River (YR), to analyze their concentrations and fluxes of dissolved silicate (DSi), biogenic silica (BSi) and other amorphous forms of Si. The findings indicated seasonal variations in DSi concentrations, with higher levels observed during the flood season. Annually, approximately 105 × 10 t DSi and 200 × 10 t BSi were transported to the BS, with SR and YR contributing equally to the total riverine BSi flux. The smaller rivers were found to increase the BSi fraction of RSi due to elevated biological fixation. The ratios of average DSi and BSi fluxes to the river watershed area of SR were 3.5 and 6 times higher, respectively, compared to those of YR. SR play a critical role in the terrestrial Si export in the BS Rim. Human activities have led to significant deviations in the Si ratios to nitrogen and phosphorus in these rivers from the Redfield-Brzezinski ratio. This discrepancy could impact the phytoplankton community, primary production, and the environment of the BS. The study highlights the substantial contribution of SR to coastal environments, particularly in semi-closed marine environments like the BS.
河流将硅（Si）输送到海洋，作为沿海环境硅收支的外部来源，对海洋碳循环具有至关重要的作用。然而，在科学研究中，小河流向沿海海域的活性硅（RSi）输送常常被忽视。本研究聚焦于渤海（BS）沿岸的24条河流，包括小河流（SR）以及该地区最大的河流黄河（YR），分析它们溶解硅酸盐（DSi）、生物源硅（BSi）和其他无定形硅形式的浓度和通量。研究结果表明，DSi浓度存在季节性变化，洪水季节浓度较高。每年，约105×10 t DSi和200×10 t BSi被输送到渤海，小河流和黄河对河流总BSi通量的贡献相当。由于生物固定作用增强，较小的河流中RSi的BSi比例增加。与黄河相比，小河流平均DSi和BSi通量与河流流域面积的比值分别高出3.5倍和6倍。小河流在渤海沿岸陆地硅输出中发挥着关键作用。人类活动导致这些河流中硅与氮、磷的比例与雷德菲尔德 - 布热津斯基比值存在显著偏差。这种差异可能影响浮游植物群落、初级生产力以及渤海的环境。该研究强调了小河流对沿海环境的重大贡献，特别是在像渤海这样的半封闭海洋环境中。
