大肚溪口潮間帶地區大型底棲動物群聚現象與相關重金屬含量分析

Benthic Macro-Invertebrate Community in the Tatu Estuary and Its Relation to Heavy Metal Contents

大肚溪口位於臺灣中西部，是臺灣目前所設立之海岸保護區中面積最大的。為瞭解底棲動物群聚現象及其與土壤重金屬含量之關係，本研究選定9個固定採樣站（station），每隔三個月於各採樣站設置一個樣區，採集樣區內的底棲動物，調查工作自2000年1月至12月，共四季，取得36個樣區資料，並分別檢測樣區內水體之鹽度、pH值、溶氧飽和度及土壤中鎘、鎳、鉛、鋅、鉻、銅、砷、汞等8項重金屬含量，以探討底棲動物群聚與環境因子之關係。結果顯示，不同樣區間之區別明顯，而季節的差異則不甚明顯，水質及土壤重金屬含量皆會影響底棲動物群聚。由所設置的9個採樣站採取的生物體樣本，進行8項重金屬含量的檢驗，分析顯示鎘、鋅、鉛、鎳、鉻、砷在貝類中之含量高於蟹類，再對應分析土壤的8項重金屬全量檢驗值，各樣區的底棲動物體內重金屬之含量雖然有差異，但不若土壤重金屬含量在各樣區的差異大，反而物種的差異大些。 Tatu Estuary in the central western Taiwan is the largest coastal sanctuary of the island. Tounderstand the interaction of the benthic macro-invertebrate community and its surroundingenvironments in the tidal zone, macro-invertebrates were sampled seasonally at nine sampling stations atintervals of three months in 2000. Salinity, pH value, and dissolved oxygen saturation were measuredseasonally. Contents of heavy metals, including cadmium, nickel, lead, zinc, chromium, copper, arsenicand mercury in soil and macro-invertebrates were analyzed. The results indicated that there wasconspicuous variation in the benthic macro-invertebrate community structure among the samplingstations, but not among the seasons. Water quality affected the community structure. The heavy metalcontents were highly variable among the stations for soils, but not for macro-invertebrates. The heavymetal contents were also more variable among species than among sampling stations. The contents ofcadmium, nickel, lead, zinc, chromium and arsenic in bivalves were higher than those in crabs.