Environmental variability is found across earth systems in local, regional, and global drivers. Variability occurs at diverse temporal and spatial scales, occasionally leading to unpredictable extremes. This talk illustrates the variability of multiple drivers in a coastal marine system, the significance of the timing of extreme events, and provides insights into how species can cope with, and potentially benefit from, environmental variability in a climate change context. We highlight the responses of the widespread ectotherm filter feeder Mytilus edulis to diurnal variability across thermal gradients, prevalent pattern in shallow coastal habitats. In a 5-weeks experiment, variability amplified thermal stress at average summer temperatures but acted as a temporal refuge during heatwave conditions. We conducted short-term lab assays to test for capacity for suppression and recovery of feeding and respiration in response to immediate thermal stress. We finally generated short-term thermal metabolic performance curves to explain growth responses observed in the long-term experiment. In a long-term mesocosm study, we show extremely warm conditions to select rare recruits capable of expressing increased metabolic suppression and recovery in response to daily fluctuations. These findings will be discussed in the framework of how environmental variability can provide temporal (and spatial) refugia, and how short-term metabolic assays, combined with theoretical frameworks, can predict long-term effects, and we highlight the significance heat selection in ectothermic populations.

Primary Presenter: Christian Pansch, Abo Akademi University (ch.pansch@gmail.com)

Authors:

Christian Pansch, Åbo Akademi University  (ch.pansch@gmail.com)

Jahangir Vajedsamiei, GEOMAR  (jvajedsamiei@geomar.de)