海洋浮游微食物网对氮、磷营养盐的再生研究综述

海洋浮游微食物网包括病毒、细菌、聚球藻蓝细菌、原绿球藻、微微型自养真核生物、微型浮游动物(混合营养和异养鞭毛虫、纤毛虫)等生物类群,其中病毒、细菌及微型浮游动物等异养生物类群是海洋中氮、磷营养盐再生的重要贡献者。海洋中细菌吸收还是释放营养盐取决于细菌与底物中元素的比例,在多数海区,异养细菌都是吸收营养盐。病毒主要通过溶解宿主来释放宿主细胞中的物质,释放的营养元素的存在形态大多为有机物。微型浮游动物对营养盐的再生主要通过排泄来完成,目前在实验室内测定微型浮游动物排泄率的研究比较少,进行研究的主要困难有两个:第一,微型浮游动物的室内培养较难;第二,测定微型浮游动物的代谢率技术难度较高。根据已有研究结果,鞭毛虫的单位体重排氮率为2.8~140μg N(mg DW)~(-1)h~(-1),最大排氮率为7.0×10-9~13.8×10-6μg NH4+N cell~(-1)h~(-1),再生效率为0~100%;最大排磷率为3.8×10-9~6.6×10-7μg P cell~(-1)h~(-1),再生效率为0~100%。鞭毛虫的营养盐排泄率和再生效率受鞭毛虫自身的生长阶段和生活策略、饵料中元素比例及温度的影响。纤毛虫的单位体重排氮率为0.25~178μg N(mg DW)~(-1)h~(-1),最大排氮率为1.59×10-7~1.2×10-4μg NH4+N cell~(-1)h~(-1);单位体重排磷率为13~363μg P(mg DW)~(-1)h~(-1),最大排磷率为0~1.3×10-5μg P cell~(-1)h~(-1)。影响纤毛虫排泄率和再生速率的主要因素为纤毛虫生长阶段和温度。自然海区测定微型浮游生物对营养盐的再生的方法主要为同位素稀释法,此外还可以根据其他资料推算微型浮游生物的营养盐再生速率及产生率以反映再生能力。多数野外实验结果证明微型浮游动物是营养盐主要的再生者。     

热带西太平洋浮游纤毛虫的垂直分布

于2014年12月至2015年1月在热带西太平洋沿台湾南部到雅浦海山一个断面和雅浦海山海区研究了浮游纤毛虫丰度和生物量的垂直分布。浮游纤毛虫丰度变化范围为0—635ind./L,生物量范围为0—1.53μg C/L,丰度和生物量高值分布于200m以浅,其中,砂壳纤毛虫丰度为0—45ind./L,占总纤毛虫丰度的比例在0—14.62%之间。浮游纤毛虫丰度垂直分布均呈现"双峰型"模式:在表层和叶绿素极大值层(DCM)出现高值。共鉴定出砂壳纤毛虫33属76种。雅浦海山海区优势种为纤弱细瓮虫、卢氏真铃虫、管状真铃虫、膨大波膜虫,西太平洋海区优势种为纤弱细瓮虫、海勒斯真铃虫、酒杯类管虫、尖锐号角虫。有些种类分布在100m以浅,有的种类分布在100m以深,说明砂壳纤毛虫在100m水深左右种类发生变化。     

北黄海冷水团对獐子岛微微型浮游生物分布的影响

Picoplankton distribution around the Zhangzi Island(northern Yellow Sea)was investigated by monthly observation from July 2009 to June 2010.Three picoplankton populations were discriminated by flow cytometry,namely Synechococcus,picoeukaryotes and heterotrophic prokaryotes.In summer(from July to September),the edge of the northern Yellow Sea Cold Water Mass(NYSCWM)resulting from water column stratification was observed.In the NYSCWM,picoplankton(including Synechococcus,picoeukaryotes and heterotrophic prokaryotes)distributed synchronically with extremely high abundance in the thermocline(20 m)in July and August(especially in August),whereas in the bottom zone of the NYSCWM(below 30 m),picoplankton abundance was quite low.Synechococcus,picoeukaryotes and heterotrophic prokaryotes showed similar response to the NYSCWM,indicating they had similar regulating mechanism under the influence of NYSCWM.Whereas in the non-NYSCWM,Synechococcus,picoeukaryotes and heterotrophic prokaryotes exhibited different distribution patterns,suggesting they had different controlling mechanisms.Statistical analysis indicated that temperature,nutrients(NO3–and PO43–)and ciliate were important factors in regulating picoplankton distribution.The results in this study suggested that the physical event NYSCWM,had strong influence on picoplankton distribution around the Zhangzi Island in the northern Yellow Sea.     

海洋微型浮游动物摄食聚球蓝细菌研究综述

聚球蓝细菌是Pico级浮游植物的重要组成部分,微型浮游动物对聚球蓝细菌的摄食是海洋微食物网研究的重要内容。实验室内测定微型浮游动物对聚球蓝细菌摄食速率的方法有饵料浓度差减法和体内饵料颗粒增多法2种,研究表明:鞭毛虫对聚球蓝细菌的摄食速率为0~2.9 syn grazer-1h-1,清滤速率0.4~10.9 nl grazer-1h-1;甲藻对聚球蓝细菌的摄食速率的范围为0.86~83.8 syn grazer-1h-1。实验室内研究纤毛虫对聚球蓝细菌摄食速率和清滤速率的资料不多。在自然海区,海水稀释培养、添加生物抑制剂培养和分粒级培养等方法被用来测定微型浮游动物对聚球蓝细菌摄食速率,海水稀释培养法表明微型浮游动物对聚球蓝细菌的摄食率大多低于0.9 d-1,最大为1.54 d-1;使用生物抑制剂方法获得的微型浮游动物对聚球蓝细菌的摄食率为0.04~1.06 d-1;海水分粒级培养法表明聚球蓝细菌的主要摄食者个体微小,绝大部分小于20μm。     

Picoplankton distribution in different water masses of the East China Sea in autumn and winter

Picoplankton distribution was investigated in different water masses of the East China Sea in November,2006 and February,2007.The autumn and winter cruises crossed three major water masses:the coastal water mass(CWM),the mixed water mass(MWM),which forms on the continental shelf,and the Kuroshio water mass(KWM).Picoplankton composition was resolved into four main groups by flow cytometry,namely Synechococcus,Prochlorococcus,picoeukaryotes,and heterotrophic bacteria.The average abundances of Synechococcus,picoeukaryotes,and heterotrophic bacteria were(0.63±10.88)×103,(1.61±1.16)×103,(3.39±1.27)×105 cells/mL in autumn and(6.45±8.60)×103,(3.23±2.63)×103,(3.76±1.37)×105 cells/mL in winter,respectively.Prochlorococcus was not found in the CWM and seldom observed in surface samples in either season.However,Prochlorococcus was observed in the MWM and KWM(approximately 10 3 cells/mL) in both autumn and winter.Synechococcus distribution varied considerably among water masses,with the highest levels in KWM and lowest levels in CWM.The depth-averaged integrated abundance of Synechococcus was approximately 5-fold higher in KWM than in CWM,which may be due primarily to water temperature.In the MWM,Synechococcus was resolved as two subgroups;the presence of both subgroups was more common in autumn.Picoeukaryote abundance varied less among water masses than Synechococcus,and heterotrophic bacteria depth-averaged integrated abundance exhibited the smallest seasonal variations with respect to water mass.Correlation analysis showed that relationships between picoplankton abundances and environmental factors(temperature,nutrients,and chlorophyll a) differed among the three water masses,suggesting that the three water masses have different effects on picoplankton distribution(particularly Synechococcus).     

黄海春季水华过程中微微型浮游生物的变化特点

于2007年3—4月在黄海中部海域采用流式细胞术研究了春季水华过程中聚球藻、微微型真核浮游生物和异养细菌的生物量变化。聚球藻和微微真核型浮游生物的生物量与叶绿素a浓度变化基本呈现相反的趋势,在水华前期较高,水华期迅速下降,直至水华后期又有所升高。异养细菌在整个水华过程中变化较小,生物量在水华期最高,与水柱叶绿素a浓度呈极显著正相关(r=0.319,p<0.01)。水华期这三类微微型浮游生物对浮游植物总碳生物量的贡献很低。纤毛虫和鞭毛虫捕食可能是导致聚球藻和微微型真核浮游生物在水华期生物量降低的主要原因。     

上层海洋浮游生物地理分布

确定海洋浮游生物的分布区域是海洋浮游生态学研究的首要任务之一,本文总结了上层海洋(0-200 m)浮游生物地理分布的研究历史、已有的认知及全球变化的影响.对浮游生物地理分布的研究可以分为19世纪末期至20世纪70年代、20世纪80年代至2000年,以及2000年以后三个时期.根据分布区资料的时间长短,浮游生物分布区分为...