The biogeochemistry of inorganic carbon and nutrients in the Pearl River estuary and the adjacent Northern South China Sea
The biogeochemistry of inorganic carbon and nutrients in the Pearl River estuary and the adjacent Northern South China Sea
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DOI：
10.1016/j.csr.2004.04.005
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发表时间：
2004-08-01
影响因子：
2.3
通讯作者：
Wang, ZH
中科院分区：
文献类型：
--
作者：
Cai, WJ;Dai, MH;Wang, ZH
南海北方珠江口及其邻近大陆架的独特之处在于其流域完全位于人口密集的亚热带，因此是研究大型河流对大陆架影响的重要生态地球化学体系。近零盐度端元具有高营养盐浓度（硅酸盐130-140 μ M、硝酸盐75-100 μ M和磷酸盐0.2-1.2 μ M）以及相对较高的总溶解无机碳（DIC）（1500 μ M）和碱度（类似于1650 μ M）值。水柱DIC，碱度和营养物在河口在很大程度上是由不同的流域化学，人为影响和河口再循环程度的不同支流的沃茨的混合控制。营养盐和无机碳的生物吸收发生在河口外和内陆架地区的河流营养盐的支持。河口内的N/P和Si/P比值一般都很高。根据相对于保守混合线和羽流行进时间的DIC和碱度的消耗，估计夏季区域综合生物生产率为0.8 gCm（-2）d（-1）。这一估计与基于C-14的初级生产率（PP）和有效河流磷酸盐通量相当吻合。在开阔的大陆架和陆坡，生物产量减少约10倍，主要靠与地下水混合维持。将表层混合层和真光层底部的DIC、磷酸盐和硝酸盐浓度与基于C-14的PP（0.13 gCm（-2）d（-1））进行比较，表明北方南海表层水的停留时间近似于1.3年。N/P、Si/P和Si/C比率分别为15、25和0.15。亚热带珠江的研究还比较了其他大型河流在两个自然过程（即，风化率）和人为影响（即，营养物输入）之间的这些不同的河口系统。(C)2004爱思唯尔有限公司保留所有权利。
The Zhu-jiang (Pearl River) estuary and its adjacent continental shelf in the Northern South China Sea (SCS) is unique in that its drainage basin is located entirely in a subtropical zone with heavy population development, and therefore represents an important regime for biogeochemical studies on how large rivers influence continental shelves. The near-zero salinity end member has high nutrient concentrations (silicate 130-140 muM, nitrate 75-100 muM and phosphate 0.2-1.2 muM) and relatively high total dissolved inorganic carbon (DIC) (1500 muM) and alkalinity (similar to1650 muM) values. Water column DIC, alkalinity, and nutrient in the estuary are largely controlled by mixing of waters from different tributaries with different drainage basin chemistry, anthropogenic influence, and degree of estuarine recycling. Biological uptake of nutrients and inorganic carbon occur in the outer estuary and inner shelf areas supported by riverine nutrients. The N/P and Si/P ratios are generally very high within the estuary. The summertime area-integrated biological production rate of 0.8 gCm(-2) d(-1) is estimated based on the depletion of DIC and alkalinity relative to the conservative mixing line and a plume travel time. This estimate agrees reasonably well with C-14 based primary production rates (PP) and with that from effective river phosphate flux. Biological production decreases about 10-fold in the open continental shelf and slope and is largely supported by mixing with subsurface water. A comparison of DIC, phosphate, and nitrate concentrations in the surface mixing layer and at the bottom of the euphotic zone with the C-14-based PP (0.13 gCm(-2)d(-1)) suggests that the surface water residence time in the Northern SCS is similar to1.3 years. The N/P, Si/P, and Si/C ratios are 15, 25, and 0.15, respectively. The subtropical Pearl River study is also compared to other large rivers with regard to differences in both natural processes (i.e., weathering rates) and anthropogenic influences (i.e., nutrient input) between these different river estuary systems. (C) 2004 Elsevier Ltd. All rights reserved.