Table 2. Summary of effects of ambient (400 μatm) and elevated (1100 μatm) levels of pCO₂ on Fucus vesiculosus measured as ten responses.

Response variable	p-value	t-value	Df	Mean (400ppm)	95%CI (400ppm)	Mean (1100ppm)	95%CI (1100ppm)
Growth: area (%)	9.2e-07	-5.48	59	147.5	6.54	180.1	11.47
Growth: weight (%)	0.767	-0.30	59	136.0	5.91	136.7	4.68
Breaking force (N)	0.032	2.33	18	1.36	0.54	0.59	0.27
Photosystem II (Fv/Fm)	0.407	-0.83	59	0.695	0.011	0.701	0.007
Photosystem II (P index)	0.147	-1.47	59	1.5	0.20	1.7	0.19
Phlorotannin content (% dw)	0.030	2.22	59	10.6	0.53	10.3	0.57
% Nitrogen	0.379	0.89	59	1.32	0.055	1.29	0.066
% Carbon	0.865	0.17	59	36.04	0.43	36.00	0.37
C:N	0.236	-1.20	59	28.2	1.44	29.3	1.80
δ13C	4.762e-09	6.85	59	-11.77	0.32	-13.33	0.41
δ15N	0.315	-1.01	59	6.51	0.14	6.57	0.13

P-values and corresponding t-values and degrees of freedom of paired t-tests are reported for the analyses of all response variables as well as means and 95% confidence intervals. Values in bold denote statistically significant values.