TABLE 2.

Models that most effectively predict ureC copy number (ureolytic potential) as a function of geochemistry using multivariate linear regression.

Model	AICc	Delta AICc	Model weight
ammonia	404.1	0.00	0.068
ammonia + bromide	404.3	0.17	0.062
Intercept	404.7	0.51	0.052
pH + ammonia + bromide	404.7	0.58	0.051
ammonia * bromide + pH	405.2	1.10	0.039
ammonia + bromide + DNA	405.6	1.43	0.033
ammonia * bromide + ammonia * pH	405.8	1.63	0.030
ammonia * pH + bromide	406.0	1.86	0.027
ammonia * pH + ammonia * sulfate	406.1	1.96	0.025
pH + ammonia	406.1	1.96	0.025

Only models with a delta AICc value < 2 are included in the model averaging. Model weight is the weight of all possible models. The multiple R² for the top model presented (ammonia) is 0.13.