Microhabitat temperature variation combines with physiological variation to enhance thermal resilience of the intertidal mussel Mytilisepta virgata

• Published in: Functional ecology Vol. 35; no. 11; pp. 2497 - 2507
• Main Authors: Li, Xiao‐xu, Tan, Yue, Sun, Yong‐xu, Wang, Jie, Dong, Yun‐wei
• Format: Journal Article
• Language: English
• Published: London Wiley Subscription Services, Inc 01.11.2021
• Subjects: Acclimatization; Ambient temperature; Anthropogenic factors; Body temperature; Climate change; Climate models; Divergence; Environmental impact; Habitats; Heart; heart rate; High temperature; Human influences; Intertidal zone; microclimate; Microenvironments; Microhabitats; Mollusks; Mussels; Mytilisepta virgata; physiological variation; Physiology; Safety margins; Seasonal variations; Sensitivity; Species; temperature; Temperature effects; Temporal variations; thermal safety margin; Thermal stress
• ISSN: 0269-8463; 1365-2435
• DOI: 10.1111/1365-2435.13885

Predicting the effects of rising temperature entails measuring both habitat thermal characteristics and the physiological variation of the species as it relates to this microhabitat variation; these two types of measurements can generate what is termed a ‘physiological landscape’ for the species. Mapping the micro‐scale physiological landscape across space and time, rather than relying on large‐scale averages of temperature and means of thermal limits in a species, can allow more accurate estimates of an organism's sensitivity to temperature change and support development of more refined models of the impacts of anthropogenic climate change that have higher predictive power. We thus continually monitored the body (operative) temperature of the intertidal mussel Mytilisepta virgata in both sun‐exposed and shaded microhabitats and determined the seasonal variations of cardiac performance of field‐acclimatized and laboratory‐acclimated mussels from different microhabitats for calculating the thermal sensitivity, as indicated by the difference between the maximum ambient temperature and an individual's upper thermal limit (thermal safety margin, TSM), in each microhabitat and each month. The mussels experienced divergent thermal stress, in average temperature, acute and chronic thermal stress and thermal predictivity among different microhabitats, and presented high spatial–temporal variations of cardiac function as results of seasonal acclimatization and inter‐individual variations. Results of TSMs indicated that the thermal sensitivities of the mussels to high temperature were season‐ and microhabitat specific, and the mussels in the shaded microhabitats were predicted to survive the hottest summer temperatures; however, some individuals in the sun‐exposed microhabitats experienced temperatures above their sublethal temperature. With the large, high‐resolution dataset of thermal environmental characteristics and the cardiac performances with high variations, we were able to integrate the effects of synchronized changes in microenvironmental temperatures and cardiac thermal responses and thereby characterize the physiological landscape of thermal sensitivity. The complex physiological landscape that exists in the intertidal zone must be taken into account when predicting the effects of changes in environmental temperature, such as those occurring with global climate change. A free Plain Language Summary can be found within the Supporting Information of this article. 摘要 评估和预测气候变化的生态效应需要测定栖息地温度特征及生物生理耐受水平, 计算生物对环境温度变化的敏感性, 进而绘制 ‘生理景观’ 格局。通过分析小时空尺度生理景观的变化, 而不是单纯依赖于大尺度环境温度平均值和生物温度耐受能力的平均值, 可更为准确地预测生物对温度变化的敏感性及气候变化的生态效应。 本研究连续测定了潮间带条纹隔贻贝阴阳面不同微生境温度变化特征, 并分析了不同微环境生物贝类的心脏性能, 计算不同季节、不同微环境生物的温度安全区间 (Thermal safety margin, TSM), 以阐明小尺度生物温度敏感性的时空格局。 条纹隔贻贝在不同微生境面临着不同强度的温度胁迫, 呈现出高度的时空异质性。条纹隔贻贝心脏性能也表现出了高度的可塑性, 这主要与不同驯化温度和个体间差异有关。TSM结果表明, 贻贝对高温的敏感性是具有季节特异性和微生境特异性。在阴面微生境, 所有的条纹隔贻贝都可以在高温季节存活, 然后在阳面微生境, 部分个体可能会由于环境温度高于其亚致死温度而受到生理损害。 基于高清晰度的环境温度数据和生物心脏性能数据库, 可整合分析微生境温度与心脏性能曲线可塑性的生态效应, 评估生物对环境温度的敏感性。因此在评估和预测气候变化生态效应时, 需要充分考虑生理景观格局的复杂性及其时空变化格局。 A free Plain Language Summary can be found within the Supporting Information of this article.