Contrasting patterns and controls of soil carbon and nitrogen isotope compositions in coastal wetlands of China

作者：Xia, Shaopan; Song, Zhaoliang^*; Singh, Bhupinder Pal; Guo, Laodong; Bolan, Nanthi; Wang, Weiqi; Lin, Guanghui; Fang, Yin; Wen, Xuefa; Wang, Jing; Hartley, Iain P.; Liu, Xueyan; Wang, Yidong; Wang, Hailong

来源：Plant and Soil, 2023, 489(1-2): 483-505.

DOI：10.1007/s11104-023-06034-2

• Soil organic matter
• Stable C and N isotopes
• Vegetation type
• Edaphic variables
• SOM source tracing
• Environmental changes
• Coastal wetlands

AimsNatural stable isotope compositions of carbon (delta C-13) and nitrogen (delta N-15) can reveal biogeochemical mechanisms that control ecosystem carbon (C) and nitrogen (N) processes. However, little is known about the latitudinal patterns and controlling mechanisms for soil delta C-13 and delta N-15 in coastal wetlands based on a large spatial scale.MethodsA total of 76 sites of coastal wetlands were sampled along a 5000 km transect across temperate-subtropical-tropical zones to explore biological and environmental controls on soil stable C and N isotopic compositions.ResultsThe results showed that soil delta C-13 (ranging from -27.5 parts per thousand to -18.3 parts per thousand) and delta N-15 (from 2.66 parts per thousand to 9.97 parts per thousand) varied over a broad geographic scale. The C4-plant (Spartina alterniflora) dominated sites have 2-6 parts per thousand higher delta C-13 values than those of other vegetation types, while mangrove soils have lower delta C-13 values compared to those of marshes; and soils with vegetated C4-plants and mangroves have 1-3 parts per thousand higher delta N-15 values relative to native grass marshes. There were no significant relationships between mean annual temperature (MAT) or precipitation (MAP) and delta C-13, but positive correlations between MAT and delta N-15, as well as MAP and delta N-15.ConclusionsVegetation composition and plant C inputs directly control the spatial variability of delta C-13 patterns. Simultaneously, climate and edaphic variables (e.g., soil water content, pH, and C availability) are the predominant factors influencing delta N-15 patterns. These findings provide new insights into soil organic matter turnover and response to climate and environmental changes and improve the prediction of C stability and burial in coastal wetlands.

• 单位
  浙江农林大学; 中国科学院; 佛山科学技术学院; 南京农业大学; 清华大学; 天津大学