南通沿海潮间带土-气界面CO_2交换特征

Characteristics of soil-air CO_2 exchange fluxes in intertidalite of Nantong

选择南通协兴港附近裸露潮滩,使用便携式土壤通量测量系统开展潮间带湿地CO_2通量监测,研究无植被覆盖条件下潮间带碳通量特征及其影响因素的关系.实验结果表明,各潮滩CO_2固定水平表现为高潮带<中潮带<低潮带.低潮带叶绿素a含量较高,对CO_2的吸收能力较强,而高潮带有机碳含量高,微生物呼吸作用释放的CO_2通量较高,研究区整体上表现为对CO_2净吸收.此外,CO_2净固定通量随土壤有机碳含量和落潮时间增加而下降,与土壤叶绿素a含量和地下水位关系密切.研究成果对于明确人类活动对江苏沿海潮间带裸露光滩碳循环的影响具有重要意义.

The CO2 flux was measured by a portable soil flux measurement system at a bare tidal flat,where is close to Xiexing Port of Nantong.The relationship between the characteristics of carbon flux and their determinants on a non-vegetation area was explored.The results showed that the abilities of carbon fixation for different intertidal zones are the high intertidal<middle intertidal<low intertidal.It might be because of the higher contents of chlorophyll a in the low intertidal zones and higher CO2 absorbing ability.Meanwhile,the organic carbon contents and the CO2 emission fluxes esulting from microbial respiration in the high intertidal zone were the highest.It was a net CO2 fixation for the whole research area.In addition,CO2 net fixation fluxes decreased with the increase of organic carbon content in the soil and the duration of the ebb tide,closely related to the chlorophyll a content and the groundwater.Our findings highlight the importance of human activities in shaping the carbon cycling in the bare flats of the intertidal zones in Jiangsu province.