Effect of Phosphorus, Iron and Colloid on Chlorophyll and N2 Fixation of surface Seawater of Beibu Gulf

海洋生物固氮作用是海洋生物化学的重要过程，对海洋中氮通量起重要的调控作用。以往的研究认为深层水中的硝酸盐通过上升流进入表层水体是贫营养海域中新氮的主要来源，而新近研究表明生物固氮才是海洋中新氮的主要提供者。同时，生物固氮作为海洋氮循环的重要环节，对海洋C、N循环以及对大气CO2吸收能力也具有极其重要的调节作用。因此，对生物固氮限制因子的研究有助于深入认识海洋中N循环过程及生物固氮过程对气候的影响。 在地质年代学上海水中的Fe被认为是生物固氮和海洋初级生产力的限制因素，P被假定为营养盐限制因素。一些研究者试图通过现场调查验证这一理论，但缺乏直接的证据。本文利用乙炔还原法（ARA）测定了北部湾2...Nitrogen fixation pay an important role in the process of biochemical, which is one of dominate control the ocean nitrogen inventory. There is long-standing assumed that the deep water nitrate is the major source of ocean new nitrogen supporting primary production in oligotrophic regions of the open ocean, but recently studies show that nitrogen fixation by unicellular diazotrophs can support a si...学位：理学硕士院系专业：海洋与环境学院海洋学系_海洋化学学号：2242006115229

Biological fixed nitrogen of Tokin Gulf in winter

2006年12月至2007年1月(冬季)期间,对北部湾海区的生物固氮作用进行了初步研究,结果表明:当培养时间为2 H时,水体浮游生物固氮速率最高,且固氮速率随着培养时间的延长而逐渐降低。北部湾冬季固氮速率存在周日变化,8∶10~11∶10时段内固氮速率达到最高值。10 M和30 M水深在夜间仍能检测到固氮活性,这可能是浮游生物昼夜垂直移动引起的。北部湾冬季固氮速率的范围为447.5~1447.2 PMOl/(l.H),固氮速率呈现出从湾内往湾外不断增加的趋势,湾口海区(b06站)的积分固氮速率为319.5μMOl/(M2.d)。b06站fE加富实验表明,添加100 nMOl/l fE能够明显促进生物固氮作用,北部湾冬季湾口海区生物固氮作用可能受到fE限制。The biological nitrogen fixation rates were investigated in Tokin Gulf waters in winter from Dec.2006 to Jan.2007.The nitrogen fixation rates were decreased as extension of culture time,the optimal culture time was 2 h.The nitrogen fixation rates showed diurnal variations,the highest nitrogen fixation rate appeared at 8∶ 10--11∶ 10,the diazotrophs still have the nitrogen fixation activity during the night at the depths of 10 m and 30 m,which may result from the diurnal migration of planktons.The nitrogen fixation rates ranged from 447.5 pmol/(L·h) to 1 447.2 pmol/(L·h) of Tokin Gulf waters in winter.Which showed a longitudinally increasing trend,the integral nitrogen fixation rate at station B06 was 319.5 μmol/(m2·d).The iron enrichment experiment at the mouth of the bay(B06) showed that the biological nitrogen fixation significantly promoted by adding iron concentration of 100 nmol/L.The biological nitrogen fixation rates at the bay mouth might be iron limited.国家自然科学基金重大研究计划重点项目资助(90411016);国家教育部高等学校骨干教师计划基金资助项