Table 3. Variable loadings and correlations between variables and components (PC1 – 3) defined through Principal Components Analysis of photochemical parameters.

Component	Photochemistry variable	Loading	Correlation	t	p
PC1: Light	Maximum Y(II)	0.39	0.78	10.3	< 0.001
	Minimum Y(NO)	−0.39	−0.77	−10.0	< 0.001
	Maximum Y(NO)	0.34	0.67	7.6	< 0.001
	Maximum Y(NPQ)	−0.30	−0.60	−6.3	< 0.001
	Y(NPQ) rate of change	−0.33	−0.65	−7.2	< 0.001
PC2: Species	Maximum rETR(II)	0.47	0.82	12.2	< 0.001
	rETR(II) rate of change	−0.41	−0.71	−8.5	< 0.001
	Maximum Y(ND)	0.35	0.61	6.5	< 0.001
	Minimum Y(ND)	0.31	0.54	5.4	< 0.001
PC3: Temperature	Maximum Y(NPQ)	0.30	0.40	3.6	< 0.01
	Maximum rETR(I)	−0.49	−0.66	−7.4	< 0.001
	rETR(I) rate of change	−0.57	−0.77	10.0	< 0.001
	Minimum Y(ND)	−0.38	−0.51	−5.0	< 0.001

Photochemistry variables and abbreviations are as described in Figure 1. Principal component variances and standard deviations were: 23% and 1.99 respectively for PC1, 18% and 1.76 respectively for PC2, and 11% and 1.35 respectively for PC3.