Seasonal variation of soil respiration and its influence factors in tidal flat of Yangtze Estuary
长江口潮滩土壤呼吸季节变化及其影响因素

Soil respiration in the tidal flat of Yangtze Estuary was investigated from July 2007 to May 2008,using a static chamber combined with a gas chromatograph.Environmental factors including air temperature,soil temperature,soil water content and coastal water salinity were also measured during the sampling periods.The results showed that soils from the tidal flat of the Yangtze Estuary were net sources of atmospheric CO2,and soil respiration fluctuated with distinct seasonal patterns.Seasonal variation of soil respiration was characterized by a mono-peak pattern with the highest rate in July through August.Soil respiration was observed to significantly correlate to air temperature and soil temperature,probably indicating that soil respiration at the study area was predominantly controlled by air temperature and soil temperature.In contrast,no significant correlation was found between soil respiration and soil water content.The highest soil respiration rate appeared at Station WSK,followed by BLG,DHand FX.This spatial difference in soil respiration implied that soil respiration rates generally decreased with the increasing water salinity.In conclusion,the seasonal change of soil respiration in the Yangtze Estuary was co-effected mainly by temperature and water salinity.