广东珠海双胞旋沟藻Cochlodinium geminatum赤潮事件分析   总被引：2，自引：0，他引：2       下载免费PDF全文

欧林坚  张玉宇  李扬  王华接  谢学东  荣志明  吕颂辉  齐雨藻 《热带海洋学报》2010,29(1):57-61

多环旋沟藻Cochlodinium polykrikoides赤潮在全球频繁爆发。2006年10—11月间, 在广东珠海海域爆发的双胞旋沟藻Cochlodinium geminatum赤潮则较为少见。双胞旋沟藻赤潮发生于富营养的近岸水体, 赤潮发生区内水温变化范围23.41—27.54℃, 盐度变化范围15.49—17.92。双胞旋沟藻的细胞密度随温度和盐度的升高而显著升高, 最高细胞密度达1.6×106个.L-1。在赤潮发生后期, 海区水温下降及群落中红色中缢虫Mesodinium rubrum数量的上升, 可能是导致双胞旋沟藻赤潮衰亡的重要原因。  相似文献   

Observations of sea ice interannual variations and spring bloom occurrences at the Japanese scallop farming area in the Okhotsk Sea using satellite imageries   总被引：1，自引：0，他引：1  

Muzzneena Ahmad Mustapha  Sei-Ichi Saitoh 《Estuarine, Coastal and Shelf Science》2008,77(4):577-588

The dynamics of ice formation and phytoplankton bloom development in the coastal region of the Okhotsk Sea, Hokkaido, where the Japanese scallop, Mizuhopecten yessoensis, are cultured were investigated using seven years (1998–2004) satellite data from the Special Sensor Microwave/Imager (SSM/I) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The interannual variability of sea ice cover and timing of spring bloom occurrences were analyzed. Longer ice cover in 1999, 2001 and 2003 with the presence of ice until early April and shortened ice cover in 1998, 2000, 2002 and 2004 with the occurrence of ice until early March were recognized at this area. Variability in the timing of sea ice retreat and development of spring blooms at the scallop areas were observed. Progression of a single ice edge bloom showed higher Chl-a concentration compared to development of an initial ice edge bloom followed by a later open water bloom. Higher concentration of phytoplankton biomass was observed in the initial bloom when sea ice melting is delayed compared to when the sea ice leaves earlier. Wind events were also observed to affect the occurrences of spring bloom.  相似文献   

Light climate as the key factor controlling the spring dynamics of phytoplankton in Lake Zürich     

Willi Bleiker  Ferdinand Schanz 《Aquatic Sciences - Research Across Boundaries》1997,59(2):135-157

During the spring seasons of 1983, 1986 and 1987 the development of phytoplankton in Lake Zürich was investigated (from February to May) using samples taken at short term intervals. The aim was to describe the effects of the short term dynamics of environmental factors on the algal growth. The results could then be used to discuss the existing theories to assess the start of phytoplankton growth pulses in spring. Only 7 to 10 days without wind driven vertical mixing were required in spring to start the first growth pulse, despite of a still very unstable water column (sometimes inverse thermal stratification). Mainly flagellates andStephanodiscus hantzschii increased their biomass and achieved net growth rates of 0.1 and up to 0.65 d⁻¹ respectively. During such a phase the mixing depth was always smaller than the euphotic depth. Later on, at the start of the spring bloom (=last growth pulse in spring before the clear water stage), the intensity of vertical mixing as well as the mixing depth were markedly reduced due to an increase in heat input and low wind. Then flagellates dominated (contribution up to 75.5% of the areal biomass reaching 60 g fresh weight m⁻²) and the growth rate rose to a maximum of 0.65 d⁻¹. Standard models of critical depth considers that there is only a biomass increase if the mixing depth is smaller than the depth of a water layer positive balanced between production and respiration. This model for determining the beginning of a phytoplankton growth pulse in spring takes no account of the favorable light conditions for phytoplankton cells at calm and sunny days in February and March. The newly developed threshold value model takes these situations into account: It assumes that the phytoplankton biomass increases when the calculated effective light climate is equal or greater than a previously fixed threshold. The calculations are based on the mean light intensity within the mixed layer at windy days or within the euphotic depth (z _eu) at calm days. In Lake Zürich a minimum of 0.2 10⁶ J m⁻²d⁻¹ (=0.9 mol quanta m⁻²d⁻¹) has to be reached or surpassed in at least 3 days before an exponential increase of algal biomass can occur. The value does not depend on short term fluctuations in neither radiation nor mixing depth. It seems that this value is rather low comparing with those of investigations in other water bodies (up to 0.8 10⁶ J m⁻² d⁻¹) but high related to values from algal cultures (0.02 10⁶ J m⁻²d⁻¹). As the weather can only be forecasted a few days ahead with any certainty the period for a more or less accurate prediction of an algal bloom is restricted to about 1 to 5 days.  相似文献   

One Dimensional Ecosystem Model Simulation of the Effects of Vertical Dilution by the Winter Mixing on the Spring Diatom Bloom     

Naoki Yoshie  Yasuhiro Yamanaka  Michio J. Kishi  Hiroaki Saito 《Journal of Oceanography》2003,59(5):563-571

A one-dimensional ecosystem model has been used to investigate the processes relevant to the spring diatom bloom which play important roles in the biogeochemical cycle in the western subarctic Pacific. The model represents the plankton dynamics and the nutrient cycles in the spring diatom bloom; its results show the importance of dilution by deep mixing in winter. It is supposed that the vertically integrated biomass of phytoplankton decreases in the winter due to the decrease of photosynthesis, because the deep mixing transports phytoplankton to a layer with a low light level. However, the observed integrated diatom biomass increases as the mixed layer deepens. This is because the decrease of concentration due to dilution by mixing causes the diatom grazed pressure to be less significant than diatom photosynthesis. In other words, the effect of dilution on the grazed rate is more significant than the effect on the photosynthesis rate because the grazed rate depends on the concentrations of both diatom and grazer, whereas the photosynthesis rate depends only diatom concentration. The average specific diatom grazed rate, defined as grazed rate divided by diatom biomass, decreases by 35% associated with the deepening, while the average specific photosynthesis rate of diatom decreases by 11%. As a result, the average specific net diatom growth rate during the deep mixing is about 70% of its maximum during the spring diatom bloom. The deep mixing significantly affects the amplitude of the spring diatom bloom not only by the supply of nutrients but also by the dilution which drastically decreases the grazed pressure. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Seasonal variations in dissolved organic carbon concentrations and characteristics in a shallow coastal bay   总被引：8，自引：0，他引：8  

Elizabeth C. Minor  Jean-Paul Simjouw  Margaret R. Mulholland 《Marine Chemistry》2006,101(3-4):166-179

Dissolved organic matter (DOM) composition and dynamics in temperate shallow coastal bays are not well described although these bays may be important as local sources of organic carbon to ocean waters and are often sites of economically-important fisheries and aquaculture. In this study surface water samples were collected on a monthly to bi-monthly basis over two years from a mid-Atlantic coastal bay (Chincoteague Bay, Virginia and Maryland, USA). Dissolved organic carbon (DOC) concentrations and light absorbance characteristics were measured on sterile-filtered water, and high-molecular weight (> 1 kDa) dissolved OM (DOM) was isolated to determine stable isotope composition and molecular-level characteristics. Our time series encompassed both a drought year (2002) and a year of above-average rainfall (2003). During the dry year, one of our sites developed a very intense bloom of the brown tide organism Aureococcus anophagefferens while during the wet year there were brown tide bloom events at both of our sampling sites. During early spring of the wet year, there were higher concentrations of > 1 kDa DOC; this fraction represented a larger proportion of overall DOC and appeared considerably more allochthonous. Based upon colored dissolved organic matter (CDOM) and high-molecular weight DOM analyses, the development of extensive phytoplankton blooms during our sampling period significantly altered the quality of the DOM. Throughout both years Chincoteague Bay had high DOC concentrations relative to values reported for the coastal ocean. This observation, in conjunction with the observed effects of phytoplankton blooms on DOM composition, indicates that Chincoteague Bay may be a significant local source of “recently-fixed” organic carbon to shelf waters. Estimating inputs of DOC from Chincoteague Bay to the Mid-Atlantic Bight suggests that shallow productive bays should be considered in studies of organic carbon on continental shelves.  相似文献   

有机改性黏土对海水中营养盐及主要水质因子的影响     

高咏卉  俞志明  宋秀贤  曹西华 《海洋科学》2007,31(8):30-37

为了阐明黏土方法治理有害赤潮的生态环境效应，研究了有机改性黏土对海水中营养盐和溶解氧、化学耗氧量、pH等主要水质因子的影响。结果表明，有机改性黏土对营养盐，尤其是磷酸盐有一定的吸附作用，吸附量随水体中磷酸盐浓度的增加而增大，不同有机改性黏土对海水中磷酸盐的吸附能力为：有机改性黏土Ⅰ〉有机改性黏土Ⅱ〉有机改性黏土Ⅲ。通过有机改性黏土对磷酸盐的吸附再释放作用研究，进一步探讨了磷酸盐释放作用对赤潮异弯藻（Heterosigma akashiwo）、东海原甲藻（Prorocentrum donghaiense）等赤潮生物生长的影响。实验结果表明，经过有机改性的黏土有利于提高其对磷酸盐的吸附能力，降低对磷酸盐的解吸率，缓解海水富营养化程度，虽然少量被吸附的磷酸盐能缓慢释放，但仍不足以维持赤潮生物的正常生长。同时利用有机改性黏土治理赤潮能显著改善溶解氧、pH、化学耗氧量等水质指标，有利于治理赤潮后的环境修复。  相似文献   

福建沿岸海域赤潮发生特点及防治措施   总被引：17，自引：2，他引：17  

许珠华  侯建军 《台湾海峡》2006,25(1):143-150

根据多年来福建沿岸海域发生赤潮的情况及相关资料，概述了该海域赤潮发生的主要趋势、时间、区域、种类和危害等特点，分析和讨论了赤潮发生的自然因素和人为因素；并指出赤潮防灾和减灾工作中存在的主要问题是海洋综合管理力量薄弱，海洋法律法规不够健全，海洋执法能力有待加强，海洋事业经费投入不足．在此基础上提出了防治福建沿岸海域赤潮灾害的如下措施和建议：进一步调查和研究赤潮发生的类型并分析其主要成因；建立健全福建省近岸海域环境监测网络和海洋环境监测系统，大力开展具有福建区域特色的赤潮生物及其有害赤潮发生机理等科学研究；控制陆源污染，减少含氮污染物的排放总量和入海量，提倡和推广使用农家肥，提高生活污水的处理效率；认真研究和分析港湾的环境容量，合理开发福建的海水养殖业；加强围填海等涉海工程对海水动力学影响的研究，以及加强对船舶压仓水等带来外来赤潮生物影响的研究等．  相似文献   

Potential of Argo Drifters for Estimating Biological Production within the Water Column     

SeungHyun Son  Emmanuel Boss  Jae Hoon Noh 《Ocean Science Journal》2006,41(2):121-124

Argo drifters provide information of the vertical structure in the water column and have a potential for the improvement of understanding phytoplankton primary production and biogeochemical cycles in combination with ocean color satellite data, which can obtain the horizontal distribution of phytoplankton biomass in the surface layer. Our examples show that using Argo drifters with satellite-measured horizontal distribution of phytoplankton biomass at the sea surface allow an improved understanding of the development of the spring bloom. The other possible uses of Argo drifter are discussed.  相似文献   

A Numerical Simulation on the Mesoscale Dynamics of the Spring Bloom in the Sea of Japan     

Tetsuo Yanagi  Goh Onitsuka  Naoki Hirose  John-Hwan Yoon 《Journal of Oceanography》2001,57(6):617-630

The northward migration of spring bloom was observed in the Sea of Japan from April to May 1997 by the Ocean Color and Temperature Scanner (OCTS) on board the Advanced Earth Observing Satellite (ADEOS). This phenomenon is well simulated with a numerical ecosystem model coupled with a hydrodynamic model. The hydrodynamic model is the Geophysical Fluid Dynamics Laboratory (GFDL) Modular Ocean Model (MOM). The ecosystem model consists of five components: dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), phytoplankton, zooplankton and detritus. Results of the numerical ecosystem model suggest that the mesoscale development of the spring bloom in the Sea of Japan is related to that of sea water temperature, and that the bloom is limited by the depletion of DIN. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

The role of mixotrophy in plankton bloom dynamics, and the consequences for productivity     

Hammer  Astrid C.; Pitchford  Jonathan W. 《ICES Journal of Marine Science》2005,62(5):833-840

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