樟湖库湾网箱养殖区沉积物氮的时空变化特征

Characteristics on spatial and temporal variations of nitrogen in the sediments from cage culture area of Zhanghu reservoir bay

为研究网箱养殖区表层沉积物中氮的时空变化特征,于2016年6月—2017年5月在樟湖库湾选取不同网箱养殖区采集沉积物,按月测定和分析总氮、铵态氮、硝态氮含量,并探讨不同网箱养殖区沉积物中各形态氮之间的相关关系。结果表明,网箱养殖区沉积物中总氮、铵态氮、硝态氮含量年变化范围分别为530.00~3 570.00、28.29~362.46、3.36~7.98 mg/kg,总氮和铵态氮呈现明显的季节变化,总氮含量总体趋势为冬季高夏季低,铵态氮含量为夏季最高,而硝态氮季节变化差异不大;不同网箱养殖区域沉积物中氮含量存在空间差异显著性,高密度网箱养殖区沉积物中总氮和铵态氮平均含量显著高于对照点,低密度网箱养殖区总氮平均含量显著低于对照点,但铵态氮和硝态氮含量与对照点无显著差异。各形态氮之间的相关性在不同养殖区域沉积物中也不尽相同,网箱养殖区沉积物中铵态氮含量分别与总氮、硝态氮呈现显著相关性(P<0.05)。

To study the characteristics on spatial and temporal variations of nitrogen in the sediments from cage culture area,the sediments collected from different cage culture area of Zhanghu reservoir bay were determined and analyzed monthly for the content of total nitrogen,ammonium nitrogen,and nitrate nitrogen from June 2016 to May 2017. The relationship among various forms of nitrogen in the sediments from different cage culture area was discussed. The results showed that the range of annual content of sediment total nitrogen,ammonium nitrogen,and nitrate nitrogen were 530. 00 ~ 3 570. 00,28. 29 ~ 362. 46,and 3. 36 ~ 7. 98 mg/kg,respectively. Sediment total nitrogen and ammonium nitrogen were influenced obviously by seasons,but the season variation of nitrate nitrogen was not obvious. The results showed that the content of total nitrogen was higher in winter and lower in summer,while ammonium nitrogen was the highest in summer. There were spatial significant difference in the content of various forms of nitrogen of sediments from different cages culture area. The content of total nitrogen and ammonium nitrogen in sediments of high density cage culture areas were significantly higher than that of non-cultured areas. The average content of total nitrogen in the low-density cage culture areas was significantly lower than that of non-cultured areas,but the content of ammonium nitrogen and nitrate nitrogen were not significantly different from that of non-cultured areas. The correlations of all forms of nitrogen were different in the sediments of different cage culture areas,and the significant positive correlations( P < 0. 05) between contents of ammonium nitrogen and total nitrogen,as well as between contents of ammonium nitrogen and nitrate nitrogen were found.