The results of linear mixed effects models testing explanatory variables for carbon and oxygen isotopes in Mytilus californianus.

a. δ¹³C (‰, PDB scale) and b. δ¹⁸O (‰, PDB scale) in M. californianus from 1999(or 2000)–2009. The coefficient and AIC are based on a linear mixed effects model where the individual shell was the random effect. Environmental variables were first fit in isolation. The best fit model (bold) to the δ¹³C data included all 3 significant variables: UI for the year, pH and atmospheric CO₂. Sample size ranged from 53 to 56 individual shells over 11 years. ** p<0.001, *p<0.05.