黄河口泥螺种群夏季分布特性及其与底质环境的关系

Preliminary study on distribution characteristics and living environment of Bullacta exarata population in Yellow River Estuary, China

中文关键词: 泥螺  种群  底质环境  黄河口

英文关键词: Bullacta exarata  Population  Sedimental environment  Yellow River Estuary

中文摘要:

      2011年8月对黄河口潮间带泥螺Bullacta exarata种群及底质环境条件进行了调查，以期了解泥螺与底质环境的相互作用关系。调查结果显示，1）泥螺主要分布于中值粒径Mdφ为3.73～5.25范围的中潮带，底质类型主要由砂、粉砂质砂和砂质粉砂组成；2）黄河口以南滩涂表层泥有机质含量和底质叶绿素a含量均值分别为1.39%、2.65%，总体水平高于北岸表层泥有机质含量和底质叶绿素a含量，均值分别为0.54%、1.48%，方差分析结果显示，差异显著（P<0.05）；3）黄河口南岸滩涂泥螺密度均值为16.7 ind/m2，明显高于北岸的0.6 ind/m2，经方差分析，差异显著（P<0.05）。各断面泥螺密度（x）与泥螺个体的平均壳长(y)变化趋势相反，其关系式为：y=-0.180 1x+19.184，R2=0.776，呈显著相关（P<0.05），泥螺的个体规格与密度成反比，即泥螺密度越高的站位，个体规格越小；4)Taylor幂法则、Iwao聚集格局回归分析法及Morisita指数分析结果表明，黄河口泥螺种群空间格局属于聚集型负二项分布；5) 泥螺种群密度与表层泥有机质含量和底质叶绿素a含量正相关，回归关系显著（P<0.05）,说明食物可能是影响泥螺种群分布的主要因素之一。

英文摘要:

      In order to understand the interaction between Bullacta exarata and sedimental environment, population of B.exarata and sediment characteristics were investigated at the typical distribution area of the Yellow River estuary in August, 2011. The results were as follows: (1) B. exarata was mainly distributed in mudflats with median particle diameter φ (Mdφ) ranging from 3.73~5.25; and the sediment types were composed of silt, salt-sand and sand-salt. (2) The average organic content and Chl-a concentration in surface sediment of the south intertidal zone was 1.39% and 2.65μg/g, which was significantly higher than in the north of the estuary with an average organic content of 0.54%and Chl-a concentration of 1.48μg/g. (3) The average population density was 16.7ind/m2,which was significantly higher in the south intertidal zone than in the north of the estuary with the average population densities of 0.6ind/m2. The relationship between population density (x) and average shell length (y) could best be expressed as the linear equation:y=-0.180 1x+19.184, R2=0.776．B. exarata body size and population density was inversely proportional; the higher the population density, the smaller the body size. (4) Taylor' power law, Iwao's patch regression and Morisita index analysis results showed that the spatial pattern of B. exarata population in the estuary belonged to the clumped and negative binomial distribution theoretically. (5) There were positive relationships between the density of B. exarata and organic content or Chl-a, suggesting that food source might be one of the main limiting factors for the distribution of B. exarata population.