Temperature, but not submersion or orientation, influences the rate of sulphur hexafluoride release from permeation tubes used for estimation of ruminant methane emissions

摘要: Predictable release of sulphur hexafluoride (SF6) tracer gas from permeation tubes into the reticulo-rumen is necessary to estimate methane emissions ruminants using SF6 technique. Any discrepancy between laboratory determined rate and actual in would bias calculated emissions. The purpose this investigation was determine effect temperature, submersion orientation on tubes. Four experiments were undertaken. Experiment 1 that increased by 2.5 ± 0.14% per degree Celsius increase temperature 37 41 °C (P < 0.001). 2 Arrhenius equation can be used describe dependence 0 70 °C, consistent with a change 2.3 0.08% temperature. 3 water did not affect = 0.13). 4 influenced tube 0.42). In addition we activation energy permeation, Ep, describing overall flux tubes, 18,424 680 J/mol. This research implies short-term within will vary response due animal, diet and/or environmental factors. A short term decrease contents, induced drinking cold water, expected have larger influence accuracy estimated emission derived time-averaged sampling periods less than 24 h. Use technique detect differences enteric or animal species may confounded genetic effects body Unless managed through careful implementation technique, substantial errors could caused as illustrated following example: +2 error calibration (41 °C), −2 (37 °C) assumed (39 approximately +10%.