Sampling collection details
We gathered naturally settled, adult California mussels (M. californianus between 30 and 80 mm in maximum shell length) by hand from the mid-intertidal zone of Carmet Beach, along the northern California coast. We cleaned mussels of all epibionts and external byssal threads, then transported them in buckets (< 0.5 hr transit time) to Bodega Marine Laboratory, where we acclimated individuals for seven days in flow-through seawater tables prior to subsequent experiments.
Experiment details
This experiment utilized separate incubations with de-fleshed mussel shells to quantify rates of abiotic dissolution, and we employed these dissolution rates to correct the alkalinity anomaly data to estimate gross calcification rates (gross calcification = net calcification + dissolution). The researchers dried and bleached shells (n = 60) originating from live mussels at Carmet Beach, CA, and used 7.5% sodium hypochlorite to remove excess tissue and microbial communities, before incubating them in an analogous fashion to the calcification trials (Supplementary Figure S4 in Results paper Pomano de Orte et al. (2021)). Dissolution rate data was plotted against calcium carbonate saturation state, with an Arrhenius-derived dissolution equation of the form y = b0 – b1*ea*Ω where y is the measured dissolution rate, b0 is the asymptotic dissolution rate, b1 is the y-intercept, and a is the rate of approaching the asymptote12. Dissolution corrections were applied prior to normalization by dry tissue weight.