浙江近海海域浮游病毒和异养细菌的时空分布

为了解浙江近海海域浮游病毒和异养细菌的时空生态分布, 于2014 年11 月(秋)、2015 年1 月(冬)、2015 年5 月(春)和2015 年7 月(夏)连续4 个季节采集了浙江近海海域表层海水样品, 采用流式细胞仪技术对样品浮游病毒和异养细菌丰度进行了检测, 对其时空分布特征及与环境因子的相关性做了分析。从水平分布来看, 在4 个季节中浮游病毒、异养细菌丰度均为宁波、沈家门、岱山等沿岸海域站位的丰度低, 远陆海域东极和枸杞站位的丰度高。从季节变化来看, 浮游病毒、异养细菌丰度的季节分布特征同为夏>春>秋>冬, 相关性分析结果表明, 春、夏、秋、冬4 个季节, 浮游病毒丰度与异养细菌丰度均为显著正相关。浮游病毒丰度在春、秋、冬季节均与病毒/细菌比值(VBR)显著正相关; 夏、秋季节均与盐度显著正相关; 春、夏季节均与总磷显著负相关; 春季分别于与溶解氧、pH、化学耗氧量(COD)显著正相关。异养细菌在春、秋、冬季节均与VBR 显著正相关; 春、夏季节与溶解氧显著正相关, 冬季与溶解氧显著负相关; 春、夏季节与总磷显著负相关; 秋、冬季节均与温度、盐度显著正相关; 春、冬季节均与COD 显著正相关。     

纳帕海高原湿地浮游病毒丰度及与环境因子相关性研究

目的利用EFM技术对纳帕海湿地不同季节7个水样样品中的浮游病毒丰度开展了调查,并对影响浮游病毒丰度的环境因子进行了相关性分析。方法元素检测,叶绿素a检测,荧光显微镜检测浮游细菌及浮游病毒的丰度。结果从生态分布上来看旱季和雨季浮游病毒丰度的平均值分别为3.63×10~6/mL和3.71×10~7/mL,浮游病毒丰度季节性变化不显著。从对影响浮游病毒丰度的环境因子相关性分析来看,旱季浮游病毒与Chl-a具有弱负相关性(r=0.49,P0.05);而雨季浮游病毒丰度与Chl-a具有显著正相关性(r=0.37,P0.05),表明雨季纳帕海湿地浮游病毒丰度受Chl-a含量的影响较大。旱季浮游病毒丰度与温度显著负相关,虽然在雨季浮游病毒丰度与温度也呈负相关,但并不显著;在雨季,水体pH变化较明显,而浮游病毒丰度与水体pH呈显著负相关,表明湿地的来水主要在雨季,而离子组成变化大。虽然在雨季和旱季,从多点采样的平均值来看浮游病毒丰度并无明显差异,但从一些局部的采样点来看,雨季的浮游病毒丰度显著高于旱季,说明在纳帕海区域浮游病毒的分布并不平均,因采样点环境的不同会产生明显的区别。结论对纳帕海高原湿地浮游病毒生态分布的调查,是对该地域生态学研究的补充,使得这一独特地理环境的微生物研究更加系统化。     

深圳近海表层浮游细菌分布特征及其环境影响因素

于2015年3月、5月、8月和10月在深圳市近岸海域(珠江口、深圳湾和大亚湾)采集表层水样,利用流式细胞仪测定总浮游细菌、高DNA含量亚群细菌(HNA)、低DNA含量亚群细菌(LNA)的丰度,分析它们的时空分布特点,阐释环境因子对浮游细菌时空分布格局的影响。结果表明,珠江口、深圳湾和大亚湾海域表层浮游细菌的平均丰度依次降低,分别为3.82×10~6个/mL、7.67×10~6个/mL和3.38×10~6个/mL。珠江口海域浮游细菌丰度由远岸到近岸递增,深圳湾海域湾内各站位浮游细菌丰度差异较小,大亚湾海域浮游细菌丰度空间差异不显著(P0.05)。浮游细菌丰度时间差异主要受温度影响,空间差异主要受营养盐和叶绿素a影响。HNA亚群丰度时空差异性比LNA亚群的大,HNA亚群受温度影响显著(P0.01),而LNA亚群与温度相关性不显著(P0.05)。环境对HNA和LNA亚群丰度的影响有许多相似之处,但两者对某些环境因子有着不同的响应,说明它们在近海表层生态系统中可能扮演着部分重叠但略有不同的角色。     

江苏沿岸海域浮游病毒的时空分布

在2006.7—2007.12期间,采用SYBR Green I染色-荧光显微直接计数法,对江苏沿海海域浮游病毒丰度进行了四个季度的调查,同时调查还包括细菌丰度、叶绿素a浓度。浮游病毒水平分布呈现中间高,两侧低。苏北浅滩海域病毒含量最高,最高值为47.90×106个/mL;吕泗海域最低,最低值为0.03×106个/mL。季节变化表现为冬季最高,夏季次之,春秋季相当。垂直分布也变现为明显的季节变化,除秋季外,表层浮游病毒丰度高于底层水体。浮游病毒与细菌丰度比(VBR)为0.30—180.08,平均为18.35。春季浮游病毒与叶绿素a、细菌之间均存在较强的相关性,相关系数分别为0.79和0.74(P<0.01);而在秋季,浮游病毒只与细菌有较强的相关性(r=0.79,P<0.01),这说明不同季节,浮游病毒的主要宿主会发生变化。     

纳帕海高原湿地浮游病毒丰度及其与可溶性有机碳关系

【背景】浮游病毒在有机碳循环中具有重要作用。【目的】研究纳帕海高原湿地不同季节水样及土样中的浮游病毒和细菌丰度,并分析不同季节浮游病毒丰度与可溶性有机碳的关系。【方法】利用荧光显微镜技术检测不同季节水样中浮游病毒和细菌丰度,利用流式细胞仪技术检测不同季节土壤样品中病毒颗粒和细菌丰度。【结果】雨季所有样品浮游细菌和浮游病毒丰度分别为3.38×10~6/mL和4.38×10~7/mL,旱季所有样品的浮游细菌和浮游病毒丰度分别为8.85×10~5/mL和9.66×10~6/mL,浮游细菌和浮游病毒丰度年平均值分别为2.13×10~6/mL和2.67×10~7/mL。不同季节浮游细菌和浮游病毒的丰度有显著性差异,雨季明显高于旱季(P0.01)。雨季细菌碳产量为8.01μg C/(L·h),旱季为10.30μg C/(L·h)。雨季浮游病毒裂解细菌贡献的可溶性有机碳(Dissolved organic carbon,DOC)占总DOC库的32.38%-76.38%,而旱季为8.23%-47.87%。【结论】浮游病毒在纳帕海高原湿地有机碳循环中具有重要作用。     

雷州半岛近海夏季浮游植物和浮游细菌生物量的分布及其影响因素

于2010年7月(夏季)调查了雷州半岛近海海域浮游植物和细菌生物量的空间分布特征,并分析了其与海区主要环境因子间的相互关系。结果表明:雷州半岛近海海域夏季浮游植物生物量的变化范围为15.66～1114.92mg.m-3;平均值为192.49mg.m-3;夏季浮游细菌生物量的变化范围为3.36～50.12mgC.m-3,平均值为18.43mgC.m-3;浮游植物生物量水平分布格局在不同区域间没有显著差异,浮游细菌生物量的水平分布呈现西部海区>东部海区>南部海区的格局,差异极显著;浮游植物和浮游细菌生物量在表底层的垂直分布格局没有明显的规律,表、底层生物量或高或低,差异不显著;浮游植物和浮游细菌生物量多体现近岸站位>中间站位>远岸站位,即从陆向向海向呈递减的分布格局;夏季雷州半岛近海海域浮游细菌生物量与水温、pH和硅酸盐呈显著或极显著正相关,与盐度、TOC和磷酸盐呈极显著负相关;浮游植物生物量与pH和DO呈显著或极显著正相关,与盐度和TOC呈显极显著负相关;浮游植物生物量与浮游细菌生物量存在显著的正相关性,二者存在着相互影响的调控关系。     

三峡库区典型支流浮游细菌的生态分布及其影响因素

2013年夏季对三峡库区3条典型支流朱衣河、梅溪河、草堂河进行了采样调查,分析了浮游细菌丰度的分布特征及其与环境因子的关系。结果表明:浮游细菌丰度在调查的水体中存在明显空间差异,变化范围为0.53×105~10.55×105个·m L-1,平均值为2.71×105个·m L-1;平均细菌丰度从大到小依次为梅溪河、朱衣河、长江干流和草堂河;3条支流浮游细菌丰度垂向分布特征均表现为表层中层底层。相关性分析表明,溶解氧、p H、叶绿素a与浮游细菌丰度具有显著的相关性,为该水域浮游细菌丰度空间分布的主要限制因子。根据浮游细菌丰度,各调查水域均处于富营养状态。     

长江口及邻近海域夏、冬季浮游病毒丰度分布

应用荧光显微计数法,对2006年夏季和2007年冬季长江口浮游病毒丰度(virus direct count,VDC)进行了检测.结果表明:夏季该海域VDC在2.22×106～9.97×107个·ml-1,高值分布在近海B区(122.5°-123.5°E)的表层海域;冬季VDC在1.99×106～2.66×107个·ml-1,高值分布在近岸A区(120.5°-122.5°E)海域,且由近岸向外海逐渐降低.夏季VDC与浮游细菌生物量、叶绿素含量关系密切,与营养盐相关性不显著(P＞0.05);冬季VDC与浮游细菌、营养盐含量关系密切,与叶绿素a含量相关性不显著(P＞0.05).夏季VDC显著高于冬季(P＜0.01),且两季的分布特征存在不同,此种差异主要与浮游细菌、浮游植物等病毒寄主的分布有关.冬季的营养盐含量也是影响其浮游病毒分布的重要因素.     

仿刺参养殖池塘浮游病毒丰度与环境因子的相关性分析

为了揭示仿刺参养殖池塘生态系统中浮游病毒与环境因子的关系,于2008年3—11月对大连市谢屯地区的仿刺参养殖池塘中的浮游病毒丰度进行了定期检测,同时对水温、pH、溶解氧、盐度、叶绿素a含量、化学需氧量、无机氮、活性磷酸盐、异养细菌等因子进行了监测,对浮游病毒丰度与这些环境因子之间的相关性进行了分析。结果表明:仿刺参养殖池塘中浮游病毒的平均丰度为8.32×1010VLPs.L-1(最高值为4月的18.2×1010VLPs.L-1,最低值为11月的1.31×1010VLPs.L-1),外海水中浮游病毒平均丰度为6.45×1010VLPs.L-1(最高值为4月的12.6×1010VLPs.L-1,最低值为6月的2.02×1010VLPs.L-1),仿刺参养殖池塘中营养盐、水温、pH及盐度对浮游病毒丰度的影响较大,而外海水中叶绿素a和异养细菌对浮游病毒丰度的影响较大。     

流式细胞仪检测纳帕海高原湿地浮游病毒和浮游细菌丰度

【背景】浮游病毒是水体微生物群落中重要的组成成分,深入研究浮游病毒的时空分布有助于更好地保护和开发当地的微生物资源。【目的】对采集到的纳帕海高原湿地水样中的浮游病毒和浮游细菌进行计数,揭示纳帕海高原湿地浮游病毒的分布规律。【方法】采用流式细胞仪检测2013年12月和2014年9月纳帕海高原湿地7个水样的浮游病毒与浮游细菌丰度,并对影响浮游病毒丰度的因素,如细菌丰度、叶绿素a含量以及其他环境因子进行了相关性分析。【结果】季节分布上,雨季浮游病毒和浮游细菌丰度高于旱季;水平分布上,原水样品的浮游病毒高于湿地水和淤泥水。旱季水样的浮游病毒丰度受到细菌丰度及叶绿素a浓度的影响较大;雨季水样的浮游病毒丰度受到水体的p H值和温度的影响较大。【结论】纳帕海高原湿地的浮游病毒和浮游细菌是比较活跃的。浮游病毒丰度在不同季节、不同采样点受到细菌丰度和叶绿素a浓度等因素的不同影响。在旱季噬菌体而非噬藻体或浮游植物病毒是纳帕海高原湿地中浮游病毒的优势种群。     

Dynamic of Virioplankton Abundance and Its Environmental Control in the Charente Estuary (France)

The Charente River provides nutrient- and virus-rich freshwater input to the Marennes Oléron Basin, the largest oyster-producing region in Europe. To evaluate virioplankton distribution in the Charente Estuary and identify which environmental variables control dynamic of virioplankton abundance, five stations defined by a salinity gradient (0–0.5, 0.6–5, 13–17, 20–24, and higher than 30 PSU) were surveyed over a year. Viral abundance was related to bacterioplankton abundance and activities, photosynthetic pigments, nutrient concentration, and physical parameters (temperature and salinity). On a spatial scale, virus displayed a decreasing pattern seaward with abundance ranging over the sampling period from 1.4 × 10⁷ to 20.8 × 10⁷ viruses mL⁻¹ making virioplankton the most abundant component of planktonic microorganisms in the Charente Estuary. A good correlation was found between viral and bacterial abundance (r_s = 0.85). Furthermore, bacterial abundance was the most important predictor of viral abundance explaining alone between 66% (winter) and 76% (summer) of viral variability. However, no relation existed between viral abundance and chlorophyll a. Temporal variations in viral distributions were mainly controlled by temperature through the control of bacterial dynamics. Spatial variations of viral abundance were influenced by hydrodynamic conditions especially during the winter season where virioplankton distribution was entirely driven by mixing processes.     

Seasonal Variation of Virioplankton in a Eutrophic Shallow Lake

Lake Donghu is a typical eutrophic freshwater lake in which high abundance of planktonic viruses was recently revealed. In this study, seasonal variation of planktonic viruses were observed at three different trophic sites, hypertrophic, eutrophic, and mesotrophic regions, and the correlation between their abundances and other aquatic environmental components, such as bacterioplankton, chlorophyll a, burst size, pH, dissolved oxygen, and temperature, was analyzed for the period of an year. Virioplankton abundance detected by transmission electron microscope (TEM) ranged from 5.48 × 10⁸ to 2.04 × 10⁹ ml⁻¹ in all the sites throughout the study, and the high abundances and seasonal variations of planktonic viruses were related to the trophic status at the sampled sites in Lake Donghu. Their annual mean abundances were, the highest at the hypertrophic site (1.23×10⁹ ml⁻¹), medium at the eutrophic site (1.19×10⁹ ml⁻¹), and the lowest at the mesotrophic site (1.02×10⁹ ml⁻¹). The VBR (virus-to-bacteria ratio) values were high, ranging from 49 to 56 on average at the three sampled sites. The data suggested that the high viral abundance and high VBR values might be associated with high density of phytoplankton including algae and cyanobacteria in this eutrophic shallow lake, and that planktonic viruses are important members of freshwater ecosystems.     

Uptake of picophytoplankton,bacterioplankton and virioplankton by a fringing coral reef community (Ningaloo Reef,Australia)

We examined the importance of picoplankton and virioplankton to reef trophodynamics at Ningaloo Reef, (north-western Australia), in May and November 2008. Picophytoplankton (Prochlorococcus, Synechococcus and picoeukaryotes), bacterioplankton (inclusive of bacteria and Archaea), virioplankton and chlorophyll a (Chl a) were measured at five stations following the consistent wave-driven unidirectional mean flow path of seawater across the reef and into the lagoon. Prochlorococcus, Synechococcus, picoeukaryotes and bacterioplankton were depleted to similar levels (~40% on average) over the fore reef, reef crest and reef flat (=‘active reef’), with negligible uptake occurring over the sandy bottom lagoon. Depletion of virioplankton also occurred but to more variable levels. Highest uptake rates, m, of picoplankton occurred over the reef crest, while uptake coefficients, S (independent of cell concentration), were similarly scaled over the reef zones, indicating no preferential uptake of any one group. Collectively, picophytoplankton, bacterioplankton and virioplankton accounted for the uptake of 29 mmol C m⁻² day⁻¹, with Synechococcus contributing the highest proportion of the removed C. Picoplankton and virioplankton accounted for 1–5 mmol N m⁻² day⁻¹ of the removed N, with bacterioplankton estimated to be a highly rich source of N. Results indicate the importance of ocean–reef interactions and the dependence of certain reef organisms on picoplanktonic supply for reef-level biogeochemistry processes.     

Ocean time-series reveals recurring seasonal patterns of virioplankton dynamics in the northwestern Sargasso Sea

There are an estimated 10³⁰ virioplankton in the world oceans, the majority of which are phages (viruses that infect bacteria). Marine phages encompass enormous genetic diversity, affect biogeochemical cycling of elements, and partially control aspects of prokaryotic production and diversity. Despite their importance, there is a paucity of data describing virioplankton distributions over time and depth in oceanic systems. A decade of high-resolution time-series data collected from the upper 300 m in the northwestern Sargasso Sea revealed recurring temporal and vertical patterns of virioplankton abundance in unprecedented detail. An annual virioplankton maximum developed between 60 and 100 m during periods of summer stratification and eroded during winter convective mixing. The timing and vertical positioning of this seasonal pattern was related to variability in water column stability and the dynamics of specific picophytoplankton and heterotrophic bacterioplankton lineages. Between 60 and 100 m, virioplankton abundance was negatively correlated to the dominant heterotrophic bacterioplankton lineage SAR11, as well as the less abundant picophytoplankton, Synechococcus. In contrast, virioplankton abundance was positively correlated to the dominant picophytoplankton lineage Prochlorococcus, and the less abundant alpha-proteobacteria, Rhodobacteraceae. Seasonally, virioplankton abundances were highly synchronous with Prochlorococcus distributions and the virioplankton to Prochlorococcus ratio remained remarkably constant during periods of water column stratification. The data suggest that a significant fraction of viruses in the mid-euphotic zone of the subtropical gyres may be cyanophages and patterns in their abundance are largely determined by Prochlorococcus dynamics in response to water column stability. This high-resolution, decadal survey of virioplankton abundance provides insight into the possible controls of virioplankton dynamics in the open ocean.     

Virus impact on heterotrophic bacterioplankton of water reservoirs

The quantitative distribution of viruses and their impact on heterotrophic bacterioplankton were studied in mesotrophic and eutrophic reservoirs of the Volga and Volga-Baltic waterway. The abundance of planktonic virus particles ranged from 9.4 × 10⁶ to 120 × 10⁶ ml⁻¹ and was from 2.5 to 9 times greater than the bacterial numbers. Production of virioplankton varied from 2.1 × 10⁶ to 132 × 10⁶ particles (ml day)⁻¹ and the population turnover time values were between 0.3 and 11.6 days. The maximum values of numbers and production of virio- and bacterioplankton were observed in the eutrophic Ivan’kovo reservoir. Distribution of the viruses in the Volga reservoirs depended to a significant degree on the number and activity of heterotrophic bacterioplankton. The infected bacteria accounted for 5.5–33.5% of the total bacterial abundance. Phages were an important factor of bacterial mortality. During July to September virus-induced bacterial mortality varied between 6.1 and 40.6% (20.2% on average) of daily bacterioplankton production.     

Abundance and community composition of bacterioplankton in the Northern South China Sea during winter: geographic position and water layer influences

The abundance and composition of bacterioplankton of the Northern South China Sea (NSCS) were investigated using flow cytometry and high-throughput sequencing. The results showed that the absolute abundance of bacterioplankton retained high values in surface waters at both continental shelf and oceanic sites and Proteobacteria, Cyanobacteria, and Bacteroidetes represented the three typical dominant phyla in NSCS. The average bacterioplankton abundances at 5 m, 75 m, and 200 m were 9.55, 5.04, and 1.32?×?10⁵ cells mL^?1, respectively, and there was a significantly positive correlation between bacterioplankton abundance and Chl a content (r?=?0.84, p?<?0.01). Drastic changes of the bacterioplankton community occurred in different water layers. Three operational taxonomic units (OTUs), whose distribution were significantly different between 5-m and 75-m water layers, all belonged to Flavobacteriales of the Bacteroidetes (p?<?0.05). In addition, bacterioplankton community richness and diversity at the continental shelf (CS) was generally higher than at oceanic stations (SB and KI). Five OTUs, which favored the habitat of continental shelf, belonged to Alphaproteobacteria including the orders of the SAR11 cluster, Rhodospirillales, Rhodobacterales and other unclassified orders (p?<?0.05). Two OTUs, which favored the habitat of oceanic stations, were assigned to the orders of Flavobacteriales and Alteromonadales. Furthermore, the abundances of two OTUs belonging to the Cyanobacteria phylum and Verrucomicrobiales order were significantly different between the sea basin (SB) and Kuroshio influenced area (KI) stations (p?<?0.05).     

Distribution of viruses and their impact on bacterioplankton in mesotrophic and eutrophic reservoirs

Spatial distribution of planktonic viral particles (virioplankton) and mortality of heterotrophic bacteria caused by viral lysis were studied in the eutrophic Ivan’kovskoe and mesotrophic Uglichskoe reservoirs (the Upper Volga). During the summer peak of phytoplankton, the number of viral particles was higher in the Ivan’kovskoe Reservoir ((55.1 ± 9.5) × 10⁶ ml⁻¹ on average) than in the Uglichskoe Reservoir ((42.9 ± 5.1) × 10⁶ ml⁻¹ on average). The ratio of viral to bacterial abundances ranged from 2.5 to 7.0. The average number of mature phages in infected heterotrophic bacteria varied from 17 to 109 particles/cell. Most of the infected bacterial cells in the Ivan’kovskoe Reservoir were rod-shaped, and, in the Uglichskoe Reservoir, they were mainly vibrio-shaped. In the Ivan’kovskoe Reservoir, from 8.3 to 22.4% of planktonic bacteria were infected by phages, suggesting phage-induced mortality of bacterioplankton equal to 10.5–34.8% (19.1% on average) of the daily bacterial production. In the Uglichskoe Reservoir, from 9.4 to 33.5% of bacteria were phage-infected, suggesting phage-induced bacterial mortality of 13.7–40.2% (23.5% on average) of the daily bacterial production. The obtained results testify to an important role of autochthonous viruses in the regulation of bacterioplankton abundance and production in the reservoirs.     

Influence of the Hydrological Cycle on the Bacterioplankton of an Impacted Clear Water Amazonian Lake

Abstract Free-living and attached bacterial population sizes were determined fortnightly from December 1991 to December 1992 in natural and disturbed areas of an Amazonian clear water lake (Batata Lake, Pará, Brazil) impacted by bauxite tailings. The bacterioplankton showed distinct patterns during different phases of the hydrological cycle. Total bacterial population size and rates of thymidine incorporation (measured during high and low water phases) were high during low water, with values ranging from 3.3 × 10⁵ to 1.1 × 10⁶ cells ml⁻¹, and from 0.28 to 4.01 μg C l⁻¹ h⁻¹, respectively. The population size of free-living bacteria was larger at the natural station, while no differences were observed between attached bacterial populations at both stations. However, production and turnover rate of attached bacteria were high at the disturbed area. During low water, bacterial growth appeared to be driven mainly by the input of dissolved organic carbon (DOC) from phytoplankton origin. During high water, bacterial abundance was reduced, probably as the result of dilution and the input of less labile DOC from floodplains. The presence of bauxite tailings seems to influence bacterial dynamics in an indirect way, probably due to shading of phytoplankton cells and, hence, reducing the DOC supply for bacterial growth. This study, the first on the microbial ecology of an Amazonian clear water lake, demonstrated that water level variations exert a strong influence on the bacterioplankton dynamics. Received: 9 January 1996; Accepted 6 November 1996