Spatiotemporal variations of internal P-loading and the related mechanisms in the large shallow Lake Chaohu   总被引：2，自引：1，他引：2  

ZHANG Min  XIE Ping  XU Jun  LIU Bingqin  YANG Hong 《中国科学D辑(英文版)》2006,49(Z1)

Spatiotemporal variations of P species and adsorption behavior in water column, interstitial water, and sediments were investigated in the large shallow eutrophic Lake Chaohu. Ortho-phosphate (Ortho-P) and total phosphorus (TP) concentrations were significantly higher in the western part than in the eastern part of the lake, due to different nutrient inputs from the surrounding rivers. Moreover, paniculate phosphorus (PP) concentration was in a similar spatial pattern to Ortho-P and TP concentrations, and also showed significantly positive correlation with the biomass of Microcystis, indicating more uptake and store of phosphorus by Microcystis than by other algae. Increase of pH and intensive utilization of P by phytoplankton were the main factors promoting P (especially Fe-P) release from the sediment to interstitial water during the cyanobacterial blooms in Lake Chaohu. Spatial dynamics in TP concentration, P species and adsorption behavior of the sediment, coupled with the statistical analyses, suggested that the spatial heterogeneity of P contents in the sediment was influenced by various factors, e.g. human activities, soil geochemistry and mineral composition. In spite of similar TP contents in the sediments, increase in proportion of Fe-P concentration in the sediment may result in a high risk of P release.  相似文献   

The effect of the causative algae of large-scale HAB in the East China Sea on egg hatching of Argopecten irradians, and population growth of Brachionus plicatilis and Moina mongolica     

CHEN Taoying  YAN Tian  WANG Liping  ZHANG Bin  ZHOU Mingjiang 《海洋学报(英文版)》2007,26(4):112-122

The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monoculture and mixture of the two species were examined on the egg-hatching success of Argopecten irradians Lamarck, and the population growth of Brachionus plicatilis Müller and Moina mongolica Daday. The results showed that monoculture of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities (ED_50) inhibiting the egg hatching success of A. irradians for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm3, respectively. Monoculture of P. donghaiense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis (1×104~3×104cells/cm3) and M. mongolica (2×104~5×104cells/cm3); P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis (4×104~10×104cells/cm3) and M. mongolica (10×104cells/cm3). When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.  相似文献   

The development of a bloom of the dinoflagellate [Gyrodinium aureolum (Hulbert)] on the south-west Irish coast     

Raine  R.; Joyce  B.; Richard  J.; Pazos  Y.; Moloney  M.; Jones  K. J.; Patching  J. W. 《ICES Journal of Marine Science》1993,50(4):461-469

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Physical Hydrography and Algal Bloom Transport in Hong Kong Waters   总被引：2，自引：1，他引：2  

匡翠萍  李行伟 《中国海洋工程》2005,19(4):539-556

In sub-tropical coastal waters around Hong Kong, algal blooms and red tides are usually first sighted in the Mirs Bay, in the eastern waters of Hong Kong. A calibrated three-dimensional hydrodynamic model for the Pearl River Estuary （Delft3D） has been applied to the study of the physical hydrography of Hong Kong waters and its relationship with algal bloom transport patterns in the dry and wet seasons. The general 3D hydrodynamic circulation and salinity structure in the partially-mixed estuary are presented. Extensive numerical surface drogue tracking experiments are performed for algal blooms that are initiated in the Mirs Bay under different seasonal, wind and tidal conditions. The probability of bloom impact on the Victoria Harbour and nearby urban coastal waters is estimated. The computations show that： i） In the wet season （May - August）, algal blooms initiated in the Mirs Bay will move in a clockwise direction out of the bay, and be transported away from Hong Kong due to SW monsoon winds which drive the SW to NE coastal current; ii） In the dry season （November- April）, algal blooms initiated in the northeast Mirs Bay will move in an anti-clockwise direction and be carried away into southern waters due to the NE to SW coastal current driven by the NE monsoon winds; the bloom typically flows past the east edge of the Victoria Harbeur and nearby waters. Finally, the role of hydrodynamic transport in an important episodic event -- the spring 1998 massive red tide -- is quantitatively examined. It is shown that the strong NE to E wind during late March to early April, coupled with the diurnal tide at the beginning of April, significantly increased the probability of bloom transport into the Port Shelter and East Lamma Channel, resulting in the massive fish kill. The results provide a basis for risk assessment of harmful algal bloom （HAB） impact on urban coastal waters around the Victoria Habour.  相似文献   

Short-term Effects of Intertidal Macroalgal Blooms on the Macrohabitat Selection and Feeding Behaviour of Wading Birds in the Mondego Estuary (West Portugal)     

T. Múrias  J. A. Cabral  J. C. Marques  J. D. Goss-Custard 《Estuarine, Coastal and Shelf Science》1996,43(6):677-688

The possible effects of intertidal macroalgal blooms on the feeding distribution and behaviour of the waders in the Mondego Estuary (West Portugal) are discussed in the present paper. The presence of algae over the sediments did not deter the waders absolutely from feeding in a place, but most species did show some tendency to avoid highly eutrophic areas. However, there were no clear signs that the species redistributed themselves within the Estuary as the amount of algae changed, nor did the alternative feeding habitats (the salt pans) seem to be used more when algae were particularly abundant on the mud flats. In one species, bird numbers, rather than the amount of algae present, explained the numbers of birds using the salt pans when the two factors were considered together in a multiple regression analysis. There were no striking differences between algae-free and algae-weeded areas in some aspects of the foraging of two representative species, the scolopacid DunlinCalidris alpinaand the charadriid Grey PloverPluvialis squatarola. The results suggest either: (1) that the presence of algae did not strongly influence the distribution of the feeding waders, at least in the conditions prevailing during the study; or (2) that most waders were able to adapt to feeding on weeded areas; perhaps through subtle and undetected alterations in their feeding behaviour.  相似文献   

长江口邻近海域春季藻华与水体层化的关系     

周正熙  于仁成  吕颂辉  管卫兵  周名江 《海洋与湖沼》2016,47(6):1166-1175

长江口邻近海域是我国近海有害藻华高发区之一。受长江冲淡水和台湾暖流影响,海域环境条件复杂,有可能影响到藻华的分布状况、动态过程和危害效应。本文利用"藻华973项目"2011年的现场实测数据,从水体层化状况与藻华的关系入手,绘制出各要素的平面及剖面分布图,对比分析了春季硅藻藻华和甲藻藻华期间的温、盐跃层及其变化情况,探讨了硅、甲藻藻华的分布状况及其与温、盐跃层之间的关系。研究发现,2011年春季藻华期间该海域存在明显的温跃层和盐跃层。硅藻藻华期的温、盐跃层主要受到长江冲淡水影响;而在甲藻藻华期,受外海水入侵影响导致的温、盐跃层现象更加显著。藻华期间,浮游植物生物量高值区均出现在跃层上方的长江冲淡水影响区,其中硅藻藻华分布区与高强度跃层区基本一致,而甲藻藻华则主要分布在层化强度相对较弱的近岸海区,其分布可能受到上升流的影响。综合上述分析结果可以看出,长江口邻近海域春季的硅藻藻华主要受到长江冲淡水影响,而甲藻藻华的分布则在一定程度上受到外海水入侵及上升流影响。这一认识为进一步分析该海域春季硅、甲藻藻华演替过程及藻华优势种的长期演变趋势提供了新的思路和依据。  相似文献   

生活史(休眠孢囊)作为甲藻有害藻华年际频发和地理扩散的一种关键机制的研究进展   总被引：2，自引：0，他引：2  

唐赢中  胡章喜  邓蕴彦 《海洋科学集刊》2016,51(51):132-154

过去几十年,中国近海有害藻华的发生频率、规模和面积不断增大, 对我国水产养殖业、渔业和近岸生态系统造成了重大损失和威胁。 在引起有害藻华的众多原因中,藻华甲藻的特殊生活史策略,尤其是形成休眠孢囊,提供了一种关键的机理,因为孢囊的形成过程常伴随着基因重组从而增加了藻华藻的生态适应性;孢囊厚的囊壁增加了其对不利环境条件的耐受性;厚的囊壁使其免于病原体感染和捕食攻击;孢囊的适时萌发为藻华提供了“种源”;孢囊可通过自然或人为原因如船舶压舱水传播从而扩大了其地理分布。我们综述并讨论了甲藻生活史和孢囊研究的如下几个重要方面：１）甲藻生活史的复杂性和有关甲藻孢囊概念及归类的争议;２）沉积物中孢囊“作图（cyst mapping）”在藻华模型和预测（报）中的重要性以及孢囊分布/丰度与藻华规模耦合关系的复杂性和条件依赖性;３）孢囊形成和萌发的若干影响因子及其复杂性和可变性;和４）最近些年来分子生物学技术和各种组学手段在甲藻生活史和孢囊研究中的部分应用,特别是植物激素在孢囊形成、萌发过程中的可能作用。在简要评述了国际、国内有关研究历史中的路标性成果后,最后强调了四个值得重视的研究方向。  相似文献   

The growth dynamics of Karenia brevis within discrete blooms on the West Florida Shelf     

D.G. Redalje  S.E. Lohrenz  M.J. Natter  M.D. Tuel  G.J. Kirkpatrick  D.F. Millie  G.L. Fahnenstiel  F.M. Van Dolah 《Continental Shelf Research》2008

As part of the ECOHAB: Florida Program, we studied three large blooms of the harmful bloom forming dinoflagellate Karenia brevis. These blooms formed on the West Florida Shelf during Fall of 2000 off Panama City, and during Fall 2001 and Fall 2002 off the coastline between Tampa Bay and Charlotte Harbor. We suggest that these blooms represent two different stages of development, with the 2000 and 2001 blooms in an active growth or maintenance phase and the 2002 bloom in the early bloom initiation phase. Each bloom was highly productive with vertically integrated primary production values of 0.47–0.61, 0.39–1.33 and 0.65 g C m⁻² d⁻¹ for the 2000, 2001 and 2002 K. brevis blooms, respectively. Carbon specific growth rates were low during each of these blooms with values remaining fairly uniform with depth corresponding to generation times of 3–5 days. Nitrogen assimilation by K. brevis was highest during 2001 with values ranging from 0.15 to 2.14 μmol N L⁻¹ d⁻¹ and lower generally for 2000 and 2002 (0.01–0.64 and 0.66–0.76 μmol N L⁻¹ d⁻¹ for 2000 and 2002, respectively). The highest K. brevis cell densities occurred during the 2001 bloom and ranged from 400 to 800 cells mL⁻¹. Cell densities were lower for each of the 2000 and 2002 blooms relative to those for 2001 with densities ranging from 100 to 500 cells mL⁻¹. The 2000 and 2001 blooms were dominated by K. brevis in terms of its contribution to the total chlorophyll a (chl a) pool with K. brevis accounting generally for >70% of the observed chl a. For those populations that were dominated by K. brevis (e.g. 2000 and 2001), phytoplankton C biomass (C_p,0) constituted <30% of the total particulate organic carbon (POC). However, in 2002 when diatoms and K. brevis each contributed about the same to the total chl a, C_p,0 was >72% of the POC. The fraction of the total chl a that could be attributed to K. brevis was most highly correlated with POC, chl a and salinity. Nitrogen assimilation rate and primary production were highly correlated with a greater correlation coefficient than all other comparisons.  相似文献   

Physical–biological coupling in the Pearl River Estuary     

Paul J. Harrison  Kedong Yin  J.H.W. Lee  Jianping Gan  Hongbin Liu 《Continental Shelf Research》2008

The Pearl River Estuary is a subtropical estuary and the second largest in China based on discharge volume from the Pearl River. Processes in the estuary vary spatially and temporally (wet vs dry season). In the dry season at the head of the estuary, hypoxic and nearly anoxic conditions occur and NH₄ reaches >600 μM, NO₃ is ∼300 μM and nitrite is ∼60 μM indicating that nitrification and denitrification may be important dry season processes in the region extending 40 km upstream of the Humen outlet. There are very few biological studies conducted in this upper section of the estuary in either the dry or wet seasons and hence there is a need for further research in this region of the river. In the wet season, the salinity wedge extends to the Hongqimen outlet and oxygen is low (35–80% saturation). Nitrate is ∼100 μM, silicate ∼140 μM; and phosphate is relatively low at ∼0.5 μM, yielding an N:P ratio up to ∼200:1 in summer. Nutrients decrease in the lower estuary and primary productivity may become potentially P-limited. Eutrophication is not as severe as one would expect from the nutrient inputs from the Pearl River and from Hong Kong's sewage discharge. This estuary shows a remarkable capacity to cope with excessive nutrients. Physical processes such as river discharge, tidal flushing, turbulent dispersion, wind-induced mixing, and estuarine circulation play an important role in controlling the production and accumulation of algal blooms and the potential occurrence of hypoxia. Superimposed on the physical processes of the estuary are the chemical and biological processes involved in the production of the bloom. For example, the 100N:1P ratio indicates that P potentially limits the amount of algal biomass (and potential biological oxygen demand) in summer. While extended periods of hypoxia are rare in Hong Kong waters, episodic events have been reported to occur during late summer due to factors such as low wind, high rainfall and river discharge which result in strong density stratification that significantly dampens vertical mixing processes. Nutrient loads are likely to change over the next several decades and monitoring programs are essential to detect the response of the ecosystem due to the future changes in nutrient loading and the ratio of nutrients.  相似文献   

微囊藻水华期间水体及藻体上细菌的动态   总被引：1，自引：1，他引：0  

朱丽萍  高光  汤祥明  晁建颖  沈燕 《湖泊科学》2009,21(3):395-400

通过对水体中及附着在藻类上的细荫数量、代谢活性细菌、Chl.a浓度等的研究,探讨了藻类与细菌之间的代谢耦联关系,结果表明:1)水体中细菌的丰度随着Chl.a浓度的增加而逐渐增大(r2=0.466,P<0.05),但其峰值滞后于Chl.a;附在藻体表面上的细菌也呈现出相似的变化规律;2)水体中代谢活性细菌数量与总细菌数量显著相关(r2=0.678,P<0.05);附着在藻体上的代谢活性细菌虽然总数量低于水体中的代谢活性细菌,但二者之间亦存在显著的相关性(r2=0.836,P<0.05).3)藻类表面附着细菌的数量取决与藻类的生长状况,附着在藻类体上的代谢活性细菌的比率均高于水体中代谢活性细菌的比率,且在水华盛行期间呈逐渐增加的趋势.  相似文献