Table 3.

Seasonal water column volumetric O₂ rates for the CL, CW, and GN. Values for day and night O₂ rates are reported as bottle‐averaged, i.e., depth‐averaged values. Daytime rates were obtained from the average daytime production rates in clear bottles (n = 3). Night time rates were obtained by averaging respiration rates in the dark bottles during the daytime and at night (n = 2). The rates were obtained from linear regressions of the respective O₂ time series (R ² > 0.8).

Campaign	Site	Day (n = 3) (μmol L−1 h−1)	Night (n = 2) (μmol L−1 h−1)	Total PAR (mol quanta m−2 d−1)	Daylight day/night (h)	ERw a (mmol m−2 d−1)	GPPw a (mmol m−2 d−1)	NEMw a, b (mmol m−2 d−1)
Spring	CL	43.2	−1.6	6.4	15.3/8.7	14.9	268.1	253.2/14.2c
	CW	<0.1	<0.1	20.2	15.2/8.8	<0.1	<0.1	<0.1
	GN	9.0	−1.0	18.4	16.4/7.6	12.1	84.5	65.0
Summer	CL	0.1	−3.6	0.5	15.4/8.6	21.4	13.9	−7.5
	CW	5.3	−1.9	21.4	15.2/8.8	13.7	32.7	19.0
	GN	<0.1	−1.2	12.1	15.9/8.1	12.6	<0.1	−12.6
Autumn	CL	−0.9	−1.3	0.3	8.9/15.1	9.1	<0.1	−8.1
	CW	−0.3	−0.3	6.0	10.9/13.1	3.8	<0.1	−3.8
	GN	−1.2	−1.6	2.0	10.4/13. 6	26.2	<0.1	−23.5
Winter	CL	n.d.	n.d.	n.d.	n.d.	n.d.	n.d.	−8.1d
	CW	<0.1	−0.3	0.6	9.9/14.2	2.5	<0.1	−2.5
	GN	−0.3	−0.3	0.6	8.8/15.2	4.9	<0.1	−5.1

^aWater‐column based ecosystem respiration (ER_w), GPP and (GPP_w), and net water column metabolism (NEM_w) were expressed as a flux (mmol m⁻² d⁻¹) by multiplying the volumetric rates (mmol m⁻³ d⁻¹) by the average stream depth (Table 2).

^bNet water column metabolism, NEM_w, for sites with no detectable daytime rates, was computed by multiplying the hourly nighttime‐dark average rates by 24.

^cWhole spring estimates of NEM_w assuming 1 week of peak primary production and the remaining 11 weeks with NEM_w = summer NEM_b.

^dWinter NEM_w rate is assumed equal to the autumn NEM_w rate.