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101.
海洋异养浮游细菌生物量及生产力的制约因素   总被引:15,自引:0,他引:15  
根据海洋异养浮游细菌既是分解者,又是生产者的特点,从生态学方面探讨了海洋异养浮游细菌在海洋生态系统中的作用、研究现状及细菌生物量和生产力的制约因素。认为具有重要生态学意义的海洋异养浮游细菌生物量和生产力的主要影响因素有溶解性有机碳的性质及含量、无机营养盐浓度、海水温度、微量金属元素(如铁)含量、海洋异养浮游动物的摄食能力和噬菌体的感染等。  相似文献   
102.
Dynamics of picoplankton in the Nansha Islands area of the South China Sea   总被引:5,自引:0,他引:5  
Dynamics of major picoplankton groups, Synechococcus (Syn), Prochlorococcus (Pro), picoeukaryotes (Euk) and heterotrophic bacteria (Bact) was investigated by flow cytometry for the first time in the Nansha Islands area in the South China Sea. Averaged over the whole investigation area, depth-weighted integrated cell abundance (DWA) of Syn, Pro, Euk and Bact was 1.6 (0.4-5.7)×103, 5.4 (0.1-7.3)×104, 0.7 (0.2-2.2)×103, and 2.3 (1.4-3.2)×105 cells/mL respectively. Picoautotrophic cell abundance was low in the northwest part of the Nansha Islands where surface water temperature was low and the upper mixed layer was shallow. Concurrently, a surface maximum vertical distribution pattern was observed in this area. While in the southeast and east zones where temperatures were relatively higher and nitraclines were deeper, picoplankton is abundant and a subsurface maximum around 50-75 m is observed. Coupling of horizontal and vertical distribution patterns of picoplankton abundance and hydrological status wa  相似文献   
103.
The plankton community composition comprising heterotrophic bacteria, pro-/eukaryotes, heterotrophic nanoflagellates, microzooplankton and mesozooplankton was assessed during the spring bloom and at non-bloom stations in the English Channel and Celtic Sea between 6 and 12 April 2002. Non-bloom sites were characterised by a dominance of pro-/eukaryotic phytoplankton <20 μm, higher abundance of heterotrophic nanoflagellates, microzooplankton standing stocks ranging between 60 and 380 mg C m−2, lower mesozooplankton diversity and copepod abundance of between 760 and 2600 ind m−3. Within the bloom, the phytoplankton community was typically dominated by larger cells with low abundance of pro-/eukaryotes. Heterotrophic nanoflagellate cell bio-volume decreased leading to a reduction in biomass whereas microzooplankton biomass increased (360–1500 mg C m−2) due to an increase in cell bio-volume and copepod abundance ranged between 1400 and 3800 ind m−3. Mesozooplankton diversity increased with an increase in productivity. Relationships between the plankton community and environmental data were examined using multivariate statistics and these highlighted significant differences in the abiotic variables, the pro-/eukaryotic phytoplankton communities, heterotrophic nanoflagellate, microzooplankton and total zooplankton communities between the bloom and non-bloom sites. The variables which best described variation in the microzooplankton community were temperature and silicate. The spatial variation in zooplankton diversity was best explained by temperature. This study provides an insight into the changes that occur between trophic levels within the plankton in response to the spring bloom in this area.  相似文献   
104.
2006年6月12日至22日“东方红2号”考察船夏季航次期间,在长江口3个连续观测站位进行了水样采集,应用流式细胞仪分析了水样中的极微型浮游生物(Femtoplankton)和微微型浮游生物(Picoplankton)。结果显示,原绿球藻(Prochlorococcus)在所有样品中均未检测到;检测到的聚球藻(Synechococcus)和微微型真核浮游植物(Picoeukaryotes)平均丰度达数量级10^5~10^6个/L,异养细菌(Heterotrophic bacteria)和病毒(Viruses)平均丰度达数量级10^8~10^9个/L。在浑浊的长江口水域,极微型和微微型浮游生物的垂向分布特征不同,主要与各站位特有的水动力条件密切相关:浊度是调控微微型真核浮游植物、异养细菌和病毒周日变化的关键因子之一;微微型真核浮游植物成为微微型浮游植物中最重要的组成部分,与异养细菌具有显著的正相关关系。  相似文献   
105.
2008年4月和7月于黄河三角洲南部潮间带进行了大面站调查,采用DAPI荧光染色荧光显微镜计数法测定了沉积物中异养细菌数量,研究其分布特征,探讨满足其生长繁殖需要的物质来源.结果表明,春季和夏季潮间带沉积物中异养细菌丰度的变化范围分别为4.0~31.9×105 cells/g dw(平均值为11.81×105 cell...  相似文献   
106.
通过现场调查和模拟培养实验,对辽河口湿地芦苇生长期内土壤异养细菌的变化规律及其主要影响因素进行了研究。野外现场调查结果表明,异养细菌数量6月份最多,8月份最少;植被长势良好区异养细菌数量比裸滩区高1倍左右。现场培养实验结果表明,盐分、C/N、石油、植被对异养细菌数量均有影响,异养细菌数量随盐分增加而减少;C/N比值增加,异养细菌数量明显增多,碳氮比为10∶1时,异养细菌数最大,约为对照组的3倍;石油会显著抑制异养细菌生长,浓度越高,异养细菌数量越少;有植被组的异养细菌数量明显高于无植被组。  相似文献   
107.
Seven surveys were carried out in April, September, October, December 2006 and March, May, August 2007 in the Yellow Sea, China. Variations in the spatial and temporal distribution of Synechococcus, picoeukaryotes and heterotrophic bacteria are quantified using flow cytometry. Synechococcus and heterotrophic bacteria are most abundant from late spring to autumn, while picoeukaryotes concentration is high in spring. Synechococcus and heterotrophic bacteria concentrated high in the northwest part of the Yellow Sea in spring and autumn, while picoeukaryotes distributed evenly over the whole study area except for a small frontal zone in the coastal area on the west (in spring) and central Yellow Sea (in autumn). Under mixing conditions, the vertical distribution of the three picoplankton groups showed a well-mixed pattern. Upon a well-established stratification, the maximum abundance of picoplankton occurred above the mixed layer depth (~30 m). Cell sizes of Synechococcus and picoeukaryotes were estimated by converting forward scatter signals (FSC) from cytometry analysis to cell diameter, showing the results of 0.65–0.82 μm for Synechococcus and 0.85–1.08 μm for picoeukaryotes. The average integrated carbon biomasses ranged 15.26–312.62 mgC/m2 for Synechococcus, 18.54–61.57 mgC/m2 for picoeukaryotes, and 402.63–818.46 mgC/m2 for heterotrophic bacteria. The distribution of Synechococcus and heterotrophic bacteria was temperature dependent, and picoplankton presence was poor in the Yellow Sea Cold Water Mass.  相似文献   
108.
During the period January to December 2004, monthly intertidal sand samples were collected from John U. Lloyd State Park beach, Florida. This study is the first to report on spatial and temporal distributions of heterotrophic (apochlorotic) diatoms in a sub-tropical beach, or indeed any sandy beach. Two non-pigmented, apochlorotic diatom morphotypes (strains III and IV) were consistently isolated from two intertidal beach sites and neither conformed to the morphologies of described species. Apochlorotic diatoms were found throughout the year and formed significant peaks in April, attaining total diatom counts of 71.1 and 94.9 cells g−1 wet sand, for the upper tidal zone and lower tidal zone, respectively. Valve morphology is described in detail for the two diatom morphotypes isolated from the beach sites (strains III and IV). Growth responses to changes in salinity (reflecting those of the intertidal zone) were examined in the laboratory for these diatoms. Both morphotypes were euryhaline, tolerating salinities between 10 and 50, and maximum growth rates were achieved at salinities between 20 and 40. Diatoms grew equally well whether grown in the light or the dark and showed no evidence of pigments when viewed by epifluorescence microscopy. The ability of diatoms to burrow into agar and carrageenan at different concentrations was tested. Both morphotypes were observed to develop burrows through non-nutrient agar up to twice the standard concentration (30 g agar l−1). The ease with which these heterotrophic diatoms formed burrows suggests that they were digesting these complex carbohydrates (i.e. phycocolloids) as a nutrient source. Strain IV, however, failed to burrow in a different phycocolloid, carrageenan. Similar degradative actions in the field might have implications for the breakdown of recalcitrant materials or allow diatoms to effectively compete with bacteria for carbon and nutrients.  相似文献   
109.
本研究针对高温时期(6月、9月)广东沿海地区的香港牡蛎(Crassostrea hongkongensis)体内异养细菌总数和弧菌总数进行了深入的调查,并由添加单种抗生素(分别是:庆大霉素、呋喃唑酮、利福平、环丙沙星、恩诺沙星、氯霉素、复方新诺明)的培养基中分离得到310个菌株。进一步采用纸片扩散法(kirby-bauer法)针对常见的抗生素对此310个菌株进行药敏测试,了解不同来源菌株的耐药状况。结果表明310个菌株分属48个不同种属,主要是肠杆菌(Enterobacter)、弧菌(Vibrio)、芽孢杆菌(Bacillus)、肺炎克雷伯菌(Klebsiella)、希瓦氏菌(Shewanella)、不动杆菌(Acinetobacter)、假单胞菌(Pseudomonas)、短波单胞菌(Brevundimonas)、发光杆菌(Photobacterium)、黄杆菌(Tenacibaculum)、盐单胞菌(Halomonas)等。在9月份从牡蛎体内分离的异养细菌比6月份分离的异养细菌高出1~2个数量级(除台山外)。6月份从台山地区牡蛎分离的异养细菌数(2.6×10~6~5.8×10~6 cfu/g)最多,高出其他地区1~3个数量级。药敏测试结果显示牡蛎体内异养细菌对20种抗生素普遍存在抗性,尤其对青霉素、卡拉霉素、呋喃唑酮、阿莫西林、克林霉素及万古霉素表现出较高的耐药率。高温时期(6月、9月)分离的异养菌大多数为多重耐药细菌,其比例分别为84.18%和91.72%。本研究将为牡蛎养殖业的疾病控制以及水产养殖中细菌的耐药状况提供重要参考依据。  相似文献   
110.
The seasonal abundance of flagellates has been monitored over a period of 1 year from December 2013 to November 2014(divided into 4 conjugative seasons namely winter,spring,summer,and autumn)in an experimental pond located in Rajshahi City Corporation area,Bangladesh.To our knowledge,this study is the fi rst to shed light on the occurrence and possible interrelationships among heterotrophic flagellates(HF),bacteria and zooplankton in Bangladesh and the result obtained by this study will be beneficial for similar water ecosystem all over the world.Standard methods were used to determine the prescribed hydrological parameters and zooplankton cell density.Maximum HF abundance(14 346.00 cells/mL)was found in the spring and the minimum(5 215.00 cells/mL)occurred in the summer.Inverse to HF,significantly(P<0.05)higher zooplankton abundance was found during the winter(782.00±47.62 cells/mL)and the lowest value was found in the autumn(448.00±39.15 cells/mL).Whereas similar to the HF,total bacterial abundance was significantly higher during the spring((2.25±1.05)×10^5 cells/mL)and lower in the summer((0.79±0.06)×10^5 cells/mL).Multivariate analyses(ANOSIM and MDS)have shown significant seasonal differences for cell numbers where MDS ordination plot and cluster analysis based on similarity in the genera abundance of HF revealed overlapping condition between winter and spring.Canonical correspondence analysis(CCA)also showed a distinct separation among the genera based on the prevailing hydrological situation and indicated that temperature,pH,BOD5,and NO3^-were the most important environmental variables in determining the observed variation in HF community structure.Among the biological factors,zooplankton showed negative but total bacteria were positively correlated with HF abundance.  相似文献   
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