大亚湾大鹏澳水域春季浮游植物优势种的演替

根据2002年4月28日～5月27日大亚湾大鹏澳内每日采样的现场连续观测资料,使用主分量分析方法和多元回归方法,分析浮游植物优势种类之间的关系及影响其生长与演替的主要理化因子,建立春季浮游植物优势种类的演替模型。模型表明,中肋骨条藻和柔弱菱形藻之间为竞争关系;与浮游植物(以硅藻为主)生长密切相关的理化因子为温度(T)、溶解氧饱和度(DOsat)、铵氮(NH4-N)、亚硝酸氮(NO2-N)、磷酸盐(PO4-P)、硅酸盐(SiO3-Si)。影响中肋骨条藻的理化因子还有盐度(S)和氮磷比值(NO3／PO4)。并根据优势种类发生演替期间的环境变化(降雨),分析了浮游植物优势种由中肋骨条藻演替为柔弱菱形藻的过程。     

The diatom Mediopyxis helysia Kühn, Hargreaves & Halliger 2006 at Helgoland Roads: a success story?

The Helgoland Roads phytoplankton long-term data set is one of the longest and the most detailed data sets in Europe, having provided continuous work-daily observations of phytoplankton abundance since 1962. These high frequency counts have undergone and are continuously subject to a high level of quality control. The Helgoland data set thus is useful in the evaluation of new records in phyto- and zooplankton. Here, we report the first appearance of the relatively recently described diatom Mediopyxis helysia in the Helgoland Roads counts. This species was first detected in Helgoland samples in March 2009. Importantly, it has rapidly become a prominent member of the Helgoland phytoplankton community. While in 2009 it only produced a moderate spring peak of 4,000 cells?l^?1, it was one of the dominant diatoms in the 2010 spring bloom with Mediopyxis reaching cell densities above 300,000 cells?l^?1 and total chlorophyll concentrations exceeding 40?μg?l^?1. In 2010, this species was repeatedly present throughout the year. There was no clear relationship between temperature and cell abundance with all Mediopyxis cells occurring at temperatures between 3 and 12°C. However, the extensive peak in 2010 was associated with a sudden drop in salinity, which could indicate that this bloom might have been the result of inflow of low salinity water into the area. This was supported by a laboratory growth experiment in which a clonal culture of M. helysia grew fastest at a salinity of 27 and slowest at a salinity of 31.5. Further long-term observations will be required to establish whether this species will become a regular feature at Helgoland and how this might affect the local food web.     

Short-term photosynthetic responses in the diatom Nitzschia americana to a simulated salinity environment

The effect of short-term variations in saiinity on photosynthesisand respiration in an estuarine clone of the diatom Nitzschiaamericana was examined using a laboratory environmental simulationsystem. A computer-controlled culturing system simulated surfacelongitudinal salinity gradients in the Cape Fear River Estuary,NC by regulating the growth conditions of a continuous culturein real-time. Salinity changes were programmed based on a one-dimensionalhorizontal advection model of the Cape Fear River Estuary. Thesystem proved useful in evaluating phytoplanklon photosyntheticresponses to changes in its local environment on time scalessimilar to those operating in natural systems. As more sophisticatedmodels of the physical environment and particle transport areincorporated into the simulation program, realistic physiologicalmodels of phytoplankton production can be developed. Averagerates of net carbon fixation measured during the environmentalsimulation were compared to rates predicted by long-term adaptationstudies. These results indicate that rates of net carbon fixationdecline sharply following a rapid (hours) increase in salinity.Rates of net carbon fixation return, however, approximatelyto maximum predicted rates if the salinity environment is constantfor approximately 24 h, suggesting an adaptation period. Presumablythis time is necessary for N. americana to initiate physiologicalmechanisms responsible for osmoregulation and various compensatoryresponses to changes in salinity. These results further indicatethat significant errors may result when production models basedon long-term adaptive responses are used to describe phytoplanktonproductivity in variable environments.     

Interpretation of in vivo fluorescence and cell division rates of natural phytoplankton using a cell cycle model

A natural population of phytoplankton was collected from theMenai Straits and incubated in a continuous culture system undernatural illumination. In vivo fluorescence data were used toderive cell cycle parameters, and the division rates of cellsin the population were analysed using a transition-point modelof the cell cycle. The results indicated that for modellingpurposes the mixed population could be regarded as being composedof a single species having properties equivalent to the averagefor the population. Fluorescence measurements were subsequcntlyrepeated on samples of the in situ population at the collectionsite, and the cell cycle model used to interpret the growthrate of the phytoplankton in the natural environment.     

The relationship between phytoplankton distribution and water column characteristics in North West European shelf sea waters

Phytoplankton underpin the marine food web in shelf seas, with some species having properties that are harmful to human health and coastal aquaculture. Pressures such as climate change and anthropogenic nutrient input are hypothesized to influence phytoplankton community composition and distribution. Yet the primary environmental drivers in shelf seas are poorly understood. To begin to address this in North Western European waters, the phytoplankton community composition was assessed in light of measured physical and chemical drivers during the "Ellett Line" cruise of autumn 2001 across the Scottish Continental shelf and into adjacent open Atlantic waters. Spatial variability existed in both phytoplankton and environmental conditions, with clear differences not only between on and off shelf stations but also between different on shelf locations. Temperature/salinity plots demonstrated different water masses existed in the region. In turn, principal component analysis (PCA), of the measured environmental conditions (temperature, salinity, water density and inorganic nutrient concentrations) clearly discriminated between shelf and oceanic stations on the basis of DIN:DSi ratio that was correlated with both salinity and temperature. Discrimination between shelf stations was also related to this ratio, but also the concentration of DIN and DSi. The phytoplankton community was diatom dominated, with multidimensional scaling (MDS) demonstrating spatial variability in its composition. Redundancy analysis (RDA) was used to investigate the link between environment and the phytoplankton community. This demonstrated a significant relationship between community composition and water mass as indexed by salinity (whole community), and both salinity and DIN:DSi (diatoms alone). Diatoms of the Pseudo-nitzschia seriata group occurred at densities potentially harmful to shellfish aquaculture, with the potential for toxicity being elevated by the likelihood of DSi limitation of growth at most stations and depths.     

Estimating Trans-Seasonal Variability in Water Column Biomass for a Highly Migratory,Deep Diving Predator

The deployment of animal-borne electronic tags is revolutionizing our understanding of how pelagic species respond to their environment by providing in situ oceanographic information such as temperature, salinity, and light measurements. These tags, deployed on pelagic animals, provide data that can be used to study the ecological context of their foraging behaviour and surrounding environment. Satellite-derived measures of ocean colour reveal temporal and spatial variability of surface chlorophyll-a (a useful proxy for phytoplankton distribution). However, this information can be patchy in space and time resulting in poor correspondence with marine animal behaviour. Alternatively, light data collected by animal-borne tag sensors can be used to estimate chlorophyll-a distribution. Here, we use light level and depth data to generate a phytoplankton index that matches daily seal movements. Time-depth-light recorders (TDLRs) were deployed on 89 southern elephant seals (Mirounga leonina) over a period of 6 years (1999–2005). TDLR data were used to calculate integrated light attenuation of the top 250 m of the water column (LA₂₅₀), which provided an index of phytoplankton density at the daily scale that was concurrent with the movement and behaviour of seals throughout their entire foraging trip. These index values were consistent with typical seasonal chl-a patterns as measured from 8-daySea-viewing Wide Field-of-view Sensor (SeaWiFs) images. The availability of data recorded by the TDLRs was far greater than concurrent remotely sensed chl-a at higher latitudes and during winter months. Improving the spatial and temporal availability of phytoplankton information concurrent with animal behaviour has ecological implications for understanding the movement of deep diving predators in relation to lower trophic levels in the Southern Ocean. Light attenuation profiles recorded by animal-borne electronic tags can be used more broadly and routinely to estimate lower trophic distribution at sea in relation to deep diving predator foraging behaviour.     

Aspects of the ecology of Prymnesium parvum (Haptophyta) and water chemistry in the Norfolk Broads, England

SUMMARY. Prymnesium parvum , an ichthyotoxic phytoplankter, has been recorded, at times abundantly, in the River Thurne, Norfolk, and its associated Broads. Its occurrence has been apparently more frequent and its population sizes probably larger since the late 1960s than previously and fish mortalities due to it now occur almost annually.
The Thurne system is brackish and may have become more so, due to exploitation by drainage pumps, of a saline water table, in recent years. Evidence for this is conflicting, but in any case an increase in salinity is unlikely to have made increased Prymnesium growth more likely. Eutrophication of some Broads in the system is most likely to have increased the populations of Prymnesium since the late 1960s and data are presented on the present water chemistry of the system for comparison with previous records, and on current phytoplankton and Prymnesium crops in different parts of it.
P. parvum has been isolated from the system as a unialgal culture and compared in morphology, salinity tolerance and ichthyotoxicity with a strain of P. parvum from Israel. The Broads strain differs slightly in size and pigmentation, but not in salinity tolerance. In culture it produces more ichthyotoxin than the Israeli strain.     

Shifts in the dominance between diatoms and cryptophytes during three late summers in the Bransfield Strait (Antarctic Peninsula)

Recent global warming reduces surface water salinity around the Antarctic Peninsula as a result of the glacial meltwater runoff, which increases the occurrence and abundance of certain phytoplankton groups, such as cryptophytes. The dominance of this particular group over diatoms affects grazers, such as Antarctic krill, which preferentially feed on diatoms. Using three late summer data sets from the Bransfield Strait (2008–2010), we observed variations in the dominant phytoplankton groups determined by HPLC/CHEMTAX pigment analysis and confirmed by microscopy. Results indicate that the dominance of diatoms, particularly in 2008 and 2009, was associated with a deeper upper mixed layer (UML), higher salinity and warmer sea surface temperature. In contrast, cryptophytes, which were dominant in 2010, were associated with a shallower UML, lower salinity and colder sea surface temperatures. The low diatom biomass observed in the summer of 2010 was associated with high nutrient concentration, particularly silicate, and low chlorophyll a (summer monthly average calculated from satellite images). The interannual variability here observed suggests a delayed seasonal succession cycle of phytoplankton in the summer of 2010 associated with a cold summer and a late ice retreat process in the region. This successional delay resulted in a notable decrease of primary producers’ biomass, which is likely to have impacted regional food web interactions. This study demonstrates the susceptibility of the Antarctic phytoplankton community structure to air temperature, which directly influences the timing of ice melting and consequently the magnitude of primary production and succession pattern of phytoplankton groups.     

North Atlantic Oscillation primary productivity and toxic phytoplankton in the Gullmar Fjord,Sweden (1985—1996)

The evaluation of the time-series data set of primary production, chlorophyll a (1985-1996) and toxic phytoplankton species abundance measurements (1986–1996) in the Gullmar Fjord as part of the Swedish Monitoring Program, revealed the importance of considering climatic and environmental forces among the factors that may be responsible for the observed fluctuations. The results suggested that the occurrence of toxic phytoplankton blooms in the Skagerrak may be related to changes in the phase of the North Atlantic Oscillation (NAO). The Dinophysis species were related to the NAO, temperature and salinity and the fluctuations in the phytoplankton biomass expressed as chlorophyll a were also shown to be related to the NAO. The results pointed to the need to understand further the role played by climatic and environmental forces in relation to the formation and duration of harmful algal blooms and the need for continuous quality monitoring programmes and novel statistical methods for detecting trends and cycles in ecological time-series related to environmental forces.     

Composition and variation of phytoplankton communities during Microcystis bloom in an artificial lagoon of Hangzhou Bay,China

The interaction of various environmental triggers on phytoplankton communities of an artificial lagoon of Hangzhou Bay China, was studied during a Microcystis bloom in summer 2016. Forty-two phytoplankton genera (six phyla) were defined, with Bacillariophyta accounting for half of all phytoplankton genera. It was determined that Melosira, Chlorella, Cyclotella, Microcystis, Merismopedia, Anabaena and Selenastrum, which were identified and counted by an inverted microscope, were the dominant genera. In addition, a series of environmental indicators were analyzed, including salinity, seawater temperature, dissolved inorganic nitrogen, soluble reactive phosphorus (PO₄-P), ammonium (NH₄-N), nitrate nitrogen (NO₃-N), nitrite (NO₂-N), silicate (SiO₄-Si), and chemical oxygen demand of the water samples, as well as zooplankton community. The results of variance partitioning by R language revealed that the most influential factor driving the change in the phytoplankton community was the environment (49.7%), and zooplankton grazing represented only 7.9%. The results of redundancy analysis indicated that the change and composition of the phytoplankton community correlated significantly with the interaction of salinity, PO₄-P, transparency, seawater temperature, and the dominant zooplankton species. Notably, salinity and temperature fluctuation were the key factors inducing the rapid succession of the plankton community in artificial lagoons such as within the Jinshan City Beach (Shanghai, China).

     

不同类型虾池的理化因子及浮游植物群落的调查

于2001年10月和2002年4月两次调查分析了高位池、低位池两种类型的南美白对虾养殖池的理化因子及浮游植物群落的特征.结果表明:低位池的营养盐浓度普遍高于高位池,而高位虾池的盐度则高于低位.盐度是影响两类虾池浮游植物群落特征的主要因素.盐度较小(<5)的养殖池中,蓝藻占优势,主要为微囊藻、平裂藻、水花束丝藻、色球藻等;盐度介于10～30的池中,硅藻占优势,主要为舟形藻、桥弯藻等.     

长江口夏季浮游植物群落与环境因子的典范对应分析

于2004年8月28日至9月6日在长江口水域进行了水文、化学和生物的综合嵌套式外业调查,应用CANOCO4.0软件对获得的浮游植物物种数据和环境因子数据进行了典范对应分析(CCA),并作出了物种、样点分布与环境因子关系的二维排序图。结果表明,长江水入海所带来的泥沙及其形成的营养盐梯度差异是影响这一区域物种分布格局最重要的因素。根据环境因子与排序轴的相关系数,影响这一海区浮游植物分布的主要环境因子依次为透明度、硝酸盐和硅酸盐。主要浮游植物优势种中肋骨条藻(Skeletonema costatum)和细长翼鼻状藻(Proboscia alata f. gracillima)的分布和硝酸盐以及盐度、浊度密切相关,中肋骨条藻适合在低盐度高浊度高硝酸盐浓度的河口水域生存,而细长翼鼻状藻则分布于高盐度高透明度低硝酸盐浓度的开阔海。排序揭示了浮游植物物种对于生态环境的需求以及它们在不同资源维上的生态分化现象。     

纺锤水蚤摄食生态学研究进展

纺锤水蚤(Acartia)是温带、亚热带近岸水域优势的小型桡足类,在区域生态系统的物质循环与能量流通中起着重要作用。综述了国内外对纺锤水蚤食性、摄食机制、摄食影响因子及摄食转化效率的研究工作:纺锤水蚤为杂食性,偏爱高营养的动物性饵料,摄食浮游植物和微型浮游动物时分别采取滤食策略和伏击策略,摄食过程受到自身生理状态和环境因子的共同调节。其对食物的利用效率约为60%,其他40%通过Sloppy feeding和排泄等方式以溶解形式释放到海水中。目前摄食研究多以实验模拟为主,自然现场研究手段有限,分子生物学技术有望促进认识其在自然生态系统中的地位与作用。     

Etudes expérimentalles sur la sensibilité du phytoplancton d'eau douce aux variations de salinité dans le fjord du Saguenay (Estuaire du St-Laurent), Canada Experimental Studies on the Susceptibility of Freshwater Phytoplankton to Variation of Salinity in the Fjord of Saguenay (St. Lawrence Estuary), Canada

The Saguenay Fjord is characterized by very high run-offs. The annual flow varies between 1.2 and 4.2 × 10³ m³ . s⁻¹. During the summer the surface salinity shows a sharp horizontal gradient (from 1 0/00 to 20 0/00). The surface phytoplankton, mainly freshwater and even some euryhaline species is submitted to salinity stress. Continuous culture experiments were conducted to study the susceptibility of this freshwater phytoplankton under different salinity conditions. Some pennate diatoms (dominant group) are found as relatively tolerant to salinity. Microflagellates have been found to be resistant to salinity up to 26 0/00. Chlorophyll concentrations and rates of primary production of those organisms are as high as those of the control.     

Assessment distribution of the phytoplankton community structure at the fishing ground,Banyuasin estuary,Indonesia

The research objective was to describe the distribution of phytoplankton community structure and corelated to the physic-chemical parameters at fishing ground, Banyuasin estuarine waters. The methodology of research was phytoplankton sampling; physicochemical waters parameters data collected such as; dissolved oxygen, pH, temperature, brightness, salinity, current speed, nitrate, and phosphate. Identifications and calculations phytoplankton are based on photography under a light microscope. Data were analyzed by calculated abundance, diversity (H′ index) and dominance (C index), and Principal Component Analysis (PCA). There were 24 species of phytoplankton on the all-observation station grouped in three classes, Bacillariophyceae 91.3%, Dinophyceae 9%, and Cyanophyceae 0.1%. The abundance of phytoplankton species obtained in the range of 666.48 to 184,592.68 cells L^?1, were mostly found in high Chaetoceros affinis and Bacteriastrum furcatum. The distribution of phytoplankton abundance in these waters was found to be more influenced by seawater mass than freshwater. Phytoplankton diversity is considered a moderate category (1.37 < H′ < 2.57), and there were no species of phytoplankton that dominates (C < 0.5). Principal component analyzes showed that waters can be classified based on their physical-chemical characteristics, which were temperature, salinity, pH, transparency, current speed in the south coast around river estuaries, while DO and nutrients on the north coast of the waters. Based on the distribution of phytoplankton abundance is illustrated that the northern part is more potential for fishing area than the southern part with an abundance of phytoplankton >90,000 cells L^?1 and more stable water dynamics.     

内陆水体盐度升高对小球藻生理特性的影响

全球气候变化引起内陆水体盐度缓慢升高，对浮游植物造成显著影响。为了探究水体盐度升高对浮游植物生理特性的影响，以普通小球藻为试验对象，在原水和不同盐度（1、3、5 g·L^-1）条件下研究普通小球藻生长增殖情况，分析其抗氧化酶活性及对光合作用的生理响应。结果显示，盐度升高会抑制普通小球藻生长，当达到3 g·L^-1以上时抑制作用明显，细胞分裂增殖指标均明显下降，叶绿素a合成速率衰减，藻细胞膜损坏严重，同时其光合活性显著降低。这表明过高盐度（>3 g·L^-1）极有可能破坏藻细胞的生理结构和抗氧化能力，导致其生长增殖受到抑制。研究结果从细胞增殖和生理特性角度分析了水体盐度变化对水体浮游藻类的影响，以期为保护内陆水体生物多样性提供参考。     

Facteurs hydrologiques et phytoplancton en Baie de Morlaix (Manche Occidentale)

Phytoplankton in Roscoff waters (Western English Channel) was studied in spring and summer of 1979 and 1980, parallel to seasonal changes in physical, chemical and biological variables. Strong tides prevent the formation of a seasonal thermocline and the water column remains well mixed throughout the year. Seasonal changes in temperature and salinity show a continuous increase from April to August-September. Dissolved oxygen, dissolved mineral and organic nitrogen and phosphorus vary in relation to phytoplankton production. Silicate shows a seasonal cycle, but is not completely depleted in the sea-water. A decrease of ammonia during the phytoplankton blooms in 1980 suggests that ammonia plays an important role as a nitrogen source. The NO₃/PO₄ ratio indicates that the sea-water is heavily loaded with nitrate, and shows peak values during phytoplankton blooms, due to a fall in the concentration of phosphate, which may become a limiting nutrient. However, this effect may be offset by a rapid recycling of this nutrient. Chlorophyll a and potential primary production show significant variations. The major blooms are observed in June during both years. The mean production/chl. a ratio is around 6 in both years. Phytoplankton development is marked by the succession of three major groups during the spring-summer blooms: Thalassiosira spp, Rhizosolenia spp and Chaetoceros spp. The regularity in phytoplankton species succession over a number of years suggests that the species concerned are autochtonous and well adapted to their environment.     

锦州湾浮游植物群落结构特征及其对环境变化的响应

锦州湾是我国北方污染严重的海湾,以水体的富营养化和重金属污染为特征。基于2011年8月(夏季)和2012年5月(春季)在锦州湾进行的航次调查,研究了该湾水采浮游植物的群落结构、时空分布及其对生态环境变化的响应。研究结果表明:锦州湾海域浮游植物群落主要由硅、甲藻组成,其生态类型主要为温带近岸型。春季和夏季共鉴定出浮游植物4门41属62种,硅藻在两个季节的物种数和细胞丰度上均占绝对优势,且底栖硅藻比例较高。夏季浮游植物细胞丰度平均值为41.44×103个/L,主要优势种为海链藻Thalassiosira spp.和叉角藻Cerarium furca;春季浮游植物细胞丰度平均值为13.80×103个/L,主要优势种为新月柱鞘藻Cylindrotheca closterium和中肋骨条藻Skeletonema costatum。锦州湾春季和夏季浮游植物群落组成差异明显,冗余分析(Redundancy analysis,RDA)表明硝酸盐浓度和水温分别是夏季和春季影响浮游植物群落结构的最重要环境因子。与历史资料相比,锦州湾优势种发生了显著变化,适于富营养化环境的微型浮游植物和部分耐污种在群落中占优势,表明人类活动引起的水体富营养化以及其它污染物,可能对浮游植物种类组成及分布产生了一定影响。     

中度嗜盐菌产木聚糖酶发酵条件的研究

中度嗜盐菌在盐碱环境下生长繁殖,其产生的木聚糖酶也同样具有在盐碱环境下发挥作用的特性。本文对一株中度嗜盐菌的产木聚糖酶活性进行了初步研究。研究包括氮源、液体种子接种量、培养温度、pH值、培养时间等因素对该菌株产木聚糖酶能力的影响。结果表明,最佳培养氮源为蛋白胨;最佳产生木聚糖酶的发酵条件是液体种子接种量为6%,温度为35℃,pH值7,培养时间为4 d。     

Seasonality in Southern Hemisphere freshwater phytoplankton assemblages

Seasonal climatic cycles induce corresponding fluctuations in phytoplankton abundance and productivity at all latitudes, the magnitude of these fluctuations tending to increase with distance from the Equator. In equatorial regions seasonality is dependent on prevailing wind and rainfall patterns while annual temperature fluctuations exert increasing control over seasonal events at higher latitudes. The small annual temperature range of equatorial aquatic systems increases their sensitivity to localized climatic events which can bring about diel changes that exceed normal month-to-month variations. Long-term hydrological cycles with a periodicity greater than one year can also cause dramatic changes in equatorial and tropical aquatic systems leading to greater unpredictability.The factors regulating seasonal patterns of phytoplankton abundance and species composition in equatorial and low-latitude temperate regions of the Southern Hemisphere are examined and compared with similar features in the Northern Hemisphere. Despite the striking diversity of phytoplankton populations and the wide variety of habitats they occupy, seasonal succession follows a common sequence controlled, successively, by physical, chemical and biotic factors. This permits a high degree of predictability in the environmental conditions promoting growth of different taxa.Examination of Southern Hemisphere data indicates that, at class level, phytoplankton successional sequences in Southern Hemisphere aquatic systems are in agreement with the successional paradigm formulated for northern tropical and temperate latitudes. Diatoms characterize early successional episodes and these are followed by chlorophytes, and finally blue-green algae. Extreme habitat modification (e.g. hypertrophy, salinity) tends to lead to dominance of the habitat by a single taxon, often represented by a single species. Predictions of within-taxon species succession in phytoplankton assemblages are far less precise.