摘要
利用分级浸取分离法首次将自然粒度下渤海表层沉积物中的氮分为可转化态氮和非转化态氮,并将可转化态氮区分为四种形态:离子交换态氮(IEF-N)、碳酸盐结合态氮(CF-N)、铁锰氧化态氮(IMOF-N)及有机态和硫化物结合态氮(OSF-N),并对其分布进行了研究,估算了各形态氮对沉积物-海水界面循环的贡献。结果表明,渤海沉积物氮中可转化态氮占总氮(TN)的比例为30.85%,其中IEF-N、CF-N、IMOF-N和OSF-N所占比例分别为3.67%、0.31%、0.42%和26.45%,其分布呈现不同的地球化学特征,分布的控制因素亦不同;各形态氮释放的顺序与其在沉积物中结合的牢固程度一致,对界面循环的相对贡献随时间尺度发生变化,绝对贡献的大小与其在沉积物中的储存量大小一致,为OSF-N(84.6%)>IEF-N(13.0%)>IMOF-N(1.4%)>CF-N(1.0%);非转化态氮占TN的69.15%,其中约有49%是由于粒度因素所致。
Nitrogen forms in marine sediments play an important role in its biogeochemical cycling. Previous studies focused on total nitrogen (TN), organic nitrogen (ON) and inorganic nitrogen (IN), with any information not being obtained on nitrogen cycling because nitrogen forms depend on different combination with sediment components and contribute to recycling differently. In this paper, nitrogen in natural grain size sediments of the Bohai Sea is defined as two parts,transferable part and nontransferable part, with sequential extraction method for the first time. Four forms in the transferable part are ion exchangeable form (IEF N), carbonate form (CF N), iron manganese oxides form (IMOF N) and organic matter sulfide form (OSF N), respectively. Their distributions are given and their contribution patterns to sediment water exchange are estimated. The results show that transferable nitrogen accounts for 30.85%of TN in the Bohai Sea sediments and nontransferable nitrogen for 69.15%, and IEF N, CF N, IMOF N and OSF N account for 3.67%, 0.31%, 0.43%and 26.45%of TN, respectively. Distributions of nitrogen forms are controlled by several environmental factors. Contribution degree of nitrogen forms in recycling varies with time scale. The absolute contribution degree is decided by its content in sediments, which has the sequence of OSF N (84.6%) > IEF N (13.0%) > IMOF N (1.4%) > CF N (1.0%).
出处
《地球化学》
CAS
CSCD
北大核心
2003年第1期48-54,共7页
Geochimica
基金
国家杰出青年科学基金(49925614)
中国科学院知识创新工程重大项目(KZCX1-SW-01-08)
