海州湾表层沉积物中氮的赋存形态及其生态意义

于2014年10月在海州湾采集表层沉积物,利用分级浸取分离的方法,对其中的离子交换态氮(IEF-N)、弱酸可浸取态氮(WAEF-N)、强碱可浸取态氮(SAEF-N)及强氧化剂可浸取态氮(SOEF-N)4种可转化态氮(TTN)的含量进行了分析测定,结合沉积物的有机质含量(TOC)、粒度分布,讨论了各形态氮的生态意义.结果表明:IEF-N、WAEF-N、SAEF-N、SOEF-N、非转化态氮(NTN)、总氮(TN)的平均含量分别为12.63、5.78、8.93、85.32、568.93和681.59 mg·kg-1;各形态氮在TTN中所占的比例大小顺序为SOEF-N(75.73%)IEF-N(11.21%)SAEF-N(7.93%)WAEF-N(5.13%).研究还表明,沉积物中TN与TOC和粒径具有显著的相关性(p0.01);WAEF-N与TOC具有显著的相关性(p0.01),与粒径也具有显著相关性(p0.05),其他形态氮与TOC、粒度分布均有一定程度的相关关系;各形态氮与水体中的溶解态无机氮(DIN)、叶绿素a具有相关性,说明沉积物中的氮对海洋生态环境有着重要意义.

Nitrogen forms in the surface sediment of Haizhou Bay and their ecological significance

The sequential extracted surface sediment samples collected from Haizhou Bay in October 2014 were analyzed to determine different forms of nitrogen, including ion exchangeable form-nitrogen (IEF-N), weak acid extractable form-nitrogen (WAEF-N), strong alkaline extractable form-nitrogen (SAEF-N) and strong oxidant extractable form-nitrogen (SOEF-N), along with total organic content (TOC) and particle size distribution. The ecological significance of different forms of nitrogen was also discussed. The results show that the mean concentrations of IEF-N, WAEF-N, SAEF-N, SOEF-N, nontransferable nitrogen (NTN), total nitrogen (TN) were 12.63 mg·kg^-1, 5.78 mg·kg^-1, 8.93 mg·kg^-1, 85.32 mg·kg^-1, 568.93 mg·kg^-1 and 681.59 mg·kg^-1, respectively. The percentage and order of the different forms of TTN was as follows: SOEF-N (75.73%)> IEF-N (11.21%)> SAEF-N (7.93%)> WAEF-N (5.13%). The study also show that the TN and TOC are significantly correlated to particle size (p<0.01), while other forms of TTN are associated with dissolved inorganic nitrogen and chlorophyll-a in water, which means the nitrogen in surface sediments have essential biogeochemical significance.