Höhn Danja P, Lucas Cathy H, Thatje Sven
National Oceanography Centre Southampton, University of Southampton, Southampton, United Kingdom.
PLoS One. 2017 May 17;12(5):e0177913. doi: 10.1371/journal.pone.0177913. eCollection 2017.
The benthic life stage (polyp or scyphistoma) of the bloom-forming jellyfish, Aurelia aurita (Linnaeus, 1759), also known as the moon jellyfish, contributes to the seasonal occurrence and abundance of medusa blooms via asexual reproduction. A. aurita is widely distributed in coastal areas in northern Europe, and one of the most studied jellyfish species. While the physiology of the visible medusa is largely understood, understanding of the physiology of the perennial benthic life-stage is scarce. To measure the physiological tolerance of A. aurita, the scyphistoma's temperature sensitivity across its distributional range was investigated. Respiration rates of polyps from three northern European locations exposed to 11 temperatures between 2 and 22°C were measured. There was a significant difference in respiration rate among the three polyp populations, which may reflect on differences in their thermal tolerance window. A critical temperature was reached at 14°C with the metabolic rate decreasing below and above that temperature. This pattern was less pronounced in the Norwegian population but polyps were able to survive, at least temporarily, those temperatures exceeding their natural range. While polyps collected from northern Norway, with a narrow environmental thermal window, displayed a low baseline metabolism with a Q10 value of 1.2, polyps from southern England and Scotland had Q10 values of 1.6 and 2.5, respectively. Differences in polyps' respiration rates across their distributional range suggest that populations have evolved adaptations to local environmental thermal conditions.
形成水华的海月水母（Aurelia aurita，林奈，1759 年）的底栖生活阶段（螅状体或钵水母幼体）通过无性繁殖影响着水母体水华的季节性出现和丰度。海月水母广泛分布于北欧沿海地区，是研究最多的水母物种之一。虽然对可见水母体的生理学已有较多了解，但对多年生底栖生活阶段的生理学了解却很少。为了测量海月水母的生理耐受性，研究了钵水母幼体在其分布范围内的温度敏感性。测量了来自北欧三个地点的螅状体在 2至22°C之间的 11 个温度下的呼吸速率。三个螅状体种群的呼吸速率存在显著差异，这可能反映了它们耐热窗口的差异。在 14°C 时达到临界温度，高于和低于该温度时代谢率都会下降。这种模式在挪威种群中不太明显，但螅状体能够在至少暂时的情况下在超出其自然范围的温度下存活。从环境热窗口较窄的挪威北部采集的螅状体显示出较低的基础代谢率，Q10 值为 1.2，而来自英格兰南部和苏格兰的螅状体的 Q10 值分别为 1.6 和 2.5。螅状体在其分布范围内呼吸速率的差异表明种群已经进化出对当地环境热条件的适应性。
