Collaborative Research: Visual adaptations in hydrothermal vent shrimp and the role in feeding modalities and habitat selection

合作研究：热液喷口虾的视觉适应及其在摄食方式和栖息地选择中的作用

• 批准号: 2154146
• 负责人: Jonathan Cohen
• 金额: $ 36.71万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154146&HistoricalAwards=false
• 关键词: Collaborative; Research; Visual; adaptations; hydrothermal

Hydrothermal vents have given rise to remarkable marine ecosystems that contain organisms with specific adaptations for surviving in this extreme environment. Alvinocarid decapod shrimp are among the most abundant animals inhabiting these habitats and can be found in massive swarms at Pacific, Indian and Atlantic vent sites. Different species are found at different vent sites; and when species occupy the same vent site, some species are found close to the vents, with others on the periphery. Previous studies have demonstrated that vent shrimp species with enlarged eyes on their backs rely primarily on carbon provided by bacteria on the sides of black smokers, while others with fused, forward-facing eyes are predators/scavengers, around the vent periphery, suggesting that there may be a correlation between eye structure, feeding mode and habitat selection. However, adult vent shrimp are thought to be blind, but this conclusion may have resulted from the eyes being severely damaged due to collections under extremely bright submersible lights. Using methods the PIs have developed over decades to collect deep-sea species with extremely sensitive visual systems without blinding them, the visual systems of vent shrimp will be examined. These studies will be coupled with a systematic survey of pelagic and benthic light production (luminescence – both non-living chemiluminescence and triboluminescence as well as biological bioluminescence) at the vents to determine if vent shrimp can see any of these light sources. The results of this research will significantly advance the fields of vent biology and visual ecology, potentially transforming our current understanding of how light is generated at vent sites and how animals use this light to survive, as well as providing possible hypotheses as to how vent shrimp find these locations, and why different vents (diffuse, white smokers, black smokers) are dominated by different shrimp species. This proposal will support three graduate students, one postdoc and six undergraduate students, and outreach will be extended to secondary schools in underserved regions in three states by creating curriculum and activities correlated with this research that will help teachers blend this research into their STEM curricula. Originally described as eyeless, vent shrimp are now known to undergo dramatic transformations in eye morphology with some species having massive fused eyes on their backs (dorsal eyes), while others have fused anterior eyes, and these different eye structures may be correlated with their feeding preferences. However, all the structural studies that have been undertaken on the benthic adults suggest that they are blind or the eyes are degenerating. In addition, the supposition that the vent environment lacked enough ambient light to make the metabolic costs of vision worthwhile supported this conclusion. Other structural studies, however, demonstrated that the pelagic post-larvae/juveniles have stalked eyes with normal ultrastructure, and it is therefore unlikely that the metamorphosis from normal stalked eyes (post-larvae) to the huge dorsal eyes (adults) results in a degenerated eye. The “degeneration” likely resulted from photoreceptor destruction occurring during collections of benthic adults under extremely bright submersible lights. There may also be several sources of sufficient ambient light produced by both abiotic triboluminescence/chemiluminescence as well as bioluminescence. Although several studies suggest bioluminescence does not exist at these vent sites, incorrect methodology may have resulted in this conclusion. This project will use genetic techniques to allow for post-larvae-adult matching; physiological experiments to provide information on photosensitivity (absolute sensitivity as well as color sensitivity, as there has been speculation that the benthic adults may be able to see infrared light) in both post-larval and adult shrimp; ultrastructural techniques to characterize eyes collected in the dark as well as under bright submersible lights; and low-light imaging techniques to examine sources of abiotic and biotic light in the vent environments. These data will be utilized together with computation modeling to determine if vent light sources are visible to hydrothermal vent shrimp eyes over relevant distances. These unusual visual systems of vent shrimp, likely serving as extremely sensitive light receptors, may also serve as a model for low-light camera systems, much as the optics of lobster eyes served as a model for designing an ultra-sensitive X-ray telescope.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

热液喷口产生了非凡的海洋生态系统，其中包含具有在这种极端环境中生存的特殊适应能力的生物。 Alvinocarid十足类虾是栖息在这些生境中数量最多的动物之一，可以在太平洋、印度和大西洋喷口发现大量的虾群。 在不同的喷口地点发现不同的物种;当物种占据同一喷口地点时，发现一些物种靠近喷口，而另一些物种则在外围。 先前的研究表明，背部有大眼睛的喷口虾类主要依靠黑烟枪两侧细菌提供的碳，而其他眼睛融合、面向前方的物种则是喷口周边的捕食者/食腐动物，这表明眼睛结构、进食方式和生境选择之间可能存在相关性。 然而，成年的喷口虾被认为是失明的，但这一结论可能是由于眼睛由于在非常明亮的潜水灯下收集而严重受损。 将利用研究所几十年来开发的方法，收集具有极其敏感视觉系统的深海物种，而不使其失明，对喷口虾的视觉系统进行检查。在进行这些研究的同时，还将对喷口处的水层和底栖光的产生（发光-非生命化学发光和摩擦发光以及生物发光）进行系统调查，以确定喷口虾是否能看到任何这些光源。 这项研究的结果将大大推进喷口生物学和视觉生态学领域，有可能改变我们目前对喷口处如何产生光线以及动物如何利用这种光线生存的理解，并提供可能的假设，以解释喷口虾如何找到这些位置，以及为什么不同的喷口（扩散的白色吸烟者，黑色吸烟者）由不同的虾物种主导。该提案将支持三名研究生，一名博士后和六名本科生，并将通过创建与这项研究相关的课程和活动，帮助教师将这项研究融入他们的STEM课程，将外展扩展到三个州服务不足地区的中学。最初被描述为无眼的，现在已知的喷口虾在眼睛形态上发生了巨大的变化，一些物种在背部有巨大的融合眼睛（背眼），而另一些则有融合的前眼，这些不同的眼睛结构可能与它们的摄食偏好有关。 然而，对底栖成体进行的所有结构研究都表明，它们是盲人或眼睛正在退化。 此外，通风口环境缺乏足够的环境光线，使视觉的代谢成本值得支持这一结论。 然而，其他结构研究表明，浮游后期幼虫/幼体具有正常超微结构的柄眼，因此，从正常柄眼（后期幼虫）到巨大的背眼（成虫）的变态不太可能导致退化的眼睛。 这种“退化”可能是由于在极亮的潜水灯下采集底栖成体时发生的感光器破坏所致。 也可以存在由非生物摩擦发光/化学发光以及生物发光两者产生的足够的环境光的若干源。 虽然有几项研究表明，这些喷口地点不存在生物发光现象，但得出这一结论的方法可能不正确。 本项目将利用遗传技术进行幼虫-成虫配对;通过生理实验提供关于光敏性的信息（绝对敏感度以及颜色敏感度，因为有人猜测底栖成体可能能够看到红外光）;在黑暗中以及在明亮的潜水灯下收集眼睛的超微结构技术;和低光成像技术，以检查喷口环境中的非生物和生物光源。 这些数据将与计算模型一起用于确定热液喷口虾的眼睛在相关距离上是否能看到喷口光源。 这些不寻常的视觉系统的喷口虾，可能作为极其敏感的光受体，也可能作为一个模型，低光相机系统，很像龙虾眼睛的光学作为一个模型，设计一个超灵敏的X射线望远镜。这个奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。