Proximate Factors Affecting Vertical Migrations in Mesopelagic Organisms

该提案旨在继续该实验室正在进行的关于引发中层水生物垂直迁移的直接因素的研究。 虽然这种现象是地球上的主要行为模式之一，并对海洋生态系统的结构产生了深远的影响，但人们对这种行为的日常时间因素知之甚少。 在过去三年中进行的研究已经明确消除了关于光的特征可能提示这些迁移的假设之一。 这些研究表明，这不是光的光谱分布的变化，这发生在黄昏，这是作为一个触发器，以提示这些迁移。 此外，对近紫外光的光敏性并不是垂直迁移甲壳类动物的共同特征，因此，紫外光在触发大多数物种的这种迁移方面的作用也被低估了。 这项建议将继续解决的问题是什么因素在黄昏提示垂直迁移的中层生物在海洋学家峡谷在缅因州湾。 将被解决的潜在线索是1）暴露于绝对光强度的阈值，2）跟踪隔离带，3）下降光的相对增加或减少，以及4）光强度的变化率是否对迁移速度有影响。 还将检查其中一些迁徙物种的视觉生理学，以确定1）不同物种之间的感光器敏感性是否存在差异，这可能与其迁徙模式的差异有关，以及2）中层物种的感光器敏感性是否存在内源性节律，这可能与迁徙生活方式有关。 结合原位和净的动物分布模式的研究，其感光生理学的研究，将作出重大贡献，以确定什么样的近似因素是重要的，在控制每天的时间在中层领域的垂直迁移。

This proposal seeks to continue ongoing studies by this laboratory of proximate factors triggering vertical migrations in midwater organisms. While this phenomenon is known to be one of the dominant behavioral patterns on earth, and has a profound influence on the structure of marine ecosystems, little is known about the factors which cue the daily timing of this behavior. Studies conducted in the last three years have definitively eliminated one of the hypotheses regarding which characteristic of light might cue these migrations. These studies demonstrated that it is not the change in the spectral distribution of light, which occurs at twilight, that is serving as a trigger to cue these migrations. In addition, photosensitivity to near-UV light was not found to be a common characteristic of vertically migrating crustaceans, and therefore, the role of UV light in triggering these migrations in most species has also been discounted. This proposal will continue to address questions about what factors at twilight are cueing vertical migrations in mesopelagic organisms in Oceanographer Canyon in the Gulf of Maine. Potential cues that will be addressed are 1) exposure to a threshold value of absolute light intensity, 2) tracking of an isolume, 3) relative increase or decrease in downwelling light, and 4) if the rate of change in light intensity has an effect on migration speeds. The visual physiology of some of these migrating species will also be examined to determine if 1) there are differences in photoreceptor sensitivity between the various species that can be correlated to differences in their migration patterns, and 2) if endogenous rhythms in photoreceptor sensitivity are present in mesopelagic species that can be correlated to a migratory lifestyle. Combining in situ and net studies of animal distribution patterns with studies of their photoreceptor physiology will make a significant contribution to determining what proximate factors are important in controlling the daily timing of vertical migrations in the mesopelagic realm.