大亚湾海水中N_2O的分布特征与通量的初步研究

Primary studies on N_2O distribution in seawater and air-sea flux at Daya Bay

2004年1月(冬季)和4月(春季)在大亚湾海域设置15个采样站,采集大气和海水样品,运用静态顶空气相色谱法测定了大气和海水中溶存N2O的浓度并对其分布特征和海-气通量进行了初步研究。结果显示,海水中N2O浓度范围在10.90—40.54 nmol.L-1,饱和度为122%—454%,处于过饱和状态;N2O浓度在湾的中部分布较为均匀,大鹏岙、核电站、范和港顶和澳头等受人类活动影响较大的沿岸浓度较高,最大值出现在龙歧河口。海-气通量为0.05—0.78μmol.(m2.d)-1。海水中N2O浓度与NH4+的含量之间有较为显著的正相关性,河口与核电站是N2O的排放源,说明人类活动影响了大亚湾海水中N2O的分布。

Nitrous oxide （N2O） is one of the green house gases. Coastal area is an important emission source of nitrous oxide. The samples from 15 chosen sites at the Daya Bay were collected and studied for the N20 distributions in both seawater and air during Jan. and Apr. , 2004. The static head space gaschromatography method was employed to measure the concentrations of N2O in atmosphere and seawater. The result showed that the N2O concentration ranged between 10.90 and 40.54 nmol · L ^1, with saturation ranging between 122% and 454%. The concentration distributed homogeneously in the central part of the bay, and was higher in the nearshore areas influenced by human being, such as the Dapeng anchorage ground, the nuclear power station, the Fanhe Port, the Adotou Port, and the highest concentration ap- peared at the Longqi estuary. The air-sea flux of N2O ranged between 0.05 and 0.78 μmol·（m^2·d）^-1. There was a notable positive correlation between the concentrations of N2O and NH4^＋ in the seawater, which confirmed that human being activities have influence on the distribution of N2O in the seawater of the Daya Bay.