Ecosystems

, Volume 16, Issue 4, pp 604–616

Hydrologic Drivers and Seasonality of Dissolved Organic Carbon Concentration, Nitrogen Content, Bioavailability, and Export in a Forested New England Stream

  • Henry F. Wilson
  • James E. Saiers
  • Peter A. Raymond
  • William V. Sobczak
Article

DOI: 10.1007/s10021-013-9635-6

Cite this article as:
Wilson, H.F., Saiers, J.E., Raymond, P.A. et al. Ecosystems (2013) 16: 604. doi:10.1007/s10021-013-9635-6

Abstract

We present the results of a full year of high-resolution monitoring of hydrologic event-driven export of stream dissolved organic matter (DOM) from the forested Bigelow Brook watershed in Harvard Forest, Massachusetts, USA. A combination of in situ fluorescent dissolved organic matter (FDOM) measurement, grab samples, and bioassays was utilized. FDOM was identified as a strong indicator of concentration for dissolved organic carbon (DOC, r2 = 0.96), dissolved organic nitrogen (DON, r2 = 0.81), and bioavailable DOC (BDOC, r2 = 0.81). Relationships between FDOM and concentration were utilized to improve characterization of patterns of hydrological event-driven export and the quantification of annual export. This characterization was possible because DOM composition remained relatively consistent seasonally; however, a subtle shift to increased fluorescence per unit absorbance was observed for summer and fall seasons and percent BDOC did increase slightly with increasing concentrations. The majority of export occurred during pulsed hydrological events, so the greatest impact of bioavailable exports may be on downstream aquatic ecosystems. Export from individual events was highly seasonal in nature with the highest flow weighted mean concentrations (DOCFW) being observed in late summer and fall months, but the highest total export being observed for larger winter storms. Seasonal trends in DOC export coincide with weather driven changes in surface and subsurface flow paths, potential for depletion and rebuilding of a flushable soil organic matter pool, and the availability of terrestrial carbon sources such as leaf litter. Our approach and findings demonstrate the utility of high frequency FDOM measurement to improve estimates of intra-annual temporal trends of DOM export.

Keywords

dissolved organic carbon (DOC)dissolved organic nitrogen (DON)bioavailable organic carbon (BDOC)fluorescent dissolved organic matter (FDOM)forestedstream carbon exporthydrologic eventseasonalannual

Supplementary material

10021_2013_9635_MOESM1_ESM.doc (708 kb)
Supplementary material 1 (DOC 707 kb)

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Henry F. Wilson
    • 1
    • 2
  • James E. Saiers
    • 1
  • Peter A. Raymond
    • 1
  • William V. Sobczak
    • 3
  1. 1.School of Forestry and Environmental StudiesYale UniversityNew HavenUSA
  2. 2.Brandon Research CentreAgriculture and Agri-Food CanadaBrandonCanada
  3. 3.Biology DepartmentHoly Cross CollegeWorcesterUSA