闽江河口盐沼湿地沉积物有机碳含量及储量特征

Organic Carbon Contents and Storages in the Salt Marsh Sediments in the Min River Estuary

以闽江河口最大的鳝鱼滩湿地为研究区,选择远、近潮沟2个不同潮水水淹区域设置样线,对研究区3种建群植物芦苇(Phragmites australis)、短叶茳芏(又称咸草)(Cyperus malacceusis)和藨草(Scirpus triqueter)下18个沉积物剖面分层取样,研究闽江河口湿地远、近潮沟区不同植物下沉积物有机碳含量和储量的垂直分布特征。结果表明,芦苇下沉积物有机碳含量及储量最大,咸草下沉积物次之,藨草下沉积物最小;芦苇、咸草和藨草下0～60cm沉积物中有机碳储量平均为10045.7t/km2、9706.9t/km2和5303.9t/km2;湿地沉积物有机碳含量及储量与植物种类及生物量密切相关;近潮沟区藨草下沉积物有机碳含量和储量大于远潮沟区,而远、近潮沟区芦苇和咸草下沉积物有机碳含量波动变化,且差异不明显,其近潮沟区有机碳储量小于远潮沟区。3种植物下沉积物有机碳含量与容重呈显著指数负相关关系(n=36,r=-0.8041,p<0.001),其与盐度、pH不相关。

The Shanyutan wetland （26°00′36″N - 26°03′42″N, 119°34′ 12″E - 119°40′40″E） is the largest salt wetland in the Min River estuary area. The climate is relatively warm and wet, with a mean annual temperature of 19.6 ℃ and an annual precipitation of 1 350 mm. Samples from 18 sediment profiles （0 to 60 cm） under 3 dominated plants （Phragmites australis, Cyperus malacceusis and Scirpus triqueter） in 2 different districts far and near a tide ditch in the middle of the Shanyutan wetland were collected. These sediment samples were divided into 0 to 10 cm, 10 to 20 cm, 20 to 30 cm, 30 to 40 cm, 40 to 50 em, 50 to 60 cm depth layers. The organic carbon contents and storages in the sediment profiles were measured. The results indicated that the organic carbon contents and storages in the sediments under P. australis were highest, and then were those under C. malacceusis and S. triqueter. The mean organic carbon storages in the sediments （0 to 60 cm） in the P. australis, C. malacceusis and S. triqueter were 10 045.7 t/km^2, 9 706.9 t/km^2 and 5 303.9 t/km^2 respectively. The organic carbon contents and storages in the sediments had a relationship with plant species and biomass. The organic carbon contents and storages in the sediments under S. triqueter near the tide ditch were higher than that far from the tide ditch, however, for the P. australis wetland and C. malacceusis wetlands, the differences of the organic carbon contents in the sediments far and near the tide ditch were not significant （ n = 6 ,p 〉 0.05 ）, the organic carbon storages near the tide ditch were lower than that far the tide ditch. The organic carbon contents in the sediments under 3 plants had a significant negative relationships with the sediment bulk density（ n = 36 ,r = -0.804 1 ,p 〈0.001 ）, and had no relationship with the sediment salinity and pH.