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．     

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。     

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。     

香港水域夏季微型浮游动物摄食研究

20 0 0年 8月在香港牛尾海 ( A站 )和龙鼓水道 ( B站 )的 2个典型站位采样 ,用半现场的稀释法研究了夏季香港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。结果表明 :A、B站浮游植物主要以硅藻为主 ,但 A站甲藻比重比 B站要高。A站 <5 μm的微型浮游植物比 B站要少 ,从细胞大小上 B站的浮游植物更易被微型浮游动物所摄食。A站微型浮游动物类群主要以异养鞭毛藻为主 ,而 B站为砂壳纤毛虫 ,其细胞丰度分别为 770和 62 0 ind./L。 A、B站浮游植物碳 /叶绿素 a浓度比率分别为 2 7.1 5和88.66。 A站浮游植物的内禀生长率相似于 B站 ,分别为 1 .0 4和 0 .98d- 1。浮游植物在 A站的净生长率是0 .33d- 1,而在 B站则出现了负增长 ,其净生长率是 - 0 .5 8d- 1。微型浮游动物在 A、B站的摄食率分别为0 .71和 1 .5 6d- 1,摄食压力分别占到了浮游植物现存量的 1 43.7%和 2 0 9.7% ,初级生产力的 78.6%和1 2 6.6% ,对浮游植物碳的摄食率分别达到 35 1和 5 5 2 μg C/( L·d)。A站的浮游植物生长要高于 B站 ,B站的微型浮游动物摄食压力要明显高于 A站。与其它海区比较香港水域微型浮游动物摄食压力处于中等水平。黑暗长时间培养实验的结果表明此水域微型浮游动物摄食率稀释法实验应在适量添加营养盐并在     

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。     

东海赤潮高发区春季叶绿素a和初级生产力的分布特征

2002年4-5月对东海海域进行了综合调查,分析了海区叶绿素a和初级生产力的分布特性．结果表明,大面站表层平均叶绿素a浓度为1．086mg·m-3．分级叶绿素a结果显示．春季东海浮游植物以微型和微微型(<20μm)占优势,其对海区叶绿素a的贡献为64％,超微型浮游植物(<5μm)占浮游植物生物量的27％．营养盐分布和浮游动物的摄食压力影响了叶绿素a及其粒级结构的分布．平均初级生产力为10．091mg·m-3·h-1。赤潮跟踪的R-03、RL-01、RG-01站的平均初级生产力为399．984mg·m-3·h-1．光和营养盐成为叶绿素和初级生产力平面分布的主要限制因子．表层叶绿素a和初级生产力均在调查海区的123·E纵断面冲淡区产生高值区．DC-11站浮游植物生物量异常高,表层叶绿素a达到9．082mg·m-3,初级生产力为128．79mg·m-3·h-1．但并未出现水色异常．     

太湖湖岸带浮游植物初级生产力特征及影响因素

利用高频溶解氧监测,估算了太湖梅梁湾湖岸带浮游植物初级生产力的高频变化特征。结合同步气象监测及浮游植物、浮游动物和营养盐的周年逐周观测数据,分析了气象和环境条件对富营养化湖泊浮游植物初级生产力的影响。结果发现,高频溶解氧监测估算的初级生产力变化与浮游藻类生物量的变化一致,能够反映出浮游植物生产力的昼夜变化、季节变化等规律。统计分析表明,气温对太湖这一富营养化湖泊初级生产力影响很大;氮的供给与浮游动物的选择性牧食也是影响浮游植物初级生产力的重要因素。湖岸带的水华堆积过程对初级生产力影响巨大,气象、水文过程又加剧了蓝藻水华初级生产力的变化幅度,反映出富营养化湖泊初级生产力可能存在极大的时空不均一性。研究表明,溶解氧高频监测法估算初级生产力能够捕捉到湖泊初级生产力的快速变化过程,可以用于富营养化湖泊初级生产力监测、蓝藻水华灾害预警中。     

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.     

海洋微型浮游动物的丰度和生物量

综合了海洋微型浮游动物研究的历史沿革,微型浮游动物在海洋生态系统中的作用、丰度和生物量,微型浮游动物的研究方法以及我国研究海洋微型浮游动物的情况。     

Grazing impact of micro- and mesozooplankton during a spring situation in coastal waters off the Gironde estuary

The aim of this study was to characterize the grazing link betweenphytoplankton and zooplankton. Quantifying rates of phytoplanktonutilization by micro- and mesozooplankton is an attempt to understandthe control of phytoplankton populations in marine ecosystemsand the export flux of organic matter to the depths. Sampleswere taken in the plume of dilution of the Gironde estuary duringspring (May 1995). The mesozooplankton community was dominatedby the heterotrophic dinoflagellate Noctiluca scintillans andby copepods. Our estimates showed that on average, 26% of thetotal primary production was grazed daily by mesozooplankton.However, the pressure exerted by microzooplankton on the primaryproduction was estimated to be approximately four times higher.As a consequence, during this spring situation in the plumeof dilution of the Gironde estuary when small cells dominated,microzooplankton represented the most important grazing communityand could potentially control the growth of phytoplankton.     

Summer feeding activities of zooplankton in Prydz Bay, Antarctica

Grazing of dominant zooplankton copepods (Calanoides acutus, and Metridia gerlachei), salps (Salpa thompsoni) and microzooplankton was determined during the austral summer of 1998/1999 at the seasonal ice zone of the Prydz Bay region. The objective was to measure the ingestion rates of zooplankton at the seasonal ice zone, so as to evaluate the importance of different groups of zooplankton in their grazing impact on phytoplankton standing stock and primary production. Grazing by copepods was low, and accounted for <1% of phytoplankton standing stocks and 3.8-12.5% of primary production for both species during this study; even the ingestion rates of individuals were at a high level compared with previous reports. S. thompsoni exhibited a relatively high grazing impact on primary production (72%) in the north of our investigation area. The highest grazing impact on phytoplankton was exerted by microzooplankton during this investigation, and accounted for 10-65% of the standing stock of phytoplankton and 34-100% of potential daily primary production. We concluded that microzooplankton was the dominant phytoplankton consumer in this study area. Salps also played an important role in control of phytoplankton where swarming occurred. The grazing of copepods had a relatively small effect on phytoplankton biomass development.     

Abundance, species composition of microzooplankton from the coastal waters of Port Blair, South Andaman Island

ABSTRACT: BACKGROUND: Microzooplankton consisting of protists and metazoa <200 mum. It displays unique feeding mechanisms and behaviours that allow them to graze cells up to five times their own volume. They can grow at rates which equal or exceed prey growth and can serve as a viable food source for metazoans. Moreover, they are individually inconspicuous, their recognition as significant consumers of oceanic primary production. The microzooplankton can be the dominant consumers of phytoplankton production in both oligo- and eutrophic regions of the ocean and are capable of consuming >100% of primary production. RESULTS: The microzooplankton of the South Andaman Sea were investigated during September 2011 to January 2012. A total of 44 species belong to 19 genera were recorded in this study. Tintinnids made larger contribution to the total abundance (34%) followed in order by dinoflagellates (24%), ciliates (20%) and copepod nauplii (18%). Foraminifera were numerically less (4%). Tintinnids were represented by 20 species belong to 13 genera, Heterotrophic dinoflagellates were represented by 17 species belong to 3 genera and Ciliates comprised 5 species belong to 3 genera. Eutintinus tineus, Tintinnopsis cylindrical, T. incertum, Protoperidinium divergens, Lomaniella oviformes, Strombidium minimum were the most prevalent microzooplankton. Standing stock of tintinnids ranged from 30--80 cells.L-1 and showed a reverse distribution with the distribution of chlorophyll a relatively higher species diversity and equitability was found in polluted harbour areas. CONCLUSIONS: The change of environmental variability affects the species composition and abundance of microzooplankton varied spatially and temporarily. The observations clearly demonstrated that the harbor area differed considerably from other area in terms of species present and phytoplankton biomass. Further, the phytoplankton abundance is showed to be strongly influenced by tintinnid with respect to the relationship of prey--predator. Consequently, further investigation on microzooplankton grazing would shed light on food web dynamics.     

Changes in the microzooplankton assemblages in the northern Adriatic Sea during 1989 to 1992

Microzooplankton were sampled at five fixed stations in theopen waters of the northern Adriatic during four cruises in1989, nine in 1990, six in 1991 and 12 in 1992. Changes in thequalitative-quantitative composition, together with the spatial-temporaldistribution of the microzooplankton assemblages in the northernwaters of the open Adriatic, were the result of atypical oceanographicand productivity conditions in the entire region of this sea.Owing to low values of ciliated protozoa, which comprised only26% (1989) and 36% (1991) of the total number of microzooplankton,primary production cannot be controlled through grazing. Thismay possibly explain the occurrence of marine snow. The presenceof the larger mucous aggregates in the later phase causes asignificant decrease in the density of the naupliar copepodpopulation. Therefore, the usual dominance of copepods in summerdoes not occur and their development cycle is displaced to lateautumn. Consequently, only Olihona nana, a species of widerecological tolerance, comprised up to 73% of the total numberof postnaupliar copepods during the presence of mucous aggregatesin 1989. Thus, this small copepod plays an important role inthe processes of remineralization in the northern Adriatic.     

DECOMPOSITION IN PELAGIC MARINE ECOSYSTEMS

SUMMARY

During the decomposition of plant detritus, complex microbial successions develop which are dominated in the early stages by a number of distinct bacterial morphotypes. The microheterotrophic community rapidly becomes heterogenous and may include cyanobacteria, fungi, yeasts and bactivorous protozoans.

Microheterotrophs in the marine environment may have a biomass comparable to that of all other heterotrophs and their significance as a resource to higher trophic orders, and in the regeneration of nutrients, particularly nitrogen, that support ‘regenerated’ primary production, has aroused both attention and controversy.

Soluble low molecular weight substrates (dissolved organic matter, or DOM) are for the most part rapidly turned over and readily taken up with a high growth efficiency by bacteria although detrital particulate organic material (POM) is turned over slowly and utilized with a low growth efficiency, owing to the structural complexity of the detritus. The presence of appropriate substrate-specific strains of bacteria Is important in the decomposition of both DOM and POM.

Estimates of the transfer of photosynthetically fixed carbon and nitrogen through the pelagic microbial community have recently become widespread. However, the quantification of C and N fluxes through bacteria and microzooplankton is very sensitive to accurate measures of microbial biomass, production, net growth yield, bacterial activity and bactivory by microzooplankton. These processes also vary significantly in both spatial and temporal dimensions during the development and decay of phytoplankton blooms.

Recent attempts to model decomposition processes and C and N fluxes In pelagic marine ecosystems are described. This review examines the most sensitive components and predictions of the models with particular reference to estimates of bacterial production, net growth yield and predictions of N cycling determined by ¹⁵N methodology.     

Photosynthetic rates in the surface waters of the Red Sea: the radiocarbon versus the non-isotopic dilution method

Experiments carried out on board the research vessel FS ‘Meteor’in the open waters of the Red Sea in July–August 1987showed an apparent underestimation of primary production measuredwith the radiocarbon method. Short-term experiments with dilutedwater samples that estimated the growth rate of phytoplanktonand the grazing rate of herbivorous microzooplankton providedthe means to calculate the primary production. These valueswere compared with those measured simultaneously by means ofthe [¹⁴C]bicarbonate uptake method. The comparison yielded alarger difference between both methods. The radiocarbon valuesamounted to a maximal possible average of only ~12% of the calculatedones.     

景观生态学:海洋生态系统研究的一个新视角

全球海洋生态系统作为异质性的复杂巨系统是一类景观生态系统 ,具有明显的等级结构 ,因此 ,景观生态学的原理和方法完全可以应用到海洋生态学的研究中来。生态系统的尺度限制了海洋生态学向更加宏观的方向进一步发展 ,在景观的水平上 ,运用景观生态学的理论和方法可以更好地在多个尺度上开展深入广泛的研究。本文不仅讨论了海洋景观的空间异质性 ,而且就海洋景观生态学的若干研究方向进行了探讨。