Sources and Transformation of Dissolved Organic Carbon in the Harp Lake Forested Catchment: The Role of Soils

Trumbore, Susan E.; Schiff, Sherry L.; Aravena, Ramón; Elgood, Richard J.

doi:10.1017/s0033822200063918

Cited by 62 publications

(46 citation statements)

References 22 publications

(39 reference statements)

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“…The SOM2 pool has a turnover time of approximately 20 years. Thus, in DAISY the main source of DOM can be attributed to humified material with an age comparable with the findings of Trumbore et al (1992) and Tegen and Dorr (1996).…”

supporting

confidence: 77%

“…Data on change in 14 C indicate that most of the DOC in soil is fairly old, at least 30 years at 5 cm depth (Tegen and Dorr, 1996) and at 10-25 cm (Trumbore et al, 1992), supporting that SOM is the major source of DOM. This is also supported by findings of Hagedorn et al (2004) who found that the DOC in topsoils contained only 5-10% of C which could be attributed to recent additions from the vegetation (throughfall, litter, roots) of spruce and beech.…”

mentioning

confidence: 93%

“…In 14 old agricultural fields that had been abandoned, Zak et al (1990) observed that water-extractable C and microbial biomass C were highly correlated and the water-extractable C was about 20% of microbial biomass C. On the contrary, Zsolnay (1996) stated that the largest and most consistent source of DOM presumably is the immobile SOM, which is approximately 100-fold more abundant than the DOM itself. Findings of 14 C studies by Trumbore et al (1992) and Tegen and Dorr (1996) suggest that mobile DOM is produced from rather old fractions of organic material.…”

Section: Introductionmentioning

confidence: 99%

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Challenges in modelling dissolved organic matter dynamics in agricultural soil using DAISY

Gjettermann

Styczen

Hansen

et al. 2008

Soil Biology and Biochemistry

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Because dissolved organic matter (DOM) plays an important role is terrestrial C-, N-and P-balances and transport of these three components to aquatic environments, there is a need to include it in models. This paper presents the concept of the newly developed DOM modules implemented in the DAISY model with focus on the quantification of DOM sorption/desorption and microbial-driven DOM turnover. The kinetics of DOM sorption/desorption is described by the deviation of the actual DOM concentration in solution from the equilibrium concentration, C eq . The C eq is soil specific and estimated from pedotransfer functions taking into account the soil content of organic matter, Al and Fe oxides. The turnover of several organic matter pools including one DOM pool are described by first-order kinetics.The DOM module was tested at field scale for three soil treatments applied after cultivating grass-clover swards. Suction cups were installed at depths 30, 60 and 90 cm and soil solution was sampled for quantification of dissolved organic C (DOC) and dissolved organic N (DON). In the topsoil, the observed fluctuations in DOC were successfully simulated when the sorption/desorption rate coefficient k was low. In the subsoil, the observed concentrations of DOC were steadier and the best simulations were obtained using a high k. The model shows that DOC and DON concentrations are levelled out in the subsoils due to soil buffering. The steady concentration levels were based on the C eq for each horizon and the kinetic concept for sorption/desorption of DOC appeared a viable approach. If C eq was successfully estimated by the pedotransfer function it was possible to simulate the DOC concentration in the subsoil. In spite of difficulties in describing the DOC dynamics of the topsoil, the DOM module simulates the subsoil concentration level of DOC well, and also-but with more uncertainty-the DON concentration level. r

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supporting

confidence: 77%

mentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Challenges in modelling dissolved organic matter dynamics in agricultural soil using DAISY

Gjettermann

Styczen

Hansen

et al. 2008

Soil Biology and Biochemistry

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“…A S13C profile for SOM at Harp 4-21 subcatchment agrees with the data reported by Natelhoffer and Fry (1988), which show a S13C change from -29%o at the surface to -25%o at a depth of 35 cm (Trumbore et al 1992 (114)(115)(116)(117)(118) at the very shallow part of the soil, with values close to 100 pMC at a depth between 5 and 10 cm. Older carbon, with 14C content equal to or less than 80 pMC, is present at depths below 15 cm (Trumbore et al 1992).…”

Section: C Composition Of Soil Co2supporting

confidence: 88%

Evaluating Dissolved Inorganic Carbon Cycling in a Forested Lake Watershed Using Carbon Isotopes

et al. 1992

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ABSTRACT. Dissolved inorganic carbon (DIC) is the main acid buffer in forested lake watersheds in Canada. We used carbon isotopes (13C, 14C) to evaluate the production and cycling of DIC in an acid-sensitive lake watershed of the Precambrian Shield. Soil C02, groundwater and stream DIC were characterized chemically and isotopically. Soil CO2 concentration profiles reflect both changes in production and in losses due to diffusion. S13C soil CO2 profiles (b13C values of -23%o in summer, slightly enriched during the fall and -25%o during the winter) are a reflection of the isotopic composition of the sources and changes in isotopic fractionation due to diffusion. Carbon isotopic composition (13C, 14C) of the groundwater and stream DIC clearly indicate that weathering of silicates by soil CO2 is the main source of DIC in these watersheds.14C data show that, in addition to recent groundwater, an older groundwater component with depleted 14C

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“…Factor 1 accounted for 60.1% of the variability in the data set, whereas Factor 2 accounted for 21% of the variability. from soil leachates that have been found in previous studies to be depleted in 13 C but enriched in 14 C (Trumbore et al 1992) and to have C : N ratios of ,15 (Schlesinger 1997). In addition, during high-flow conditions, increased water column turbidity may limit the growth of microalgae in this region of the bay, thereby reducing the potential contribution of freshwater phytoplankton as a primary source of organic matter.…”

Section: Discussionmentioning

confidence: 94%

Dissolved and particulate organic matter source-age characterization in the upper and lower Chesapeake Bay: A combined isotope and biochemical approach

2006

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In order to characterize the sources and ages of organic matter contributing to river and estuarine outflow waters, the present study investigated D 14 C and d 13 C signatures of the major operationally defined biochemical classes of ultrafiltered dissolved organic matter (UDOM) in conjunction with lipid biomarker and elemental compositions of UDOM and suspended particulate organic matter (POM) in the Chesapeake Bay. Freshwater (Susquehanna River) UDOM was dominated by a molecularly uncharacterized (MUC) fraction, followed by total carbohydrate (TCHO), total hydrolysable amino acid (THAA) and total lipid (TLE) components. In contrast, UDOM at the bay mouth (salinity ,22-24) was comprised mainly of TCHO, followed by MUC, THAA, and TLE. The D 14 C and d 13 C signatures of both UDOM and its major biochemical classes indicate that Susquehanna DOM is derived in part from old allochthonous terrestrial sources, whereas young marine sources dominate at the bay mouth. In contrast to the other biochemical classes, lipophilic DOM at both sites was very old (,5,000-7,000 years B.P.). In addition, factor analysis of lipid biomarker compounds revealed unique signatures for the UDOM and POM pools that imply disparate source and/or recycling properties as well as potential influences due to physical partitioning. Lipid biomarker compounds showed that although autochthonous riverine/estuarine sources dominated both the UDOM and POM pools, terrigenous lipids were elevated in the Susquehanna during high flow conditions. The presence of lipid biomarkers diagnostic of ''fresh'' algal material in UDOM further suggested its greater reactivity than POM. The observed biochemical and lipid biomarker compositions and isotopic signatures of UDOM and POM are consistent with previous findings suggesting that these two major organic matter pools have dissimilar reactivities and cycling times, and they derive from comparatively unique source-age materials in rivers and estuaries.Global riverine discharge of dissolved (DOM) and particulate organic matter (POM) is on the order of ,0.4 3 10 15 g C yr -1 (Meybeck 1982;Hedges 1992), making it a potentially major source of organic carbon (C) to the world's oceans. However, much of this carbon is transported through, and modified within, riverine and estuarine environments before entering the coastal ocean. Organic matter in these systems is comprised of variable amounts of identifiable biomolecules such as carbohydrates, proteins, and lipids (Mannino and Harvey 2000;Minor et al. 2001), as well as operationally defined (e.g., humic and fulvic substances in the dissolved phase) and other noncharacterizable, long-lived geomacromolecules. Radiocarbon ( 14 C) studies indicate that DOM and POM in rivers and estuaries range from modern to thousands of years in age (Hedges et al. 1986;Masiello and Druffel 2001;Raymond and Bauer 2001). Previous studies have also shown, however, that young subcomponents of estuarine DOM can be reactive and cycle on timescales of days to weeks (Guo and Santschi 1997;Mc...

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Sources and Transformation of Dissolved Organic Carbon in the Harp Lake Forested Catchment: The Role of Soils

Cited by 62 publications

References 22 publications

Challenges in modelling dissolved organic matter dynamics in agricultural soil using DAISY

Challenges in modelling dissolved organic matter dynamics in agricultural soil using DAISY

Evaluating Dissolved Inorganic Carbon Cycling in a Forested Lake Watershed Using Carbon Isotopes

Dissolved and particulate organic matter source-age characterization in the upper and lower Chesapeake Bay: A combined isotope and biochemical approach

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