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周围寒冷的南大洋（SO）生命的食物网的重要组成部分。它们以较小的生物为食，反过来又被较大的动物吃掉，包括海豹和虎鲸。对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。该项目将通过评估高温对胚胎活力、胚胎发育速度以及对温度胁迫作出反应的基因“工具包”的影响来解决这一差距。其中一种被研究的物种不产生红细胞，这一缺陷可能使其胚胎特别容易受热。这项研究的结果将为公众和政策制定者提供“真实世界”的数据，这些数据对于制定应对地球气候变化的决策和设计策略是必要的，特别是在保护SO中的生命方面。该项目还将进一步实现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，并使科学发现向公众开放。这包括为本科生提供参与南极研究的独特教育机会，并以多种方式吸引公众参与，包括制作专业制作的双语封闭字幕教育视频。自从大约4000万年前北冰洋开始降温以来，南极海洋生物的进化一直受到低温发展的推动。因为南极鱼类的体温下降在一个由它们的栖息地决定的狭窄范围内（-1.9到+2.0摄氏度），它们是特别有吸引力的模型，可以用来理解有机体生理学和生物化学是如何形成的，以便在寒冷的环境中维持生命。该项目的长期目标是通过分析南极鱼类潜在的遗传“工具箱”，了解它们适应和/或适应快速海洋变暖的能力。这一目标将通过三个具体目标来实现：1)评估高温对胚胎发育过程中基因表达的影响；2)研究高温对胚胎形态和基因表达时空格局的影响；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研究。差异基因表达将通过使用高通量RNA测序进行检查。胚胎形态背景下基因表达的时空模式（Aim 2）将通过显微镜分析胚胎“染色”（杂交到）Aim 1显示的差异表达基因探针来确定；其他发育标记基因也将被使用。通过比较两种鱼类的基因和基因组，将检查由白血鱼的红细胞损失引起的遗传病变（目的3）。

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.