Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
School of Medical and Life and School of Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia.
Sci Total Environ. 2021 Nov 25;797:149215. doi: 10.1016/j.scitotenv.2021.149215. Epub 2021 Jul 22.
Marine heatwaves are occurring with greater frequency and magnitude worldwide and can significantly alter community structure and ecosystem function. Predicting changes in community structure in extreme temperatures requires an understanding of variation among species in their thermal tolerance, and how potential acclimatization to recent temperatures influences survival. To address this, we determined the tolerance to extreme temperatures in a crustacean epifaunal assemblage that inhabits macroalgae in the southeast Australian ocean warming hotspot. Amphipods were the most abundant group and the thermal tolerance of the most abundant species (two in winter and four in summer) was tested to determine their thermal limits and probability of survival in near-future extreme temperatures. Survival, measured as time to immobilization, was compared across species, sexes, life stage and body size. The greatest variation in tolerance to extreme temperatures was among species (not body sizes or life stages), indicating that heatwaves could shift the composition of the macroalgal associated epifaunal assemblage. Comparison of recent thermal history (between 18 °C to 22 °C) revealed greater thermal tolerance of warm acclimatized individuals. Our results indicate that the impacts of a marine heatwave will depend on local species composition and their timing relative to recent climate conditions.
海洋热浪在全球范围内发生的频率和强度越来越大，它们会显著改变群落结构和生态系统功能。预测极端温度下的群落结构变化需要了解物种在热耐受方面的差异，以及它们对近期温度的潜在适应如何影响生存。为了解决这个问题，我们确定了在东南澳大利亚海洋变暖热点地区栖息在大型海藻上的甲壳类附生群落对极端温度的耐受能力。端足类是最丰富的群体，我们测试了最丰富物种（冬季两种，夏季四种）的热耐受能力，以确定它们在未来极热条件下的热极限和生存概率。通过测量固定时间来衡量生存情况，并在物种、性别、生命阶段和体型之间进行比较。对极端温度的耐受能力的最大差异存在于物种之间（而不是体型或生命阶段之间），这表明热浪可能会改变与大型海藻相关的附生群落的组成。最近的热历史（18°C 到 22°C 之间）比较表明，温暖驯化个体的热耐受能力更强。我们的结果表明，海洋热浪的影响将取决于当地的物种组成及其与近期气候条件的相对时间。
