Application of Dissolved Organic Carbon Runoff Model Considering Soil Infiltration and River Runoff Processes in Multiple Forested Watersheds

2021 ◽  
Author(s):  
Kazunori Ebata ◽  
Yutaka Ichikawa ◽  
Hiroshi Ishidaira ◽  
Yoshitaka Matsumoto ◽  
Kei Nishida
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Transport Processes ◽  
Subsurface Water ◽  
Short Time Scale ◽  
Seasonal Temperature ◽  
Soil System ◽  
System A ◽  
Monsoon Area ◽  
Doc Load

<p>Estimation of dissolved organic carbon (DOC) runoff load in forested watershed is important for the assessment of the global carbon cycle as well as for the control of regional water environments. A few process-based models have been proposed to estimate the DOC load to water environments, which assume DOC source in topsoil and transport processes to the river, however, these models exhibited difficulties with the availability of input data and applicability to short time-scale rainfall-runoff processes in the Asian monsoon area. This study presents a new process-based model that consists of two separate systems for determining DOC load enforced by DOC Source Area (DSA) concept. For the runoff system, a semi-distributed hydrological modelling unit (‘modified-TOPMODEL’) was installed, by which surface and subsurface water flows, representing for DSA, were sequentially simulated. For the soil system, a wet-dry cycle was successfully simulated by an advection-diffusion and dissolution formulation as well as seasonal temperature effect. The model is first evaluated upstream (98ha) and downstream (1798ha) in the Mizugaki Watershed, Yamanashi, Japan and then applied for a Miuchi (203ha) watershed, Aichi, Japan during 2014 to 2018. The results of cumulative DOC load at baseflow and stormflow periods that the model performed well between the simulations and observations for both study sites. Considering the stormflow periods, from 25.2% to 32.0%, and 31.1% of high flows contributed to 50% of the total DOC load at Mizugaki and Miuchi watershed, respectively. Overall, the proposed model successfully simulated DOC load under different geochemical and hydrological condition by capturing the DSA variability.</p>

scholarly journals Seasonal Variations in Dissolved Organic Carbon in the Source Region of the Yellow River on the Tibetan Plateau

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2901
Author(s):  
Xiaoni You ◽  
Xiangying Li
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Yellow River ◽  
Source Region ◽  
Precipitation Amount ◽  
Transport Processes ◽  
The Yellow River ◽  
Deposition Flux ◽  
The Tibetan Plateau ◽  
Permafrost Degradation

Rivers as the link between terrestrial ecosystems and oceans have been demonstrated to transport a large amount of dissolved organic carbon (DOC) to downstream ecosystems. In the source region of the Yellow River (SRYR), climate warming has resulted in the rapid retreat of glaciers and permafrost, which has raised discussion on whether DOC production will increase significantly. Here, we present three-year data of DOC concentrations in river water and precipitation, explore the deposition and transport processes of DOC from SRYR. Results show that annual mean concentrations of riverine DOC ranged from 2.03 to 2.34 mg/L, with an average of 2.21 mg/L. Its seasonal variation is characterized by the highest concentration in spring and summer (2.65 mg/L and 2.62 mg/L, respectively), followed by autumn (1.95 mg/L), and the lowest in winter (1.44 mg/L), which is closely related to changes in river runoff under the influence of precipitation and temperature. The average concentration of DOC in precipitation (2.18 mg/L) is comparable with riverine DOC, while the value is inversely related to precipitation amount and is considered to be the result of precipitation dilution. DOC deposition flux in precipitation that is affected by both precipitation amount and DOC concentration roughly was 86,080, 105,804, and 73,072 tons/yr from 2013 to 2015, respectively. DOC flux delivered by the river ranged from 24,629 to 37,539 tons/yr and was dominated by river discharge. Although permafrost degradation in SRYR is increasing, DOC yield is not as significant as previously assumed and is much less than other large rivers in the world.

Optical in-situ sensors capture dissolved organic carbon (DOC) dynamics after prescribed fire in high-DOC forest watersheds

2019 ◽  
Vol 28 (10) ◽  
pp. 761 ◽  
Author(s):  
Christopher I. Olivares ◽  
Wenbo Zhang ◽  
Habibullah Uzun ◽  
Cagri Utku Erdem ◽  
Hamed Majidzadeh ◽  
...  
Keyword(s):  
South Carolina ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Optical Sensors ◽  
Prescribed Fire ◽  
Second Order ◽  
In Situ Sensors ◽  
Forest Watersheds ◽  
Doc Load

Fires alter terrestrial dissolved organic carbon (DOC) exports into water, making reliable post-fire DOC monitoring a crucial aspect of safeguarding drinking water supply. We evaluated DOC optical sensors in a pair of prescribed burned and unburned first-order watersheds at the Santee Experimental Forest, in the coastal plain forests of South Carolina, and the receiving second-order watershed during four post-fire storm DOC pulses. Median DOC concentrations were 30 and 23mgL−1 in the burned and unburned watersheds following the first post-fire storm. Median DOC remained high during the second and third storms, but returned to pre-fire concentrations in the fourth storm. During the first three post-fire storms, sensor DOC load in the burned watershed was 1.22-fold higher than in the unburned watershed. Grab samples underestimated DOC loads compared with those calculated using the in-situ sensors, especially for the second-order watershed. After fitting sensor values with a locally weighted smoothing model, the adjusted sensor values were within 2mgL−1 of the grab samples over the course of the study. Overall, we showed that prescribed fire can release DOC during the first few post-fire storms and that in-situ sensors have adequate sensitivity to capture storm-related DOC pulses in high-DOC forest watersheds.

scholarly journals Temperature controls production but hydrology controls export of dissolved organic carbon at the catchment scale

2019 ◽  
Author(s):  
Hang Wen ◽  
Julia Perdrial ◽  
Susana Bernal ◽  
Benjamin W. Abbott ◽  
Rémi Dupas ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Soil Water ◽  
Flow Regime ◽  
Production Rate ◽  
Low Flow ◽  
Seasonal Temperature ◽  
Catchment Scale ◽  
Doc Export ◽  
Doc Production

Abstract. Lateral carbon flux through river networks is an important and poorly-understood component of the global carbon budget. This work investigates how temperature and hydrology control the production and export of dissolved organic carbon (DOC) in the Susquehanna Shale Hills Critical Zone Observatory in Pennsylvania, USA. We applied the catchment-scale hydro-biogeochemical reactive transport model BioRT-Flux-PIHM to simulate the DOC dynamics. We estimated the daily DOC production rate (Rp; the sum of local DOC production rates in individual modeling grid cell) and the daily DOC export rate (Re; the product of concentration and discharge at the stream outlet) to downstream ecosystems. Simulations showed that Rp varied by less than an order of magnitude and primarily hinged on seasonal temperature change. In contrast, Re varied by more than three orders of magnitude with a strong dependence on discharge and hydrological connectivity. During summer, high temperatures led to high atmospheric water demand (and evapotranspiration) that dried and disconnected hillslope to stream. Rp reached its maximum but Re was at its minimum. The stream only exported DOC from the organic-poor groundwater and from soil water in the narrow organic-rich swales with enriched DOC such that DOC accumulated in the catchment. During the wet period (winter and spring), Rp reached its minimum but Re peaked because the stream was re-connected to a greater uphill area, flushing out the stored DOC. The model reproduced the observed concentration discharge (C–Q) relationship characterized by a flushing-dilution pattern with a rise in concentrations to a maximum (flushing) at a threshold discharge and then followed a general dilution with concentrations decreasing with discharge. This pattern was explained by the comparable contribution of organic-poor deeper groundwater and soil water from organic-rich swales at the minimum flow, maximized percentage contribution of soil water from organic-rich swales at the low flow regime, and increased contribution of uphill soil water interflow from uphill with less DOC at the high flow regime. This pattern persisted regardless of DOC production rate as long as the contribution of deeper groundwater flow remained low ( 18 %, the flushing-dilution C–Q pattern shifted towards a flushing-only pattern with DOC concentrations increasing with discharge. This study illustrates the temporal asynchrony of DOC production, mostly controlled by temperature, and DOC export, primarily governed by hydrological flow paths at the catchment scale. The occurrence of warmer and more extreme hydrological events in the future could accentuate this asynchrony, with major lateral export of DOC dominated by a few major storm events whereas DOC is produced and stored in the catchment in the prolonged drought periods.

Influence of seasonal changes in runoff and extreme events on dissolved organic carbon trends in wetland- and upland-draining streams

2008 ◽  
Vol 65 (5) ◽  
pp. 796-808 ◽  
Author(s):  
M Catherine Eimers ◽  
Jim Buttle ◽  
Shaun A Watmough
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Extreme Events ◽  
Seasonal Pattern ◽  
South Central ◽  
Doc Export ◽  
Doc Concentration ◽  
Spring Flow ◽  
Doc Load ◽  
Headwater Basins

Dissolved organic carbon (DOC) fluxes at eight headwater basins in south-central Ontario were strongly related to seasonal streamflow, and extreme events contributed to both interannual and intercatchment variability. Six catchments with high stream DOC and greater peatland coverage exhibited a different seasonal pattern of DOC concentration compared with two catchments with low DOC and less wetland influence. In wetland-dominated catchments, DOC concentrations decreased during fall wet-up and spring melt, and because of the dominance of the spring melt period in annual budgets, variations in spring flow explained 39%–48% of the intervariability in DOC concentration. Significant increases in average DOC concentration between 1980 and 2001 at all six wetland-dominated catchments were driven by relatively high DOC concentrations in the latter years of record, consistent with low spring flow in these years, and were not translated into greater DOC export to downstream lakes. Localized rainstorms in summer and fall resulted in differences in DOC export among adjacent catchments, and a single fall storm in September 1998 was only detected at one of six catchments draining into Harp Lake but accounted for one-quarter of the annual tributary DOC load to the lake.

CHARACTERISATION OF DISSOLVED ORGANIC CARBON (DOC) LEACHED FROM LEAVES IN WATER

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Markus Heryanto Langsa
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Total Organic Carbon ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography ◽  
Chromatography Mass Spectrometry ◽  
Pinus Radiate

<p>Penelitian ini bertujuan untuk menentukan senyawa organik khususnya organic karbon terlarut (DOC) dari dua spesies daun tumbuhan (<em>wandoo eucalyptus </em>and <em>pinus radiate, conifer</em>) yang larut dalam air selama periode 5 bulan leaching eksperimen. Kecepatan melarutnya senyawa organic ditentukan secara kuantitatif dan kualitatif menggunakan kombinasi dari beberapa teknik diantaranya Total Organic Carbon (TOC) analyser, Ultraviolet-Visible (UV-VIS) spektrokopi dan pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).</p><p>Hasil analisis DOC dan UV menunjukkan peningkatan yang tajam dari kelarutan senyawa organic di awal periode pengamatan yang selanjutnya berkurang seiring dengan waktu secara eksponensial. Jumlah relatif senyawa organic yang terlarut tergantung pada luas permukaan, aktifitas mikrobiologi dan jenis sampel tumbuhan (segar atau kering) yang digunakan. Fluktuasi profil DOC dan UV<sub>254</sub> disebabkan oleh aktifitas mikrobiologi. Diperoleh bahwa daun kering lebih mudah terdegradasi menghasilkan senyawa organic dalam air dibandingkan dengan daun segar. Hasil pyrolysis secara umum menunjukkan bahwa senyawa hidrokarbon aromatic dan fenol (dan turunannya) lebih banyak ditemukan pada residue sampel setelah proses leaching kemungkinan karena adanya senyawa lignin atau aktifitas humifikasi mikrobiologi membuktikan bahwa senyawa-senyawa tersebut merupakan komponen penting dalam proses karakterisasi DOC.</p>

Sign in / Sign up

Export Citation Format

Share Document