Antarctic Notothenioid Fishes: Sentinel Taxa for Southern Ocean Warming

南极鱼类及其早期发育阶段是维持南极洲周围寒冷南大洋生命的食物网的重要组成部分。它们以较小的有机体为食，然后被包括海豹和虎鲸在内的较大动物吃掉。关于海洋温度上升将如何影响南极鱼类胚胎的发育及其孵化后的生长，人们知之甚少。该项目将通过评估温度升高对胚胎活力、胚胎发育速度和对温度应激反应的基因“工具箱”的影响来解决这一差距。将被研究的两个物种中有一个不会产生红细胞，这一缺陷可能会使其胚胎特别容易受到高温的影响。这项研究的结果将为公众和政策制定者提供必要的“真实世界”数据，为应对地球气候变化的决策和设计战略提供必要的信息，特别是在保护地球上的生命方面。该项目还将促进国家科学基金会培养新一代科学家的目标，包括为本科生和研究生提供科学培训，以及向公众提供科学发现。这包括为本科生提供独特的教育机会，让他们参与南极洲的研究，并以多种方式与公众接触，包括开发专业制作的带有双语隐藏字幕的教育视频。自从大约4000万年前南极冰盖开始变冷以来，南极海洋生物的进化一直受到低温发展的推动。由于南极鱼类的体温落在由它们的栖息地决定的狭窄范围内(-1.9至+2.0摄氏度)，它们是特别有吸引力的模型，可以用来理解生物生理和生物化学是如何形成的，以在寒冷的环境中维持生命。该项目的长期目标是通过分析其潜在的遗传“工具包”，了解南极鱼类适应和/或适应海洋快速变暖的能力。这一目标将通过三个具体目标来实现：1)评估温度升高对胚胎发育过程中基因表达的影响；2)检测温度升高对胚胎形态和基因表达的时空模式的影响；3)评估导致白血鱼失去红细胞遗传程序的进化机制。目标1和目标2将通过使红血鱼和白血鱼的实验胚胎适应高温来进行研究。将通过使用高通量RNA测序来检查差异基因的表达。胚胎形态(AIM 2)中基因表达的时间和空间模式将通过对AIM 1揭示的“染色”(与之杂交)差异表达基因探针的胚胎的显微分析来确定；也将使用其他发育标记基因。将通过比较两种鱼的基因和基因组来检查白血鱼(目标3)造成的红血球丢失所造成的遗传损伤。

Antarctic fish and their early developmental stages are an important component of the food web that sustains life in the cold Southern Ocean (SO) that surrounds Antarctica. They feed on smaller organisms and in turn are eaten by larger animals, including seals and killer whales. Little is known about how rising ocean temperatures will impact the development of Antarctic fish embryos and their growth after hatching. This project will address this gap by assessing the effects of elevated temperatures on embryo viability, on the rate of embryo development, and on the gene "toolkits" that respond to temperature stress. One of the two species to be studied does not produce red blood cells, a defect that may make its embryos particularly vulnerable to heat. The outcomes of this research will provide the public and policymakers with "real world" data that are necessary to inform decisions and design strategies to cope with changes in the Earth's climate, particularly with respect to protecting life in the SO. The project will also further the NSF goals of training new generations of scientists, including providing scientific training for undergraduate and graduate students, and of making scientific discoveries available to the general public. This includes the unique educational opportunity for undergraduates to participate in research in Antarctica and engaging the public in several ways, including the development of professionally-produced educational videos with bi-lingual closed captioning.Since the onset of cooling of the SO about 40 million years ago, evolution of Antarctic marine organisms has been driven by the development of cold temperatures. Because body temperatures of Antarctic fishes fall in a narrow range determined by their habitat (-1.9 to +2.0 C) they are particularly attractive models for understanding how organismal physiology and biochemistry have been shaped to maintain life in a cooling environment. The long-term objective of this project is to understand the capacities of Antarctic fishes to acclimatize and/or adapt to rapid oceanic warming through analysis of their underlying genetic "toolkits." This objective will be accomplished through three Specific Aims: 1) assessing the effects of elevated temperatures on gene expression during development of embryos; 2) examining the effects of elevated temperatures on embryonic morphology and on the temporal and spatial patterns of gene expression; and 3) evaluating the evolutionary mechanisms that have led to the loss of the red blood cell genetic program by the white-blooded fishes. Aims 1 and 2 will be investigated by acclimating experimental embryos of both red-blooded and white-blooded fish to elevated temperatures. Differential gene expression will be examined through the use of high throughput RNA sequencing. The temporal and spatial patterns of gene expression in the context of embryonic morphology (Aim 2) will be determined by microscopic analysis of embryos "stained" with (hybridized to) differentially expressed gene probes revealed by Aim 1; other developmental marker genes will also be used. The genetic lesions resulting from loss of red blood cells by the white-blooded fishes (Aim 3) will be examined by comparing genes and genomes in the two fish groups.