Seasonal variations of particulate silicon in the Changjiang (Yangtze River) Estuary and its adjacent area
Seasonal variations of particulate silicon in the Changjiang (Yangtze River) Estuary and its adjacent area
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DOI：
10.1007/s13131-013-0293-5
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发表时间：
2013-04
影响因子：
1.4
通讯作者：
Lu Cao;Sumei Liu;J. Ren
中科院分区：
文献类型：
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作者：
Lu Cao;Sumei Liu;J. Ren
研究了长江口及其邻区生物硅（BSi）和岩石硅（LSi）的时空分布特征。BSi和LSi的年平均浓度分别为（1.71±1.79）µmol/L和（0.56±1.41）mmol/L。BSi和LSi在近岸区域均高，受到长江陆源排放，向近岸区域降低。由于沉积物的高沉积速率和再悬浮作用，BSi和LSi在近底层最为丰富。夏季表层Chl a浓度高，硅藻华发生，导致夏季表层BSi明显高于其他季节。LSi浓度在秋季和春季最高，夏季最低，与SPM值的季节变化有关。为了了解营养物质通过改变浮游植物组成对BSi的影响，在甲藻华期间进行了漂流调查和中生态实验。结果表明：低溶解无机磷浓度和高N/P（溶解无机氮/溶解无机磷）摩尔比是导致研究区硅藻生物量减少的重要因素，并会导致水生生态系统BSi浓度降低。
Temporal and spatial distribution of biogenic (BSi) and lithogenic (LSi) silica were studied in the Changjiang (Yangtze River) Estuary and its adjacent area. The annual average BSi and LSi concentrations were (1.71±1.79) µmol/L and (0.56±1.41) mmol/L, respectively. Both BSi and LSi were high in the inshore areas, where they received terrigenous discharge from the Changjiang, and decreased towards the offshore region. BSi and LSi were most abundant at the near bottom layer due to the high sedimentation rates and resuspension of sediment. Diatom blooms occurred in summer with high Chl a concentration in the surface layer, which induced that BSi in the surface layer during summer was obviously higher than that in the surface layer of other seasons. LSi concentration was maximal in autumn and spring and minimum in summer, associated with the seasonal variation of SPM values. Drifting investigation and mesocosm experiments were conducted during dinoflagellate bloom, aiming to understand the effect of nutrients on BSi by changing the phytoplankton composition. The results show that the low dissolved inorganic phosphorus concentration and high molar ratio of N/P (dissolved inorganic nitrogen vs. dissolved inorganic phosphorus), were the important factors for decreasing diatombiomass in the study area, and it would subsequently decrease the BSi concentration in aquatic ecosystem.