【摘要】 利用15 N示踪法实测南海水体反硝化速率的研究发现,培养水样在长时间密闭放置过程中也会受到外界空气的污染,且其29N2/28N2比值恒定为0.007 35。根据空气背景中29N2/28N2比值恒定的特征,提出基于质量平衡关系校正空气N2污染的方法,通过将样品实测29N2浓度扣除由外界空气贡献的29N2浓度,可获得由生物反硝化作用所产生的29N2准确浓度,进而可计算出准确的反硝化速率。经空气29N2背景校正后,29N2浓度的偏差明显小于未经校正的结果,且29N2浓度与培养时间之间的线性相关性显著加强,凸显出空气29N2背景校正是获取准确反硝化速率的关键。鉴于15 N示踪法已被广泛应用于海洋水体与沉积物反硝化速率的测定中,所提出的空气29N2背景校正方法具有重要的意义。更多还原

【Abstract】 15 N tracer technique was widely applicated in measuring water column denitrification rate in water samples,however,the sealed samples could be contaminated by air during a long time storage.Our study suggested that N2in air has a constant 29N2/28N2ratio of 0.007 35.According to this feature,a mass-balance calculation was proposed to calibrate the interference from air background.It helps obtain more accurately 29N2concentrations produced by biological activity and further the denitrification rates.After the calibration,the deviations of 29N2concentrations were much less than those of the raw data,and the linear correlation between 29N2concentration and the incubation time was more significant.It is important to calibrate extra 29N2signals from air contamination for accurately quantification of denitrification rate,considering the 15 N technique has been widely used in pelagic and beneath denitrification rate measurements.更多还原