Table 1.

Summary of trace gas, dimethylsulfoniopropionate, and chlorophyll-a data

	Bloom phase May 10–17, all mesocosms			Postbloom phase May 18–23, M3 and M4			Whole experiment May 6–23 (M3 and M4 only after May 15)
	High CO2	Present day	% diff.	High CO2	Present day	% diff.	High CO2	Present day	% diff.
CH3I*	6.9	12.1	−43	3.6	10.7	−67	5.4	9.2	−41
C2H5I*	0.7	1.0	−32	0.3	1.0	−73	0.5	0.7	−32
CH2I2*	197.4	283.4	−30	4.6	63.9	−93	134.6	200.8	−33
CH2ClI*	189.3	207.2	−9	131.1	321.7	−59	136.9	191.0	−28
CHBr3*	41.2	38.1	+7	14.0	12.1	+14	39.8	34.7	+13
CH2Br2*	1.6	1.9	−17	3.29	3.3	+0.3	2.4	2.2	+8
CHBr2Cl*	0.5	0.4	+17	0.7	0.5	+29	0.6	0.5	+22
DMS†	6.1	14.1	−57	15.7	42.0	−63	5.7	14.1	−60
DMSP†	191.7	252.3	−24	182.9	184.3	−0.8	139.0	182.9	−24
Chl a‡	3.2	5.3	−40	3.6	1.8	+49	2.5	3.5	−28

Means and percentage differences of measured variables for high CO₂ treatment and present-day CO₂ treatment for the bloom phase (May 10–17) in all mesocosms, postbloom phase (May 18–23) in M3 and M4, and for the whole experiment.

*pM.

^†nM.

^‡mg m⁻³.