广西北部湾茅尾海浮游真菌群落结构及其影响因子

浮游真菌在海洋食物网和生物地球化学循环中发挥着关键作用。【目的】为解析广西北部湾茅尾海不同季节浮游真菌群落结构及其关键环境影响因子，于2017年7月(夏季)、9月(秋季)、12月(冬季)和2018年3月(春季)期间在该海域设置7个站点，采集表层海水样品。【方法】利用内部转录间隔区(internal transcribed spacer, ITS)基因高通量测序技术，分析茅尾海浮游真菌群落结构与多样性。【结果】茅尾海海域浮游真菌隶属6个门、26个纲、71个目、167个科、282个属和374个种。主要浮游真菌类群为子囊菌门(Ascomycota, 82.14%)和担子菌门(Basidiomycota, 10.74%)，共占浮游真菌总丰度的92.88%。茅尾海浮游真菌群落Shannon指数和Simpson指数在春季最高，Chao1指数和丰富度(richness)指数在冬季最高。主坐标分析(principal coordinates analysis, PCoA)和相似性分析(analysis of similarities, ANOSIM)结果显示，不同季节浮游真菌群落的β多样性具有极显著差异(R=0.591 2, P<0.001)。通过随机森林模型分析(random forest modeling analysis, RF)，发现黄曲霉(Aspergillus flavus)、二色胶孔菌(Gloeoporus dichrous)、杂色曲霉(Aspergillus subversicolor)和微扁沃利雅炭皮菌(Whalleya microplaca)、翹鱗香菇(Lentinus squarrosulus)等20种海洋浮游真菌对环境变化敏感，可用于评估茅尾海富营养化状况。Spearman相关性分析表明，浮游真菌α多样性与海水pH、盐度和溶解氧(dissolved oxygen, DO)呈显著正相关关系(P<0.05)，与温度、叶绿素-a (chlorophyll a, Chl-a)以及总有机碳(total organic carbon, TOC)呈显著负相关关系(P<0.05)。方差分解分析(variance partitioning analysis, VPA)发现营养因子是浮游真菌群落结构的主要驱动因子。【结论】本研究可为揭示北部湾海洋浮游真菌多样性提供理论参考，并为茅尾海生态环境监测与资源利用提供科学依据。     

夏季达里诺尔湖浮游细菌群落表、底层结构特征及其关键驱动因子

浮游细菌是湖泊水体物质循环和能量流动过程中的关键要素, 影响着整个生态系统的迁移转化。为探索中国北方典型内陆封闭型湖泊浮游细菌群落结构对环境因子变动的响应, 以夏季内蒙古达里诺尔湖(以下简称“达里湖”)为例, 采集表、底层水共32个样品, 基于16S rRNA基因测序, 详细分析了浮游细菌群落结构的表、底层变化特征及其主要影响因素, 结果显示: (1)夏季达里湖水体中浮游细菌群落多样性和均匀度均呈现表层＞底层, 丰富度则呈底层＞表层。(2)浮游细菌群落以变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、蓝细菌门(Cyanobacteria)和拟杆菌门(Bacteroidetes)四大优势菌门为主要组成部分, 且变形菌门含量在表、底层水体中均占绝对优势: 在底层水中占比46.46 %, 在表层水中占比36.21 %。(3)基于不同环境因子和浮游细菌优势菌门间的Pearson相关性分析, 表层水体中总溶解性固体(TDS)、溶解态无机磷(DIP)是多数优势菌门的主要驱动因子, 而底层水体中的总氮(TN)、叶绿素a(Chl a)和水温(WT)为主要驱动因子。总的来说, 达里诺尔湖表、底层浮游细菌群落结构与不同环境因子间存在显著相关, 而水体环境因子的表、底层差异是影响多数优势菌门演化的重要因素。     

贫营养湖泊花神湖和紫霞湖浮游细菌群落结构分析

以南京市花神湖和紫霞湖两个贫营养型湖泊为研究对象,通过构建花神湖和紫霞湖16S rRNA基因克隆文库探讨了浮游细菌群落结构组成的变化。结果表明,花神湖和紫霞湖两湖泊水体中浮游细菌群落结构相似,主要隶属于放线菌门(Actinobacteria)、蓝藻门(Cyanobacteria)、α-变形菌门(Alphaproteobacteria)、β-变形菌门(Betaproteobacteria)、杆菌门(Bacteroidetes)、浮霉菌门(Planctomycetes)、疣微菌门(Verrucomicrobia)和芽单胞菌门(Gemmatimonadetes),其中放线菌门(Actinobacteria)、蓝藻门(Cyanobacteria)、β-变形菌门(Betaproteobacteria)是优势细菌类群。两个湖泊水体中75%的细菌与GenBank中已有的未培养细菌同源性高于97%,同时在两个克隆文库中还发现了6个淡水细菌新类群。通过对低纬度区域贫营养型湖泊浮游细菌群落结构的分析,加深了我们对浮游细菌多样性的了解,表明湖泊浮游细菌多样性有待进一步认识。     

福州左海湖冬春季浮游细菌群落16S rRNA多样性

【目的】为揭示福州左海湖冬春不同季节水体中浮游细菌群落的多样性。【方法】通过对2012年1月(冬季)和2012年4月(春季)的左海湖水体样品构建细菌16S rRNA基因克隆文库,对2个季节样品中细菌群落的多样性和均匀度等进行比较,并对其群落结构特征进行分析。【结果】冬季左海细菌群落的多样性指数Shannon-Wiener(H)达到3.53,均匀度指数(E)达到0.66;春季细菌群落的多样性指数Shannon-Wiener(H)为3.37,均匀度指数(E)为0.64,这2个季节样品的细菌群落均具有很高的多样性,但均匀度都偏低。2个季节水体中共检测到5个细菌门类:α-变形菌纲(α-proteobacteria)、β-变形菌纲(β-proteobacteria)、拟杆菌门(bacteroidetes)、放线菌门(actinobacteria)、蓝细菌门(cyanobacteria),此外还存在一些未被认知的序列。冬季的优势菌群为β-proteobacteria,次优势菌群为cyanobacteria;春季的最优势菌群为cyanobacteria。【结论】左海湖水体细菌在冬春2季节中的菌群结构存在差异,特别是最优势的细菌发生了很大变化,其中冬季细菌群落的多样性及均匀度相对较高。     

舟山群岛不同功能区划海域细菌群落结构分析

浮游细菌在海洋生态系统中不可或缺,在海洋生物地球化学循环过程中起着关键性作用。【目的】为了解舟山群岛不同功能区划海域细菌群落结构及丰度变化,探索海洋生态因子对细菌群落结构的影响。【方法】于2016年夏季(8月)在舟山群岛不同功能区划海域共设置8个典型站位采集表层海水,基于细菌16S rRNA基因进行高通量测序;利用流式细胞术揭示各海域细菌丰度;利用典范对应分析(Canonical correspondence analysis,CCA)探讨海洋生态因子与细菌多样性之间的关系。【结果】共获取到305487条原始序列,基于97%相似性水平进行OTU(Operational Taxonomic Units)聚类分析,共得到1088个OTUs,包括29个门、62个纲、138个目、239个科、416个属。细菌群落组成在各个站位之间不尽相同,但都主要包括Flavobacteria、Alphaproteobacteria、Gammaproteobacteria三大优势菌纲。CCA结果表明细菌群落结构和多样性情况与站位分布和所在站位的环境因子息息相关,Cyanobacteria受硝酸盐影响显著,Parcubacteria受温度影响最大,而磷酸盐对本实验海域菌群影响甚微。对海洋菌群潜在功能进行预测的结果显示,各海域菌群在氨基酸代谢、碳水化合物代谢、膜运输等方面功能较为突出,为今后舟山海洋微生物研究提供了新的方向。【结论】高通量测序分析可以更精确地揭示海洋菌群的群落结构信息。该研究为细菌群落结构与环境因素的关联提供参考。本研究所取得的大量数据既可以作为对舟山市海洋功能区划施行情况的响应,又将为舟山及其邻近海域浮游细菌群落结构的进一步研究奠定基础。     

洪潮江水库浮游细菌群落空间分布及其与环境因子的关系

【目的】为了解洪潮江水库浮游细菌群落组成、空间分布及其与环境因子的相互作用关系。【方法】基于16S rRNA基因高通量测序技术,对洪潮江水库浮游细菌群落结构与多样性进行了分析,同步对水体的理化指标进行检测。【结果】洪潮江水库共注释浮游细菌28门79纲168目243科325属85种。优势门为变形菌门、放线菌门、蓝细菌门、疣微菌门、拟杆菌门、浮霉菌门,分别占比21.95%、21.30%、17.98%、12.27%、11.72%、9.51%。基于Bray-Curtis距离的PCoA分析表明,洪潮江水库9个采样点可以被分为3组,细菌群落呈现沿上下游梯度变化的趋势。perMANOVA检验显示,各组差异显著,但是各组的多样性指数没有显著性差异。Mantel分析表明,透明度、浊度、总磷、亚硝酸盐氮、硝酸盐氮、叶绿素a、pH、溶解氧、氧化还原电位、比电导、总溶解固体以及营养状态会显著影响浮游细菌群落结构。【结论】洪潮江水库浮游细菌空间分布特征是自然环境理化因子和农业活动综合作用的结果。研究结果对了解浮游细菌群落空间格局及其对人类活动的响应,以及水库管理具有科学参考价值。     

东太湖地区湿地水质与浮游细菌群落结构关联性研究

[目的]考察东太湖地区湿地水质与浮游细菌群落结构之间的关联,探索对湿地水质具有指示作用的微生物。[方法]应用高通量测序研究浮游细菌群落结构;通过相关性分析考察了浮游细菌群落多样性与水质的关联,并运用LEf Se分析定位不同水质水样的标志微生物。[结果]东太湖湿地浮游细菌主要分布于放线菌门(相对丰度34.78%)、变形菌门(26.30%)及蓝细菌门(19.28%)等7个门;水质指标综合得分与浮游细菌群落香农-威纳指数和辛普森指数分别显著相关(r=-0.597,p0.05;r=0.694,p0.01);蓝细菌门与伯克氏菌科的相对丰度在不同水质水样中差异最为显著(LDA得分4.0)。[结论]东太湖地区,较高的浮游细菌多样性表征较好的湿地水质;蓝细菌相对丰度较高(27.80%)指示湿地水质较差,而伯克氏菌相对丰度较高(5.48%)指示湿地水质相对较好。     

鄱阳湖湖泊细菌群落组成及结构——以松门山为例

于2011年5月在鄱阳湖——松门山湖区采集底泥与表层水样,分别提取了表层水体浮游和底泥微生物基因组DNA,利用454高通量测序技术对细菌的16S rRNA基因进行了序列测定,分析了湖泊底泥细菌、水体浮游细菌群落结构特征。结果显示:底泥细菌OTUs(Operational Taxonomic Units)为1454,表层水体浮游细菌OTUs为269;底泥细菌群落比表层水体更加多样化,底泥细菌的物种数大大多于表层水体。同时,底泥细菌群落与表层浮游细菌群落结构存在显著差异。物种分类显示鄱阳湖底泥细菌种类隶属于20门,228属,其中优势种群为δ-变形菌纲(Deltaproteobacteria)、β-变形菌纲(Betaproteobacteria)和疣微菌门(Verrucomicrobia);表层水体浮游细菌隶属于13门116属,优势种群为β-变形菌纲、拟杆菌门(Bacteroidetes)和放线菌门(Actinobacteria)。结果进一步揭示,无论是浮游细菌群落还是沉积物细菌群落,优势细菌种群的基因型多样性更高。     

鄱阳湖流域锦江水体污染胁迫下浮游细菌群落结构及交互作用

【目的】为了探索河流水体污染胁迫对浮游细菌群落的影响。【方法】本研究使用主成分分析将水体污染胁迫分为高、中、低3级,基于高通量测序技术分析了鄱阳湖流域锦江干流浮游细菌群落的多样性、组成以及交互作用。【结果】锦江污染胁迫下的浮游细菌群落优势菌群包括假单胞菌门(Pseudomonadota,13.53%–45.83%)、放线菌门(Actinobacteriota,17.05%–40.50%)、拟杆菌门(Bacteroidota,5.79%–31.56%)、蓝藻菌门(Cyanobacteria,0.41%–59.31%)和芽孢杆菌门(Bacillota,0.11%–4.81%)。其中Bacillota在污染胁迫等级下显著差异(P=0.03)。浮游细菌群落组成在不同水体污染胁迫等级下存在显著差异(P=0.046)。群落丰富度Chao1与ACE指数在低污染胁迫地区显著高于中污染胁迫地区(P=0.024和0.037),Shannon多样性指数差异不显著。共生网络拓扑特征表明,随着水体污染胁迫减小,细菌共生网络的复杂性与稳定性增强,浮游细菌群落之间的交互作用增强。【结论】污染胁迫显著改变了水体细菌群落结构与交互作用。以上研究有助于从微生物角度为水体污染的检测、监测和控制提供生态学参考。     

东太湖地区湿地水质与浮游细菌群落结构关联性研究北大核心

[目的]考察东太湖地区湿地水质与浮游细菌群落结构之间的关联,探索对湿地水质具有指示作用的微生物。[方法]应用高通量测序研究浮游细菌群落结构;通过相关性分析考察了浮游细菌群落多样性与水质的关联,并运用LEf Se分析定位不同水质水样的标志微生物。[结果]东太湖湿地浮游细菌主要分布于放线菌门(相对丰度34.78%)、变形菌门(26.30%)及蓝细菌门(19.28%)等7个门;水质指标综合得分与浮游细菌群落香农-威纳指数和辛普森指数分别显著相关(r=-0.597,p<0.05;r=0.694,p<0.01);蓝细菌门与伯克氏菌科的相对丰度在不同水质水样中差异最为显著(LDA得分>4.0)。[结论]东太湖地区,较高的浮游细菌多样性表征较好的湿地水质;蓝细菌相对丰度较高(27.80%)指示湿地水质较差,而伯克氏菌相对丰度较高(5.48%)指示湿地水质相对较好。     

秋、冬季北部湾浮游介形类群落多元分析

根据对北部湾生态环境综合调查所采集的浮游动物样品,对北部湾秋、冬季浮游介形类组成及群落结构进行了多元分析.结果表明,测区内浮游介形类种类为11种,分属于低盐暖水类群、广温广盐类群和高温高盐类群3个生态类群;海区内的平均丰度较低,其中针刺真浮萤数量最多,为海区的绝对优势种,左右着整个北部湾浮游介形类的数量.聚类分析和MDS分析表明,北部湾浮游介形类为一个结构相对稳定的群落,秋、冬季可看成是一个群落的2个亚群;对各聚类组的丰度与水温、盐度相关分析表明,水温、盐度对浮游介形类群落结构变化所产生的作用较小,但存在一定的规律性;在冬季,底层温盐对群落Ⅱ产生显著影响.     

Planktonic larval stages of Brachyura in the Gulf of Tigullio (Ligurian Sea,Italy)

Summary

Horizontal planktonic catches made in the Gulf of Tigullio (Genoa, Ligurian Sea) have been analyzed with the aim of identifying the zoeae of Brachyura, whose knowledge is poor in all the northern Mediterranean Sea. Forty-four taxa (42 species plus Liocarcinus spp. and Brachynotus spp.) have been identified, 12 of which were present with all the larval stages. The seasonal distribution of the taxa has been analyzed, and it was possible to recognize species present throughout the year as well as spring/summer, summer/autumn, and winter/summer species. Problems regarding zoeae of dubious identification are discussed.     

Spatial and seasonal characteristics of dissolved heavy metals in the aquaculture areas of Beibu Gulf,South China

Abstract

To study the contamination of heavy metals in the aquaculture area of Beibu Gulf, the concentrations of seven metals in seawater were investigated. The results showed that significant seasonal and spatial distributions of heavy metals were observed in the four aquaculture areas. Generally, the heavy-metal concentrations in the Maowei Sea were higher than the other three aquaculture areas, which may be related to local industrialization and urbanization development. The concentrations of some metals were obviously higher in wet seasons than in dry seasons, which may be attributed to the seasonal river discharge, rainfall and seawater intrusion. Compared to other regions, some metal levels revealed relatively high contamination. Remarkably, the concentrations of Hg, Cu and Cd were much higher than concentrations found in the past 20?years in the seawater of the Guangxi Beibu Gulf, suggesting that there were increasing anthropogenic inputs of those metals in the aquaculture areas. The assessment of ecological risk index (ERI) indicated that the highest ERI value was found in the Maowei Sea, followed by Pearl Bay, Lianzhou Bay and Hongsha. Hg is the main ecological risk factor, and the heavy-metal contamination in the aquaculture areas must not be ignored.     

广西北部湾茅尾海红树林生境放线菌分离培养基的比较

【背景】红树林生境拥有丰富的微生物资源,分离获得更多的纯培养放线菌为新型抗生素的发现提供菌种资源。【目的】使用新型放线菌分离培养基,发掘广西北部湾茅尾海红树林生境放线菌资源,评估新型放线菌分离培养基分离效果。【方法】设计出新型放线菌分离培养基——椰子汁-海藻糖培养基,对广西北部湾茅尾海红树林根际土壤和红树林根皮放线菌进行分离。基于分子生物学鉴定方法,对获得的纯培养放线菌进行多样性分析。【结果】从红树林根际土壤样品中分离获得65株放线菌,分布在5个目10个科15个属,使用YIM171培养基分离到7个属,MA培养基分离到5个属,椰子汁-海藻糖培养基分离到11个属,其中包括4株潜在新种;从红树林根皮样品中分离获得19株放线菌,分布在4个目7个科10个属,使用YIM171和椰子汁-海藻糖培养基分别分离到7个属,包括4株潜在新种;使用椰子汁-海藻糖培养基在红树林生境两类样品中获得3株潜在新种。【结论】广西北部湾茅尾海红树林根际土壤和根皮中放线菌多样性丰富,使用椰子汁-海藻糖培养基分离放线菌效果较佳,可用作放线菌的分离培养基。     

Investigation of the sulfate-reducing bacterial community in the aerobic water and chemocline zone of the Black Sea by the fish technique

Fluorescent in situ hybridization (FISH) was used to analyze the abundance and phylogenetic composition of sulfate-reducing bacteria in the aerobic waters and in the oxic/anoxic transitional zone (chemocline) of the Black Sea, where biogenic formation of reduced sulfur compounds was detected by radioisotope techniques. Numerous sulfate-reducing bacteria of the genera Desulfotomaculum (30.5% of detected bacterial cells), Desulfovibrio (29.6%), and Desulfobacter (6.7%) were revealed in the aerobic zone at a depth of 30 m, while Desulfomicrobium-related bacteria (33.5%) were prevalent in the upper chemocline waters at 150-m depth. Active cells of sulfate-reducing bacteria were much more abundant in the samples collected in summer than in the winter samples from the deep-sea zone. The presence of physiologically active sulfate reducers in oxic and chemocline waters of the Black Sea correlates with the hydrochemical data on the presence of reduced sulfur compounds in the aerobic water column.     

Diet composition of the juvenile chub mackerel (Scomber japonicus) in the Aegean Sea (Izmir Bay, Turkey)

Stomach contents of 296 juvenile chub mackerel (Scomber japonicus Houttuyn, 1782) specimens were examined based on samplings carried out in Izmir Bay (Aegean Sea, Turkey) during 2001. In terms of percentage weight (W%), fishes were the main food during summer and autumn. Thaliaceans (Salpa sp.) constituted the most important food source in winter, whereas planktonic crustaceans (Amphipoda, Copepoda) were the main prey during spring. According to the Bray–Curtis similarity index, diet of the chub mackerel was 64.1% similar during the summer, winter and autumn seasons.     

Viral Abundance and a High Proportion of Lysogens Suggest That Viruses Are Important Members of the Microbial Community in the Gulf of Trieste

Epifluorescence microscopy and transmission electron microscopy were applied to study virioplankton community in the Gulf of Trieste (northern Adriatic Sea). The total viral abundance was in a range between 2.5 × 10⁹/L and 2.9 × 10¹⁰/L and was positively correlated with trophic status of the environment. Viruslike particles were significantly correlated with bacterial abundance in all samples studied. Correlations with other physicochemical or biological parameters were not significant. The data suggest that, because of the substantial fraction of tailed viruses present (26%), bacteriophages are an important component of the virioplankton community in the Gulf of Trieste. The abundance of viruslike particles in the seawater changed at hour intervals in a range from 1.3 × 10⁹/L to 5.1 × 10⁹/L. A significant fraction (71%) of the bacterial isolates was inducible in vitro by mitomycin C, and a high occurrence (51%) of lysogenic isolates with more than one phage morphotype present in the lysate was detected. The presence of lysogenic bacteria in the seawater was confirmed in situ with a mitomycin C induction experiment on the natural bacterial population. Results suggest that virioplankton is an abundant component of the microbial community in the Gulf of Trieste.     

Recurrent seasonal changes in bacterial growth efficiency,metabolism and community composition in coastal waters

The microbial response to environmental changes in coastal waters of the eastern Cantabrian Sea was explored for four years by analysing a broad set of environmental variables along with bacterial community metabolism and composition. A recurrent seasonal cycle emerged, consisting of two stable periods, characterized by low bacterial metabolic activity (winter) from October to March, and high bacterial metabolic activity (summer) from May to August. These two contrasting periods were linked by short transition periods in April (T_A) and September (T_S). The phylogenetic groups Alphaproteobacteria and Bacteroidetes were dominant during winter and summer respectively, and their recurrent alternation was mainly driven by the bloom of eukaryotic phytoplankton before T_A and the bloom of prokaryotic phytoplankton before T_S. Bacterial growth efficiency remained high and stable during the winter and summer periods but dropped during the two short transition periods. Our results suggest that bacterial growth efficiency should be considered a very resilient property that reflects different stages in the adaptation of the bacterial community composition to the environmental changes occurring throughout the seasonal cycle in this coastal ecosystem.     

Seasonal and Geographic Distribution of Luminous Bacteria in the Eastern Mediterranean Sea and the Gulf of Elat

Luminous bacteria in the Mediterranean Sea and the Gulf of Aqaba-Elat have different distribution patterns. In the Mediterranean Sea, Beneckea harveyi is present all year round, with different subtypes alternating in summer and winter; Photobacterium fischeri was only present during the winter. In the Gulf of Elat, P. leiognathi is present throughout the water column in similar densities during the entire year. This constancy in distribution is presumably due to the near-constancy in water temperature. In summer, Photobacterium leiognathi is replaced by B. harveyi in coastal surface waters. In the hypersaline Bardawil lagoon, only B. harveyi types are present. P. fischeri, a major component of the Mediterranean Sea winter communities, is absent from the lagoon. Luminous Beneckea strains show a great diversity in properties, e.g. temperature range for growth, sensitivity to infection by phages, sensitivity to attack by Bdellovibrio strains, and differences in tolerance to high-salinity shock. Therefore, subdivision of the taxonomic cluster of B. harveyi into subtypes is indicated. The composition of the luminous bacteria communities may serve as indicators of different marine water bodies. The symbiotic luminous bacteria of the light organ of the common Gulf of Elat fish, Photoblepharon palbebratus steinitzi, is different from any of the types described.