南黄海表层沉积物中氮的分布特征及其在生物地球化学循环中的功能

Distribution Characteristics of Nitrogen in the Southern Yellow Sea Surface Sediments and Nitrogen Functions in Biogeochemical Cycling

本文报道了南黄海表层沉积物中不同形态氮的区域分布特征及其在生物地球化学循环中的作用。结果显示 ,在粒径 <31 μm的粒度组分含量 >6 5 %( )、35 %～ 6 5 %( )和 <35 %( )的三个区域中 ,沉积物中不同形态氮的含量比值分别为 :1 .6 5 :1 .2 6 :1 (IEF- N) ,1 .2 3:1 .1 0 :1 (WAEF- N) ,1 .4 1 :1 .0 4 :1 (SAEF- N) ,2 .0 8:1 .4 5 :1 (SOEF- N) ,TN(1 .70 :1 .2 6 :1 ) ,即在细粒度组分 (<31 μm)含量较高的区域 ,不同形态氮的含量也相对较高 ;在三个分区内 ,不同形态氮的埋藏通量非常相近 ,而埋藏效率自 至 区逐渐递增 ,在细粒度组分 (<31 μm)含量最低的 区内 ,埋藏效率最高 ,TN的埋藏效率可达 30 .2 1 %,即南黄海表层沉积物中 70 %以上的氮在适当的条件下可释放进入水体参与其生物地球化学循环 ,能提供海洋新生产力所需氮的 6 .5 4 %,对海洋生产力具有一定的补充和调控作用。

The distributions and functions of various forms of nitrogen in the biogeochemical cycling in the southern Yellow Sea surface sediments were investigated. The southern Yellow Sea was divided into three regions according to the grain size of the sediments. In regions Ⅰ, Ⅱ and Ⅲ, the contents of the fine sediments are >65%, 35～65% and <35%, respectively. The ratios of different forms of nitrogen contents between region Ⅰ, Ⅱ and Ⅲ were 1.65∶1.26∶1 (IEF-N), 1.23∶1.10∶1 (WAEF-N), 1.41∶1.04∶1 (SAEF-N), 2.08∶1 45∶1 (SOEF-N), TN (1.70∶1.26∶1) respectively, indicating that the contents of various forms of nitrogen were higher with that of fine grain-size sediment increasing. Nitrogen burial fluxes were also similar in the three regions, while the burial efficiency increased from region Ⅰ to Ⅲ, and the highest burial efficiency of TN was 30.21% in region Ⅲ, indicating that exceeding 70% of nitrogen in the southern Yellow Sea surface sediments could release to take part in biogeochemical recycling. The nitrogen released from sediments(19.54×109 mol N/a)could supply 6.54% nitrogen of the new primary productivity of the southern Yellow Sea.