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: 2154144
• 负责人: Sonke Johnsen
• 金额: $ 29.28万
• 依托单位: Duke University
• 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=2154144&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.

热液喷口催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定适应能力的生物体。 十足目虾是栖息在这些栖息地的最丰富的动物之一，可以在太平洋、印度和大西洋的喷口处发现大群的虾。 不同的喷口地点发现了不同的物种；当物种占据同一喷口地点时，一些物种被发现靠近喷口，而另一些物种则在外围。 先前的研究表明，背部眼睛增大的喷口虾主要依赖黑烟虾侧面细菌提供的碳，而其他眼睛融合、向前的喷口虾是捕食者/清道夫，位于喷口周边，这表明眼睛结构、摄食模式和栖息地选择之间可能存在相关性。 然而，成年文口虾被认为是盲目的，但这一结论可能是由于在极亮的潜水灯下采集而导致眼睛严重受损所致。 PI 几十年来开发了一些方法来收集具有极其敏感视觉系统的深海物种而不致盲它们，将对文口虾的视觉系统进行检查。这些研究将与对喷口处的中上层和底栖光产生（发光——非生命化学发光和摩擦发光以及生物生物发光）的系统调查相结合，以确定喷口虾是否可以看到这些光源。 这项研究的结果将极大地推进喷口生物学和视觉生态学领域的发展，有可能改变我们目前对喷口地点光如何产生以及动物如何利用这种光生存的理解，并为喷口虾如何找到这些位置以及为什么不同的喷口（漫射型、白烟型、黑烟型）以不同虾种为主提供可能的假设。该提案将支持三名研究生、一名博士后和六名本科生，并将通过创建与本研究相关的课程和活动，将服务范围扩展到三个州服务欠缺地区的中学，帮助教师将这项研究融入他们的 STEM 课程。文口虾最初被描述为无眼，现在人们知道它们的眼睛形态发生了巨大的变化，一些物种的背部有巨大的融合眼睛（背眼），而另一些物种则具有融合的前眼，这些不同的眼睛结构可能与它们的摄食偏好有关。 然而，对底栖成虫进行的所有结构研究都表明它们是失明的或眼睛正在退化。 此外，通风口环境缺乏足够的环境光，使得视觉的代谢成本值得的假设也支持了这一结论。 然而，其他结构研究表明，中上层幼体/幼体的有柄眼具有正常的超微结构，因此从正常有柄眼（后期幼体）到巨大背眼（成体）的变态不太可能导致眼睛退化。 这种“退化”可能是由于在极亮的潜水灯下收集底栖成虫时发生的光感受器破坏所致。 还可能存在由非生物摩擦发光/化学发光以及生物发光产生的充足环境光的多个来源。 尽管一些研究表明这些喷口处不存在生物发光，但错误的方法可能导致了这一结论。 该项目将使用遗传技术来实现幼体后与成体的匹配；生理实验，提供幼体虾和成虾的光敏性（绝对敏感度和颜色敏感度，因为有人推测底栖成虾可能能够看到红外光）信息；用于表征在黑暗以及明亮的潜水灯下收集的眼睛的超微结构技术；以及低光成像技术，用于检查通风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使用，以确定在相关距离内热液喷口虾的眼睛是否可以看到喷口光源。 口虾的这些不寻常的视觉系统可能是极其敏感的光感受器，也可以作为低光摄像系统的模型，就像龙虾眼睛的光学系统可以作为设计超灵敏 X 射线望远镜的模型一样。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。