Direct and indirect effects of metal pollutants on lotic food webs: comparative sensitivities of warmwater and coldwater forage fish

对我们沃茨的保护取决于我们对生态系统复杂性的理解能力，这种理解足以使我们对污染物与暴露生物体的反应之间的预测关系具有一定程度的信心。由于水生生态系统的复杂性，我们对污染物（例如，金属和金属混合物）对河流食物网的影响有限。将我们的结果从暖水鱼类外推到冷水鱼类也是非常有限的。拟议研究的长期目标是更好地了解污染物（包括金属）对海洋食物网的直接和间接影响，以及鱼类物种之间的比较敏感性。我们将使用硒作为模型污染物。硒是一种必需的微量营养素，在很窄的浓度范围内既有益又有毒。采矿、农田灌溉、石油炼制和煤燃烧可增加水生态系统中的硒。直接（水暴露）和间接（饮食暴露）硒的部分生命周期的温水（黑头呆鱼）和冷水（粘杜父鱼）饲料鱼和生命周期的一个占主导地位的猎物项目（吸浆虫）将使用简单的食物网（藻类，无脊椎动物，鱼）的影响。本研究将建立一个泥杜父鱼的部分生命周期生殖生物测定方法。在不同的温度制度下，当这些鱼在同一个自我维持的四级食物网（藻类，无脊椎动物，粘杜父鱼，黑头呆鱼）相互作用时，黑头呆鱼和粘杜父鱼对硒的敏感性将进行评估。这项研究将有助于我们更好地了解硒对河流食物网的影响以及冷水和温水鱼类的不同敏感性。了解单一金属的生物反应将有助于我们了解复杂混合物的反应（例如，金属矿废水）。

Protection of our waters depends upon our ability to understand ecosystem complexity enough to attain a level of confidence in predictive relationships between a pollutant and the response of exposed organisms. Due to the complexities of aquatic ecosystems, our understanding of how pollutants (e.g., metals and metal mixtures) affect lotic (river) food webs is limited. Extrapolation of our results from warm water to coldwater fishes is also very limited. The long term objectives of the proposed research are to better understand direct and indirect effects of pollutants including metals on lotic food webs and comparative sensitivities among species of fish. We will use selenium as our model pollutant. Se is an essential micronutrient that is both beneficial and toxic within a narrow concentration range. Mining, irrigation of agricultural land, petroleum refining and coal combustion can increase Se in aquatic ecosystems. Direct (waterborne exposure) and indirect (dietary exposure) effects of Se on the partial lifecycles of warm water (fathead minnow) and cold water (slimy sculpin) forage fishes and the lifecycle of a dominant prey item (midge) will be investigated using simple food webs (algae, invertebrate, fish). A partial lifecycle reproductive bioassay will be developed for slimy sculpin. Sensitivities of fathead minnow and slimy sculpin to Se will be assessed under different temperature regimes and when these fish are interacting in the same self-sustaining four-level food web (algae, invertebrate, slimy sculpin, fathead minnow). This research will better our understanding of how river food webs are affected by Se and the different sensitivities of cold and warm water fishes. Understanding biological responses for single metals will assist our understanding of responses to complex mixtures (e.g., metal mine effluents).