HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Scheel, T. Articles by Kalbitz, K. Search for Related Content PubMed Articles by Scheel, T. Articles by Kalbitz, K. Agricola Articles by Scheel, T. Articles by Kalbitz, K. Related Collections Humic Substances Carbon Sequestration Soil Organic Matter

Precipitation of Dissolved Organic Matter by Aluminum Stabilizes Carbon in Acidic Forest Soils

Dep. of Soil Ecology, Bayreuth Center of Ecology and Environ., Research (BayCEER), Univ. of Bayreuth, D-95440 Bayreuth, Germany

View larger version (26K): [in this window] [in a new window]   Fig. 1. Specific ultraviolet (UV) absorption at 2 0 nm of the extracted dissolved organic matter solutions from the oa and oi horizons of a beech and a spruce forest in relation to their aromatic c content, determined by­ solution 1 c nuclear magnetic resonance.

View larger version (19K): [in this window] [in a new window]   Fig. 2. The maximum percentage of dissolved organic C precipitated from the dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest (at pH 4.5 and Al/C ratio of 0.3, except for the Oi-spruce solution, which had an Al/C ratio of 0.1) after Al addition in relation to the content of aromatic C and aromatic H.

View larger version (17K): [in this window] [in a new window]   Fig. 3. The Al/C ratios in precipitates (solid phase) of the dissolved organic matter (DOM) solutions from the Oa and Oi horizons of a beech and a spruce forest in relation to the initially adjusted Al/C ratios in the DOM solutions. Precipitation was initiated at two different pH values: pH 3.8 (left) and pH 4.5 (right). Mean values and standard error of three replicates.

View larger version (22K): [in this window] [in a new window]   Fig. 4. Ratio of Al needed to precipitate similar amounts of dissolved organic C at pH 4.5 and 3.8 (dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest, different Al/C ratios). Ratios >1 mean that more Al was necessary at pH 4.5 to precipitate the same amount of C as at pH 3.8.

View larger version (30K): [in this window] [in a new window]   Fig. 5. Specific ultraviolet (UV) absorption (280 nm) of initial dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest (Al/C ratio 0) and after removal of precipitates by filtration. Precipitation was initiated at two pH values and four different Al/C ratios. Mean values and standard error of three replicates.

View larger version (27K): [in this window] [in a new window]   Fig. 6. Aromatic C content of initial dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest (Al/C ratio 0) and of precipitates for two pH values and four Al/C ratios. Mean values and standard error of three replicates.

View larger version (28K): [in this window] [in a new window]   Fig. 7. Organic C/organic N ratios of initial dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest (Al/C ratio 0) and of precipitates for two pH values and four Al/C ratios. Mean values and standard error of three replicates.

View larger version (31K): [in this window] [in a new window]   Fig. 8. Dynamics of C mineralization of Al–organic matter (OM) precipitates (as a percentage of initial C) during 7 wk of incubation at pH 4.5 and 20°C. The Al–OM precipitates were produced from dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest at two pH values and four Al/C ratios. Mean values and standard error of three replicates.

View larger version (22K): [in this window] [in a new window]   Fig. 9. Mineralization of Al–organic matter precipitates (Al/C ratio 0.1) produced from dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest at pH 3.8 and 4.5 (incubation at pH 4.5 and 20°C for 7 wk). Mean values and standard error of three replicates.

View larger version (54K): [in this window] [in a new window]   Fig. 10. Mineralization of Al–organic matter precipitates (from dissolved organic matter solutions from the Oa and Oi horizons of a beech and a spruce forest) in dependence on the aromatic C content and the organic C/organic N ratio of the precipitates (multiple linear regression: R2 = 0.76; dissolved organic carbon [DOC] mineralized [as a percentage of initial DOC] = 9.992 – 0.091(C/N ratio) – 0.161(aromatic C) [%]).