Rogers Nicholas J, Urbina Mauricio A, Reardon Erin E, McKenzie David J, Wilson Rod W
Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building , University of Exeter , Stocker Road, Exeter EX4 4QD , UK.
Centre for Marine Biodiversity Exploitation and Conservation (Marbec), UMR 9190 CNRS-Université Montpellier-Ifremer-IRD , Université Montpellier , Place Eugène Bataillon, Montpellier cedex 5 34095 , France.
Conserv Physiol. 2016 Apr 27;4(1):cow012. doi: 10.1093/conphys/cow012. eCollection 2016.
Hypoxia is a common occurrence in aquatic habitats, and it is becoming an increasingly frequent and widespread environmental perturbation, primarily as the result of anthropogenic nutrient enrichment and climate change. An in-depth understanding of the hypoxia tolerance of fishes, and how this varies among individuals and species, is required to make accurate predictions of future ecological impacts and to provide better information for conservation and fisheries management. The critical oxygen level (P crit) has been widely used as a quantifiable trait of hypoxia tolerance. It is defined as the oxygen level below which the animal can no longer maintain a stable rate of oxygen uptake (oxyregulate) and uptake becomes dependent on ambient oxygen availability (the animal transitions to oxyconforming). A comprehensive database of P crit values, comprising 331 measurements from 96 published studies, covering 151 fish species from 58 families, provides the most extensive and up-to-date analysis of hypoxia tolerance in teleosts. Methodologies for determining P crit are critically examined to evaluate its usefulness as an indicator of hypoxia tolerance in fishes. Various abiotic and biotic factors that interact with hypoxia are analysed for their effect on P crit, including temperature, CO2, acidification, toxic metals and feeding. Salinity, temperature, body mass and routine metabolic rate were strongly correlated with P crit; 20% of variation in the P crit data set was explained by these four variables. An important methodological issue not previously considered is the inconsistent increase in partial pressure of CO2 within a closed respirometer during the measurement of P crit. Modelling suggests that the final partial pressure of CO2 reached can vary from 650 to 3500 µatm depending on the ambient pH and salinity, with potentially major effects on blood acid-base balance and P crit itself. This database will form part of a widely accessible repository of physiological trait data that will serve as a resource to facilitate future studies of fish ecology, conservation and management.
缺氧在水生栖息地中很常见,并且正成为一种日益频繁和广泛的环境干扰,主要是人为营养物质富集和气候变化的结果。为了准确预测未来的生态影响,并为保护和渔业管理提供更好的信息,需要深入了解鱼类的耐缺氧能力,以及这种能力在个体和物种之间的差异。临界氧水平(P crit)已被广泛用作耐缺氧能力的可量化特征。它被定义为动物无法再维持稳定的氧摄取率(氧调节)且摄取变得依赖于环境氧可用性(动物转变为氧顺应)时的氧水平。一个包含来自96项已发表研究的331次测量值的P crit值综合数据库,涵盖了58个科的151种鱼类,提供了对硬骨鱼耐缺氧能力最广泛和最新的分析。对确定P crit的方法进行了严格审查,以评估其作为鱼类耐缺氧指标的有用性。分析了与缺氧相互作用的各种非生物和生物因素对P crit的影响,包括温度、二氧化碳、酸化、有毒金属和摄食。盐度、温度、体重和常规代谢率与P crit密切相关;这四个变量解释了P crit数据集中20%的变异。一个以前未被考虑的重要方法问题是在测量P crit期间封闭呼吸计内二氧化碳分压的不一致增加。模型表明,根据环境pH值和盐度,最终达到的二氧化碳分压可在650至3500微大气压之间变化,这可能对血液酸碱平衡和P crit本身产生重大影响。该数据库将成为一个广泛可访问的生理特征数据存储库的一部分,该存储库将作为一种资源,促进未来对鱼类生态、保护和管理的研究。