Typhoon-induced precipitation impact on nutrient and suspended matter dynamics of a tropical estuary affected by human activities in Hainan, China
Typhoon-induced precipitation impact on nutrient and suspended matter dynamics of a tropical estuary affected by human activities in Hainan, China
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DOI：
10.1016/j.ecss.2011.05.004
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发表时间：
2011-07-20
影响因子：
2.8
通讯作者：
Jennerjahn, Tim C.
中科院分区：
文献类型：
--
作者：
Herbeck, Lucia S.;Unger, Daniela;Jennerjahn, Tim C.
在夏季风期间，台风经常袭击北方南海沿着。然而，很少有人知道台风相关的强降水对河口动力学和海岸生态系统的影响。分析了2008年8月台风北冕前后中国热带岛屿海南岛文昌/温角河口（WWE）的物理化学特征、溶解物和悬浮物的浓度和组成。台风前河口呈现出垂直梯度和水平梯度。农业和广泛的水产养殖业的高营养投入在很大程度上转化为生物量的河口泻湖内，导致低出口的营养物质到沿海沃茨和主要是土生土长的总悬浮物（TSM）的起源。强台风降水增加了河川径流量，使河口盐度梯度向外海移动。台风过后一天，溶解物和颗粒物被输送到沿海沃茨。溶解营养盐增加了一个数量级和TSM增加约两倍台风前的值相比。较低的三角洲C-13（org）和三角洲N-15和TSM的C/N比升高，以及较低的叶绿素a（chl a）浓度表明，来自台风引起的土壤侵蚀的陆地物质的贡献增加。由于透明度降低和浮游植物的缺乏，泻湖内多余的营养物质的局部吸收受到抑制，这些浮游植物已被最初的淡水脉冲冲走。台风过后两周。总悬浮颗粒物的浓度和组成已基本恢复到台风前的水平。但是，河口的理化性质和营养盐仍与台风前的状况不同，表明河口系统尚未完全恢复。海岸带chl a浓度异常高，表明台风引起的营养盐输出导致浮游植物水华。台风引发的WINE冲刷导致低盐度、水透明度降低、淤积以及沿海沃茨的暂时性富营养化。这些都是生理压力，已知会损害邻近的海草草甸和珊瑚礁的性能。预计台风频率和强度的增加将导致沿海生态系统经常反复受到这些威胁，特别是在水产养殖广泛和热带气旋频率最高的南中国海地区。(C)2011爱思唯尔有限公司版权所有。
Typhoons regularly hit the coasts along the northern South China Sea during summer monsoon. However, little is known on the effects of typhoon-related heavy precipitation on estuarine dynamics and coastal ecosystems. We analyzed physico-chemical characteristics, and concentrations and composition of dissolved and suspended matter in the Wenchang/Wenjiao Estuary (WWE) on the tropical island of Hainan, China, prior to and after typhoon Kammuri in August 2008. Before the typhoon, the estuary displayed vertical and horizontal gradients. High nutrient inputs from agriculture and widespread aquaculture were to a large extent converted into biomass inside the estuarine lagoon resulting in low export of nutrients to coastal waters and a mainly autochthonous origin of total suspended matter (TSM). Heavy typhoon-associated precipitation increased river runoff, which moved the location of the estuarine salinity gradient seaward. It resulted in an export of dissolved and particulate matter to coastal waters one day after the typhoon. Dissolved nutrients increased by up to an order of magnitude and TSM increased approximately twofold compared to pre-typhoon values. Lower delta C-13(org) and delta N-15 and elevated C/N ratios of TSM together with lower chlorophyll a (chl a) concentrations indicated an increased contribution of terrestrial material originating from typhoon-induced soil erosion. Local uptake of excess nutrients inside the lagoon was inhibited because of reduced water transparency and the lack of phytoplankton, which had been washed out by the initial freshwater pulse. Two weeks after the typhoon. TSM concentration and composition had almost returned to pre-typhoon conditions. However, physico-chemical properties and nutrients were still different from pre-typhoon conditions indicating that the estuarine system had not fully recovered. Unusually high chl a concentrations in the coastal zone indicated a phytoplankton bloom resulting from the typhoon-induced nutrient export. The typhoon-induced flushing of the WINE resulted in hyposalinity, reduced water transparency, siltation, as well as temporary eutrophication of coastal waters. These are physiological stressors, which are known to impair the performance of adjacent seagrass meadows and coral reefs. The predicted increase in typhoon frequency and intensity will lead to a frequently recurring exposure of coastal ecosystems to these threats, particularly in the South China Sea region where aquaculture is widespread and tropical cyclone frequency is at a maximum. (C) 2011 Elsevier Ltd. All rights reserved.