Proximate Factors Affecting Vertical Migrations in Mesopelagic Organisms

影响中层生物垂直迁移的直接因素

• 批准号: 9730073
• 负责人: Tamara Frank
• 金额: $ 32.92万
• 依托单位: Harbor Branch Oceanographic Institution, Inc.
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-06-01 至 2001-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9730073&HistoricalAwards=false
• 关键词: Proximate; Factors; Affecting; Vertical; Migrations

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.

这项提议寻求继续本实验室正在进行的关于引发水中生物垂直迁徙的最近因素的研究。虽然这种现象被认为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，但人们对导致这种行为每天发生的因素知之甚少。过去三年进行的研究已经彻底消除了关于光的哪种特征可能导致这些迁移的假设之一。这些研究表明，引发这些迁移的并不是发生在黄昏时的光的光谱分布的变化。此外，对近紫外光的敏感性并不是垂直迁移甲壳类动物的共同特征，因此，在大多数物种中，紫外光在触发这些迁移中的作用也被打折扣。这项提案将继续解决以下问题：在黄昏时分，哪些因素正在暗示缅因湾海洋学家峡谷中上层生物的垂直迁徙。要解决的潜在线索是1)暴露在绝对光强度的阈值下，2)等值线的跟踪，3)下流光的相对增加或减少，以及4)光强度的变化率是否影响迁移速度。还将检查其中一些迁徙物种的视觉生理学，以确定1)不同物种之间光感受器敏感性的差异是否与它们迁徙模式的差异有关，以及2)中层物种是否存在与迁徙生活方式相关的内源性感光敏感度节律。将对动物分布模式的现场和网络研究与对其光感受器生理学的研究结合起来，将对确定哪些邻近因素对控制中层海洋领域每日垂直迁徙的时间具有重要意义。