Shell morphometrics and shell composition.

<p>Mean values ±SE for shell dry weight, shell length, shell width, shell height and shell thickness (umbo and distal edge), and molar fraction of calcite:aragonite in <i>M. edulis</i> following a six month exposure period to four pH-temperature treatments: ambient pH and ambient temperature (ambient); ambient pH and elevated temperature (warming); reduced pH and ambient temperature (acidified); or reduced pH and elevated temperature (warming+acidified). N = 18 per treatment for the morphometric determinations, and N = 4 for shell composition, with the exception of the acidified treatment when only 2 values were recorded and both of these are given. ML: maximum load, E: extension, MF: molar fraction, U: umbo, DE: distal edge.</p

Seawater carbonate chemistry values for the four treatments.

<p>Values represent the mean ±SD of bimonthly measures taken over the six months exposure period (n = 12 for each treatment). Mussels were either exposed to: ambient pH and ambient temperature (ambient); ambient pH and elevated temperature (warming); reduced pH and ambient temperature (acidified); or reduced pH and elevated temperature (warming+acidified). TRT represents treatment, T = temperature, Sal = Salinity, pH_T = pH (total scale), TA = total alkalinity, DIC = dissolved inorganic carbon, pCO₂ = CO₂ partial pressure, HCO₃⁻ = bicarbonate, CO₃²⁻ = carbonate, Ω_arag = aragonite saturation state, and Ωcalc = calcite saturation state. Measured values are: temperature, salinity, TA, and DIC. Calculated values are pH, pCO₂, HCO₃, CO₃²⁻, Ω_arag and Ω_calc.</p

Effects of warming and/or acidification on shell strength.

<p>A) Maximum load endured until fracture and B) extension or distance a shell will bend/flex before failure of shells from <i>M. edulis</i> held for six months under: ambient temperature and ambient pH (ambient); ambient temperature and reduced pH (acidified); elevated temperature and ambient pH (warming); and elevated temperature and reduced pH (warming+acidified). Values given as means <b>±</b>SE (n = 18 per treatment). Acidified treatments shown in dark grey. Significant differences indicated by different lowercase letters (p<0.05).</p

Effects of warming and/or acidification on shell surface area.

<p>Shell surface area was determined in at least three subsamples consisting of a number of shell fragments (of 0.1–0.3 g total mass) per shell from <i>M. edulis</i> held for six months at either: ambient temperature and ambient pH (ambient); ambient temperature and reduced pH (acidified); elevated temperature and ambient pH (warming); or elevated temperature and reduced pH (warming+acidified). Values given as means <b>±</b>SE (n = 3). Acidified treatments shown in dark grey. Significant differences indicated by different lowercase letters (p<0.05).</p

Sub-surface seawater temperature in the Menai Strait (Wales, UK) between October 2011 and October 2012.

<p>Temperature was measured at 3</p