Impact of Toxic Dinoflagellates on Digestive Physiology and Metabolism of Copepods

[402186]由于赤潮的戏剧性和有时灾难性的后果，有毒鞭毛藻多年来一直被深入研究。然而，这些研究中相对较少涉及鞭毛藻对浮游动物的影响。本项目的主要目的是确定鞭毛藻、塔玛力山Alexandrium tamarensis和trochoidea Scrippsiella对桡足动物消化系统和代谢的作用。这些研究将考察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对几种以两种鞭毛虫为食的桡足类动物的肠道细胞进行视觉描述和形态计量学分析。将在光镜和电子显微镜下对肠道形态进行分析，并在光镜下对活桡足动物的消化系统进行观察。生理速率（消化酶活性、代谢酶活性、排泄速率和呼吸速率）和摄食速率的变化也将被确定，以评估摄入有毒甲藻或暴露于甲藻毒素的后果。在确定了桡足类与两种鞭毛藻之间的相互作用后，本项目将以此为基础，调查其他鞭毛藻物种对桡足类的影响。

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.