Dissolved organic carbon in headwater streams and riparian soil organic carbon along an altitudinal gradient in the Wuyi Mountains, China

PLoS One. 2013 Nov 12;8(11):e78973. doi: 10.1371/journal.pone.0078973. eCollection 2013.

Abstract

Stream water dissolved organic carbon (DOC) correlates positively with soil organic carbon (SOC) in many biomes. Does this relationship hold in a small geographic region when variations of temperature, precipitation and vegetation are driven by a significant altitudinal gradient? We examined the spatial connectivity between concentrations of DOC in headwater stream and contents of riparian SOC and water-soluble soil organic carbon (WSOC), riparian soil C:N ratio, and temperature in four vegetation types along an altitudinal gradient in the Wuyi Mountains, China. Our analyses showed that annual mean concentrations of headwater stream DOC were lower in alpine meadow (AM) than in subtropical evergreen broadleaf forest (EBF), coniferous forest (CF), and subalpine dwarf forest (SDF). Headwater stream DOC concentrations were negatively correlated with riparian SOC as well as WSOC contents, and were unrelated to riparian soil C:N ratio. Our findings suggest that DOC concentrations in headwater streams are affected by different factors at regional and local scales. The dilution effect of higher precipitation and adsorption of soil DOC to higher soil clay plus silt content at higher elevation may play an important role in causing lower DOC concentrations in AM stream of the Wuyi Mountains. Our results suggest that upscaling and downscaling of the drivers of DOC export from forested watersheds when exploring the response of carbon flux to climatic change or other drivers must done with caution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbon / analysis*
  • Carbon / chemistry*
  • China
  • Organic Chemicals / analysis*
  • Organic Chemicals / chemistry*
  • Plant Development
  • Rain
  • Rivers / chemistry*
  • Soil / chemistry*
  • Temperature
  • Water / chemistry*

Substances

  • Organic Chemicals
  • Soil
  • Water
  • Carbon

Grants and funding

This study was supported by the National Science Foundation of China (No. 31170417), Chinese National Public-Welfare Program (No. 200804006), Doctorate Fellowship Foundation of Nanjing Forestry University (No. 163010106) and Scientific and Technological Innovation Foundation for Graduate Student of Jiangsu Province (No. CXZZ_110510). The funders had role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.