黄河口大型底栖动物群落结构特征及其与环境因子的耦合分析

为探究复杂环境下的河口大型底栖生物群落结构特征,研究了黄河口及其毗邻海域内14个站位的底栖生物群落结构及其与主要环境因子的耦合关系。研究结果表明调查海域底栖生物群落组成和结构的空间异质性较高。底栖生物优势度不明显,优势物种集中于河口附近站位。生物多样性随离河口距离增加而增加,物种丰富度和生物多样性指数等的高值区均出现在远离河口的渤海湾和渤海中部站位,低值区位于近河口站位。对底栖生物群落的非参数多维排序(nMDS)和等级聚类分析显示,底栖生物群落结构相似性较低。丰度/生物量曲线(ABC曲线)分析显示,黄河口底栖生物群落整体上处于稳定状态,但近河口和莱州湾中西部站位受到干扰影响,群落结构不稳定。研究还表明生物量大的底栖生物(软体动物)倾向于向重金属含量较高的站位聚集。综合沉积物化学、预测毒性和底栖生物群落结构变化的评价结果可知,远离黄河口的沉积物环境质量普遍较好,而河口附近的沉积物环境质量较差。

Characteristics of benthic macroinvertebrate community structure and its coupling relationships with environment factors in Huanghe estuary

Benthic macroinvertebrate assemblages in 14 sediment stations from Huanghe estuary were investigated to explore the characteristics of benthic community structure and its relationships to potential explanatory factors. Results showed there was a substantial spatial heterogeneity in species composition and community structure. Low degree of dominance was found in the surveyed area and dominance species was found aggregating in the stations near the river mouth. We also found a trend of increasing species diversity with increasing distance from the river mouth in Huanghe estuary. High values of richness and diversity index usually appeared in stations from Bohai Bay and central areas of Bohai Sea, but low values occurred near the river mouth. Reduction of benthic data by non-metric multidimensional scaling (nMDS) and hierarchical cluster suggested low similarity among stations. Ecosystem health assessment examined by combined abundant biomass k-dominance curve (ABC) indicated the overall status of benthic community in the area investigated remained stable. The stations with unstable benthic community mainly situated adjacent to the river mouth and located in the central and west Laizhou Bay. In addition, the presence of larger size species with increasing proximity to stations with higher metal contamination level was inferred from Pearson correlation analysis between benthic data and coupling factors. A holistic assessment of sediment quality by incorporating sediment chemistry, predicted toxicity and benthic community structure indicated that impacted sediment (degraded) was distributed near the river mouth, while unimpacted sediment located far from the river mouth.