Fig. 4. Gross nitrification rates as a function of temperature for the tropical-forest soils in Australia. Data pooled across sites and seasons. [•]: gross nitrification rate ± standard error (SE), N = 9; [] linear regression: y = -12.0 + 1.17 x; r² = 0.865, p < 0.001; [------] 95% confidence limit of the linear regression line.