【作者】 刘海滨；

【导师】 张志南；

【作者基本信息】 中国海洋大学 ， 生态学， 2007， 博士

【摘要】 2004年10月到2005年10月对青岛太平湾进行了连续13个月的小型底栖生物的调查采样,对小型底栖生物栖息的沉积环境、小型底栖生物的丰度和生物量、自由生活海洋线虫群落结构、多样性和分类学进行了研究。同时,建立了不同季节的青岛砂质潮间带的底栖群落粒径谱,对砂质潮间带粒径谱季节变化规律进行了研究,并采用连续积分模型利用粒径谱数据计算了调查区域的底栖群落生产力和耗氧量。结果表明,研究区域的沉积物的主要成分为中砂和细砂,粉砂和粘土含量极少,属于砂质潮间带。沉积物各特征参数之间具有显著的相关关系。在沉积物中,叶绿素a（Chl-a）的平均含量分别为0.396 mg·kg-1沉积物,冬季较低,而在夏季和秋季较高。脱镁叶绿酸（Pha-a）全年都维持较低水平,平均含量分别为0.045 mg·kg-1沉积物。有机碳含量年平均值为0.304%,在春季含量较高,在4月份达到最高值0.460%,秋季和冬季则含量低,在11月和12月分别达到全年最低值0.133%和次低值0.190%。Pearson相关分析结果表明,叶绿素a与温度显著正相关（p<0.05）,证明初级生产力受到温度和太阳辐射强度的制约。重金属Cr、Cu、Zn、As、Cd和Pb的年平均含量分别为2.568μg/g、1.240μg/g、13.158μg/g、3.748μg/g、0.045μg/g和3.156μg/g。各种重金属含量季节变化有所不同,含量均未超标,表明青岛太平湾潮间带区域未受重金属污染。共鉴定出自由生活海洋线虫、底栖桡足类、多毛类、双壳类、介形类、端足类、涟虫类、腹毛类、寡毛类、海螨类、涡虫类和其它类等12个小型底栖动物类群,小型底栖动物的平均丰度为（1025.40±168.84）ind.10cm-2,其中海洋线虫占绝对优势,其平均丰度为（914.24±208.65）ind.10cm-2,占小型动物总丰度的89.16%;其次是多毛类,占3.91%。小型底栖动物的平均生物量和生产量分别是（1195.87±476.53）μg dwt 10cm-2和（10762.80±4288.77）μg dwt 10cm-2 a-1。小型底栖动物的垂直分布上,小型底栖动物分布于沉积物0-4、4-8cm和8-12cm的数量比例分别为51.5%、25.9%和10.0%。多数小型底栖生物分布在0-4cm表层。小型底栖生物的垂直分布存在季节变化,夏季表层数量较少,也可能与人为扰动有关;秋季多集中在表层,在冬季随温度降低向下迁移。太平湾共鉴定出自由生活海洋线虫77属,23科,4目。优势属是Microlaimus,Bathylaimus,Neochromadora,Enoplolaimus,Metadesmolaimus,Theristus,Metoncholaimus,Axonolaimus,Ascolaimus,Paracanthonchus,Chromadorita,Promonhystera,Rhynchonema,Nannolaimus,Oncholaimus,Spiliphera, Paracyatholaimus,Tricoma,Camacolaimus,Paramonhystera,Chromadorita,Elzalia,Oxyonchus,Acantholaimus,Doliolaimus,Daptonema,Prochromadorella,Halalaimus等。研究区域13个月份的平均丰富度指数、均匀度指数、多样性指数和优势度指数分别为3.92、0.63、1.91和0.72。线虫群落的营养结构,按属数目统计,刮食者（2A）最占优势,有29属,占总属数的37%;选择性沉积食性者（1A）最少,只有8属,占11%;捕食食性者（2B）和非选择性沉积食性者（1B）分别有12属和28属,分别占16%和36%。按所有个体数量统计,刮食者占37.2%,非选择性沉积食性者占37.1%,选择性沉积食性者占11.3%,捕食者占13.4%。从统计结果看,刮食者（2A）在个体数量和属数上最占优势,由此推断藻类和有机碎屑是食物的主要来源。在线虫群落中幼龄个体占到线虫总数的21.51%,雌雄比例平均为1:1.128,与类似生境研究结果相一致。根据CLUSTER等级聚类树枝图和MDS标序图,可以将调查区域划分为2组类型的线虫群落（或者说是站位组群）,分别是A:春夏季群落B:秋冬季群落。One-Way ANOSIM检验证实了各组群之间线虫群落结构差异显著,线虫群落的营养结构与多样性分析也表明了以上群落划分是合理的。线虫群落结构与环境因子的BIOENV分析表明,在A组群,控制线虫群落结构的主要环境因子是:盐度、pH、中值粒径（Mdφ）以及重金属Cd、Pb。而在B组群解释线虫群落结构特征的最佳环境因子组合是:pH、有机碳含量和重金属Cr、Cu、Pb。底栖生物群落粒径谱结构有明显的季节变化。在1月和4月粒径谱为具有2个生物量谷的三峰模式,但7月和10月份的粒径谱却仅具有1个强度较大的生物量谷,粒径谱分布模式为双峰模式。粒径谱生物量谷的强弱与溶氧条件有着密切联系,表明与其他粒级处的生物相比,生物量谷处的生物对溶氧条件更为敏感。青岛砂质潮间带4个季节的正态化粒径谱适合直线回归模型,平均回归系数分别为0.873,平均截距分别为14.48,平均斜率分别为-0.854。正态化粒径谱直线回归参数表现出与沉积物间隙水溶氧含量有直接或间接的联系。通过正态化粒径谱直线回归标准化残差分析,发现底栖动物粒径谱存在两个不同性质的生物量谷,谷底对应的粒级分别为0～1和5～6。提出底栖动物粒径谱生物量谷可能是群落对低氧条件的适应现象。大型和小型底栖动物通过不同的选择对低氧环境有着不同的适应方式,而粒级在两者之间的生物对低氧的适应能力最差。粒径谱生物量谷可以用生物对低氧条件的适应对策分化来解释,为粒径谱不连续性提供了新的理论依据。利用青岛砂质潮间带底栖动物粒径谱数据,运用连续模型计算出青岛砂质潮间带底栖动物群落的季节平均次级生产力为2.541 g dwt·m^-2·a^-1,耗氧量为0.120 mmol·m^-2·h^-1,小型和大型底栖动物次级生产力占总次级生产力的百分比分别为38.6%和61.4%,小型和大型底栖动物耗氧量占总耗氧量的百分比分别为36.3%和63.7%;研究结果表明,群落次级生产力和耗氧量之间具有相同的变化趋势,且都与正态化生物量粒径谱截距呈显著正相关,而与斜率无显著关系。利用正态化生物量粒径谱和连续模型可以得到可信的底栖动物群落次级生产力和耗氧量结果。更多还原

【Abstract】 The meiofauna was quantitatively investigated in the sandy beach of Taiping Bay, Qingdao based on monthly sampling from Oct.2004 to Oct.2005. The sedimentary environment, abundance and biomass of meiofauna, community structure and biodiversity and systematics of free-living marine nematodes, were quantitatively studied at the middle intertidal zone during the periods of investigation. In spite of detailed variety across temporal and spatial scale, conservative bimodal metazoan benthic biomass size spectra were observed in different environmental condition. Sheldon-type and normalized biomass size spectra of metazoan benthos were constructed in the sandy intertidal zone. Seasonal variation of biomass size spectrum was analyzed using the data of the sandy intertidal zone. Secondary productions and oxygen consumptions of metazoan benthic assemblages were estimated by the method of continuous integral model. The main results are as follows:The dominant sediment types of the sampling stations are MS and FS, silt and clay contents were very low. The studied site is a typical sandy beach. Sediment characteristic parameters had significant correlations with each other. The average content of chlorophyll a （Chl-a） in the sediment was 0.396 mg·kg-1 sediment with low value in winter and high in summer and autumn. The average content of phaeophorbide a （Pha-a） in the sediment was low in the whole year, on average 0.045 mg·kg-1 sediment. The average content of organic matter was 0.304%. The highest value was 0.460% in spring and the lowest one was 0.133% in winter. Correlation analysis showed that sediment Chl-a content correlated with temperature positively, which suggests that the primary production is controlled by temperature and solar radiation. The average contents of the heavy metals Cr, Cu, Zn, As, Cd and Pb were 0.568μg /g, 1.240μg/g, 13.158μg/g, 3.748μg/g, 0.045μg/g and 3.156μg/g, respectively. The whole year contents of heavy metals at the studied site differed a lot. All the contents of heavy metals at the studied site were lower than the national standard, which means the Taiping Bay is still clean and not polluted by heavy metals. A total of 12 groups of meiofauna were identified at the studied site: Nematoda, Copepoda, Polychaeta, Bivalvia, Ostracoda, Amphipoda, Cumacea, Gastrotricha, Turbellaria, Oligochaeta, Halacaroidea and others. The average abundance of meiofauna was （1025.40±168.84） ind.10cm-2. Free-living marine nematode was the most dominant group, accounting for 89.16% of total abundance of meiofauna, with Polychaeta being the second, accounting for 3.91%.The mean biomass and production of meiofauna were （1195.87±476.53）μgdwt10cm-2 and （10762.80±4288.77）μg dwt 10cm-2 a-1, respectively. In terms of vertical distribution, 51.5% of total meibenthos was found in the surface sediment 0-4cm, 25.9% in 4-8cm and 10.0% in 8-12cm. The vertical distribution of meiofauna exhibited seasonal variation. In the summer months, meiofauna density decreased in the upper layers. In autumn, meiofauna concentrated in the upper layers and with the decreasing of temperature, they migrated to the deeper layers.A total of 77 genera of free-living marine nematodes, belonging to 23 families and 4 orders, were identified. The dominant genera in the sampling area are: Microlaimus, Bathylaimus, Neochromadora, Enoplolaimus, Metadesmolaimus, Theristus, Metoncholaimus, Axonolaimus, Ascolaimus, Paracanthonchus, Chromadorita, Promonhystera, Rhynchonema, Nannolaimus, Oncholaimus, Spiliphera, Paracyatholaimus, Tricoma, Camacolaimus, Paramonhystera, Chromadorita, Elzalia, Oxyonchus, Acantholaimus, Doliolaimus, Daptonema, Prochromadorella, Halalaimus. The average species abundance index, evenness index, diversity index and dominance index were 3.92, 0.63, 1.91 and 0.72, respectively.The trophic structure of free-living marine nematodes was studied. It included 29 genera of epigrowth feeders （2A）, which accounted for 37% of the total genus number, 8 genera （11%） of selective deposit feeders （1A）, 28 genera （36%） of non- selective deposit feeders （1B） and 12 genera （16%） of predators/omnivores （2B）. Epigrowth feeders （2A） were dominant by total genus number and relative abundance, which showed the food sources of nematodes are mainly detritus and benthic diatoms in the sampling area. Juveniles accounted for 21.51% of total nematodes and female/male ratio was 1: 1.128. It is similar to other studies. The community structure of nematode was studied. CLUSTER and MDS analyses divided the sampling stations into two groups （or sampling months）. They are A: spring and summer group, and B: autumn and winter group. One-Way ANOSIM test showed that the community structures of different season were significantly different. The trophic structure and biodiversity analyses of the nematodes community also proved the division of seasons. BIOENV analysis between the nematodes community and environmental factors showed that salinity, pH, Mdφ, and the content of Cd and Pb were important factors for the spring and summer nematode communities. The best combination of environmental factors, which can explain the autumn and winter nematodes community structure, were pH, organic matter content and the content of Cr, Cu and Pb.Structure of biomass size spectrum transformed seasonally. Sheldon-type biomass size spectra appeared tri-modal at January and April, but bimodal with a strong trough at July and October. Closely coupling between trough strength and DO suggested that species located in the size classes of trough might be more sensitive to hypoxia than those in other size classes. All normalized biomass size spectra fitted linear regression reasonably. Two different troughs, however, were revealed by analyzing standardized residuals of normalized biomass size spectra. Bottoms of troughs located respectively in 0 to 1 and 5 to 6 size classes. Therefore a hypothesis is set forth: DO is one of the reasons for conservative trough in benthic biomass size spectra, since meiofauna and macrofauna take different strategies to adapt hypoxia. At least the hypothesis is reasonable at the site examined in this study, because it can explain almost all the abnormal characters at the sandy intertidal zone.By the method of continuous integral model, secondary productions and oxygen consumptions of macro- and meiofuana were calculated in the sandy intertidal zone. Average of secondary productions of 4 seasons was 2.541 g dwt·m^-2·a^-1, and average of oxygen consumptions was 0.120 mmol·m^-2·h^-1 at the intertidal zone. Both secondary production and oxygen consumption showed positive correlations with intercept of normalized biomass size spectra. Compared with the method following the formula P = 9B, continuous integral model can provide more reliable evaluation of secondary production of meiofauna.更多还原