北部湾北部海域夏季微型浮游动物对浮游植物的摄食压力

2011年8月份于北部湾北部海域5个观测站位获得的分层水样,分析了表层叶绿素a含量和表层微型浮游动物丰度以及类群组成;同时于现场采用稀释培养法研究了该海域浮游植物生长率(μ)和微型浮游动物的摄食率(g)。分析和测定结果表明:调查海区的微型浮游动物丰度400—1167个/L,类群组成以无壳纤毛虫为主;浮游植物的生长率为-1.50—1.13 d-1,微型浮游动物摄食率为0.33—1.08 d-1;推算微型浮游动物对浮游植物现存量以及初级生产力的摄食压力分别为28.1%—66.0%和-7.4%—438.4%。相对于中国其他海区,8月份北部湾北部海域微型浮游动物摄食速率处于中等水平。调查期间,广西沿海高生产力海区,浮游植物生长率大于微型浮游动物动物的摄食率,浮游植物生物量处于积累期;涠洲岛以南海域,浮游植物生产力较低,微型浮游动物摄食作用是控制浮游植物生长的重要因素。     

虾塘养殖中后期微型浮游动物的摄食压力

2008年8月底到10月初,用现场稀释法对虾塘中≤200 μm、≤100 μm和≤20 μm 3个粒级的微型浮游动物对浮游植物的摄食压力进行了研究。共进行了三次培养实验,结果表明：浮游植物的生长率为0.0834～0.4498 d-1,微型浮游动物的摄食率为0.1212～0.2998 d-1,微型浮游动物摄食率对浮游植物生长率比值(g:k)为0.4271～3.4901,占浮游植物现存量的11.41%～25.90%,对初级生产力的摄食压力为48.20%～314.69%。≤20 μm微型浮游动物的摄食率、对浮游植物现存量和初级生产力的摄食压力,占微型浮游动物(≤200 μm)的相关比例范围为73.85%～97.69%、76.67%～97.91%、78.87%～98.59%。这表明≤20 μm微型浮游动物比≥20 μm的微型浮游动物在对虾养殖中后期虾塘能量流动和物质循环方面起到更重要的作用。     

春季赤潮频发期东海微型浮游动物摄食研究

2002年4～5月在东海长江口及其邻近水域的8、11、14、23和28号5个典型站位采样。用现场稀释法对春季东海水域浮游植物的生长率和微型浮游动物对浮游植物的摄食压力等方面进行了研究．结果表明,微型浮游动物的摄食行为在东海赤潮过程起到关键作用．各站位微型浮游动物主要以急游虫、红色中缢虫和夜光藻为主,在种类上砂壳纤毛虫是主要的类群．微型浮游动物的摄食速率范围在0．28～1．13d-1,对浮游植物现存量的摄食压力范围在35．14％～811．69％。对浮游植物潜在初级生产力的摄食压力范围在74．04％～203．25％,对浮游植物碳的摄食率范围在9．58～97．91μg·L-1·d-1,靠近岸边的站位,微型浮游动物的摄食速率、对浮游植物现存量的摄食压力和对浮游植物碳的摄食率相对较高。而远离岸边的站位对浮游植物潜在初级生产力的摄食压力却较高．与世界其它海区比较此水域微型浮游动物摄食压力处于较高水平．急游虫是控制东海主要赤潮原因生物具齿原甲藻生长的关键种类．     

中华哲水蚤(Calanus sinicus)对浮游植物和微型浮游动物的摄食速率估算

2005年4月27日至5月30日在东海有害藻华高发区的6个典型站位采样,结合稀释法实验和Frost的直接计量法研究了中型浮游动物对浮游植物和微型浮游动物群落的现场摄食速率,并对中华哲水蚤(Calanus sinicus)的食物组成、中型浮游动物和微型浮游动物对浮游植物群落的摄食压力进行了估算。研究结果表明春季调查区:中华哲水蚤对浮游植物的物种比摄食率介于0.01~8.43d-1,平均值为(2.72±2.14)d-1。中华哲水蚤对浮游植物的物种摄食速率介于0.05~838.23cells ind.-1d-1,平均值为(52.72±154.21)cells ind.-1d-1,对几种有害藻华原因生物的摄食速率较高。中华哲水蚤对浮游植物物种摄食速率具有食物密度依赖性,在低浮游植物丰度下,其摄食速率会随着浮游植物丰度的增加而增加,达到一定阈值后随着浮游植物丰度增加而逐渐降低。中型浮游动物群落对浮游植物群落碳摄食速率介于0.53~4.97ngC L-1d-1,平均值为(2.16±1.63)ngC L-1d-1。微型浮游动物对浮游植物群落物种平均碳摄食速率介于0.04~13.20ngC ind.-1d-1,平均值为(2.91±5.22)ngCind.-1d-1。微型浮游动物群落对浮游植物群落碳摄食速率介于61.07~8632.85ngC L-1d-1,平均值为(2801.01±4198.46)ngC L-1d-1。分析比较中型浮游动物和微型浮游动物对浮游植物现存量摄食压力表明,海区中微型浮游动物的摄食压力要远高于中型浮游动物,介于95.59%~99.98%,平均值为97.88%±2.33%。调查海区中型浮游动物还通过对微型浮游动物的摄食影响浮游植物生长。     

东海春季水华期浮游植物生长与微型浮游动物摄食

2005年4～6月在东海有害水华频发区14个站位采样,通过现场稀释法实验对春季东海水域浮游植物比生长率和微型浮游动物比摄食率进行了研究.结果表明东海有害水华频发区浮游植物群落以甲藻为优势.浮游植物比生长率在水华爆发前相对较低,平均为1.18 d~(-1);进入水华期后比生长率明显升高,但在水华站位随现存量增加而降低;非水华区比生长率近岸高、远岸低.微型浮游动物主要以急游虫和桡足类幼体为主,而种类上以砂壳纤毛虫居多.微型浮游动物比摄食率在水华爆发前波动较大,介于0.53～1.73 d~(-1),平均为0.90 d~(-1);在水华区比摄食率较为稳定,浮游植物比生长率的降低导致群落净生长率持续下降;在非水华区,比摄食率整体较高,近岸低而远岸高.微型浮游动物的摄食对浮游植物群落的生长有一定的控制作用,但在水华爆发后这种控制作用将减弱.     

夏季胶州湾微型浮游动物摄食初步研究

2002年6月至7月间对胶州湾内、外和港口3个典型站位进行了微型浮游动物对浮游植物的摄食研究．按陆基半现场方式进行了4次稀释法实验,对湾外相同的站位进行了两次实验,对湾内和港口各进行了一次实验,获取了研究站位浮游植物和微型浮游动物种类、丰度、体积转换浮游植物碳含量、碳／叶绿素比率、浮游植物净生长率、微型浮游动物摄食率、对潜在初级生产力的摄食压力、对浮游植物现存量的摄食压力以及碳摄食通量等参数．湾外和湾内站位的浮游植物组成相似,优势种为新月柱鞘藻(Cylindrotheca closterium)和中肋骨条藻(Skeletonema costatum),港口浮游植物优势种类为中肋骨条藻、浮动湾角藻(Eucampia zodiacus)和旋链角毛藻(Chaetoceros curvisetus)．湾外微型浮游动物的优势种为百乐拟铃虫(Tintinnopsis beroidea),而在湾内为百乐拟铃虫和急游虫(Strombidium sp．),港口主要为急游虫,也有少数的百乐拟铃虫．微型浮游动物对浮游植物的摄食率和对潜在初级生产力的摄食压力,在湾内最高,其次在湾外,港口最低．微型浮游动物对浮游植物的摄食率,在湾外,分别为0．96和1．20d^-1,在湾内为1．33d^-1,在港口为0．36d^-1．微型浮游动物对潜在初级生产力的摄食压力,在湾外,分别为74％和84％,在湾内为93％,在港口为53％．微型浮游动物的碳摄食通量在港口最高达到281mgC·m^-3·d^-1,在湾内为102mgC·m^-3·d^-1,在湾外最低范围在31～49mgC·m^-3·d^-1．浮游植物的细胞大小和两种微型浮游动物的摄食习性的不同是造成研究站位微型浮游动物摄食率和摄食压力不同的主要原因．同世界其它内湾相比,胶州湾微型浮游动物的摄食压力处于中等水平。     

海洋微型浮游动物对浮游植物和初级生产力的摄食压力

综述了国际上研究微型浮游动物对浮游植物和初级生产力摄食的方法,并重点介绍了稀释法的理论和在实践中遇到的问题。各种方法的微型浮游动物对浮游植物和初级生产力摄食压力的估计表明,微型浮游动物在海洋生态系统中的扮演重要角色。     

三门湾浮游动物的季节变动及微型浮游动物摄食影响

2002年8月、11月、2003年2月和5月,在三门湾进行了4个航次生物、化学和水文等专业综合调查。根据采集的浮游动物样品的分析鉴定及海上现场实验结果,对浮游动物的群落组成、生物量、丰度、多样性指数的分布和季节变动及其浮游动物对浮游植物的摄食影响进行研究。结果表明,三门湾浮游动物有67属,89种,16类浮游幼体,主要可划分为4个生态类群：以近岸低盐类群为主,其优势种为中华哲水蚤Calanus sinicus、真刺唇角水蚤Labidocera etwhaeta、捷氏歪水蚤Tortanus derjugini、太平洋纺锤水蚤Acartiapacifica、中华假磷虾Pseudeuphausia sinica和百陶箭虫Sagitta bedoti等。半咸水河口类群、暖水性外海类群和广布种相对较少。浮游动物生物量和丰度的平面分布趋势除了夏季有所差异外,其它季节基本一致。2月份和5月份,浮游动物生物量和丰度,从湾顶向湾口呈逐渐增加趋势;8月份,湾口区生物量最高,而丰度高值区出现在湾顶部;11月份,生物量和丰度的平面分布相对均匀。浮游动物种类多样性指数有明显的季节变化,其动态变化与浮游动物种数和丰度的变化一致。微型浮游动物对浮游植物存在摄食压力,且有季节变化,摄食率的变化在0．18．0．68d^-1,微型浮游动物的摄食率低于相同季节的浮游植物生长率。微型浮游动物对浮游植物摄食压力的变化范围为16．1％-49．1％d^-1,对初级生产力摄食压力的变化在58．3％-83．6％d^-1。11月份,微型浮游动物对浮游植物和初级生产力的摄食压力均出现最高值。     

南沙群岛邻近海区春夏季浮游植物多样性研究

1999年春季和夏季对南沙海区网采浮游植物分布与多样性进行了调查。 1999年春季渚碧礁湖观测站及春、夏季大面站的浮游植物细胞数量平均值分别为 2 .4 9× 10 4cells/m3 、0 .73× 10 4cells/m3 和 1.0 3× 10 4cells/m3 。1999年春季在渚碧礁湖共采到浮游植物 2 6属 5 1种 ,大面站 31属 10 9种 ;夏季大面站共检出 38属 172种。海区大面站春季、夏季浮游植物Shannon Wiener多样性指数平均值分别为 4 .35和 4 .0 1;春季渚碧礁浮游植物多样性指数为 2 .92 ,低于外部开阔海域。南沙海区浮游植物的分布与水文、营养盐、浮游动物的摄食等均有一定的关系     

厦门港表层水体磷周转的生物学过程Ⅱ：桡足类对浮游植物的摄食压力

为了解桡足类在磷的生物地球化学循环中的作用,于2005年5、8、11月和2006年3月分别在厦门时间序列站（XMTS）采用肠道色素法,研究了桡足类对浮游植物的现场摄食率,同步分析了桡足类的种类组成和数量变化,进而得到桡足类群体对浮游植物的摄食率.结果表明：厦门港桡足类对浮游植物的年平均摄食率为55.53 μg·m^-3·d^-1;其中秋季最高,为108.98 μg·m^-3·d^-1,夏季最低,为7.18 μg·m^-3·d^-1.根据试验数据估算,厦门港桡足类对浮游植物现存量的摄食压力四季平均为1.81%,春、夏、秋、冬分别为3.22%、0.06%、3.52%和0.46%.     

Using XAD resins to study the effects of reduced organic micropollutant concentrations in River Rhine and Meuse water on phytoplankton growth

Laboratory incubation experiments were used to study the effect of reduced concentrations of organic micropollutants in water from the rivers Rhine and Meuse on the specific growth rate of the river phytoplankton community. Before incubation, part of the water sampled was treated with XAD-4 and XAD-8 resins to absorb dissolved organic compounds. Four dilutions were made by mixing untreated water with XAD-treated water in the ratios 100:0 (control), 70:30, 40:60 and 0:100. The phytoplankton specific growth rate increased significantly with the increased fraction treated with XAD in all but one incubation experiment. In these experiments, the specific growth rate was on average 9% higher in the fraction in which 100% was treated with XAD than in the controls. In the Rhine and Meuse river water, phytoplankton growth seemed to be inhibited by organic compounds. This inhibition was ascribed to the presence of dissolved organic micropollutants. Removing organic micropollutants using XAD resins to study the toxic effects of these compounds on field phytoplankton communities can be concluded to be a promising tool for risk assessment of micropollutants but needs to be supported by additional methodological research.     

Effect of temperature on rate of photosynthesis in Antarctic phytoplankton

Summary The rate of photosynthesis of marine antarctic phytoplankton (western Scotia Sea and Bransfield Strait) was determined as a function of temperature, from ambient (-0.8°C to 1.0°C) to 28°C. Photosynthetic rates, based on radiocarbon incorporation during half-day incubations, were increased by as much as 2x with temperatures up to 7°C; at higher temperatures the rates decreased rapidly, so that at 28°C the rates were only 3% of that at ambient temperatures. In antarctic surface waters during the austral summer the rate of photosynthesis by phytoplankton thus is limited by thermodynamic effects on metabolic reactions, in spite of high nutrient concentrations and saturating light levels. The observed rates were in agreement with thermodynamic models of the dependence of phytoplankton growth rate on temperature.     

长江口锋面附近咸淡水混合对浮游植物生长影响的现场培养

通过2009年6月调查航次,获得了营养盐等参数断面分布,表明咸淡水混合是控制营养盐分布的主要因素。为了解不同盐度梯度下浮游植物生长与营养盐吸收的关系,采集两个站位水样分别代表长江冲淡水(C1站)和外海水(I10站),按C1站水样比例,分100%、75%、50%、25%、0%不同比例混合进行现场模拟咸淡水混合培养,有以下认识:(1)平行结果表明培养过程中活体荧光极大值在100%混合组,且淡水比例越低,指数生长期0—48 h内生长速率越低,100%、75%、50%、25%组分别为1.18/d、1.12/d、1.14/d、0.77/d;(2)低于26盐度的水体中PO34-在48 h内可被迅速消耗而产生限制作用,是控制浮游植物生长的潜在限制因子;(3)除0%组外,各混合组DIN/P(DIN:溶解无机氮,Dissolved Inorganic Nitrogen,DIN=NO3-+NO-2+NH4+)比值在浮游植物指数生长期有升高趋势,100%组DIN/P比值增加了一倍。各组培养48 h后DIN/Si比值逐渐降低至原来的0.7左右,初始DIN/Si小于一定时间内硅藻吸收的(ΔDIN/ΔSi)比,是造成各组DIN/Si比值减小的原因。以上结果表明咸淡水混合过程中形成的营养盐梯度可造成浮游植物生长程度和速率差异,且可因局部浮游植物旺发而改变海水营养结构。     

Nutrient removal from sewage by an artificial food web system composed of phytoplankton and Daphnia magna

In order to remove nutrients from sewage, ecotechnology with an artificial food web composed of phytoplankton and Daphnia magna was used. To optimise performance of the system, phytoplankton growth, zooplankton growth, and a continuous-flow system were used. For phytoplankton growth, stirring was 6.7 times faster than the settling in growth rate of Scenedesmus. Zooplankton growth was not influenced by phytoplankton succession, and the specific production coefficient of D. magna was 110.4 mg Daphnia dry weight (DW) per mg chlorophyll a (Chl a). Results indicated that removal of nutrients was better in a long hydraulic residence time (HRT) system than in a system with short HRT. The optimum retention time was found to be 3 days for the phytoplankton chamber and 1.5 days for the subsequent D. magna chamber, respectively, with total retention time of the combined chambers being kept at 4.5 days. When a pilot plant was operated under these conditions, the removal rates of total nitrogen (TN) and total phosphorus (TP) were 68 and 56%, respectively. In the material budget of TN, 32% of inputs passed on to effluent, 39% to sludge, 27% to air and 2% to harvested Daphnia. For TP, 44% of inputs passed on to effluent, 51% to sludge and 4% to Daphnia.     

Seasonal dynamics of zooplankton and grazing impact of microzooplankton on phytoplankton in Sanmen Bay, China

The species composition, biomass, abundance and species diversity of zooplankton were determined for samples collected from 12 stations in Sanmen Bay, China, in four cruises from August 2002 to May 2003. Growth of phytoplankton and grazing rates of microzooplankton were measured using the dilution technique. The spatial and temporal variation of zooplankton and its relationship with environmental factors were also analyzed. The results showed that a total of 89 species of zooplankton belonging to 67 genera and 16 groups of pelagic larvae were found in Sanmen Bay. The coastal low-saline species was the dominant ecotype in the study area, and the dominant species were Calanus sinicus, Labidocera euchaeta, Tortanus derjugini, Acartia pacifica, Pseudeuphausia sinica and Sagitta bedoti. Maximum biomass was recorded in August, followed by November and May, and the lowest biomass was recorded in February. Similarly, the highest abundance of zooplankton was observed in August, followed by May, November, and February. Grazing pressure of microzooplankton on phytoplankton in Sanmen Bay existed throughout the year, although the grazing rate of microzooplankton on phytoplankton varied with the season. Estimates for growth rate of phytoplankton ranged from 0.25 d^?1 to 0.89 d^?1, whereas grazing rate of microzooplankton ranged between 0.18 d^?1 and 0.68 d^?1 in different seasons. The growth rate of phytoplankton exceeded the grazing rate of microzooplankton in all the seasons. Grazing pressure of microzooplankton on phytoplankton ranged from 16.1% d^?1 to 49.1% d^?1, and the grazing pressure of microzooplankton on primary production of phytoplankton ranged from 58.3% d^?1 to 83.6% d^?1 in different seasons.     

Nutrient pulsing as a regulator of phytoplankton abundance and community composition in Galveston Bay, Texas

Galveston Bay, Texas, is a large shallow estuary with a watershed that includes 60% of the major industrial facilities of Texas. However, the system exhibits low to moderate (2-20 μg l⁻¹) microalgal biomass with sporadic phytoplankton blooms. Both nitrogen (N) and phosphate (P) limitation of phytoplankton growth have been proposed for the estuary. However, shifts between N and P limitation of algae growth may occur due to annual fluctuations in nutrient concentrations. The primary goal of this work was to determine the primary limiting nutrient for phytoplankton in Galveston Bay. Nutrient addition bioassays were used to assess short-term (1-2 days) phytoplankton responses (both biomass and community composition) to potentially limiting nutrients. The experimental bioassays were conducted over an annual cycle using natural water collected from the center to lower part of the estuary. Total phytoplankton biomass increased in the nitrate (10 μM) additions in 11 of the 13 bioassays, but no significant increases were detected in the phosphate (3 μM)-only additions. Bioassay results suggest that the phytoplankton community was usually not phosphate limited. All major groups increased in biomass following nitrate additions but diatoms increased in biomass at a faster rate than other groups, shifting the community composition toward higher relative abundance of diatoms. The results of this study suggest that pulsed N input events preferentially favor increases in diatom biomass in this estuary. The broader implications of this study are that N pulsing events, primarily due to river discharge, play an important role in structuring the phytoplankton community in the Galveston Bay estuary.     

Erosion,phosphorus and phytoplankton response in rivers of South-Eastern Norway

The development of P fractions and phytoplankton was studied in three rivers with varying concentrations of seston.Less than 1% of the yearly TP transport may take place during periods with high algal biomass.The observation of a high growth rate of phytoplankton in the rivers coinciding with high concentrations of RP, low content of seston and high TP:Chl a ratio, indicate that the growth was often not P-limiting. During short periods with high phytoplankton biomass the ratio TP:Chl a may be low, indicating that a high fraction of TP was available.The content of P in soil samples and in samples with high seston content was about 0.1% of dry weight, and the algal availability of P often varied between 25 and 75% of TP for both types of samples.Decreasing biomass or low growth rates were observed at secchi depths less than 0.5 m and seston concentrations less than about 25 mg dry weight 1^–1. High flow rate also depressed the development of the total phytoplankton biomass. The assimilation of available P is incomplete under such conditions, i.e. under conditions of light limitation and high dilution rate.The availability of P for phytoplankton in rivers with different length, light conditions and stream velocity is discussed.