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1.
大亚湾拟菱形藻水华及其在生物群落中的生态地位 总被引：5，自引：1，他引：5
对2000年4~5月藻类水华高发期大亚湾澳头海域的拟菱形藻进行逐日调查,并对其与浮游植物、浮游动物的相关关系进行分析.调查初期,整个生物群落的种类组成数量都相对贫乏;拟菱形藻数量急剧增长,最高的测站密度可达2.93×106个/dm3.拟菱形藻水华的组成种类有拟极细拟菱形藻和尖刺拟菱形藻两种,以尖刺拟菱形藻稍占优势.水华形成中其他种类硅藻和甲藻在种类组成和数量上也有一定程度的增加.分析表明,拟菱形藻在浮游植物群落的种间竞争中具有优势,并成为春季硅藻水华的最重要的组成者.桡足类等浮游动物对拟菱形藻的下行控制并不能明显抑制拟菱形藻的增长及水华的产生,这与其偏爱以其他种类藻类为食有关.以上因素外加拟菱形藻对环境的广泛适应性促使其在该水域成为最常见的赤潮生物之一. 相似文献
2.
Sofia Loureiro Esther Garcs Margarita Fernndez-Tejedor Dolors Vaqu Jordi Camp 《Estuarine, Coastal and Shelf Science》2009,83(4):539-549
Samples were collected during one annual cycle (April 2007–March 2008) at Alfacs Bay (NW Mediterranean Sea) central station in order to assess the influence of organic nutrients in the growth of the microalgae assemblage, with special reference to Pseudo-nitzschia spp. This potentially toxic diatom forms natural and recurrent blooms in the study area. To assess further the relationship between Pseudo-nitzschia spp. and nutrients an enrichment experiment with high molecular weight dissolved organic matter (HMWDOM) was performed with field samples obtained during a Pseudo-nitzschia spp. bloom. HMWDOM was extracted from water collected at Alfacs Bay. Five bioassays were prepared: N + P (seawater with addition of nitrate and phosphate), DOM (addition of HMWDOM), (−N + P) + DOM (nitrogen deficient, with addition of phosphate and HMWDOM), (N + P) + DOM (addition of nitrate, phosphate and HMWDOM), seawater control (without added nutrients), and B + DOM (control of bacteria, without microalgae). The experiment was run in batch mode over 4 days. Results from the field study revealed that the concentrations of organic nutrients mostly surpassed the inorganic pool. Pseudo-nitzschia spp. was the most frequent and abundant taxa of the microalgae community. The micro-planktonic assemblage was arranged according to a seasonal factor (ANOSIM and cluster analysis). DON, nitrate and silicate were the most important abiotic parameters contributing to the dissimilarities between seasons (SIMPER analysis) and thereby potentially influencing the seasonal distribution of microalgae in the representative station. In the experimental investigation, Pseudo-nitzschia cells increased by the end of the experiment in the DOM bioassay but no respective increase was observed for chlorophyll a. This could point to an acquisition of nutrients through the DOM fraction that would conjointly reduce the need of chlorophyll a. The data obtained suggest that organic nutrients may exert an important role in the development of microalgae, including Pseudo-nitzschia spp., in the selected location. 相似文献
3.
拟菱形藻属（Pseudo-nitzschia）物种是一类备受关注的海洋有毒有害硅藻，我国相关研究仍然不足，已报道的物种多样性偏低，产毒物种也较少。为了解我国海域拟菱形藻属的物种多样性，阐述产毒物种信息，在我国东南海域建立了8个拟菱形藻单克隆培养株系，结合形态学和分子系统学数据，鉴定到2个物种:环孔拟菱形藻（Ps.circumpora C.H.Lim，C.P.Leaw&P.T.Lim）和多列拟菱形藻[Ps.multiseries（Hasle） Hasle]，其中环孔拟菱形藻是我国的新记录种。利用高效液相色谱-质谱联用法检测了藻株的多莫酸（domoic acid，DA）特征，在5个多列拟菱形藻株系中检测到DA，单细胞产毒水平为1.01~96.11 fg。此外，利用卤虫（Artemia salina L.）和强额拟哲水蚤（Paracalanus crassirostris Dahl）对多列拟菱形藻的产毒株系（MC4177）进行诱导，发现能够提高其单细胞产毒水平，提高幅度在26~55倍。 相似文献
4.
Seyfettin Ta Erdoan Oku Asl&#x; Aslan-Y&#x;lmaz 《Estuarine, Coastal and Shelf Science》2006,68(3-4):593
The distribution of toxic cyanobacterium Microcystis cf. aeruginosa in the severely polluted Golden Horn Estuary was studied from 1998 to 2000. Microcystis persisted at the upper estuary where the water circulation was poor and values ranged between 2.9 × 104 and 2.7 × 106 cells ml−1 throughout the study. Simultaneously measured physical (salinity, temperature, rainfall and secchi disc) and chemical parameters (nutrients and dissolved oxygen) were evaluated together with Microcystis data. Although the Microcystis blooms generally occur in summer due to the increase in temperature, the blooms were recorded in winter in the present study. The abundance of Microcystis depended on the variations in salinity and both blooms were recorded below S = 2. A moderate partial correlation between Microcystis abundance and salinity was detected in the presence of temperature, dissolved oxygen and precipitation data (r = −0.561, p = 0.002). The M. cf. aeruginosa abundance was low in the summer when the salinity was higher than winter. A remarkable increase in the eukaryotic phytoplankton abundance following the improvements in the water quality of the estuary occurred, whilst the Microcystis abundance remained below bloom level. 相似文献
5.
为了提高对我国海域拟菱形藻属(Pseudo-nitzschia)物种多样性的认识,并明确其是否能够产生多莫酸(domoic acid,DA)。本文从中国沿海分离和建立了拟菱形藻的单克隆培养株系,结合光学显微镜下的群体特征、透射电镜下的超微形态学特征、基于核糖体转录间隔区(internal transcribed spacer,ITS)的分子系统学数据,以及基于ITS2转录RNA的二级结构分析,鉴定到我国拟菱形藻属的1个新记录种:福氏拟菱形藻(P.fukuyoi Lim,Teng,LeawLim)。本文对其形态学特征进行描述,与相似物种进行了对比分析;对其ITS2-RNA序列进行了分析;利用高效液相色谱-串联质谱联用法(liquid chromatography tandem mass spectrometry,LC-MS/MS)对培养藻株的产毒特征进行了分析,多个株系中均检测到DA,单细胞产毒水平为0.02—0.23pg,这是我国报道的第二种产毒拟菱形藻。利用卤虫(Artemia salina)和褶皱臂尾轮虫(Brachionus plicatilis)对福氏拟菱形藻的产毒水平进行了诱导,发现浮游动物能够提高福氏拟菱形藻的DA含量,增强幅度在4.7—28.5倍之间。本文提高了对我国拟菱形藻属物种多样性的认识,明确了福氏拟菱形藻的产毒特征和水平,为后续深入研究提供了基础数据。 相似文献
6.
Summer algal blooms in a coastal ecosystem: the role of atmospheric deposition versus entrainment fluxes 总被引：2，自引：1，他引：2
Jacob Carstensen Lise Marie Frohn Charlotte Bay Hasager Bo G. Gustafsson 《Estuarine, Coastal and Shelf Science》2005,62(4):595-608
The nitrogen inputs from atmospheric deposition and bottom water entrainment to the surface layer were modelled in the summer period (May–September) over a 11-year period (1989–1999) and compared to investigate the significance of these fluxes for generating blooms in the Kattegat. In the summer periods the average atmospheric deposition was 2.81 mg N m−2 d−1 compared to average entrainment fluxes of 5.42 mg N m−2 d−1, 1.21 mg N m−2 d−1 and 1.15 mg N m−2 d−1 for the northern, central and southern part of the Kattegat, respectively. Atmospheric nitrogen deposition alone could not sustain biomass increases associated with observed blooms and entrainment fluxes dominated the high nitrogen inputs to the surface layer. The potential for a bloom through growth was typically obtained after several days of high nitrogen inputs from entrainment in the frontal area of the northern Kattegat and to some extent from atmospheric deposition. The modelled nitrogen input in this area could account directly for 30% of the observed blooms in the Northern sub-basin, and through advective transport 24% and 19% of the observed blooms in the central and southern Kattegat. The direct nitrogen inputs through atmospheric deposition and entrainment to the central and southern sub-basins were small and could not be linked to any bloom observation. 相似文献
7.
为丰富我国海域产毒拟菱形藻(Pseudo-nitzschia)的物种多样性,并了解其毒性特征,于2017年5月在台湾海峡建立了4个拟菱形藻培养株系.利用光镜和透射电镜观察了形态学特征,构建了基于核糖体转录间隔区的分子系统树,预测了第二间隔区转录RNA的二级结构.结合形态学和分子生物学数据,报道了我国拟菱形藻属的1个新记录种:隆氏拟菱形藻(Pseudo-nitzschia lundholmiae).该种的典型形态特征是壳面披针形,具有中央较大船骨点,点条纹由一排孔纹组成,孔纹多分为2个部分.采用高效液相色谱-质谱联用法检测了藻株的多莫酸(domoic acid,DA)特征,有1个株系检测到DA,单细胞产毒水平为2. 3 fg.利用卤虫(Artemia salina)和强额拟哲水蚤(Paracalanus crassirostris)混合培养来探索隆氏拟菱形藻的产毒特征,发现均能提高其DA水平,增强幅度在3～4倍之间.本研究丰富了我国产毒拟菱形藻的物种多样性,明确了隆氏拟菱形藻的毒性特征和产毒水平,可为后续深入研究提供基础数据. 相似文献
8.
The production of the toxin Domoic Acid (DA) by the diatoms Pseudo-nitzschia spp. is affected by several environmental factors, among them copper and silica. The effects of these nutrients upon DA production have been studied individually, but not in combination. There is evidence, however, that in diatoms copper can enter the cell via the silicic-acid transport site. The goal of this study was to analyze the effect of the interaction between copper and silicic-acid supply upon DA production in Pseudo-nitzschia multiseries. The study was motivated by concerns about the risk of toxigenic Pseudo-nitzschia spp. impacting mussel aquaculture in New England (USA). The results of the present study do not indicate that copper uses the silicic acid transport site to enter the cell; nevertheless, there is an interaction between these two nutrients that produces a synergistic affect upon toxin production. A small increase in copper, without a simultaneous increase in silicate, as well as an increase in both copper and silicate, leads to DA up-regulation. Furthermore, the field component of this study reports the presence of species of Pseudo-nitzschia on the New England coast that are capable of producing DA. Together these findings indicate that risk of DA impacting mussel aquaculture along the coast of New England would be increased by an unusual enrichment of copper in the vicinity of mussel farms. 相似文献
9.
Factors controlling the timing of major (>10 mg chlorophyll a m−3) spring bloom events in the estuarine waters of the Solent, on the south coast of the UK, have been investigated. Winter to summer variations in chlorophyll a concentration together with relevant meteorological and hydrographical data have been analysed for 5 years (1988, 1992, 2001, 2002 and 2003). Mean water column irradiance is demonstrated to be the main factor controlling the timing of the first major spring bloom event, usually dominated by large chain-forming diatoms. When chlorophyll a concentration first exceeds 10 mg m−3 in spring (usually in May) the mean water column photosynthetic active radiation (PAR) averaged for one week prior to the sampling date was always >380 W h m−2 d−1. Prior to the main spring bloom event surface incident radiation and water turbidity combine to limit chlorophyll a concentration to levels <10 mg m−3. Chlorophyll a concentrations >10 mg m−3 do not occur in the Solent until almost the entire 10 m water column is within the euphotic zone (i.e. above 1% light level) and light extinction coefficient (k) is ca. ≤0.5 m−1. Statistically, river flow explains the largest percentage of the variations in k and the delayed bloom in June 2002 is due to increased cloud cover and high levels of rainfall in May, which caused a reduction in surface incident irradiance and increased turbidity. Chlorophyll a peaks during these major bloom events generally occur on spring tides when increased mixing rates favour net growth of diatoms. 相似文献
10.
An extremely dense bloom of the potentially toxic dinoflagellate Alexandrium tamarense was observed in the lagoons of Cà Pisani (Veneto, Italy) in summer 1993. The lagoons were experiencing a significant eutrophication impact, receiving waste waters from intensive fish culture plants. During their bloom dinoflagellates in the lagoons reached densities of 2 to 4 × 106 cells·dm−3 and a biomass of over 100 g·m−3. The bloom produced drastic ecological changes in the lagoons. It caused nocturnal anoxia, mortality of macrophytes and the build-up of labile organic matter in the water column. Grazing by the tintinnid Favella sp. contributed to the termination of the bloom of the flagellates. The results show that coastal aqua culture probably stimulates dinoflagellate blooms in shallow brackish lagoons. 相似文献
11.
Fleur C. van Duyl Winfried W. C. Gieskes Arjen J. Kop Wilma E. Lewis 《Journal of Sea Research》1998,40(3-4)
In the spring of 1995, short-term variations in the concentration of particulate and dissolved dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS) were monitored in the western Wadden Sea, a shallow coastal region in open connection with the North Sea. Significant correlations were found between abundance of Phaeocystis globosa and particulate DMSP; concentrations increased rapidly from 100 to 1650 nM in the middle of April. Highest DMS concentrations were found during the initial phase of the exponential growth of the bloom. DMS production and loss rates of DMSP and DMS were estimated experimentally during various phases of the bloom. DMS production and consumption were roughly in balance, with production only slightly exceeding consumption at the start of the bloom. Rates of production and consumption were highest during the exponential growth phase of Phaeocystis and declined in the course of the bloom (from 300–375 to less than 5 nmol dm−3 d−1). Demethylation of DMSP increased during the bloom (from 11 to 1300 nmol dm−3 d−1); it accounted for up to 100% of the DMSP loss at the end of the bloom. The shift from DMSP cleavage to demethylation in the course of a Phaeocystis bloom implies that DMS concentrations are not necessarily highest at the peak or towards the end of blooms. 相似文献
12.
近年来,随着对抑藻微生物认识的深入,利用藻-菌相互作用控制有害藻华展现出极大的应用前景。在前期改性粘土治理有害藻华方法的基础上,首次将不同种类的微生物与传统的改性粘土复合,研究了不同的复合比例、制备方式等对典型有害藻华生物——东海原甲藻(Prorocentrum donghaiense)去除效率的影响,初步探讨了其作用机制。结果表明:菌密度1.5×1010 cells/L的EM菌(effectivemicroorganisms,有效性微生物)及其滤液可以有效去除东海原甲藻;利用EM菌对粘土进行复合改性处理可以进一步提高改性粘土的除藻能力,呈现出1+12的效果。在适宜范围内,增加熟化时间与温度有利于复合改性粘土除藻效率的提升。文章进一步分析探讨了EM菌复合改性粘土的除藻机制,认为改性粘土通过富集EM菌和分泌的抑藻物质,增加了其对微藻的直接和间接除藻作用;适宜的熟化温度和熟化时间可促进EM菌的繁殖及其在改性粘土上的吸附,有利于复合改性粘土去除效率的提升。上述研究结果为改性粘土治理有害藻华技术的进一步提升和完善提供了新的探索。 相似文献
13.
近十年来,我国黄、东海沙海蜇的数量呈上下波动趋势,除2008、2010、2011、2013年为不暴发年外,其余年份均为暴发年或弱暴发年(本文界定沙海蜇平均丰度范围为2—10ind./100m2为暴发年,1—2ind./100m2为弱暴发年,0—1ind./100m2为不暴发年)。为研究沙海蜇数量年际变化的原因,本文借助同化的海洋模式结果,分析了2006—2013年南黄海沙海蜇平均丰度与表底层海水温度的关系、与不同温度持续时间的关系。研究结果发现,在海州湾附近,对于暴发年2007年和2009年,春季底层海水10—18°C持续时间为130天,比不暴发年2010年和2011年多近15天。在长江口区域,不暴发年2008年和2011年夏秋季底层海水18—25°C持续时间较长,约80天,比暴发年2007年多20天。在长江口、苏北近岸以及海州湾区域,春季底层海水10—18°C持续时间越长,南黄海水母丰度呈现越大的趋势;夏秋季底层海水18—25°C持续时间越长,第二年水母生物量则越大。结果支持和验证了春季底层10—18°C持续时间长有利于当年水母暴发及夏秋季底层18—25°C持续时间长有利于来年水母暴发的推论。本文通过分析沙海蜇丰度和温度变化的关系,可以为将来预测该水母数量提供基础。 相似文献
14.
Diel fluctuations in dissolved free amino acids and monosaccharides in Chesapeake Bay dinoflagellate blooms 总被引：1，自引：0，他引：1
The accumulation of phytoplankton biomass in recurring summer dinoflagellate blooms of Chesapeake Bay is accompanied by large pools of dissolved organic matter (DOM). Two fractions of the DOM, free amino acids (DFAA) and monosaccharides (MONO), were measured at 3 h intervals in mixed species dinoflagellate blooms (Katodinium rotundatum, Gymnodinium spp.) and related to productivity, biomass and photoperiod. Peak chlorophyll levels for the three blooms were 28, 65 and 938 μg1−1. In general, DFAA and MONO concentrations increased with increasing biomass of bloom-forming species, reaching 203 and 844 μg1−1. MONO appeared to accumulate during the day while there was no consistent pattern for DFAA. The accumulations of DFAA and MONO in blooms indicate that bloom production might stimulate microheterotrophy, thereby enhancing carbon and nutrient cycling in bloom-impacted regions. 相似文献
15.
Laboratory experiments demonstrated that migrant juvenile banded kokopu (Galaxias fasciatus Gray) were more sensitive to suspended sediment (SS) than other native fish species. If juvenile migrants avoid waters made turbid by SS and their recruitment to adult habitats up stream is reduced, then adult abundance may decline in turbid rivers. To test this, we compared the abundance of diadromous native fish between turbid and clear rivers. The duration (% time) for which SS concentrations exceeded 120 mg litre‐1 (a critical level from laboratory experiments) during the migration season (August‐December) was estimated for over 150 New Zealand river sites. Turbid rivers were defined as those where SS concentrations exceeded 120 mg litre‐1 for over 20% of the time and clear rivers as those where SS concentrations exceeded 120 mg litre‐1 for less than 10% of the time. Eight turbid rivers and seven clear ones were identified where sufficient data on SS and native fish populations existed to permit a comparison. The mean occurrence of banded kokopu was reduced by 89.5% in turbid rivers and, although other diadromous fish species were also less common, banded kokopu was most affected. Densities of adult banded kokopu were also significantly lower in optimal stream habitats in three turbid compared with three matched clear rivers. We therefore concluded that the abundance of adult banded kokopu was reduced in turbid rivers and propose that this is because of reduced recruitment of juveniles in turbid rivers. 相似文献
16.
Abu Affan Joon-Baek Lee Jun -Teck Kim Young -Chan Choi Jong -Man Kim Jung -Goo Myoung 《Ocean Science Journal》2007,42(2):117-127
The dynamics of phytoplankton abundance with seasonal variation in physicochemical conditions were investigated monthly at
10 stations around the Chagwi-do off the west coast of Jeju Island, Korea, including inshore, middle shore, and offshore in
the marine ranching area from September 2004 to November 2005. Water temperature varied from 12.1 to 28.9°C (average 18.8°C),
and salinity from 28.9 to 34.9 psu (average 33.7 psu). The chlorophyll a concentration was 0.02-2.05 μg L1 (average 0.70 μg L1), and the maximum concentration occurred in the bottom layer in April. A total of 294 phytoplankton species belonging to
10 families was identified: 182 Bacillariophyceae, 52 Dinophyceae, 9 Chlorophyceae, 12 Cryptophyceae, 6 Chrysophyceae, 4 Dictyophyceae,
13 Euglenophyceae, 6 Prymnesiophyceae, 5 Prasinophyceae, and 5 Raphidophyceae. The standing crop was 2.21-48.69x104 cells L1 (average 9.23x 104 cells L1), and the maximum occurred in the bottom layer in April. Diatoms were most abundant throughout the year, followed by dinoflagellates
and phytoflagellates. A phytoplankton bloom occurred twice: once in spring, peaking in April, and once in autumn, peaking
in November. The spring bloom was represented by fourChaetoceros species andSkeletonema costatum; each contributed 10–20% of the total phytoplankton abundance. The autumn bloom comprised dinoflagellates, diatoms, and phytoflagellates,
of which dinoflagellates were predominant.Gymnodinium conicum, Prorocentrum micans, andP. triestinum each contributed over 10% of the total phytoplankton abundance. 相似文献
17.
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19.
Winter-spring phytoplankton blooms in Dabob Bay, Washington 总被引：4，自引：2，他引：4
Rita A. Horner James R. Postel Claudia Halsband-Lenk James J. Pierson Georg Pohnert Thomas Wichard 《Progress in Oceanography》2005,67(3-4):286
Scientific investigations in Dabob Bay, Washington State, USA, have been extensive since the early 1960s, but phytoplankton blooms have been studied mostly with regard to chlorophyll concentrations and little is known about the phytoplankton species themselves. Here we provide information on the species present, their abundances during blooms, their contribution to organic carbon concentrations and the ability of some phytoplankton species to produce toxic aldehydes that may impact metazoan grazers.Multiple blooms of phytoplankton, dominated by diatoms, occurred in the late winter-early spring period, with depth-integrated chlorophyll levels ranging from <20 to 230 mg m−2 and peaks in February and April. The major bloom species included Skeletonema costatum, Thalassiosira spp. and Chaetoceros spp; Phaeocystis cf. pouchetii occurred in 2002 and 2004. Other taxa or groups of organisms that were sometimes abundant included unidentified small flagellates <10 μm in size and unidentified heterotrophic dinoflagellates. Large diatoms usually comprised most of the cell carbon, but a large, heterotrophic dinoflagellate, identified only as Gyrodinium “tear” because of its shape, was a major contributor to the microplankton carbon when present even in small numbers. Five Thalassiosira species and S. costatum were found to produce polyunsaturated aldehydes (PUA) that are known to affect copepod reproduction and hatching success. Our findings are similar to the few previous studies in the last four decades that included phytoplankton species and suggest long-term similarities and relative stability in the phytoplankton species present and their timing in Dabob Bay. 相似文献
20.
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