青蟹养殖池沉积物无机氮释放通量及其影响因素

探讨了青蟹养殖池塘沉积物-水界面无机氮的通量及环境因子对沉积物无机氮释放的影响．计算了养殖池沉积物-水界面NO2-、NO3-、NH4＋的交换通量分别为238．779（μmol·m^-2）·d^-1、-1322．948（μmol·m^-2）·d^-1和199．422（μmol·m^-2）．d^-1．试验表明：35℃时沉积物NH44＋-N的释放量是15℃时的1．348倍，NO2--N和NO3--N随着温度升高释放量增加；pH=9．0时，沉积物释放NH4＋-N和NO2--N量最大，pH=7．0时最小：不充气时氨氮释放量是充气时的1．877倍，而充气时NO2--N释放量大于不充气．表明青蟹养殖中期池塘沉积物是水柱中无机氮的汇，能对水质起调节作用．

Study on Release and Flux of Inorganic Nitrogen from Sediments in Crab Ponds

Inorganic nitrogen flux and its influence on environmental conditions in crab pond are discussed in this paper. The exchanged fluxes of nitrite, nitrate and ammonium between sediment and water column interface in crab ponds on August, 2006 were measured as being 238.8, -1 322.9, and 199.4 （ μmol.m-2） .d^-1 respectively. Furthermore, 3 factors （temperature, pH and air） influencing the release of inorganic nitrogen are analyzed. The analytical results indicate that the concentration of ammonium release under 35℃is found to be 1.348 times that under 15 ℃, so are nitrite and nitrate. The release amount of ammonium reaches maximum with pH being 9, and minimum with pH being 7.0. Ammonium release from the sediments under anaerobic is found to be 1.877 times that under aerobic. All the findings indicate that sediments in crab ponds greatly contribute to the amount of inorganic nitrogen in water column, which acts to adjust the water quality.