The status and characteristics of eutrophication in the Yangtze River (Changjiang) estuary and the adjacent East China Sea, China
The status and characteristics of eutrophication in the Yangtze River (Changjiang) estuary and the adjacent East China Sea, China
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DOI：
10.1007/s10750-006-0021-7
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发表时间：
2006-06-01
期刊：
影响因子：
2.6
通讯作者：
Cao, Xihua
中科院分区：
文献类型：
--
作者：
Chai, Chao;Yu, Zhiming;Cao, Xihua
长江口及邻近东海富营养化日益严重，毒藻大量繁殖。 2003年和2004年，在河口和邻近海域的三个区域进行了四次巡航，调查了硝酸盐（NO3-N）、铵（NH4-N）、亚硝酸盐（NO2-N）、可溶性活性磷（SRP）、溶解性活性二氧化硅（DRSi）、溶解氧（DO）、浮游植物叶绿素a（Chl a）和悬浮物 颗粒物 (SPM)。 DIN(NO3-N+NH4-N+NO2-N)、SRP和DRSi的最高浓度分别为131.6、1.2和155.6μM。春季叶绿素a最高浓度为19.5 mg m(-3)。对历史和近期数据的分析表明，在过去 40 年中，硝酸盐和 SRP 浓度分别从 11 μM 增加到 97 μM，从 0.4 μM 增加到 0.95 μM。从1963年到2004年，氮磷比也从30-40增加到150。在氮磷富集的同时，检测到叶绿素a显着增加，叶绿素a最大值为20mg m(-3)，比1980年代高出近四倍。 2004年，底层水平均溶解氧浓度为4.35 mg l(-1)，远低于20世纪80年代。与其他河口相比，长江口的特点是DIN和DRSi浓度较高，SRP浓度较低。尽管营养物浓度较高，但内河口（1 区和 2 区）的叶绿素 a 浓度低于邻近海域（3 区）。根据养分有效性、SPM 和水动力，我们假设在 1 区和 2 区，高浊度、大潮汐幅度和短停留时间抑制了浮游植物的生长。此外，在3区，水分层也是导致浮游植物生物量增加和溶解氧浓度降低的一个重要因素。由于水动力和浑浊度，公海对营养物富集和相关富营养化过程出乎意料地更加敏感。
Eutrophication has become increasingly serious and noxious algal blooms have been of more frequent occurrence in the Yangtze River Estuary and in the adjacent East China Sea. In 2003 and 2004, four cruises were undertaken in three zones in the estuary and in the adjacent sea to investigate nitrate (NO3-N), ammonium (NH4-N), nitrite (NO2-N), soluble reactive phosphorus (SRP), dissolved reactive silica (DRSi), dissolved oxygen (DO), phytoplankton chlorophyll a (Chl a) and suspended particulate matter (SPM). The highest concentrations of DIN (NO3-N+NH4-N+NO2-N), SRP and DRSi were 131.6, 1.2 and 155.6 mu M, respectively. The maximum Chl a concentration was 19.5 mg m(-3) in spring. An analysis of historical and recent data revealed that in the last 40 years, nitrate and SRP concentrations increased from 11 to 97 mu M and from 0.4 to 0.95 mu M, respectively. From 1963 to 2004, N:P ratios also increased from 30-40 up to 150. In parallel with the N and P enrichment, a significant increase of Chl a was detected, Chl a maximum being 20 mg m(-3), nearly four times higher than in the 1980s. In 2004, the mean DO concentration in bottom waters was 4.35 mg l(-1), much lower than in the 1980s. In comparison with other estuaries, the Yangtze River Estuary was characterized by high DIN and DRSi concentrations, with low SRP concentrations. Despite the higher nutrient concentrations, Chl a concentrations were lower in the inner estuary (Zones 1 and 2) than in the adjacent sea (Zone 3). Based on nutrient availability, SPM and hydrodynamics, we assumed that in Zones 1 and 2 phytoplankton growth was suppressed by high turbidity, large tidal amplitude and short residence time. Furthermore, in Zone 3 water stratification was also an important factor that resulted in a greater phytoplankton biomass and lower DO concentrations. Due to hydrodynamics and turbidity, the open sea was unexpectedly more sensitive to nutrient enrichment and related eutrophication processes.