ABSTRACT: Marine heatwaves (MHWs) have caused declines in many kelp forests globally. Although the ecological effects of these climatic extremes have been well examined, studies on the role of genotypic variation in underpinning population responses under pressures are lacking. Understanding how kelps respond to different warming profiles and, in particular, intraspecific variation in responses is necessary to confidently anticipate the future of kelp forests, yet this remains a critical knowledge gap for most species. This study examined the responses of early life stages of 9 different genotypes of the Australian kelp Ecklonia radiata to different MHW profiles, where cumulative heat intensity was kept constant: control treatment (constant 19°C), heat spikes (fluctuating 19-23°C), low intensity MHW (ramp up 23°C) and high intensity MHW (ramp up 27°C). Overall, we found significant declines in E. radiata gametophyte performance in all MHW treatments and delays in sporophyte recruitment during MHW exposure. We also found significant genotype by environment (G×E) interactions, suggesting tolerance to acute thermal stress is influenced by genetic variation. Our results showed that offspring from different genotypes within the same population respond differently to MHWs, indicating that some genotypes are susceptible to MHWs while others are more resistant. While the effects on standing genetic variation and subsequent susceptibility to other stressors are unknown, our findings suggest that in addition to immediate impacts on marine organisms, natural genotypic variation in response to thermal anomalies may facilitate the gradual evolution of populations with increased thermal tolerance under future climates.

中文翻译：

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响应极端事件的基因型变异可能促进海带在未来气候下的适应

摘要：海洋热浪 (MHW) 已导致全球许多海带森林减少。尽管已经充分研究了这些极端气候的生态影响，但缺乏关于基因型变异在支持压力下人口反应中的作用的研究。了解海带如何响应不同的变暖剖面，特别是响应的种内变化对于自信地预测海带森林的未来是必要的，但这对于大多数物种来说仍然是一个关键的知识差距。本研究检查了澳大利亚海带Ecklonia radiata 9 种不同基因型的早期生命阶段的反应不同的 MHW 曲线，其中累积热强度保持恒定：对照处理（恒定 19°C）、热峰值（波动 19-23°C）、低强度 MHW（升温 23°C）和高强度 MHW（升温） 27°C）。总体而言，我们发现E. radiata所有 MHW 处理中的配子体性能和 MHW 暴露期间孢子体募集的延迟。我们还通过环境（G×E）相互作用发现了显着的基因型，表明对急性热应激的耐受性受遗传变异的影响。我们的研究结果表明，来自同一种群内不同基因型的后代对 MHW 的反应不同，表明某些基因型对 MHW 敏感，而另一些则更具抗性。虽然对常设遗传变异的影响以及随后对其他压力源的易感性的影响尚不清楚，但我们的研究结果表明，除了对海洋生物的直接影响外，响应热异常的自然基因型变异可能会促进在未来具有更高热耐受性的种群的逐渐进化。气候。