high-temperature, high-CO2 and low-oxygen

Global change is affecting marine ecosystems through a combination of different stressors such as warming, ocean acidification and oxygen depletion. Very little is known about the interactions among these factors, especially with respect to gelatinous zooplankton. Therefore, in this study we investigated the direct effects of pH, temperature and oxygen availability on the moon jellyfish Aurelia aurita, concentrating on the ephyral life stage. Starved one-day-old ephyrae were exposed to a range of pCO2 (400-4000 ppm) and three different dissolved oxygen levels (from saturated to hypoxic conditions), in two different temperatures (5 and 15 °C) for 7 days. Carbon content and swimming activity were analysed at the end of the incubation period, and mortality noted. General linearized models were fitted through the data, with the best fitting models including two- and three-way interactions between pCO2, temperature and oxygen concentration. The combined effect of the stressors was small but significant, with the clearest negative effect on growth caused by the combination of all three stressors present (high temperature, high CO2, low oxygen). We conclude that A. aurita ephyrae are robust and that they are not likely to suffer from these environmental stressors in a near future.

全球变化通过升温、海洋酸化与氧气耗竭等多种环境胁迫因子的协同作用，对海洋生态系统造成影响。目前学界对这些胁迫因子之间的交互作用知之甚少，尤其是针对凝胶状浮游动物的相关研究尤为匮乏。因此，本研究以海月水母（Aurelia aurita）的碟状体生活阶段为研究对象，探究了pH值、温度与可利用溶氧量对其的直接影响。本实验将经饥饿处理的1日龄碟状体置于不同二氧化碳分压（pCO2，范围为400~4000 ppm）、三种溶氧水平（从饱和至低氧条件）以及两种温度（5 ℃与15 ℃）下培养7天。培养周期结束后，测定其碳含量与游泳活动能力，并记录死亡率。基于实验数据拟合广义线性模型（Generalized Linear Models，GLM），最优拟合模型包含二氧化碳分压、温度与溶氧浓度之间的双向及三向交互效应。各胁迫因子的联合效应虽小但显著，当三种胁迫因子（高温、高二氧化碳分压、低溶氧）共同作用时，对生长产生了最明显的负面影响。本研究结论表明，海月水母碟状体具有较强的耐受能力，在不久的将来，它们不太可能受到这些环境胁迫因子的不利影响。