Table 4.

Modelled double first-order kinetic parameters that describe the mineralisation of ¹⁴C-labelled glucose in Arctic and temperate soils subjected to 1 and 3 freeze–thaw (FT) cycles (−7.5 to +5 °C)

Glucose
Soil	Parameter	1 Control	1 FT	3 Control	3 FT
Meadow mineral	a 1 (%)	12.6 ± 0.3!	11.3 ± 0.6	10.4 ± 0.3!	10.1 ± 0.6
	k 1 (h−1)	0.89 ± 0.04!	0.89 ± 0.06!	0.66 ± 0.05!	0.56 ± 0.06!
	a 2 (%)	87.2 ± 0.3!	88.1 ± 0.6	89.3 ± 0.3!	89.6 ± 0.6
	k 2 (×10−3 h−1)	0.39 ± 0.01	0.38 ± 0.03	0.41 ± 0.04	0.34 ± 0.04
Meadow organic	a 1 (%)	13.1 ± 0.5	10.7 ± 0.7	14.0 ± 1.0	11.1 ± 0.9
	k 1 (h−1)	0.72 ± 0.01	0.89 ± 0.05	0.67 ± 0.03	0.68 ± 0.05
	a 2 (%)	86.6 ± 0.5	89.1 ± 0.7	85.8 ± 1.1	88.8 ± 0.9
	k 2 (×10−3 h−1)	0.44 ± 0.02	0.36 ± 0.04	0.72 ± 0.01	0.46 ± 0.06
Heath mineral	a 1 (%)	10.7 ± 0.9	9.1 ± 2.1	6.0 ± 1.9	5.9 ± 1.2
	k 1 (h−1)	0.41 ± 0.11	0.34 ± 0.07	0.19 ± 0.02	0.24 ± 0.04
	a 2 (%)	89.0 ± 1.0	90.3 ± 2.2	93.5 ± 2.0	93.8 ± 1.3
	k 2 (×10−3 h−1)	0.35 ± 0.03	0.34 ± 0.03!	0.51 ± 0.1	0.66 ± 0.08!
Temperate	a 1 (%)	8.9 ± 0.1*	6.2 ± 0.1*	8.6 ± 0.3*	6.8 ± 0.2*
	k 1 (h−1)	0.54 ± 0.03*	0.93 ± 0.08*!	0.70 ± 0.06	0.55 ± 0.03!
	a 2 (%)	90.2 ± 0.1*	93.6 ± 0.1*	90.7 ± 0.4*	92.8 ± 0.2*
	k 2 (×10−3 h−1)	0.30 ± 0.01*	0.14 ± <0.01*!	0.44 ± 0.07	0.22 ± 0.01!

The parameters a ₁ and a ₂ are the proportion of substrate mineralised rapidly or slowly, whilst k ₁ and k ₂ are their respective rate constants

* A statistical difference between freeze–thaw treatment and the control (not frozen)

^! Statistical difference over time (i.e. between the first and third control or 1FT and 3FT), (p < 0.05). Values represent mean ± SE (n = 4)