Mussels' acclimatization to high, variable temperatures is lost slowly upon transfer to benign conditions [RESEARCH ARTICLE]

This study explored the rate at which field-acclimatization states are lost when temperature variability is minimized during constant submersion. California mussels (Mytilus californianus) with different acclimatization states were collected from high- and low-zone sites (~12°C vs. ~5°C daily temperature ranges, respectively) and then kept submerged at 15°C for eight weeks. Each week, mussels’ cardiac thermal performance was measured as a metric of acclimatization state; critical (Tcrit) and flatline (FLT) temperatures were recorded. Across eight weeks of constant submersion high-zone mussels’ mean Tcrit decreased by 1.07°C from baseline, but low-zone mussels’ mean Tcrit was unchanged. High- and low-zone mussels’ mean maximum heart rate (HR) and resting HR decreased ~12% and 35%, respectively. FLT was unchanged in both groups. These data suggest that Tcrit and HR are more physiologically plastic in response to the narrowing of an animal's daily temperature range than is FLT, and that an animal's prior acclimatization state (high vs. low) influences the acclimatory capacity of Tcrit. Approximately two months were required for the high-zone mussels’ cardiac thermal performance to reach that of the low-zone mussels, suggesting that acclimatization to high and variable temperatures may persist long enough to enable these animals to cope with intermittent bouts of heat stress.

Source: Journal of Experimental Biology - May 25, 2020 Category: Biology Authors: Moyen, N. E., Somero, G. N., Denny, M. W. Tags: RESEARCH ARTICLE Source Type: research