Department of Fishery Biology, Faculty of Fisheries, Kasetsart University, Chatuchak, Bangkok 10900, Thailand.
Water Sci Technol. 2011;64(6):1261-9. doi: 10.2166/wst.2011.681.
The influence of environmental factors on the abundance and temporal variation of benthic fauna resources was studied in the eutrophic Tha Chin estuary located in Samut Sakhon province. The objectives were to analyze the status of abundance and temporal variation of the benthic fauna and to clarify the impacts from environmental factors (water and sediment quality). Field surveys were conducted monthly from August 2007 to March 2008 at 11 sampling stations in the estuary. Based on freshwater runoff volumes, the high-, medium-, and low-loading periods were categorized to be from August to October 2007, November to December 2007, and January to March 2008, respectively. The benthic fauna resources were composed of 57 species in eight phyla. Annelids were the dominant species (with the maximum density being 19,885 individuals/m2), followed by the mollusks. Both densities decreased during the low-loading period in 2008. Water quality deteriorated during the high-loading period. Land-based wastewater discharges decreased the levels of salinity and dissolved oxygen but dramatically increased various nutrients. Consequently, the sediment quality deteriorated during the medium-loading period. Bottom deposits during this time depicted high accumulation of acid volatile sulfides (more than 0.76 mg/g dry weight). Analyzing the environmental relationships, deposit feeders (for example, Nereis sp. and Prionospio sp.) and a clam (Arcuatula sp.) showed potential as bio-indicators for environmental monitoring. The overall results revealed the importance of changes in the water and sediment qualities that had an influence on related benthic resources. The increase in the level of NH4(+)-N had a negative impact on the economic clam species, while the sedimentary TOM showed positive correlation (P < 0.05) with this increase. The succession of groups based on feeding behavior seemed to correspond with stress in eutrophication along the salinity gradient and in different estuarine parts. In addition, the economic clam population decreased noticeably during the medium-loading period, as a consequence of deteriorated sediment conditions. Thus, the land-based runoff should be controlled for the protection of resources. Further effective sustainable management will be enhanced by giving serious consideration to an eco-based zoning scheme for conservation and restoration of the Tha Chin estuary.
在泰国春武里府的塔钦河口进行了一项研究，旨在探讨环境因素对底栖动物资源丰度和时间变化的影响。该研究目的是分析底栖动物的丰度和时间变化状况，并阐明环境因素（水质和底质）的影响。2007 年 8 月至 2008 年 3 月，每月在河口的 11 个采样点进行实地调查。根据径流量，将高、中、低负荷期分别归类为 2007 年 8 月至 10 月、2007 年 11 月至 12 月和 2008 年 1 月至 3 月。底栖动物资源由 8 个门的 57 种组成。环节动物（最大密度为 19885 个/平方米）是优势种，其次是软体动物。这两种动物的密度在 2008 年的低负荷期都有所下降。高负荷期水质恶化。陆基废水排放降低了盐度和溶解氧水平，但大大增加了各种养分。因此，中负荷期底质恶化。此时的底沉积物显示出酸可挥发性硫化物（AVS）的高积累（超过 0.76 毫克/克干重）。分析环境关系表明，沉积食性动物（例如，Nereis sp.和 Prionospio sp.）和一种蛤（Arcuatula sp.）可作为环境监测的生物指标。总体结果表明，水质和底质变化对相关底栖资源有重要影响。NH4(+)-N 水平的升高对经济贝类物种有负面影响，而 TOM 则与这种升高呈正相关（P < 0.05）。根据摄食行为进行的分组演替似乎与沿盐度梯度和不同河口部位的富营养化应激相对应。此外，由于底质条件恶化，经济贝类种群在中负荷期明显减少。因此，应控制陆基径流，以保护资源。通过认真考虑基于生态的分区方案，加强对塔钦河口的保护和恢复，将进一步增强有效的可持续管理。
