Why do fish fail at high temperatures?

为什么鱼在高温下会失败？

• 批准号: NE/R001510/1
• 负责人: Neil Metcalfe
• 金额: $ 66.69万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR001510%2F1
• 关键词: Why; do; fish; fail; temperatures

There is increasing evidence that fish will be badly affected by increases in global temperatures due to their body temperatures matching that of the surrounding water. This is a particular problem for freshwater fishes since they have little scope for moving to colder water. The widely-quoted mechanistic explanation for the upper temperature limit for fish is that, as the temperature rises, there comes a point where the animal cannot supply sufficient oxygen to meet the increasing metabolic demands of its cells. However, recent tests of this hypothesis have found that it often does not correctly predict upper temperature limits, with fish failing at a temperature when their supply of oxygen is still adequate. This suggests that the currently-adopted hypothesis is inadequate.In this project we will use newly-developed methods to provide the first comprehensive test of an alternative hypothesis, and in so doing potentially provide the physiological mechanism that will underpin predictions of the consequences of warming temperatures for the distribution and functioning of fish species - and potentially other cold-blooded aquatic species. We will test whether the upper temperature limit for fish is determined by the point at which their mitochondria - the powerhouses of animal cells - fail to deliver enough of the energy molecule ATP to allow their cells to function properly. Using Brown trout as a test species we will investigate whether the changing functioning of their mitochondria allows us to predict the upper temperature at which they can still feed and grow. We will also test whether fish living at high temperatures age faster, as is predicted by this alternative hypothesis. Information from this project will allow us to predict what types of species of fish will be most vulnerable to high temperatures and which features of the temperature regime are most critical to survival (e.g. whether it is the daily average or the peak temperature). This information is needed if we are to prioritise species or sites for protection measures.

越来越多的证据表明，由于鱼体温与周围水的温度相匹配，鱼类的体温将受到全球温度的升高影响。对于淡水鱼而言，这是一个特殊的问题，因为它们几乎没有迁移到冷水的范围。鱼类上层温度极限的广泛引用的机械解释是，随着温度的升高，动物无法提供足够的氧气来满足其细胞的代谢需求增加。但是，最近对该假设的测试发现，它通常无法正确预测高温限制，而在氧气供应仍然足够时，鱼类在温度下失败。这表明目前所采用的假设不足。在这个项目中，我们将使用新开发的方法对替代假设进行首次全面测试，并因此提供了潜在的生理机制，这些方法可能提供了生理机制，这些机制将支持预测温暖温度和潜在的其他冷含水量和潜在冷含水量的高温和潜在的水。我们将测试鱼的高温限制是否取决于其线粒体（动物细胞的强力室）无法提供足够的能量分子ATP以使其细胞正常运行。使用棕色鳟鱼作为测试物种，我们将研究线粒体的变化功能是否使我们能够预测它们仍然可以喂养和生长的高温。正如该替代假设所预测的那样，我们还将测试生活在高温年龄的速度是否更快。来自该项目的信息将使我们能够预测哪种类型的鱼类最容易受到高温的影响，以及温度制度的哪些特征对于生存最重要（例如，是每日平均温度还是峰值温度）。如果我们要优先考虑物种或地点以进行保护措施，则需要此信息。

项目成果

Inter-individual variation in mitochondrial phosphorylation efficiency predicts growth rates in ectotherms at high temperatures.

线粒体磷酸化效率的个体间差异预测了变温动物在高温下的生长速率。

• DOI: 10.1096/fj.202101806rr
• 发表时间: 2022
• 期刊: official publication of the Federation of American Societies for Experimental Biology
• 作者: Dawson NJ

Tissue-specific reductions in mitochondrial efficiency and increased ROS release rates during ageing in zebra finches, Taeniopygia guttata.

• DOI: 10.1007/s11357-022-00624-1
• 发表时间: 2023-02
• 期刊: GEROSCIENCE
• 影响因子: 5.6
• 作者: Salmon, Pablo;Millet, Caroline;Selman, Colin;Monaghan, Pat;Dawson, Neal J.
• 通讯作者: Dawson, Neal J.

Measurement of mitochondrial respiration in permeabilized fish gills

• DOI: 10.1242/jeb.216762
• 发表时间: 2020-02-01
• 期刊: JOURNAL OF EXPERIMENTAL BIOLOGY
• 影响因子: 2.8
• 作者: Dawson, Neal J.;Millet, Caroline;Metcalfe, Neil B.
• 通讯作者: Metcalfe, Neil B.