深圳福田红树林保护区自由生活海洋线虫群落特征研究

Study on the Community Characteristics of Marine Nematodes in Futian Mangrove Reserve,Shenzhen

分别于2013年7月(夏季)、2013年10月(秋季)、和2014年1月(冬季)在深圳福田红树林保护区选取沙嘴码头(S)、凤塘河口(F)、观鸟屋(G)和基围鱼塘(Y)四个采样区10个采样站点采集样品,探讨海洋线虫在该红树林保护区的丰度、群落结构及其时空变化规律。结果表明,福田红树林保护区海洋线虫群落平均丰度为(1591.4±84.8)ind./10 cm^2,丰度变化范围与中国其他红树林生境基本一致。海洋线虫群落以轴线虫科(Axonolaimidae)和条线虫科(Linhomoeidae)为优势科,假拟齿线虫属(Pseudolella)、拟齿线虫属(Parodontophora)、微口线虫属(Terschellingia)、吞咽线虫属(Daptonema)、亚囊咽线虫属(Subsphaerolaimus)、后线形线虫属(Metalinhomoeus)等为优势属,刮食者(2A型)为优势摄食类型。优势属组成与中国各地红树林生境相似,表明海洋线虫群落种类组成相似。但是,仍有部分属或种的优势度仅在福田红树林生境较高,具有典型的地方性分布特点。福田红树林线虫群落结构和丰度具有显著的空间差异和季节性变化特征。季节动态主要表现为夏季丰度极高,秋冬季丰度低,三个季节种类组成区分度明显。线虫群落结构和丰度的空间差异主要表现为区域差异显著,而潮带差异不显著,表明同一区域线虫群落结构基本一致。区域差异表现为S区线虫丰度最高,F区丰度最低;线虫种类组成在Y区、S区和F区之间存在显著差异。从摄食结构而言,Y区以非选择性沉积食性线虫为优势,其他三区以刮食者为优势摄食类型。相关性分析结果显示,间隙水温度、盐度、沉积物粉砂黏土含量或中值粒径、脱镁叶绿酸、有机质含量等与线虫群落结构和丰度显著相关。植被类型差异、沉积物粒度特征的差异和有机质含量代表的食物资源差异是引起线虫群落空间差异的主要原因,间隙水温度、盐度、沉积物粒度特征的变化是引起季节差异的主要因素。海洋线虫群落的空间差异和季节性动态也是对变化中的红树林环境特征的响应。

Sediment samples were collected from Futian mangrove reserve of Shenzhen in July 2013(summer),October 2013(autumn),and January 2014(winter),to reveal the spatial distribution and seasonal variation of the marine nematode community.A total of 10 sampling sites were set up in four areas of Shazui Pier(S),Fengtang Estuary(F),Bird Watching House(G)and Jiwei Fish Pond(Y)in Futian mangrove reserve.The results showed that annual average abundance of marine nematodes was(1591.4±84.8)ind./10 cm^2,which was within the range of nematodes abundance variations in Chinese mangrove habitats.Axonolaimidae and Linhomoeidae were the most abundant families in the study area.The dominant genera were Pseudolella,Parodontophora,Terschellingia,Daptonema,Subsphaerolaimus and Metalinhomoeus.Several dominant genera were also very common in other Chinese mangrove habitats,indicating similar species composition.However,some dominant genera appeared in large amount only in Futian mangrove.The trophic structure analysis revealed a community dominated by epigrowth feeders in the study area.Furthermore,nematode community characteristics showed significant spatial and seasonal variations in the study area.The abundance of nematodes was extraordinarily high in summer and showed a variation of abundance as summer>winter>autumn.The species compositions of nematode communities differed among three seasons.Area differentiation was the major aspect of spatial variations of nematode community structure and abundance.Nematode community structure and abundance varied little among different tidal zones,indicating similar community structure in the same sampling area.For the area differentiation,nematodes’abundance was the highest in S area,while the lowest in area F.The species composition varied significantly between area Y,S,and F.According to the trophic structure,non-selective deposit feeders dominated in area Y while epigrowth feeders dominated in other three areas.The results of the correlation analyses showed that interstitial water salinity,temperature,sediment silt-clay content or medium grain size,phaeophytin and organic matter content were responsible for spatial and seasonal variations of nematodes’abundance and community structure.Differences in mangrove vegetation,sediment granularity characteristics and food resources were the main reasons for the spatial variations of nematode community structure,while the differences of interstitial water salinity,temperature,and sediment silt-clay content were the main reasons for the seasonal variations.The spatial and seasonal variations of nematode community reflected the nematode responses to the changing local habitat conditions.