生态环境学报 ›› 2023, Vol. 32 ›› Issue (1): 139-149.DOI: 10.16258/j.cnki.1674-5906.2023.01.015

• 研究论文 • 上一篇    下一篇

海南东寨港流域土壤-溪流连续体溶解态黑碳分子特征及其界面转化机制

王全超1(), 吉恒宽1, 李思敏1, 李财生1, 侯正伟1, 邓万刚1, 吴治澎1,*(), 王登峰2,*()   

  1. 1.海南大学热带作物学院,海南 海口 570228
    2.中国热带农业科学院热带作物品种资源研究所,海南 海口 571101
  • 收稿日期:2022-11-01 出版日期:2023-01-18 发布日期:2023-04-06
  • 通讯作者: 王登峰,E-mail: dfwang@vip.163.com
    *吴治澎,E-mail: peter@hainanu.edu.cn
  • 作者简介:王全超(1999年生),男,硕士研究生,主要研究方向为土地利用变化与生态环境效应。E-mail: 1473561136@qq.com
  • 基金资助:
    海南省基础与应用基础研究计划(自然科学领域)高层次人才基金项目(2019RC022);国家重点研发项目(2021YFD2200403-04)

Molecular Characteristics and Interfacial Transformation Mechanism of Dissolved Black Carbon in Soil-Stream Continuum in Dongzhai Harbor Watershed of Hainan Province

WANG Quanchao1(), JI Hengkuan1, LI Simin1, LI Caisheng1, HOU Zhengwei1, DENG Wangang1, WU Zhipeng1,*(), WANG Dengfeng2,*()   

  1. 1. College of Tropical Crops, Hainan University, Haikou 570228, P. R. China
    2. Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, P. R. China
  • Received:2022-11-01 Online:2023-01-18 Published:2023-04-06

摘要:

研究不同土地利用背景下土壤-溪流连续体溶解态黑碳(DBC)分子特征及其界面转化规律对调控溪流温室气体排放具有重要的指导意义。以海南东寨港3个典型热带流域为研究区,对流域内3种土地利用类型(农田、林地、湿地)的土壤、溪流进行监测,通过超滤技术、苯多羧酸法与傅里叶变换离子回旋共振质谱技术(FT-ICR-MS)对DBC粒径分布、结构组成进行表征,进一步揭示不同土地利用背景下土壤-溪流界面中DBC转化机制。结果表明,从土壤到溪流环境DBC质量浓度逐渐变小;土壤DBC平均质量浓度、DBC/DOC比值大小顺序为湿地>农田>林地,而在溪流中湿地最低,分别为0.14 mg·L-1、6.61%;林地、农田、湿地的土壤DBC分别主要分布在>10 kDa、<10 kDa、<1 kDa的粒径中,质量浓度范围为1.21—4.01 mg·L-1,所有溪流DBC在不同粒径中的分布更为均匀;所有土壤与溪流的DBC稠环结构以B4CAs和B5CAs为主,其中农田溪流B4CAs占比超过60%;DBC中CHO化合物的占比最高为73.56%,土壤DBC的CHOS/CHONS化合物在湿地中占比最高为21.84%,但在溪流DBC中湿地占比最低为6.73%;不同地类土壤-溪流界面中DBC含量平均损失率大小顺序为农田>林地>湿地,而林地、农田、湿地水土界面中具有最大损失率的DBC组分分别为>0.2 μm、1—10 kDa、<1 kDa,而农田溪流中B3CAs、B4CAs和B5CAs平均损失率显著高于地类溪流。土壤-溪流界面的DBC转化主要受分子特征的影响,其次为界面环境理化性质与微生物组成,流域内不同土地利用方式通过改变土壤-溪流界面输入性DBC结构组成与界面环境因子共同影响DBC的界面转化过程。

关键词: 溶解态黑碳, 土地利用, 土壤-溪流连续体, 结构组成, 界面转化

Abstract:

It is important to study the molecular characteristics of dissolved black carbon (DBC) in the soil-stream continuum and the interfacial transformation patterns under different land use for the regulation of greenhouse gas emissions in streams. In this study, we monitored three types of land use (farmland, woodland and wetland) derived soil and streams at three typical tropical watersheds in Dongzhai Harbor, Hainan Province. The ultrafiltration technology in combination with the benzene polycarboxylic acid method and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to investigate the size distribution and structure composition of DBC and its transformation mechanism at soil-stream interface under different land use types. Results showed that the average mass concentration of DBC gradually decreased from soil to stream environments. The average mass concentration and DBC/DOC ratio of soil DBC were ranked in the following order: wetland>farmland>woodland, while the average mass concentration and DBC/DOC ratio of wetland-dominated streams DBC were 0.14 mg·L-1 and 6.61%, respectively, significantly lower than those of other streams. The soil DBC derived from woodland, farmland and wetland was mainly distributed in particles >10 kDa, <10 kDa and <1 kDa, respectively, and the mass concentration ranged from 1.21-4.01 mg·L-1, while all streams DBC was more evenly distributed among the four molecular-weight sizes. The fused ring structure of DBC in all soils and streams was dominated by B4CAs and B5CAs. In addition, the proportion of B4CAs content in farmland streams accounted for more than 60%; The percentage of CHO compounds in DBC was the highest at 73.56%, and the percentage of CHOS/CHONS compounds in soil DBC accounted for the highest proportion of 21.84% in wetlands, but the lowest proportion of wetlands in stream DBC was 6.73%. The average loss rates of DBC content in the soil-stream interface of different types of land use were ranked in the following order: woodland>farmland>wetland, while the DBC components with the maximum loss rate under woodland, farmland and wetland environments were >0.2 μm, 1-10 kDa and <1 kDa, respectively, but the average loss rates of B3CAs, B4CAs and B5CAs in farmland streams were significantly higher than those in other land-use-dominated streams. The DBC transformation of soil-stream interface was mainly influenced by the molecular characteristics, followed by interface environmental physical and chemical properties as well as microbial composition. Different land use patterns in the watershed affect the interface transformation process of DBC by changing the input DBC structure of the soil-stream interface and interface environmental factors.

Key words: dissolved black carbon, land use, soil-stream continuum, structural composition, interfacial transformation

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