Table 3. Contribution of sampling site or temperature and pH to explaining variation in the composition of free-living and particle-attached bacterioplankton communities based on redundancy analysis (RDA).

Variation partitioning was used to test pure effects accounting for the variation explained by the other factors in the model. Akaike Information Criterion (AIC) and adjusted R squared are provided as goodness-of-fit metrics.

Explanatory variable	AIC	Adjusted R squared	F	dfa	P-valueb
Free-living
Sampling site	85.31	0.571	9.65	2,11	0.001
Temperature + pH	91.20	0.347	4.45	2,11	0.006
Temperature (pure)		0.348	7.40	1,11	0.004
pH (pure)		0.032	1.58	1,11	0.187
Particle-attached
Sampling site	84.82	0.489	7.21	2,11	0.001
Temperature + pH	89.37	0.292	3.69	2,11	0.003
Temperature (pure)		0.213	4.61	1,11	0.008
pH (pure)		0.100	2.70	1,11	0.015

Notes.

^adegrees of freedom (numerator, denominator).

^bP-values defined as significant at a threshold of 0.05 are bolded.