Table 2. Summary table of effects and interactions of temperature, *pCO₂* and initial height on organismal phenotypes in minimal models following backwards stepwise term-deletion.

<table><thead><tr><th rowspan="2">Trait</th><th rowspan="2">Population</th><th rowspan="2">Variable</th><th colspan="5">Mean</th></tr><tr><th>Squares</th><th>DF</th><th>Den DF *</th><th>F</th><th>P-value</th></tr></thead><tbody><tr><td rowspan="6">Final shell height</td><td rowspan="6">France</td><td>Hght_t0 **</td><td>42.087</td><td>1</td><td>201.67</td><td>83.21</td><td>&lt; 0.0001</td></tr><tr><td>Hght_t0</td><td>726.090</td><td>1</td><td>209.98</td><td>1508.91</td><td>&lt; 0.0001</td></tr><tr><td>pCO₂</td><td>4.580</td><td>1</td><td>204.03</td><td>9.51</td><td>0.0023</td></tr><tr><td>Temp ***</td><td>0.490</td><td>2</td><td>12.38</td><td>1.02</td><td>0.3896</td></tr><tr><td>Hght_t0 x pCO₂</td><td>3.810</td><td>1</td><td>209.98</td><td>7.91</td><td>0.0054</td></tr><tr><td>pCO₂ x temp</td><td>1.780</td><td>2</td><td>12.38</td><td>3.71</td><td>0.0548</td></tr><tr><td rowspan="6">Dry body weight</td><td rowspan="6">France</td><td>Hght_t0</td><td>5.005</td><td>1</td><td>202.86</td><td>45.28</td><td>&lt; 0.0001</td></tr><tr><td>pCO₂</td><td>0.544</td><td>1</td><td>16.24</td><td>4.92</td><td>0.0411</td></tr><tr><td>Hght_t0</td><td>53.945</td><td>1</td><td>210.65</td><td>573.48</td><td>&lt; 0.0001</td></tr><tr><td>pCO₂</td><td>0.849</td><td>1</td><td>204.30</td><td>9.02</td><td>0.0030</td></tr><tr><td>temp</td><td>0.336</td><td>2</td><td>12.14</td><td>3.58</td><td>0.0601</td></tr><tr><td>Hght_t0 x pCO₂</td><td>0.762</td><td>1</td><td>210.65</td><td>8.11</td><td>0.0049</td></tr><tr><td rowspan="6">Total shell weight</td><td rowspan="6">France</td><td>Hght_t0</td><td>6.870</td><td>1</td><td>199.85</td><td>104.89</td><td>&lt; 0.0001</td></tr><tr><td>Hght_t0</td><td>51.551</td><td>1</td><td>210.76</td><td>1373.80</td><td>&lt; 0.0001</td></tr><tr><td>pCO₂</td><td>0.515</td><td>1</td><td>204.36</td><td>13.72</td><td>0.0003</td></tr><tr><td>temp</td><td>0.027</td><td>2</td><td>12.24</td><td>0.71</td><td>0.5105</td></tr><tr><td>Hght_t0 x pCO₂</td><td>0.491</td><td>1</td><td>210.76</td><td>13.08</td><td>0.0004</td></tr><tr><td>pCO₂ x temp</td><td>0.210</td><td>2</td><td>12.24</td><td>5.60</td><td>0.0187</td></tr><tr><td rowspan="3">Condition Index</td><td rowspan="3">France</td><td>Hght_t0</td><td>0.0002</td><td>1</td><td>198.52</td><td>4.94</td><td>0.0274</td></tr><tr><td>pCO₂</td><td>0.0006</td><td>1</td><td>13.94</td><td>16.92</td><td>0.0011</td></tr><tr><td>temp</td><td>0.0002</td><td>2</td><td>14.31</td><td>5.90</td><td>0.0136</td></tr><tr><td>770</td><td></td><td>Norway</td><td>temp</td><td>0.0008</td><td>2</td><td>14.85</td><td>14.63</td><td>0.0003</td></tr></tbody></table>

768 * Den DF = denominator degrees of freedom.

769 ** Hght_t0 = initial height

770 *** Temp = temperature.