Table 1.

The effects of species (M. trossulus, M. edulis or M. galloprovincialis), acclimation temperature and salinity acclimation, as well as interactions between all three

Response ANOVA R2 Species Temperature (T) Salinity (S)
RHR (log) <0.0001 0.7533 <0.0001 <0.0001 0.3324
H crit <0.0001 0.6004 <0.0001 <0.0001 0.7791
LHR (log) 0.0001 0.4534 0.0012 <0.0001 0.8231
Scrit (log) <0.0001 0.7337 <0.0001 <0.0001 <0.0001
Response Sp×T Sp×S T×S Sp×T×S
RHR (log)0.81900.77400.06580.4491
H crit 0.62010.81100.56810.8625
LHR (log)0.2173 0.0411 0.0230 0.4998
Scrit (log) 0.0091 0.75770.64930.0701
  • Acclimation temperatures (T=7, 14 or 21°C); salinity acclimation (S=22, 28 or 34 p.p.t.).

    P-values are from three-factor ANOVA. Significant results are in bold type. Species (Sp) and temperature acclimation (T) contribute greatly to the variation in all four heart rate parameters (in both years), while salinity (S) only contributes greatly to the variation in response to salinity stress. Because there are significant interaction terms, post-hoc comparisons were done only within a single temperature and salinity combination.

    Heart activity parameters: RHR, resting heart rate at acclimation temperature (beats min-1); Hcrit, critical temperature during heat stress (°C); LHR, lowest heart rate at 0°C (beats min-1); Scrit, critical salinity during salinity stress (p.p.t.).