崇明东滩湿地不同盐沼植物群落土壤碳储量分布

海岸带盐沼植被的高生产力对湿地土壤碳库的形成具有重要意义.本文研究了长江口崇明东滩湿地3种主要盐沼植物(芦苇、互花米草和海三棱藨草)群落生物量差异、土壤碳储量时空动态和垂向分布特征.结果表明： 湿地盐沼植被总生物量表现为互花米草群落(5750.7 g·m^-2)>芦苇群落(4655.1 g·m^-2)>海三棱藨草群落(812.7 g·m^-2)，且地上生物量在夏、秋季最高，地下生物量在冬季最高.湿地土壤碳储量(0～50 cm)在春季最低，随后逐渐增加，至冬季达到最大值.土壤碳储量年增量从高潮滩向低潮滩递减，表现为芦苇群落(711.8 g·m^-2)>互花米草群落(646.2 g·m^-2)>海三棱藨草群落(185.3 g·m^-2)>光滩(65.6 g·m^-2).光滩土壤碳储量在25～30 cm处最高，海三棱藨草、互花米草和芦苇群落土壤碳储量分别在10～15、30～35和30～40 cm处达到最大值，且不同群落土壤碳储量与植被地下生物量具有显著的线性关系.

Distribution of soil carbon storage in different saltmarsh plant communities in Chongming Dongtan wetland.

The high productivity of saltmarsh vegetation in coastal wetlands plays an important role on the formation of soil carbon pool. This paper studied the biomass difference, the spatiotemporal dynamics and vertical distribution of soil carbon storage in three dominant saltmarsh plant communities, i.e., Phragmites australis, Spartina alterniflora and Scirpus mariqueter in the Chongming Dongtan wetland, in the Yangtze Estuary. The results indicated that the gross biomass in the three saltmarsh plant communities was in the order of S. alterniflora (5750.7 g·m^-2) > P. australis (4655.1 g·m^-2) > S. mariqueter (812.7 g·m^-2). The aboveground biomass was the highest in summer and autumn, and the underground biomass was the highest in winter. The soil carbon storage (0-50 cm) was the lowest in spring, gradually increased, and was the highest in winter. The annual increment of soil carbon storage decreased from the high tidal zone to the low tidal zone, and was in the order of P. australis community (711.8 g·m^-2) > S. alterniflora community (646.2 g·m^-2) > S. mariqueter community (185.3 g·m^-2) > bare mudflat (65.6 g·m^-2). The highest value was in the 25-30 cm, 10-15 cm, 30-35 cm and 30-40 cm soil layers for bare mudflat and the S. mariqueter, S. alterniflora and P. australis communities, respectively. There was a significant linear relationship between the soil carbon storage and the underground biomass in the different saltmarsh communities.