塔玛亚历山大藻藻际细菌溶藻过程

海洋微藻在生长过程中向周围环境分泌多种胞外产物,形成细菌自由生长的藻际环境,藻际细菌对微藻的生长有一定的调控作用。在指数生长期的塔玛亚历山大藻培养液中加入φ为1%的2216E培养基,在加入2216E后16h内藻细胞全部裂解。用数码显微镜记录了藻细胞形态变化,分别用DAPI法和荧光模拟底物法测定了细菌数量、胞外酶活性变化,结果表明:在溶藻过程中细菌数量、胞外酶活性在第6小时到第10小时增加了50～100倍。塔玛亚历山大藻藻际细菌主要分布在藻细胞表面,其群落结构改变和数量剧增是溶藻的主要原因,细菌分泌的β-葡萄糖苷酶和几丁质酶可能在溶藻过程中起重要作用

基于分子技术的1株产毒藻藻际细菌多样性分析

采用构建16SrDNA克隆文库的方法,对实验室保存的1株产毒塔玛亚历山大藻在不同时期的藻际细菌群落多样性进行了分析.限制性片段长度多态性(restrictionfragment length polymorphism,RFLP)结果表明,塔玛亚历山大藻藻际微生物的16SrDNA克隆文库中的克隆子总共可分为34种基因型,选取各谱型的代表克隆子测定其16SrDNA片段核苷酸序列,将所获得的序列与GenBank数据库进行BLAST比对,结果表明所有基因型分属于2个细菌类群:变形细菌门(Proteobacteria)和拟杆菌门(Bacteroidetes).在延滞期的藻培养液中,α-Proteobacteria占36.4%,β-Proteobacteria占9.1%,γ-Proteobacteria占27.3%,拟杆菌门(Bacteroidetes)占27.3%;在指数后期的培养液中,α-Proteobacteria占53.3%,β-Proteobacteria占13.3%,γ-Proteobacteria占6.7%,拟杆菌门(Bacteroidetes)占26.7%;在稳定期的培养液中,α-Proteobacteria占47.8%,β-Proteobacteria占8.7%,γ-Proteobacteria占21.7%,δ-Proteobacteria占4.3%,拟杆菌门(Bacteroidetes)占17.4%;其中有不少克隆子与已知序列同源性低于94%,表明塔玛亚历山大藻藻际环境中附着有新的未开发的微生物资源,这些细菌可能在微藻的生消过程中起着重要的调控作用,所以本研究结果在赤潮微生物调控中具有重要的理论意义和应用价值

Size structure of standing stock and productivity and new production of phytoplankton in the Prydz Bay and the adjacent Indian sector of the Southern Ocean during the austral summer of 2001/2002

2002年1～2月,在南极普里兹湾及其北部海区对浮游植物生物量、优势种类组成、细胞丰度、初级生产力和新生产力的观测结果表明,叶绿素a浓度、初级生产力和新生产力的高值均出现在湾内及湾口陆架区,并且远高于陆坡和深海区.湾内和湾口陆架区表层叶绿素a浓度均高于1mg/m3,平均为(2 34±0 85)mg/m3,而陆坡区和深海区平均只有(0 19±0 14)和(0 15±0 05)mg/m3.湾内和陆架区平均初级生产力[(355 8±192 1)mg/(m2·d)]高于陆坡区[(82 0±20 8)mg/(m2·d)]和深海区[(100 5±83 4)mg/(m2·d)].在陆坡和深海区初级生产力的粒级结构以微微型浮游生物(<2μm)对初级生产力的贡献最大(分别为49 6%和46 2%),湾内和陆架区则以小型浮游生物(为20～280μm)的贡献为主(66 2%).在湾内和湾口陆架区同时具有较高的新生产力和再生生产力.The composition of dominant species, the cell abundance, size fractionated biomass and productivity, and the new prodution of phytoplankton are studied in the Prydz Bay and its adjacent sea area during the 18th CHINARE cruise. The results show that there is marked feature of spatial zonation in the sea areas investigated. In the Prydz Bay and its adjacent continental shelf, the standing stock, and produtivity and new production are much higher than those of continental slope and deep-sea area. The results of size-frationed producitvity show that the contribution of net plankton to the total productivity (49.6% and 46.2% respectively) is the largest in the continental slope and deep-sea area, and the productivity of picoplankton is the dominant composition of total productivity (66.2%) in the bay and continental shelf area.国家自然科学基金资助项目(49876032)

Preliminary study on distribution of micro-protozoa in the Pearl River Estuary and its controlling factors

分析了2004年2月珠江口小型原生动物(包括鞭毛虫、纤毛虫和异养甲藻)的分布特征,探讨了环境因子对其分布的影响。结果表明,鞭毛虫在珠江口的丰度为3.4x103~25.6x103个/Ml,异养甲藻的丰度为11~312个/Ml,纤毛虫的丰度为7~172个/Ml。高丰度的原生动物主要集中在广州附近盐度为2~5的河口上段,而低丰度在外海盐度超过30的下段区域,原生动物的3个类群的丰度均从上段往下段呈递减的趋势。原生动物的分布特征与浮游植物叶绿素A的分布特征相似,原生动物也与细菌呈显著的正相关,表明细菌和浮游植物影响着原生动物在珠江口内的分布。冬季温度对原生动物的分布不具有直接的影响作用,而营养盐可能是通过影响浮游植物及细菌的分布而间接对原生动物的分布产生影响。原生动物的丰度表明珠江口部分水域已处于富营养化和超营养化状态。Based on the data obtained from a cruise in Feb.2004,abundance,spatial distributions and controlling factors of nanoflagellates,heterotrophic dinoflagellates and ciliates in the surface layer in the Pearl River estuary were studied.Nanoflagellates abundance ranged from 3.4×103 to 25.6×103 cells/mL,while heterotrophic dinoflagellates ranged from 11 to 312 cells/mL and ciliates were from 7 to 172 cells/mL,respectively.High abundance of these protozoa was observed at upper stream of the estuary near the Guangzhou waters with low salinity(2 to 5 psu).Low abundance was observed at lower stream of the estuary with high salinity(>30 psu).The three groups of protozoa abundance decreased from upper estuary near Guangzhou to lower estuary.The distribution patterns of these protozoa abundance were similar to that of chlorophyll a,and they had a significant relationship with bacteria,indicating that phytoplankton and bacteria influence protozoa distribution patterns.Temperature and nutrients were not direct factors influencing protozoa distribution.High abundance of protozoa suggested that the Pearl River Estuary was eutrophic water.国家自然科学基金项目(40730846;90711006

Phytoplankton in northern South China Sea in the winter of 2004

根据2004年2月在南海北部海域陆架区的采样调查,对南海北部Uterm hl浮游植物的群落结构进行了研究.初步研究结果表明,本次调查共发现浮游植物5门106属198种(不包括20种未定种).调查期内,南海浮游植物以硅藻为主,甲藻次之,以颗石藻为主要组份的金藻和固氮蓝藻也占有相当的比例,绿藻仅在珠江口个别站位被检出.菱形海线藻(Thalassionema nitzschioides Grunow)、佛氏海线藻(Thalassionema frauen feldii(Grunow) Hallegraeff)、贺胥黎艾氏颗石藻(Emiliania huxleyi(Lohmann) Hay et Mohler)、柔弱伪菱形藻(Pseudo-Nitzschia delicatissma Heiden)、长海毛藻(Thalassiothrix longissima Cleve et Grunow)、海洋桥球石藻(Gephyrocapsa oceanica Kamptner)、具齿原甲藻(Prorocentrum dentatum Stein)、具槽帕拉藻[Paraliasulcata(Ehrenberg) Cleve]和旋沟藻(Gyrodiniumspirale Bergh)为群落的优势种.南海北部浮游植物以广温、广布型为主,其次是暖水性种,热带、亚热带和冷水性种都较少.调查区浮游植物的细胞丰度介于3.8~2 810.3个/cm3,平均值为206.4个/cm3;浮游植物垂直分布总体特点是密集区位于水体表层,由水体表层到底层,细胞丰度逐渐减少;表层浮游植物细胞丰度的平面分布高值区位于调查区珠江口南部和南部海域.浮游植物群落的多样性分析显示调查海域中部的多样性较高,近岸和外海区则较低.应用典范对应分析(CCA)发现盐度和光照的梯度分布是影响南海北部浮游植物物种分布格局最重要的因素,磷酸盐和温度的梯度分布也起一定的作用.根据CCA的分析结果,将海区浮游植物物种划分为5个组,分别为:Ⅰ.高温度、高盐度、高光照和低营养盐组;Ⅱ.高温度和高光照组;Ⅲ.高磷酸盐和硅酸盐组;Ⅳ.低光强高盐度荫生物种组;Ⅴ.高硝酸盐组.They were presented that the phytoplankton species composition and cell abundance data based on the investigation in northern South China Sea(17°~23° N,111°~117° E) which was carried out from 8 th February to 4th March 2004 with 149 samples taken from 30 grid stations.A total of 195 taxa(not include uncertain species) belonging to 110 genera of 5 phyla were identified by Uterm hl method,in which Bacillariophyta were predominant and coexisted with Dinophyta.Chrysophyta which was mainly composed of coccolithophores and diazotrophs Cyanophyta were also common found in survey area.Few Chlorophyta were checked out at two stations near Zhujiang(Pearl River) Estuary.The dominant species in turn were Thalassionema nitzschioides Grunow,Thalassionema frauenfeldii Hallegraeff,Emiliania huxleyi(Lohmann) Hay et Mohler,Pseudo-nitzschia delicatissma Heiden,Thalassiothrix longissima Cleve & Grunow,Gephyrocapsa oceanica Kamptner,Prorocentrum dentatum Stein,Paralia sulcata(Ehrenberg) Cleve and Gyrodinium spirale Bergh,etc.Most of phytoplankton taxa found in survey area was cosmopolitan species,warm-water species are also common,there were just few trophic-water,subtrophic-water or cold-water species.The cell abundance of phytoplankton ranged from 3.8~2 810.3 cells/cm3,the average was 206.4 cells/cm3.Phytoplankton cell abundance were concentrated in surface water and reduced rapidly from surface layer to the bottom.Two high phytoplankton cell abundance regions can be discriminated at southern waters of Zhujiang Estuary and southern part of the survey area, this two high phytoplankton cell abundance regions were mainly caused by higher nutrients concentrations and ecotone respectively.The Shannon-Wiener diversity indices and Pielou's evenness of phytoplankton community were high in centre of survey area.Canonical correspondence analysis(CCA) was applied to explore the relationship between phytoplankton species and environmental parameters,the results showed that salinity and photosynthetically active radiation(PAR) gradient were the most important factors,and phosphate concentration and temperature gradient were secondary important factors,which influencing the phytoplankton species distribution patterns.According to CCA the first two ordination axes between the phytoplankton species and environmental factors,5 phytoplankton species groups can be discriminated,they are: Group Ⅰ.prefer to high temperature high salinity high light low nutrient environment;Group Ⅱ.prefer to high temperature high light environment;Group Ⅲ.prefer to high phosphate high silicate environment;Group Ⅳ.prefer to low light high salinity environment;Group Ⅴ.prefer to high nitrate environment.国家自然科学基金重点项目(9021102190211020);; 国家自然科学基金项目(40676089