崇明东滩海三棱藨草生长期沉积物有机碳含量变化

The variation of organic carbon content in Chongming east tidal flat sediments during Scirpus mariqueter growing stage

对长江口崇明东滩（CM-S）海三棱藨草（Scirpus mariqueter）生长期（4—12月）柱样沉积物有机碳古量及变化分析，发现柱样沉积物有机碳含量与温度、海三棱藨草地上生物量呈显著负相关（p〈0．05）．在陆源沉降、温度和海三棱藨草生长、死亡等因素的共同作用下，崇明东滩沉积物有机碳库随时间推移呈明显的“盈”“亏”变化．夏季是潮滩沉积物有机碳库的“碳亏”期，秋季9月起，海三棱藤草死亡分解使得有机碳在沉积物中累积，沉积物碳库进入“碳盈”期．可见死亡倒伏的海三棱藨草是潮滩盐沼带沉积物有机碳库的主要碳源，海三棱藨草在生长期中通过光合作用所固定的大气碳素在生长末期输送补偿入沉积物有机碳库中．

Organic carbon in column sediments sample from Chongming east tidal flat （CM-S） in the Yangtze River were investigated during the growth season （ April to December） of Scirpus mariqueter. Data obtained indicates that sediment organic carbon content is in negative correlation with temperature and S. martriqueter abeveground biomass （p 〈 0.05 ）. Sediment carbon content turns on significant monthly variation in the influences of allochthonous terrigenous materials inputting, temperature changing and S. mar/queter growing and defoliating. Summer is the ＂carbon losing＂ period of tidal flat sediments, while from the September, it changes into the ＂carbon accumulating＂ period of sediments organic carbon pool because of the decomposing of dead S. mariqueter community on sediments. The alternation of ＂carbon losing＂ period and ＂carbon accumulating＂ period shows that, the organic carbon of the S. mar/queter salt marshes sediments mainly comes from atmospheric carbon rooted by S. mariqueter photosynthesis.