Performance and fitness consequences of hypoxia and thermal stress in fishes

缺氧和热应激对鱼类的表现和健康影响

• 批准号: RGPIN-2015-06675
• 负责人: Chapman, Lauren
• 金额: $ 3.57万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=689788
• 关键词: Performance; fitness; consequences; hypoxia; thermal

Environmental stress, whether natural or human-induced, may constrain local adaptation if populations decline, have not had sufficient time to adapt, or if reduced predation/competition allows populations to persist despite poor adaptation to local conditions. Hypoxia (low dissolved oxygen, DO) is a serious and widespread manifestation of anthropogenic stress to inland and coastal waters driven by influx of wastes and fertilizers that accelerate eutrophication and pollution. Under severe hypoxia, oxygen can be a powerful limiting factor on fitness-related performance traits, such as endurance swimming or escaping predators. Climate change is likely to exacerbate the impacts of hypoxia on fishes, because oxygen solubility decreases with rising temperature while metabolism of ectotherms (cold-blooded organisms) increases. Conversely, hypoxia may exacerbate thermal stress by limiting aerobic performance at higher temperatures. Our studies of East African fishes from hypoxic swamps and normoxic river/lake sites have demonstrated that DO is a strong driver of divergence among populations in traits related to oxygen uptake. In comparisons of populations from low-DO and high-DO sites we have documented larger gills, larger heads (to accommodate larger gills), and greater tolerance to hypoxia in fish from low-DO sites. Despite this strong evidence that populations are adapted to their local environments, our recent studies suggest that adaptive divergence in morpho-physiological traits may not have positive fitness consequences in low-DO fish. This research program will build on these foundational studies, integrating the morphology and physiology of fishes with their ecology and evolution to understand performance and fitness consequences of hypoxia and the interaction of hypoxia with thermal stress. We will blend field surveys across DO and temperature gradients, lab acclimation and rearing studies, and field experiments to (a) test a series of predictions on interactive effects of hypoxia and thermal stress on performance and fitness and (b) test for signatures of local adaptation to extreme hypoxia in nature. By exploring potential exceptions to expected patterns of local adaptation and quantifying interactions between hypoxia and thermal stress, we can more fully understand the ecological and evolutionary consequences of environmental stressors and identify characteristics of organisms that may facilitate persistence in extreme environments or in the face of environmental change. **

环境压力，无论是自然或人为引起的，可能会限制当地的适应，如果人口下降，没有足够的时间来适应，或者如果减少捕食/竞争允许人口持续存在，尽管对当地条件的适应不良。缺氧（低溶解氧，DO）是一种严重的和广泛的表现人为应力内陆和沿海沃茨驱动的废物和化肥的涌入，加速富营养化和污染。在严重缺氧的情况下，氧气可能是一个强大的限制因素，对健身相关的性能特征，如耐力游泳或逃避捕食者。气候变化可能会加剧缺氧对鱼类的影响，因为随着温度的升高，氧的溶解度降低，而外温动物（冷血生物）的代谢增加。相反，缺氧可能会加剧热应力，限制有氧性能在较高temperature. Our东非鱼类从缺氧沼泽和常氧河流/湖泊网站的研究表明，DO是一个强大的驱动程序的种群之间的分歧，在相关的氧摄取性状。在从低DO和高DO网站的人口比较，我们已经记录了更大的鳃，更大的头（以适应更大的鳃），和更大的耐缺氧的鱼类从低DO网站。尽管这一强有力的证据表明，人口适应当地环境，我们最近的研究表明，适应性分歧的形态生理特征可能不会有积极的健身后果，在低DO鱼。该研究计划将建立在这些基础研究的基础上，将鱼类的形态学和生理学与其生态学和进化相结合，以了解缺氧的性能和健身后果以及缺氧与热应激的相互作用。我们将结合DO和温度梯度的实地调查，实验室驯化和饲养研究，以及实地实验，以（a）测试一系列缺氧和热应激对性能和适应性的相互作用的预测和（B）测试局部适应极端缺氧的签名。通过探索局部适应模式的潜在例外，并量化缺氧和热应激之间的相互作用，我们可以更充分地了解环境应激源的生态和进化后果，并确定可能促进极端环境或面对环境变化的持久性的生物体特征。