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: 2154168
• 负责人: Heather Bracken-Grissom
• 金额: $ 41.42万
• 依托单位: Florida International 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=2154168&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.

热液喷口已经形成了非凡的海洋生态系统，其中包含了能够在这种极端环境中生存的具有特殊适应能力的生物。十足类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遗址发现大量的虾群。在不同的喷口处发现不同的物种；当物种占据同一喷口时，一些物种在喷口附近，而另一些物种在外围。此前的研究表明，眼睛放大的对虾物种主要依赖黑色吸烟者两侧细菌提供的碳，而其他眼睛融合的前视对虾是捕食者/食腐动物，位于喷口周围，这表明眼睛结构、摄食方式和栖息地选择之间可能存在关联。然而，成体喷口虾被认为是盲人，但这一结论可能是由于在极其明亮的潜水灯下收集的东西严重损害了眼睛。使用PI几十年来开发的方法，在不致盲的情况下收集具有极其敏感的视觉系统的深海物种，将检查喷口虾的视觉系统。这些研究将结合对喷口的远洋和底栖生物发光(发光--非生物化学发光和摩擦发光以及生物生物发光)的系统调查，以确定喷口对虾是否可以看到这些光源中的任何一个。这项研究的结果将极大地推动喷口生物学和视觉生态学领域的发展，潜在地改变我们目前对喷口地点如何产生光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(扩散的、白人吸烟者、黑人吸烟者)由不同的虾物种主导提供了可能的假设。这项提议将支持三名研究生、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纳入他们的STEM课程，从而扩大到三个州服务不足地区的中学。最初被描述为盲目的对虾，现在已知在眼睛形态上发生了戏剧性的变化，一些物种的背部有巨大的融合眼睛(背部眼睛)，而另一些物种的眼睛融合了前眼，这些不同的眼睛结构可能与它们的取食偏好有关。然而，所有对底栖成虫进行的结构研究都表明，它们是盲人或眼睛正在退化。此外，喷口环境缺乏足够的环境光线，使得视力的新陈代谢成本是值得的这一假设支持了这一结论。然而，其他结构研究表明，远洋后幼体/幼体具有正常超微结构的柄状眼，因此从正常柄状眼(后幼体)到巨大的背部眼(成体)的蜕变不太可能导致眼睛退化。这种“退化”很可能是在极其明亮的潜水灯光下采集海底成虫时，光感受器被破坏所致。非生物摩擦发光/化学发光以及生物发光也可能产生足够的环境光。尽管几项研究表明这些喷口不存在生物发光，但错误的方法可能导致了这一结论。该项目将利用基因技术使幼体与成体配对；进行生理学实验以提供幼体和成体的光敏性信息(绝对敏感度和颜色敏感度，因为有人推测底栖成体可能能够看到红外光)；超微结构技术，以确定在黑暗和明亮的潜水灯光下收集的眼睛的特征；以及微光成像技术，以检查喷口环境中非生物和生物光的来源。这些数据将与计算模型一起被用来确定热液喷口虾的眼睛在相关距离上是否可以看到喷口光源。这些不寻常的喷口虾视觉系统很可能是极其敏感的光感受器，也可以作为微光摄像系统的模型，就像龙虾眼睛的光学系统作为设计超灵敏X射线望远镜的模型一样。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。