珠江口淇澳岛红树林湿地沉积物碳、氮分布研究

为了对珠江口红树林湿地沉积物有机质有更为全面、深入的认识,以珠江口淇澳岛红树林湿地为对象,对其沉积物有机碳(TOC)和总氮(TN)的含量分布、储量及来源进行了研究。结果表明,淇澳岛7种主要红树秋茄(Kandelia candel)、无瓣海桑(Sonneratia opetala)、桐花(Aegiceras corniculatum)、木榄(Bruguiera gymnorhiza)、卤蕨(Acrostichum aureum)、老鼠簕(Acanthus ilicifolius)、海漆(Excoecaria agallocha)]群落表层沉积物TOC质量分数介于1.125%~1.969%,TN质量分数介于0.058%~0.136%。其中秋茄林内TOC含量最高,无瓣海桑林缘TOC含量最高,而木榄林内、林缘TOC含量均最低,且各红树群落TOC含量均呈林内大于林缘的特征。表层沉积物碳氮比(C/N)为12.032~26.690,显示出高等植物对其有机质组成具有较高的贡献率,其中植被内源有机碳的平均贡献率约为70.21%。受土地利用变化等因素的影响,0~30 cm层沉积物的TOC和TN含量均呈现出波动变化的趋势。0~30 cm层沉积物有机碳储量(SOC)介于56.83~69.54 t·hm?2,显示出淇澳岛红树林湿地较强的有机碳埋藏能力。

Study on distribution of sediment carbon and nitrogen in mangrove wetland of Qi'ao Island,Pearl River Estuary

In order to have a deep and thorough understanding of sediment organic matter in mangrove wetland of the Pearl River Estuary,we analyzed the distribution,stocks and source of soil organic carbon(TOC)and total nitrogen(TN)of the mangrove wetland in Qi'ao Island.The results show that the TOC content in the surficial sediment of seven main mangrove communities(Kandelia candel,Sonneratia opetala,Aegiceras corniculatum,Bruguiera gymnorhiza,Acrostichum aureum,Acanthus ilicifolius,Excoecaria agallocha)was 1.125%?1.969%,and the TN content was 0.058%?0.136%.Among the seven main mangrove communities,K.candel had the highest TOC content of inner forest,while S.opetala had the highest TOC content of forest edge.The lowest TOC contents of inner and edge both appeared in B.gymnorhiza communities.Moreover,the TOC content of inner forest was always higher than that of edge.The C/N of the surficial sediment was 12.032?26.690,showing that higher plants have a higher contribution rate to its organic matter composition.According to the C/N bivariate mixture model,about 70.21%of TOC input came from endogenous input of vegetation.Affected by factors such as land use change,TOC and TN content fluctuated in 0?30 cm soil layer.The storage of organic carbon(SOC)was 56.83?69.54 t·hm?2,showing the strong TOC storage ability of this mangrove wetland in Qi'ao Island.