2009年春季东海的生物固氮速率  

Biological N_2 fixation rates in the East China Sea in spring 2009

作　　者：林峰[1] 陈敏[1,2] 杨伟锋[1,2] 张润[1] 郑敏芳[1] 邱雨生[1,2] 童金炉[1] 林志裕[1] 张馨星[1] 

机构地区：[1]厦门大学海洋与地球学院,福建厦门361005 [2]厦门大学近海海洋环境科学国家重点实验室,福建厦门361005

出　　处：《应用海洋学学报》2013年第4期445-454,共10页Journal of Applied Oceanography

基　　金：国家自然科学基金杰出青年基金资助项目(41125020);国家海洋局大洋专项资助项目(DY125-13-E-01)

摘　　要：2009年4～5月间,应用15N2示踪法实测了东海25个站位的生物固氮速率,结合温度、盐度等要素的分布,分析生物固氮速率的空间变化及其影响因素.结果表明,春季东海的生物固氮速率介于102 ～ 16 349 nmol/（m3·d）之间,平均为2441 nmol/（m3·d）.生物固氮速率的空间变化呈现径流影响区最高,黑潮影响区与陆架其他区域相近的特点,径流影响区的平均生物固氮速率约为黑潮影响区和陆架其他区域的2倍,这可能与固氮生物种类的空间变化有关.春季东海的积分固氮速率平均为129 μmol/（m2·d）,结合此前获得的夏、秋、冬季的积分固氮速率,估算出东海生物固氮速率的年均值为50 μmol/（m2·d）,因而东海的年固氮通量估计为1.4×1010 mol/a,约占全球海洋年固氮通量的0.15％.对东海进行的氮源汇分析表明,生物固氮作用、长江径流输入和大气沉降输入等氮输入通量分别为1.4×1010、7.9×1010和3.9×1010mol/a,反硝化作用和沉积物颗粒氮埋藏的迁出通量分别为9.5 ×1010和3.7×1010 mol/a,东海氮的源汇通量均为13.2×1010 mol/a,表明东海氮的收支基本处于平衡状态.Biological N2 fixation rates at 26 stations in the East China Sea were measured with 15 N2 tracer assay during April and May 2009.Combined with temperature and salinity,the distribution of N2 fixation rates and their influencing factors were discussed.Our results showed that the N2 fixation rates ranged from 102 to 16 349 nmol/（m3 · d） with an average of 2 441 nmol/（m3 · d）.The highest rates were observed in regions influenced by the river plume,which was about two times what observed in regions influenced by the Kuroshio current and the shelf waters,probably refleeting the spatial variation of the nitrogen fixers.The integrated N2 fixation rate in the East China Sea in spring was 129 μmol/（m2 · d） in average,and the annual N2 fixation rate was estimated as 50 μmol/（m2 · d） compared with previous data in summer,autumn and winter.This meant that the new nitrogen flux supply by N2 fixation to the East China Sea was 1.4 × 1010 mol/a,contributing to about 0.15％ of the N2 fixation flux in global oceans.The nitrogen budget in the East China Sea was evaluated in views of sources and sinks.The fluxes of nitrogen supply to the East China Sea via the nitrogen fixation,the river runoff and the atmospheric deposition were estimated as 1.4 ×1010,7.9 × 1010 and 3.9 × 1010 mol/a,respectively.The removal fluxes of nitrogen via denitrification and sedimentary burial were 9.5 × 1010 and 3.7 × 1010 mol/a,respectively.Both the nitrogen flux of the sources and the sinks were 13.2 × 1010 mol/a,indicating a balance of nitrogen budget in the East China Sea.

关 键 词：海洋化学 15N2示踪 生物固氮速率 氮收支 东海 春季 

分 类 号：P734[天文地球—海洋化学]