Impact of Toxic Dinoflagellates on Digestive Physiology and Metabolism of Copepods

9402186哈西特由于赤潮的戏剧性后果，有时甚至是灾难性的后果，多年来人们对有毒的甲藻进行了深入的研究。然而，这些研究中相对较少涉及甲藻对浮游动物的影响。这个项目的主要目标是确定甲藻、塔玛亚历山大藻和锥状斯氏藻如何对桡足类消化系统和新陈代谢产生作用。这些研究将研究不同的桡足类物种是否具有不同的敏感性，以及这些敏感性与摄食史和营养状况的关系，并将确定其他甲鞭毛类物种是否对桡足类有类似的影响。该项目将在实验室实验中使用视觉描述和形态计量学分析几种以两种双鞭毛类为食的桡足类动物的肠道细胞。对肠道形态的分析将在光学和电子显微镜水平上进行，还将包括在光学显微镜下观察活的桡足类的消化系统。还将测定生理速率(消化酶活性、代谢酶活性、排泄率和呼吸速率)和摄食率的变化，以评估摄取有毒甲藻或暴露于甲藻毒素的后果。在确定了桡足类和两种甲藻之间的相互作用之后，该项目将利用所获得的知识作为调查其他甲藻物种对桡足类的影响的基础。

9402186 HASSETT Due to the dramatic and sometimes catastrophic consequences of red tides, toxic dinoflagellates have been intensively studied over the years. However, relatively few of these studies have dealt with effects of dinoflagellates on zooplankton. The main objective of this project is to determine how the dinoflagellates, Alexandrium tamarensis and Scrippsiella trochoidea act upon the copepod digestive system and metabolism. These studies will examine if different copepod species have different susceptibilities and how these relate to feeding history and nutritional status, and will determine if other dinoflagellate species have similar impacts on copepods. This project will use visual description and morphometric analyses of the gut cells of several copepods feeding upon the 2 species of dinoflagelattes in laboratory experiments. Analyses of gut morphology will be conducted at both the light and electron- microscope level , and also will include observations of the digestive system of live copepods under light microscope. Changes in physiological rates (digestive enzyme activities, metabolic enzyme activities, excretion rate, and respiration rate) and feeding rate also will be determined to assess the consequences of ingesting a toxic dinoflagellate or of being exposed to dinoflagellate toxins. After establishing the interactions between copepods and the two dinoflagellates, this project will use the knowledge gained as a basis for a survey of impacts of other dinoflagellate species on copepods.