李健成¹, 吴伊婧¹, 江彬彬¹, 苏建锋¹, 于俊杰², 范代读¹
1.同济大学海洋地质国家重点实验室, 上海 200092;2.中国地质调查局南京地质调查中心, 江苏南京 210016

摘要:
潮滩作为重要的湿地类型和高效的有机碳汇备受关注，近期围垦、养殖等人类活动和互花米草入侵对潮滩生化环境和有机碳埋藏产生了重要影响。本研究选取了福建三沙湾三处不同植被类型的潮滩各取得沉积物短柱样，测定沉积物的总有机碳含量（TOC）、稳定碳同位素（δ¹³C），结合²¹⁰Pb_ex测试计算的沉积速率，估算了不同区域的有机碳埋藏通量（B_C）。结果表明，互花米草阶段和红树林阶段TOC含量分别为0.67%和0.95%，比对应的光滩阶段分别提高了13.6%和26.7%，表明红树林对潮滩固碳效率的提升比互花米草更加显著。在两者的共同生长区域，随时间推移TOC含量显著下降，表明互花米草入侵挤占红树林生长空间之后，降低了潮滩的固碳效率。短柱样沉积物δ¹³C值分布范围在-24.70~-21.87‰，主要体现海源有机质同位素特征，但也会受潮滩植被生长类型影响。对各短柱样有机碳埋藏通量进行估算，得到研究区红树林生长阶段B_C平均值为149.53 g/（m²·a），远高于互花米草生长阶段的平均值57.37 g/（m²·a）。
关键词:三沙湾互花米草红树林固碳能力
DOI：10.11759/hykx20201013003
分类号:P67
基金项目:国家自然科学基金（41976070）；中国地质调查局（DD20189505）

Effects of different vegetation types on organic carbon burial in tidal flats of the Sansha Bay, Fujian Province
LI Jian-cheng¹, WU Yi-jing¹, JIANG Bin-bin¹, SU Jian-feng¹, YU Jun-jie², FAN Dai-du¹
1.State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China;2.Nanjing Geological Survey Center, China Geological Survey, Nanjing 210016, China
Abstract:
As an important wetland type and efficient organic carbon sink, tidal flats have attracted great scientific attentions. Increasing human activities such as land reclamation and aquaculture and the introduction of Spartina alterniflora have greatly impacted on the ecology and organic carbon burial capacity of tidal flats. In this study, three short sediment cores were collected from tidal flats with different vegetation types in the Sansha Bay, Fujian province. Total organic carbon (TOC) contents and stable carbon isotope compositions (δ¹³C) of bulk sediments were measured. Sedimentation rates were derived by ²¹⁰Pb_ex analysis, and organic carbon burial fluxes (B_C) in different areas were calculated. The results showed that the TOC contents during the stages of Spartina alterniflora and mangrove forests were 0.67% and 0.95%, respectively, that were 13.6% and 26.7% higher than the bare flat stage. Indicating a higher carbon sequestration efficiency of mangrove forests than Spartina alterniflora. The δ¹³C value in all three cores range from -24.70‰ to -21.87‰, which reflects the isotope characteristics of marine organic matter, the influence of vegetation types only limited within the coretop. The average B_C value of mangrove growth stage (149.53 g·m^-2·a^-1) was much higher than the Spartina alterniflora growth stage (57.37 g·m^-2·a^-1). Therefore, the carbon sequestration efficiency of tidal flats can be drastically reduced where mangrove forests are replaced by Spartina alterniflora.
Key words:Sansha BaySpartina alternifloramangrovecarbon sequestration ability





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