The effects of copper antifouling paints and marinas on the ecology of marine sessile epifaunal assemblages

This thesis has used a field based approach to assess the effects of copper liberated from antifouling paints on sessile epifaunal (or fouling) assemblages in southeastern Australia. In the field the effects of dosed copper may be influenced by site conditions, or because the organism has developed tolerance to exposure. To explore these possible effects experiments were conducted inside and outside of two enclosed marinas. Marinas were located at St Kilda (Port Phillip Bay) and Hastings (Western Port Bay), Victoria. At St Kilda, sites were located inside the St Kilda Marina and at St Kilda Pier. At Hastings, sites were located inside Westernport Marina and at Hastings Jetty. Additional sites were also sampled occasionally over the study period. Studies were carried out between 1997-1999. A novel copper dosing system was developed for use in the field. \n\nStudies comparing epifaunal assemblages inside and outside the two marinas found that marinas produced different assemblages. The marinas exerted common effects on some functional groups, but effects at the species level differed at each marina.\n \nThe effects of dosed copper inside and outside the two marinas were tested on: i) the early recruitment of assemblages, and ii) the growth rate and competitive ability of colonial fouling organisms. Results were characterised by high spatial and temporal variability. Copper dose affected a number of species recruiting to the plates but was rarely found to significantly alter growth rates of the colonial organisms; this may be attributed to the high variability observed in growth rates. The competitive ability of colonies was not found to be affected by copper dose or marinas, but few experiments examined this aspect. \n\nReciprocal transplants of settlement plates between sites and copper doses showed that the effect of marinas on assemblages was more important than dosed copper, even though dose levels were well above background concentrations. This is probably due to a large number of factors associated with marinas over and above the effects of increased background heavy metal pollution. Several taxa appeared to adapt to local conditions or copper dose and some appeared to show heterogeneity in response to copper dosing or an ability to acclimate to dose. These types of findings have important implications for the manner in which we apply the findings of traditional laboratory-based ecotoxicology experiments to environmental management.

本研究采用野外实地研究方法，评估了防污漆（antifouling paints）释放的铜对澳大利亚东南部海域固着表栖生物群落（sessile epifaunal assemblages，或称污损生物群落（fouling assemblages））的影响。野外环境中，铜投加的效应可能受生境条件影响，或是由于生物已对铜暴露产生耐受性。为探究这些潜在影响，研究团队在两座封闭游艇码头的内外区域开展了对照实验。这两座码头分别位于澳大利亚维多利亚州的圣基尔达（菲利普港湾）与黑斯廷斯（西港湾）。其中，圣基尔达的采样点包括圣基尔达游艇码头内部及圣基尔达码头周边；黑斯廷斯的采样点则涵盖西港游艇码头内部与黑斯廷斯栈桥周边。研究周期内还曾偶尔增设额外采样点。本研究的实施周期为1997年至1999年，同时开发了一套适用于野外实验的新型铜投加系统。

对两座游艇码头内外的表栖生物群落开展对比研究后发现，码头周边的生物群落结构存在显著差异。两类码头对部分功能类群产生了共性效应，但在物种层面的效应则因码头而异。

本研究针对两座码头内外的铜投加效应开展了两项测试：其一为群落的早期定居过程，其二为群居污损生物的生长速率与竞争能力。实验结果呈现出高度的空间与时间变异性。铜投加量会对附着于实验定居板的多个物种产生影响，但极少能显著改变群居污损生物的生长速率，这或许可归因于生长速率本身存在较高的自然变异性。未发现铜投加量或码头环境对群居生物的竞争能力产生影响，不过相关实验研究较为有限。

在不同采样点间以及不同铜投加梯度下开展的定居实验板互置移植实验显示，码头环境对生物群落的影响远大于铜投加的效应，即便铜投加浓度远高于当地背景水平。这大概率是因为码头环境除了提升背景重金属污染水平之外，还存在诸多其他关联影响因素。部分分类群似乎适应了当地生境或铜投加条件，另有部分分类群在响应铜投加时表现出效应异质性，或是具备对投加剂量的驯化能力。这类研究结果对于我们如何将传统实验室生态毒理学实验的结论应用于环境管理工作，具有重要的启示意义。