摘要
采用培养箱乙炔抑制和现场静态箱法,于夏季(7月)在长江河口潮滩潮间带进行了采样,研究表明,长江河口潮滩水体自身N2O产生速率很低,在潮汐淹没期沉积物是上覆水体N2O的来源,其来自沉积物中反硝化、硝化等氮素循环的多个反应过程,沉积物中N2O自然产生速率在0.10～8.50μmol/(m2·h)之间,反硝化速率在21.91～35.87μmol/(m2·h)之间。退潮出露期中潮滩是大气N2O的排放源犤交换速率在-11.03～13.17μmol/(m2·h)之间犦,5～10cm地温是影响N2O排放速率的显著性因素;低潮滩-大气界面N2O排放、吸收速率在-5.75～0.49μmol/(m2·h)之间。总体上看,中潮滩是大气N2O的排放源;而低潮滩对大气N2O有明显的吸收作用。潮滩植被(海三棱草和底栖藻类)的光合作用明显抑制了N2O的排放并可能导致吸收,而其呼吸作用则增加了N2O的排放,潮间带-大气界面N2O的排放和吸收与CO2的排放、吸收有显著的正相关关系。
Six tidal flat sections in Yangtze estuary were selected as typical sampling sites in summer, using acetylene inhibition technique, to study the denitrification in tidal flat sediment. The results indicate that nitrous oxide （N2O） production rate is very low in the water, and the intertidal flat sediment is the source of the water N2O during the submerging period and N2O comes from several progress of the nitrogen cycle. Sediment N2O natural production rate is between 0. 10 -8.50μmol/（m^2· h）, and the denitrification rate changes from 21.91-35.87μmol/（m^2·h）. During the ebb tide, in situ static closed chamber method was used in Chongrning （CM） tidal flat to measure the N2O flux through sediment-atmosphere interface. Middle tidal flat is the source of atmosphere N2O （exchange flux between -11.03- 13. 17μmol/（m^2·h）. The ground temperature between the depth of 5- 10 cm is the significant effect factors controlling the emission flux. N2O emission flux in low tidal flat-atmosphere interface is from - 5.75 to 0. 49μmol/（m^2·h）. On the whole, the middle tidal flat is the source of air N2O, while the low tidal flat adsorbs air N2O obviously. Photosynthesis of tidal flat plant （Scirpus mariqueter and benthonic alga）inhibits the emission of N2O and induces the consumption of atmosphere N2O. And the respiration of tidal flat plant enhances N2O emission from intertidal flat. N2O emission and absorption through intertidal flat-atmosphere interface has a significant positive correlation to the emission and absorption of CO2.
出处
《地球化学》
CAS
CSCD
北大核心
2006年第3期271-279,共9页
Geochimica
基金
国家自然科学基金重点项目(40131020)
上海市"十五"重大科技攻关项目(05DZ12007)
上海市基础研究重点项目(05JC14059)
上海市环保局招标项目
上海市科委重大项目(05DZ12005)
华东师范大学2005年优秀博士生培养基金资助项目。
关键词
潮间带
反硝化
N2O
排放与吸收
长江河口
intertidal flat
denitrification
nitrous oxide
emission and consumption
Yangtze Estuary
