IOCAS-IR
海州湾赤潮高发区副溶血性弧菌分布及浮游细菌群落结构初探
詹皓禹
Subtype硕士
Thesis Advisor颜天
2022-06
Degree Grantor中国科学院大学
Place of Conferral中国科学院海洋研究所
Degree Name工学硕士
Keyword副溶血性弧菌 弧菌 浮游细菌 群落结构 海州湾
Abstract

       随着人类活动的加剧,海州湾内营养物质的输入增加,富营养化状况日益加剧,赤潮频发,细菌多样性可能增加,弧菌等条件致病菌也可能出现规模性增长。赤潮和致病细菌的影响相互叠加,威胁着海州湾海水养殖产业安全、海产品食品安全和人类健康。本研究以海州湾赤潮高发区为研究区域,调查表层海水中浮游细菌,尤其是弧菌(Vibrio)、副溶血性弧菌(Vibrio parahaemolyticus)的分布状况,为评价海州湾的海洋生态环境安全提供依据。

       本研究于2020年11月、2021年3月、4月、5月、6月、8月以及2022年1月在海州湾赤潮高发区展开了7次航次调查,获取表层海水样品,分析了水温、盐度、叶绿素a以及硝酸盐、亚硝酸盐、氨氮、溶解态有机氮、磷酸盐、溶解态有机磷、硅酸盐浓度的变化情况,分析了采样期间副溶血性弧菌、弧菌的数量及浮游细菌群落结构的动态变化,并探究了环境因子与副溶血性弧菌、弧菌及浮游细菌群落的相关性。本研究主要采用了实时荧光定量PCR法,以tlh为靶基因,对海水中的副溶血性弧菌进行定量检测;采用PCR法,以trh为靶基因,对海水中的人类病原副溶血性弧菌进行定性检测;使用TCBS培养基对海水中的弧菌进行选择性培养,并进行计数;使用16S rRNA高通量测序手段,对浮游细菌多样性及群落结构进行分析。本研究得到的结果与科学认识如下:

       (1)海州湾赤潮高发区表层海水中副溶血性弧菌浓度的变化范围为16-9680 cells/mL,弧菌浓度变化范围为60-7160 CFU/L。夏季副溶血性弧菌及弧菌的浓度最高,副溶血性弧菌主要分布在近岸紫菜、贝类混合养殖区,弧菌主要分布在湾口的贝类养殖区。此次调查中,没有检出人类病原副溶血性弧菌(trh阳性)。

       (2)2021年3月到6月期间,海州湾赤潮高发区浮游细菌多样性逐渐增加。优势菌门为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、放线菌门(Actinobacteria)、蓝细菌门(Cyanobacteria)、厚壁菌门(Firmicutes)、酸杆菌门(Acidobacteria)、疣微菌门(Verrucomicrobia)、Desulfobacterota、Patescibacteria。优势纲为γ-变形菌纲(Gammaproteobacteria)、α-变形菌纲(Alphaproteobacteria)、拟杆菌纲(Bacteroidia)、酸微菌纲(Acidimicrobiia)、放线菌纲(Actinobacteria)、蓝细菌纲(Cyanobacteriia)、芽孢杆菌纲(Bacilli)、梭菌纲(Clostridia)、酸杆菌纲(Acidobacteriae)。假单胞菌目(Pseudomonadales)、SAR11类群在3月到6月期间相对丰度降低,红杆菌目(Rhodobacterales)的相对丰度则在增加。6月的调查结果显示,Nautella属细菌及弧菌属细菌取代Clade_Ia成为优势属。

       (3)Spearman相关性分析显示,海水中的副溶血弧菌数量与温度显著正相关。海水中弧菌数量与温度、硝酸盐浓度正相关,与盐度负相关。弧菌的相对丰度与温度、叶绿素、亚硝氮、硅酸盐、溶解态有机磷显著正相关,与盐度显著负相关。另外,硅藻赤潮发生的站位,弧菌浓度较高,表明硅藻赤潮对弧菌的分布具有一定影响。除弧菌属以外,红杆菌科也与表层海水中的叶绿素a 显著正相关,OM43类群、SAR86类群则与叶绿素a负相关,表明浮游植物生物量对细菌群落结构具有影响。

       冗余分析(RDA)显示,3月到6月期间海州湾赤潮高发区表层海水中浮游细菌群落结构(OTU水平)与水温、盐度、硅酸盐、溶解态有机磷显著相关,温度、叶绿素a对浮游细菌群落结构的影响不断加大。浒苔绿潮发生的站位,浮游细菌群落结构发生了改变。

       以上调查分析结果表明,水温、营养盐及浮游植物与弧菌相对丰度、浮游细菌多样性正相关,浮游植物群落对细菌群落具有一定影响。夏季海州湾赤潮多发、浒苔过境,养殖密度较大,浮游细菌群落结构发生改变,弧菌、副溶血性弧菌的数量增加,对该海域海洋生态环境及养殖生物的安全威胁加大。

Other Abstract

    With the intensification   of human activities, the input of nutrients in Haizhou Bay is increasing, and the eutrophication is increasingly severe. The plankton community structure   changes significantly, red tide occurs frequently, bacterial diversity increases, Vibrio and other opportunistic pathogens may also increase rapidly. The overlapping effects of red tide and pathogenic bacteria threaten the safety of mariculture industry, seafood and human health. This study took the frequent harmful algae blooms area in Haizhou Bay as the survey area. The distribution of phytoplankton bacteria in surface seawater, especially Vibrio and Vibrio parahaemolyticus were investigated, to provide a basis for evaluating the safety of marine ecological   environment in Haizhou Bay.

    In this study, seven cruises were conducted in November 2020, March, April, May, June, August 2021, and January 2022 to collect surface seawater samples at the frequent HAB area of Haizhou Bay. Changes of water temperature, salinity, chlorophyll a, nitrate, nitrite, ammonium nitrogen, dissolved organic nitrogen, phosphate, dissolved organic phosphorus, and silicate were analyzed. The density of V. parahaemolyticus and Vibrio, community structure of bacterioplankton were also investigated. In addition, the correlation between environmental factors and bacterioplankton was explored. In this study, real-time fluorescence quantitative PCR with tlh as target gene was used to quantitatively detect V. parahaemolyticus in seawater. PCR with trh as target gene was used to detect human pathogenic V. parahaemolyticusVibrio in seawater was selectively cultured and   counted with TCBS medium. 16S rRNA high-throughput sequencing was used to   analyze bacterial diversity and community structure.

   (1) The density of Vibrio parahaemolyticus in surface water of the frequent HAB area in Haizhou Bay   varied from 16 to 9680 cells/mL, the density of Vibrio varied from 60 to 7160 CFU/L. In summer, the density of V. parahaemolyticus and Vibrio was the highest. V. parahaemolyticus mainly distributed in the mixed aquaculture area of laver and shellfish, while Vibrio mainly   distributed in the aquaculture area of shellfish. Human pathogenic V. parahaemolyticus (trh+) was not found in this research.

    (2) From March to June 2021, the α-diversity of bacterioplankton increased at the frequent harmful algae blooms area in Haizhou Bay. The dominant phyla were Proteobacteria,   Bacteroidetes, Actinobacteria, Cyanobacteria, Firmicutes, Acidobacteria,   Verrucomicrobia, Desulfobacterota and Patescibacteria. The dominant class   were Gammaproteobacteria, Alphaproteobacteria, Bacteroidia, Acidimicrobiia,   Actinobacteria, Cyanobacteriia, Bacilli, Clostridia, Acidobacteriae. Relative   abundance of Pseudomonadales, SAR11 decreased from March to June, while   Rhodobacterales relative abundance increased. In June, Nautella and Vibrio replaced Clade_Ia as the dominant genus.

     (3) Spearman correlation analysis showed that the density of V. parahaemolyticus in surface   seawater was significantly positively correlated with water temperature. The density of Vibrio was positively correlated with temperature and nitrate concentration, but negatively correlated with salinity. The relative abundance of Vibrio was significantly positively correlated with temperature, chlorophyll a, nitrite, silicate and dissolved organophosphorus, and negatively correlated with salinity. The density of Vibrio was high at the station where diatom red tide occurred. Diatom red tide had   effects on Vibrio. Rhodobacteraceae was also positively correlated   with chlorophyll a, while OM43, SAR86 negatively correlated with chlorophyll a. The results showed that phytoplankton biomass influenced bacterial community structure.

    Redundancy analysis (RDA)   was used to analyze the influence of environmental factors on the bacteria   community structure at OTU level. The results showed that the bacterial   community structure in surface water of the frequent harmful algae blooms   area in Haizhou Bay was significantly correlated with water temperature,   salinity, silicate and dissolved organophosphorus. From March to June, the   effect of temperature and chlorophyll a increased. The bacterial   community structure changed at the station where green tide occurred.

     All investigations and   analysis showed that water temperature, nutrients and phytoplankton were   positively correlated with relative abundance of Vibrio and diversity of bacterioplankton. Phytoplankton community had impacts on bacterial community.   In summer, high frequency of harmful algae blooms, green tide and high density of cultivation exist in Haizhou Bay. The bacterial community structure changes, and the density of Vibrio and V. parahaemolyticus increases, which pose a greater threat to the safety of   marine ecosystem and mariculture.

Language中文
Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/178389
Collection中国科学院海洋研究所
Recommended Citation
GB/T 7714
詹皓禹. 海州湾赤潮高发区副溶血性弧菌分布及浮游细菌群落结构初探[D]. 中国科学院海洋研究所. 中国科学院大学,2022.
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