胶州湾滨海湿地土壤有机碳时空分布及储量

Temporal and spatial distribution of soil organic carbon and its storage in the coastal wetlands of Jiaozhou Bay,China

在胶州湾选取芦苇、碱蓬、光滩及大米草4种典型滨海湿地类型,分季节和层次采集土壤样品,测定土壤有机碳含量,分析滨海湿地土壤有机碳的时空分布及储量.结果表明:垂直方向上,除光滩湿地沿剖面呈先减小后稍有上升的趋势外,其他湿地均随土壤深度的增加而减小;水平方向上,湿地土壤有机碳含量表现为大米草湿地>光滩湿地>碱蓬湿地>芦苇湿地;季节上,湿地土壤有机碳含量表现为春季>夏季>秋季>冬季.土壤有机碳含量与土壤含盐量、含水率、TN及C/N呈正相关,与土壤容重、pH值呈负相关.不同类型湿地土壤剖面有机碳密度表现为光滩湿地>芦苇湿地>碱蓬湿地,湿地类型对土壤有机碳含量和有机碳密度分布的影响存在一定差异.因储碳层厚度及储碳层内有机碳密度的差异,光滩湿地单位面积有机碳储量明显高于碱蓬和芦苇湿地,具有较大的储碳潜能,对研究区滨海湿地起到一定的碳汇作用.

This study selected four typical types of wetlands around Jiaozhou Bay including Spartina anglica wetland, the barren wetland, Suaeda glauca wetland and Phragmites australis wetland, to analyze and compare the contents of soil organic carbon （SOC） and their stock with seasonal and vertical variations. The results showed that the SOC contents of S. anglica wetland, S. glauca wet- land and P. australis wetland all decreased with the increasing soil depth except that the concentra- tion of SOC in the barren wetland showed a decreasing trend first, and then increased slightly along the soil profile. S. anglica wetland ranked first in SOC content, followed by the barren wetland, S. glauca wetland and P. australis wetland. Seasonally, the SOC contents in Jiaozhou Bay coastal wet- lands were in an order of spring〉summer〉autumn〉winter. Correlation analysis demonstrated that SOC content was positively correlated with soil salinity, moisture content, TN and C/N. Negative relationships were observed between SOC content and pH, and between SOC content and soil bulk density. The carbon densities of soil profile were in a decreasing order of the barren wetland, P. au- stralis wetland and S. glauca wetland. There were some differences in the distributions of SOC and carbon density among the various types of wetlands. The barren wetland had a significant higher value for carbon stock per unit area than P. australis wetland and S. glauca wetland due to the differences in carbon density and thickness of carbon storage layer, playing a significant role in the carbon sink process of coastal wetlands.