Biogeochemistry

, Volume 108, Issue 1, pp 55–76

Dissolved organic matter (DOM) concentration and quality in a forested mid-Atlantic watershed, USA

Authors

    • Bioresources EngineeringUniversity of Delaware
  • Nina Finger
    • Bioresources EngineeringUniversity of Delaware
  • Shatrughan Singh
    • Bioresources EngineeringUniversity of Delaware
  • Myron Mitchell
    • SUNY-ESF
  • Delphis Levia
    • Bioresources EngineeringUniversity of Delaware
  • Harsh Bais
    • Bioresources EngineeringUniversity of Delaware
  • Durelle Scott
    • Virginia Tech
  • Patrick McHale
    • SUNY-ESF
Article

DOI: 10.1007/s10533-011-9572-4

Cite this article as:
Inamdar, S., Finger, N., Singh, S. et al. Biogeochemistry (2012) 108: 55. doi:10.1007/s10533-011-9572-4

Abstract

Understanding the quantity and quality of dissolved organic matter (DOM) in potential watershed sources is critical for explaining and quantifying the exports of DOM in stream runoff. Here, we examined the concentration and quality of DOM for ten watershed sources in a 12 ha forested catchment over a two-year period. DOM composition was evaluated for: throughfall, litter leachate, soil water (zero and tension), shallow and deep groundwater, stream water, hyporheic zone, and groundwater seeps. DOM quality was measured using a suite of optical indices including UV–visible absorbance and PARAFAC modeling of fluorescence excitation-emission matrices (EEMs). DOM concentrations and quality displayed a pronounced trend across watershed sources. Surficial watershed sources had higher DOM concentrations and more humic-like DOM with higher molecular weight whereas deeper groundwater sources were rich in % protein-like fluorescence. The greater % contribution of protein-like fluorescence in groundwater suggested that a larger fraction of groundwater DOM may be bioavailable. DOM for wetland groundwater was more aromatic and humic-like than that at the well-drained riparian location. Principal component analyses (PCA) revealed that the differences in surficial watershed compartments were dictated by humic-like components while groundwater sources separated out by % protein-like fluorescence. Observations from optical indices did not provide any conclusive evidence for preferential association of dissolved organic carbon (DOC) or dissolved organic nitrogen (DON) with any particular DOM quality pools.

Keywords

DOCDONOrganic matterAromaticBioavailableFluorescenceUV absorbanceExcitation emission matrices (EEMs)

Copyright information

© Springer Science+Business Media B.V. 2011