Table 2 Benthic oxygen fluxes.

Oxygen exchange (transparent chamber; net O2 flux), oxygen respiration (masked chamber; O2 respiration), and oxygen production [GPP = net O2 flux + (O2 respiration)] rates obtained from benthic chambers deployed in 2013; oxygen production–to–respiration (GPP/R) ratio, respiration per unit of total biomass (R/BTotal), and respiration per unit of heterotroph biomass (bacteria and animals; R/BHeterotrophs). Benthic masked chambers rates (n = 2) and average (mean with ±SD in parenthesis), maximum (Max), and minimum (Min) rates of transparent chambers (n = 3 to 4) and O2 production (n = 6 to 8) are given. nt, not tested for significance level; ns, not significant (P > 0.05).

Net O2 flux (daylight)nsO2 respiration (masked)ntO2 production**GPP/RR/BTotalR/BHeterotrophs
mmol m−2 day−1mmol m−2 day−1mmol m−2 day−1day−1day−1
REFMean−7 (6)na10 (8)0.60.06/0.140.07/0.18
Max−11−2321
Min−2−100
CO2-GMean−58 (63)−188130 (63)0.71.132.06
Max−151na173
Min−15na37
CO2-RMean−18 (6)na55 (37)§0.80.16/0.490.41/1.14
Max−24−10696
Min−11−3815

†Average (±SD; n = 6) of O2 production calculated from each Net O2 flux using O2 respiration from both masked chambers.

‡At CO2-R, only one masked chamber was available.

§Average (±SD; n = 8) of O2 production calculated from each O2 flux using O2 respiration from both masked chambers.

**P < 0.01 (Welch’s t test between REF and CO2-R).