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  • Park, Ji-Hyung  (10)
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  • 1
    Language: English
    In: Biogeochemistry, 2003, Vol.66(3), pp.265-286
    Description: Although dissolved organic matter (DOM) released from the forest floor plays a crucial role in transporting carbon and major nutrients through the soil profile, its formation and responses to changing litter inputs are only partially understood. To gain insights into the controlling mechanisms of DOM release from the forest floor, we investigated responses of the concentrations and fluxes of dissolved organic carbon (DOC) and nitrogen (DON) in forest floor leachates to manipulations of throughfall (TF) flow and aboveground litter inputs (litter removal, litter addition, and glucose addition) at a hardwood stand in Bavaria, Germany. Over the two-year study period, litter manipulations resulted in significant changes in C and N stocks of the uppermost organic horizon (Oi). DOC and DON losses via forest floor leaching represented 8 and 11% of annual litterfall C and N inputs at the control, respectively. The exclusion of aboveground litter inputs caused a slight decrease in DOC release from the Oi horizon but no change in the overall leaching losses of DOC and DON in forest floor leachates. In contrast, the addition of litter or glucose increased the release of DOC and DON either from the Oi or from the lower horizons (Oe + Oa). Net releases of DOC from the Oe + Oa horizons over the entire manipulation period were not related to changes in microbial activity (measured as rates of basal and substrate-induced respiration) but to the original forest floor depths prior to manipulation, pointing to the flux control by the size of source pools rather than a straightforward relationship between microbial activity and DOM production. In response to doubled TF fluxes, net increases in DOM fluxes occurred in the lower forest floor, indicating the presence of substantial pools of potentially soluble organic matter in the Oe + Oa horizons. In contrast to the general assumption of DOM as a leaching product from recent litter, our results suggest that DOM in forest floor leachates is derived from both newly added litter and older organic horizons through complex interactions between microbial production and consumption and hydrologic transport.
    Keywords: Dissolved organic carbon ; Dissolved organic matter ; Dissolved organic nitrogen ; Forest floor ; Litter manipulation ; Resource availability ; Water flux
    ISSN: 0168-2563
    E-ISSN: 1573-515X
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  • 2
    In: Journal of Geophysical Research: Biogeosciences, September 2012, Vol.117(G3), pp.n/a-n/a
    Description: Although land‐water carbon (C) transport represents a critical link in the global C cycle, rare attempts have been made to compare hydrologic controls over storm pulses of dissolved organic C (DOC) and particulate organic C (POC) in mountainous watersheds. An immersible UV/Vis spectrophotometer was used to comparatively investigate the rapid storm responses of stream water DOC and POC in a small mountainous forested watershed in South Korea. High‐frequency measurements at 5‐min intervals during 42 hydrologic events, including monsoon storms and winter snowmelts, showed consistent patterns: POC concentrations were lower than DOC concentrations during base flow and small storm events but exceeded them during the peak flow periods of intense storm events. Although both the DOC and POC concentrations had hysteretic relationships with discharge, the POC concentrations showed larger increases and variations after crossing a threshold discharge on the rising limb of the storm hydrograph. Stronger responses to intense storms resulted in a disproportionately large export of POC at high flow, whereas a large portion of the total DOC flux was exported under prevailing low‐flow conditions. The results demonstrate the potential of in situ optical measurements for investigating fine‐resolution dynamics of the DOC and POC export during storm events. Stronger storm responses of the POC export compared to the limited response range of the DOC export suggest that erosion‐induced POC export will become more important as a major pathway for the hydrologic soil C loss from mountainous watersheds in response to an increasing occurrence of extreme storm events. In situ optical monitoring captured differential storm responses of DOC and POC POC export was more variable on rising discharge than limited DOC responses Strong storm responses lead to disproportionately large POC export at high flow
    Keywords: Dissolved Organic Carbon ; Extreme Events ; In Situ Sensors ; Mountainous Watersheds ; Particulate Organic Carbon ; Soil Carbon Loss
    ISSN: 0148-0227
    E-ISSN: 2156-2202
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  • 3
    Language: English
    In: Geoderma, 15 January 2018, Vol.310, pp.163-169
    Description: The release of dissolved organic matter (DOM) in forest floors is a dynamic component of organic carbon transformations in forest soils. The biogeochemical processes driving the production and release of dissolved organic carbon and nitrogen (DOC and DON) in forest floors are strongly affected by hydroclimatic conditions during rainfall events. We conducted an exhaustive percolation experiment to examine the pool size and sustained production of mobilizable DOC and DON in Oi, Oe and Oa layers of spruce, larch and beech forest floors. The percolation experiment with small reconstructed soil columns was conducted at 5 and 15 °C for 25 days with a percolation volume equal to 36 mm d , adding up to a total percolation volume of 900 mm. Percolates were collected at an interval of 5 days and analyzed for DOC and DON. Simultaneously to the periodic analysis of percolates, the CO release was measured. The sustained release of DOM during the last leaching period from day 20 to 25, after 720 mm of percolation, was defined as the . The cumulative release of DOM was large: in case of the 15 °C treatment, the total amount of DOM extracted for 25 days was on average 1.6% and 2.2% of the total C and N stock, respectively. The largest cumulative release of DOM and CO was observed for the beech samples. The ratio of cumulative CO /cumulative DOC release ranged from 1 to 3 for Oi and Oe samples but was 〈 0.2 for spruce Oa. No changes in DOC/DON ratios as a result of percolation amount were detected. The production rates indicated a rapid replenishment of DOM pools after leaching. The Q values for the DOM production rates ranged from 2 to 4 and were similar to those for CO production. The positive correlation between DOM and CO production rates in Oi and Oe samples highlights the importance of microbial activity for DOM release. The pool of mobilizable DOM in forest floors seems large enough to provide a sustained rate of DOM release throughout precipitation events under field conditions although the actual rate of mobilization may vary in the field, depending on antecedent conditions and the duration and intensity of the rainfall event.
    Keywords: Dissolved Organic Carbon (Doc) ; Dissolved Organic Nitrogen (Don) ; Forest Floor ; Soil Respiration ; Q10 ; Agriculture
    ISSN: 0016-7061
    E-ISSN: 1872-6259
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  • 4
    Language: English
    In: Environmental pollution (Barking, Essex : 1987), September 2006, Vol.143(1), pp.178-85
    Description: The role of detrital quantity and quality in forest floor N leaching was investigated in a litter manipulation experiment at a deciduous forest under chronic N deposition. Dissolved inorganic nitrogen (DIN) comprised the bulk of nitrogen leaching from the control except a short period following autumn litterfall. The dominance of DIN was strengthened by litter exclusion, whereas the addition of glucose or fresh litter led to a small increase in dissolved organic nitrogen (DON) and either a temporary or gradual reduction in NO(3)(-) release, respectively. Changes in soluble organic C and microbial C in the forest floor implied that increased availability of C sources might have enhanced microbial immobilization of DIN, either temporarily following glucose application or over the longer term following litter addition. The results suggest that detrital quantity and quality can play a crucial role in determining the balance between DIN and DON in N-enriched forest soils.
    Keywords: Air Pollutants ; Biodegradation, Environmental ; Ecosystem ; Nitrogen ; Plant Leaves ; Trees
    ISSN: 0269-7491
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  • 5
    Language: English
    In: Biogeosciences, Sept 29, 2016, Vol.13(18), p.5421
    Description: Heavy storm events may increase the amount of organic matter in runoff from forested watersheds as well as the relation of dissolved to particulate organic matter. This study evaluated the effects of monsoon storm events on the runoff fluxes and on the composition of dissolved (#xE2;#x80;#xAF;POC and NO.sub.3 -N#xE2;#x80;#xAF;〉#xE2;#x80;#xAF;DON#xE2;#x80;#xAF;〉#xE2;#x80;#xAF;PON. The integrated DOC fluxes in runoff during the study period were much larger at the deciduous watershed (16#xE2;#x80;#xAF;kg#xE2;#x80;#xAF;C#xE2;#x80;#xAF;ha.sup.-1) than at the mixed watershed (7#xE2;#x80;#xAF;kg#xE2;#x80;#xAF;C#xE2;#x80;#xAF;ha.sup.-1 ), while the integrated NO.sub.3 -N fluxes were higher at the mixed watershed (5.2#xE2;#x80;#xAF;kg#xE2;#x80;#xAF;N#xE2;#x80;#xAF;ha.sup.-1) than at the deciduous watershed (2.9#xE2;#x80;#xAF;kg#xE2;#x80;#xAF;N#xE2;#x80;#xAF;ha.sup.-1). The latter suggests a larger N uptake by deciduous trees. Integrated fluxes of POC and PON were similar at both watersheds. The composition of organic matter in soils and runoff indicates that the contribution of near-surface flow to runoff was larger at the deciduous than at the mixed watershed. Our results demonstrate different responses of particulate and dissolved C and N in runoff to storm events as a combined effect of tree species composition and watershed specific flow paths.
    Keywords: Runoff
    ISSN: 1726-4170
    ISSN: 17264189
    E-ISSN: 17264189
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  • 6
    Language: English
    In: Biogeosciences Discussions, 05/13/2016, pp.1-25
    ISSN: Biogeosciences Discussions
    E-ISSN: 1810-6285
    Source: CrossRef
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  • 7
    Language: English
    In: Environmental Pollution, 2006, Vol.143(1), pp.178-185
    Description: The role of detrital quantity and quality in forest floor N leaching was investigated in a litter manipulation experiment at a deciduous forest under chronic N deposition. Dissolved inorganic nitrogen (DIN) comprised the bulk of nitrogen leaching from the control except a short period following autumn litterfall. The dominance of DIN was strengthened by litter exclusion, whereas the addition of glucose or fresh litter led to a small increase in dissolved organic nitrogen (DON) and either a temporary or gradual reduction in NO release, respectively. Changes in soluble organic C and microbial C in the forest floor implied that increased availability of C sources might have enhanced microbial immobilization of DIN, either temporarily following glucose application or over the longer term following litter addition. The results suggest that detrital quantity and quality can play a crucial role in determining the balance between DIN and DON in N-enriched forest soils. Detrital quantity and quality play a crucial role in regulating the release of DON and DIN from the forest floor under chronic N deposition.
    Keywords: C Limitation ; Dissolved Inorganic Nitrogen ; Dissolved Organic Nitrogen ; Forest Floor ; N Saturation ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
    Source: ScienceDirect Journals (Elsevier)
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  • 8
    Language: English
    In: Soil Biology and Biochemistry, 2002, Vol.34(9), pp.1391-1391
    Keywords: Agriculture ; Chemistry
    ISSN: 0038-0717
    E-ISSN: 1879-3428
    Source: ScienceDirect Journals (Elsevier)
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  • 9
    Language: English
    In: Soil Biology and Biochemistry, June 2002, Vol.34(6), pp.813-822
    Description: The forest floor in temperate forests has become recognized for its importance in the retention of elevated inputs of dissolved inorganic nitrogen (DIN) and as a source of dissolved organic matter (DOM). A laboratory leaching experiment was conducted over the period of 98 d to examine the origin of dissolved organic carbon (DOC) and nitrogen (DON) in a deciduous forest floor, and the effect of resource availability and microbial activity on the production mechanisms involved. The experiment was composed of different types of treatments: exclusion of specific forest floor layers (no Oi, no Oe) and addition of carbon sources (glucose, cellulose, leaf, wood) and NH sub(4)NO sub(3) (nitrogen). The cumulative amount of CO sub(2) evolution was positively related to the availability of C sources at each treatment: glucose 〉 leaf = wood = cellulose 〉 control = no Oe = nitrogen 〉 no Oi. DOC release was related to the amount of C sources but showed no clear correlation with CO sub(2) evolution. An increase in C availability generally led to a reduction in the release of DON as well as DIN. In contrast, the amendment of NH sub(4)NO sub(3) reduced the cumulative DOC release but enhanced the release of both DON and DIN. Fresh leaf litter was a more important DOC source than labile substrates (glucose and cellulose) as well as more stable substrates (forest floor materials and wood). Among forest floor layers, more humified horizons (Oe and Oa) were the primary source of DIN and made a similar contribution to DOM release as the Oi layer. The changes in DOM composition detected by a humification index of the leachates, in combination with a shift in the final microbial biomass C, suggested that DOM released from the soluble pools of added litter or the Oi layer contained a substantial amount of microbially processed organic matter. Our study demonstrated the importance of C availability in regulating microbial activity and immobilization of dissolved N in an N-enriched forest floor. However, the discrepancy between substrate lability and DOC production, in combination with a rapid microbial processing of DOC released from labile C pools, illustrated the complicated nature of microbial production and consumption of DOC in the forest floor.
    Keywords: Dissolved Organic Matter ; Dissolved Organic Carbon ; Dissolved Organic Nitrogen ; Dissolved Inorganic Nitrogen ; Forest Floor ; C and N Availability ; Soil Microbial Activity ; Agriculture ; Chemistry
    ISSN: 0038-0717
    E-ISSN: 1879-3428
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  • 10
    Language: English
    Description: Variability in runoff fluxes of dissolved and particulate carbon and nitrogen from two watersheds of different tree species during intense storm events...
    Keywords: Dissolved Organic Carbon ; Dissolved Organic Nitrogen ; Particulate Organic Carbon ; Particulate Organic Nitrogen ; Monsoon Storm ; Forested Watershed
    Source: DataCite
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