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Fluorescence characteristics and biodegradability of dissolved organic matter in forest and wetland soils from coastal temperate watersheds in southeast Alaska

TitleFluorescence characteristics and biodegradability of dissolved organic matter in forest and wetland soils from coastal temperate watersheds in southeast Alaska
Publication TypeJournal Article
Year of Publication2008
AuthorsFellman, JB, D’Amore, DV, Hood, E, Boone, RD
JournalBigeochemistry
Volume88
Pagination169–184
Abstract

Understanding how the concentration andchemical quality of dissolved organic matter (DOM)varies in soils is critical because DOM inXuences anarray of biological, chemical, and physical processes.We used PARAFAC modeling of excitation–emissionXuorescence spectroscopy, speciWc UV absorbance(SUVA254) and biodegradable dissolvedorganic carbon (BDOC) incubations to investigate thechemical quality of DOM in soil water collected from25 cm piezometers in four diVerent wetland and forestsoils: bog, forested wetland, fen and upland forest.There were signiWcant diVerences in soil solutionconcentrations of dissolved organic C, N, and P,DOC:DON ratios, SUVA254 and BDOC among thefour soil types. Throughout the sampling period, averageDOC concentrations in the four soil types rangedfrom 9–32 mg C l¡1 and between 23–42% of theDOC was biodegradable. Seasonal patterns in dissolvednutrient concentrations and BDOC wereobserved in the three wetland types suggesting strongbiotic controls over DOM concentrations in wetlandsoils. PARAFAC modeling of excitation–emissionXuorescence spectroscopy showed that protein-likeXuorescence was positively correlated (r2 = 0.82;P < 0.001) with BDOC for all soil types takentogether. This Wnding indicates that PARAFAC modelingmay substantially improve the ability to predictBDOC in natural environments. Coincident measurementsof DOM concentrations, BDOC and PARAFACmodeling conWrmed that the four soil typescontain DOM with distinct chemical properties andhave unique Xuorescent Wngerprints. DOM inputs tostreams from the four soil types therefore have thepotential to alter stream biogeochemical processesdiVerently by inXuencing temporal patterns in streamheterotrophic productivity.

DOI10.1007/s10533-008-9203-x
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