东海赤潮高发区营养盐时空分布特征及其控制要素   总被引：13，自引：4，他引：13  

孙霞  王保栋  王修林  祝陈坚  韩秀荣 《海洋科学》2004,28(8):28-32

东海长江口、舟山渔场附近海域是我国近海赤潮爆发严重的区域之一。在影响该海域营养盐分布的水团中 ,长江冲淡水向表层输入了大量的氮、磷、硅营养盐 ,台湾暖流主要对底层和长江口外上升流区有贡献 ,苏北沿岸水、闽浙沿岸水主要影响近岸区域。同时 ,营养盐在海水 -沉积物界面的交换作用 ,大气湿沉降作用等也影响着该海域营养盐的时空分布。结合2002年4月～2003年3月对29°00′～32°00′N、122°00′～124°00′E海域四季航次调查的营养盐分布规律 ,该海域可分为三片区域 ,由岸边向外海分别为高营养盐、低浮游植物区 ,较高营养盐、高浮游植物区和较低营养盐、低浮游植物区。随着近年来营养盐输入通量的增加 ,富营养化程度加大 ,受化学、物理、生物等因素综合作用 ,高浮游植物区赤潮爆发频率和规模逐年增加 ,已为中国近海典型的赤潮高发区  相似文献   

石油烃和营养盐的复合污染对海洋浮游植物的影响Ⅰ. 石油烃对海洋浮游植物吸收营养盐的影响          下载免费PDF全文

王江涛  赵卫红  李雪莲  李慧 《海洋与湖沼》2013,44(1):43-48

通过向具有相同营养盐浓度的培养体系中添加不同浓度的石油烃,对中肋骨条藻、赤潮异弯藻、微小亚历山大藻和锥状斯氏藻进行周期性培养,探讨了石油烃对微藻营养盐吸收动力学的影响.结果发现,在开始30min内,微藻对营养盐均有一非耗能的短暂快吸收,随后吸收速率下降并趋于稳定.石油烃对中肋骨条藻和赤潮异弯藻氮、磷的吸收都表现抑制作用,浓度从0.13 mg/L到8.25mg/L的石油烃所呈现的抑制作用基本表现为先减弱后逐渐增强,8.25mg/L浓度的石油烃抑制作用最强.与中肋骨条藻和赤潮异弯藻实验结果不同的是,石油烃对微小亚历山大藻和锥状斯氏藻的氮、磷吸收在低浓度时呈现促进作用,且促进作用的程度随石油烃浓度的增加有先增强后减弱的趋势,在高浓度下促进作用会消失,8.25mg/L的石油烃不表现促进作用.石油烃对微藻营养盐吸收动力学的影响表现出复杂性,这既受石油烃浓度的影响,也与浮游植物的种类有重要关系.  相似文献   

Bottom-up control of phytoplankton growth in spring blooms in Central Yellow Sea,China     

《Deep Sea Research Part II: Topical Studies in Oceanography》2013

The source and significance of three nutrients – nitrogen, phosphorous and silicon – were investigated by a modified dilution method performed on seawater samples from the Central Yellow Sea (CYS), in spring blooming period of 2007. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the internal and external nutrient pools, as well as nutrients supplied through remineralization by microzooplankton grazing. The results indicate that phytoplankton growth during the bloom is mostly contributed by internal nutrient pools (K_I=0.062–1.730). The external nutrient pools (K_E=<0–0.362) are also of importance for phytoplankton growth during the bloom at some sampling sites. Furthermore, the contribution of the recycled-nutrient pool by remineralization (K_R=<0–0.751) is significant when microzooplankton grazing rate was higher than 0.5 d⁻¹ during the spring phytoplankton blooms in the Central Yellow Sea. Compared with internal phosphorus, internal nitrogen and silicon contribute more to the phytoplankton production at most sampling stations.  相似文献   

Nutrient chemistry and salinity mapping of the Delhi aquifer,India: source identification perspective     

Manish Kumar  Bhawna Sharma  AL. Ramanathan  M. Someshwar Rao  Bhishm Kumar 《Environmental Geology》2009,56(6):1171-1181

Present study is an effort to distinguish between the contributions of natural weathering and anthropogenic inputs towards high salinity and nutrient concentrations in the groundwater of National Capital Territory (NCT) Delhi, India. Apart from the source identification, the aquifer of entire territory has been characterized and mapped on the basis of salinity in space and water suitability with its depth. Major element chemistry, conventional graphical plots and specific ionic ratio of Na⁺/Cl⁻, SO₄ ²⁻/Cl⁻, Mg²⁺/Ca²⁺ and Ca²⁺/(HCO₃ ⁻ + SO₄ ²⁻) are conjointly used to distinguish different salinization sources. Results suggest that leaching from the various unlined landfill sites and drains is the prime cause of NO₃ ⁻ contamination while study area is highly affected with inland salinity which is geogenic in origin. The seasonal water level fluctuation and rising water level increases nutrients concentration in groundwater. Mixing with old saline sub-surface groundwater and dissolution of surface salts in the salt affected soil areas were identified as the principle processes controlling groundwater salinity through comparison of ionic ratio. Only minor increase of salinity is the result of evaporation effect and pollution inflows. The entire territory has characterized into four groups as fresh, freshening, near freshening and saline with respect to salinity in groundwater. The salinity mapping suggests that in general, for drinking needs, groundwater in the fresh, freshening and near freshening zone is suitable up to a depth of 45, 20 and 12 m, respectively, while the saline zones are unsuitable for any domestic use. In the consideration of increasing demand of drinking water in the area; present study is vital and recommends further isotopic investigations and highlights the need of immediate management action for landfill sites and unlined drains.  相似文献   

Spatial–temporal variability in water quality and macro-invertebrate assemblages in the Upper Mara River basin,Kenya     

《Physics and Chemistry of the Earth》2014

Tropical rivers display profound temporal and spatial heterogeneity in terms of environmental conditions. This aspect needs to be considered when designing a monitoring program for water quality in rivers. Therefore, the physico-chemical composition and the nutrient loading of the Upper Mara River and its two main tributaries, the Amala and Nyangores were monitored. Initial daily, and later a weekly monitoring schedule for 4 months spanning through the wet and dry seasons was adopted. Benthic macro-invertebrates were also collected during the initial sampling to be used as indicators of water quality. The aim of the current study was to investigate the physico-chemical status and biological integrity of the Upper Mara River basin. This was achieved by examining trends in nutrient concentrations and analyzing the structure, diversity and abundance of benthic macro-invertebrates in relation to varying land use patterns. Sampling sites were selected based on catchment land use and the level of human disturbance, and using historical records of previous water quality studies. River water pH, dissolved oxygen, electrical conductivity (EC), temperature, and turbidity were determined in situ. All investigated parameters except iron and manganese had concentration values within allowable limits according to Kenyan and international standards for drinking water. The Amala tributary is more mineralized and also shows higher levels of pH and EC than water from the Nyangores tributary. The latter, however, has a higher variability in both the total phosphorus (TP) and total nitrogen (TN) concentrations. The variability in TP and TN concentrations increases downstream for both tributaries and is more pronounced for TN than for TP. Macro-invertebrate assemblages responded to the changes in land use and water quality in terms of community composition and diversity. The study recommends detailed continuous monitoring of the water quality at shorter time intervals and to identify key macro-invertebrate taxa that can be used to monitor changes of the water quality in rivers of the Mara basin as a result of anthropogenic changes.  相似文献   

Nitrogen‐Enriched Eutrophication Promotes the Invasion of Spartina alterniflora in Coastal China          下载免费PDF全文

Hui Zhao  Wen Yang  Lu Xia  Yajun Qiao  Yan Xiao  Shuqing An 《洁净——土壤、空气、水》2015,43(2):244-250

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Climate Change Impacts on Flow,Sediment and Nutrient Export in a Great Lakes Watershed Using SWAT          下载免费PDF全文

Siddhartha Verma  Rabin Bhattarai  Nathan S. Bosch  Richard C. Cooke  Prasanta K. Kalita  Momcilo Markus 《洁净——土壤、空气、水》2015,43(11):1464-1474

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Land use and topography as predictors of nutrient levels in a tropical catchment     

María M. Castillo 《Limnologica》2010,40(4):322-329

The influence of landscape on nutrient concentration and yield was analyzed in a tropical catchment, the Guare River in northern Venezuela. Spatial and temporal variation in nitrate, SRP and total P were determined in 15 sites located along the river mainstem and tributaries. Higher nitrate concentrations and yields were reported from upper sites and both decreased in the downstream direction along the river mainstem. These trends appear to be related to more pronounced slopes and larger proportions of agricultural and forest lands in subcatchments located in the upper part of the basin, and dense algal mats in the lower reaches. Nitrate values were higher during periods of high discharge, suggesting that nitrate is primarily transported by shallow subsurface flow. SRP represented between 60 and 80% of total P. Phosphorus concentrations were homogeneous along the river mainstem and showed little seasonal variation, while yields were higher in the upper basin. Multiple regression identified slope, runoff and agriculture as primary predictors of nitrate and phosphorus across the watershed, which suggests that both natural and anthropogenic landscape characteristics have a strong influence on nutrient levels in the Guare catchment.  相似文献   

Implications of nutrient decline in the seagrass ecosystem success     

P.G. Cardoso  S. Leston  M.D. Bordalo  D. Raffaelli 《Marine pollution bulletin》2010,60(4):601-608

The Mondego estuary (Portugal) suffered major changes in environmental quality due to eutrophication, however, in the late 1990s a restoration project was implemented in order to return the system to its original condition. The main goal of this paper is to evaluate the ecosystem response to the restoration measures applied at three different levels: water quality, primary producers and primary consumers.In post-restoration period a clear decline was observed in dissolved inorganic nitrogen which was reflected in the gradual recovery of Zostera noltii and a concomitant decline in green macroalgae.Macrobenthic assemblages responded variably to the recovery process. In the seagrass bed and intermediate area, there was a large increase in total biomass, but in the eutrophic area species diversity increased. Despite improvement in the ecological status of the system, full recovery has not been achieved yet, possible due to hysteresis in the dynamics of this system.  相似文献   

Reconstruction of historical nutrient levels in Korean and Japanese coastal areas based on dinoflagellate cyst assemblages     

Hyeon Ho Shin  Koichiro Mizushima  Jong Sick Park  Mitsunori Iwataki  Yang Ho Yoon 《Marine pollution bulletin》2010,60(8):1243-1258

Dinoflagellate cysts acquired from sediment cores were analyzed in order to reconstruct historical nutrient levels in Gamak Bay, Korea and Ariake Bay, Japan. Dinoflagellate cyst assemblages in Gamak Bay were characterized by high proportions of heterotrophic cysts such as Brigantedinium spp., Protoperidinium americanum and Polykrikos cysts, which suggested that nutrients levels may have already been high before 1970s, and then increased further to the hypertrophic conditions of the 1990s. In contrast, dinoflagellate cyst assemblages in Ariake Bay were characterized by high relative abundances of Lingulodinium machaerophorum and Spiniferites spp., which suggested that nutrient levels in Ariake Bay had increased gradually since the mid 1960s, and may have been significantly enhanced by the mid 1980s. Dinoflagellate cyst assemblages reflecting environmental changes in the two bays are contrasting, perhaps due to different nutrient enrichment mechanisms. This suggests that the indicators of nutrient levels encoded in dinoflagellate cyst assemblages may exhibit site-specific information.  相似文献