Table 1. Physico-chemical characteristics of the ditches used to collect natural organic matter and to perform the field OM-preference experiment.

	Transparency (cm)	Conductivity (mS)	Temperature (C)	pH	Oxygen (mg/L)	NO2 (mg/L)	NO3 (mg/L)	Hardness (dGH)	CO3 (mg/L)
Grassland ditches	22.6 ± 11.5	517.9 ± 328.7	14.9 ±1.9	8.1 ± 0.3	10.4 ± 4.2	0.2 ± 0.3	2.5 ± 5.0	15.6 ± 5.8	9.8 ± 5.0
Bulbfield Ditches	33.7 ± 22.7	785 ± 44.9	15.2 ± 2.4	8.6 ± 0.3	12.4 ± 3.2	0.6 ± 1.0	5.5 ± 4.9	17.5 ± 2.6	9.5 ± 4.4

No statistical differences were observed for all measured variables (mean ± s.d.) (Student’s T-tests).