The influence of the Guadalquivir river on spatio-temporal variability in the pelagic ecosystem of the eastern Gulf of Cádiz
The influence of the Guadalquivir river on spatio-temporal variability in the pelagic ecosystem of the eastern Gulf of Cádiz
复制标题
瓜达尔基维尔河对加的斯湾东部中上层生态系统时空变化的影响
DOI：
10.12681/mms.844
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
G. Navarro
中科院分区：
文献类型：
--
作者：
I. Caballero;E. Morris;L. Pietro;G. Navarro
本研究利用 11 年（2003-2013 年）期间的海洋颜色图像，研究了受瓜达尔基维尔河口影响的海洋区域浊度羽流和浮游植物生物量（以叶绿素计）的时空变化。使用 555 nm 处的水离开辐射率 (nLw555) 计算浊度羽流的面积。气候和月平均值显示冬季 nLw555 水平反复较高，春季叶绿素水平较高。对 8 天合成图像的经验正交函数 (EOF) 分析证实了类似的变异性，说明了具有相似行为的不同区域的存在。第一个 EOF 模式分别解释了 nLw555 和叶绿素的 60.7% 和 31% 的变异性，并且与秋冬季节总悬浮固体 (TSS) 的增加以及冬春期间浮游植物的大量繁殖有关。结果证实，浑浊羽流的发展和随后的浮游植物大量繁殖受到河流流量和降水的强烈调节。事实上，nLw555 的年际变化与大尺度气候指数、北大西洋涛动（区域降雨模式的代表）的变化一致。就浮游植物生物量而言，第二个 EOF 模式揭示了近海和近岸区域之间的差异，后者的特点是由于高 TSS 的光限制导致浮游植物水华发育延迟。这表明水柱的稳定性通过对浮游植物光限制的影响，也影响了浮游植物水华事件的时间和程度。瓜达尔基维尔河口浊流羽流的动态是加的斯湾东部浮游植物生产力的中上层生态系统的关键因素。
This study examines the spatio-temporal variability of the turbidity plume and phytoplankton biomass (in terms of chlorophyll) in the marine region influenced by the Guadalquivir estuary using ocean colour images over a period of 11 years (2003-2013). The area of the turbidity plume was calculated using water-leaving radiance at 555 nm ( nLw555 ). Climatologic and monthly averages showed recurrent high nLw555 levels in winter and high chlorophyll in spring. Similar variability was confirmed by Empirical Orthogonal Function (EOF) analysis of 8-day composite images, illustrating the existence of different regions with similar behavior. The first EOF mode explained 60.7% and 31% of the variability in nLw555 and chlorophyll, respectively, and was associated with enhanced Total Suspended Solids ( TSS ) in autumn-winter and phytoplankton blooms in winter-spring periods. The results confirmed that the development of the turbidity plume and subsequent phytoplankton blooms were strongly regulated by river discharges and precipitation. Indeed, interannual variation in nLw555 was consistent with changes in the large-scale climate index, the North Atlantic Oscillation, a proxy for regional rainfall patterns. In the case of phytoplankton biomass, the second EOF mode revealed differentiation between offshore and nearshore areas, the latter characterized by delayed development of phytoplankton bloom due to light limitation by high TSS . This suggests that the stability of the water column, via its influence on phytoplankton light-limitation, influenced also the timing and magnitude of phytoplankton bloom events. The dynamic of the Guadalquivir estuary turbidity plume is a crucial factor for the pelagic ecosystem of the Eastern Gulf of Cadiz, governing phytoplankton productivity.