• Title/Summary/Keyword: allochthonous

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Characteristics of Allochthonous Organic Matter in Large Dam Reservoir, Lake Soyang (소양호에서 외부기원유기물의 유입, 유출 특성)

  • Park, Hae-Kyung;Kwon, Oh-youn;Jung, Dong-Il
    • Journal of Korean Society on Water Environment
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    • v.27 no.1
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    • pp.88-97
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    • 2011
  • To identify the inflow and outflow characteristics of allchthonous organic matters and examine the change of allochthonous organic matter load pattern due to the climate change, we investigated the temporal variations of DOC and POC concentrations within inflow water and dam discharge water and spatio-temporal distribution of POM within the lake water in Lake Soyang which is the largest dam reservoir in Korea in 2006. Most of allochthonous DOC flowed into the lake water during initial rain and was not affected by the amount of precipitation, whereas most of allochthonous POC flowed into during concentrated heavy rain and the concentration of POC was significantly associated with the amount of inflow water and precipitation. Calculated annual allochthonous organic matter loads in Lake Soyang from 2003 to 2006 using the regression equation between the amount of inflow water and the concentration of POC indicate allochthonous organic matter loads are mainly affected by total influx and extreme influx of inflow water. The spatio-temporal distribution of POM indicated allochthonous organic matter of inflow river during flood period in July transported from upper part to middle and lower part of the lake a month later respectively along the middle layer of water column in Lake Soyang.

Variation of Allochthonous Gravels in the Beach Gravel Deposit of the Island Dokdo Natural Reserve (독도천연보호구역 해빈자갈퇴적층(몽돌 해변)의 외래 역 분포 변화)

  • Lim, Hoseong;Park, Jinsu;Kim, Jung-Hoon;Woo, Hyeon-Dong;Jang, Yun-Deuk
    • The Journal of the Petrological Society of Korea
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    • v.26 no.3
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    • pp.255-269
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    • 2017
  • Five year term monitoring investigating variation of allochthonous originated gravels are has been conducted in the beach gravel deposit of the Island Dokdo natural reserve which takes purity and uniqueness with enormous attention though a number of areas. The beach gravel deposits near the dock of the Dongdo and near the accommodation facility of the Seodo comprise various types of gravels including basalt, trachyte, and tuff from the Dokdo itself, and granite, rhyolite, gneiss, quartzite, marble, and concrete from elsewhere. The types of the allochthonous gravels on the basis of the study in 2011 and in 2016 shows no difference, so is the ranking of abundance of the allochthonous gravels; granite-concrete-gneiss in turn on the Dongdo, concrete-gneiss-granite in turn on the Seodo. Nevertheless, the relative ratio of the allochthonous gravel area against the total area is decreased. While it is suspected that the disintegrated facility and the influx of material for construction are the main 2 reasons for the contamination by allochthonous gravel, diminished total contamination ratio indicate that supervising allochthonous material has been improved; at least not worse during the 5 years. On the other hand, it is inferred that gradual influence of rockfall also has been made the gravel beach changed. Therefore, consistent rockfall investigation must be inquired.

Gas Hydrate Systems at Hydrate Ridge;Results from ODP Leg 204

  • Lee, Young-Joo;Kim, Ji-Hoon;Ryu, Byong-Jae
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.531-533
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    • 2007
  • We report and discuss molecular and isotopic properties of hydrate-bound gases from 55 samples and void gases from 494 samples collected during Ocean Drilling Program (ODP) Leg 204 at Hydrate Ridge offshore Oregon. Gas hydrates appear to crystallize in sediments from two end-member gas sources (deep allochthonous and in situ) as mixtures of different proportions. In an area of high gas flux at the Southern Summit of the ridge (Sites 1248-1250), shallow (0-40 meters below the seafloor (mbsf)) gas hydrates are composed of mainly allochthonous mixed microbial and thermogenic methane and a small portion of thermogenic C2+ gases, which migrated vertically and laterally from as deep as 2-2.5 km depths. In contrast, deep (50-105 mbsf) gas hydrates at the Southern Summit (Sites 1248 and 1250) and on the flanks of the ridge (Sites 1244-1247) crystallize mainly from microbial methane and ethane generated dominantly in situ. A small contribution of allochthonous gas may also be present at sites where geologic and tectonic settings favor vertical gas migration from greater depth (e.g., Site 1244).

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Simple Material Budget Modeling for the Paldang Reservoir in the Spring Season (팔당호의 춘계 단순물질수지 모델링)

  • Kong, Dongsoo
    • Journal of Korean Society on Water Environment
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    • v.33 no.6
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    • pp.696-714
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    • 2017
  • Simple material budget models were developed to predict the spring season (March ~ May) water quality for a river-type reservoir Paldang, in the Republic of Korea. These models are available at mixed water bodies whose light intensity is negligible at the bottom. The calculated data from the models fit quite well with field data collected for 30 years, from 1988 to 2017. The apparent settling velocity of total phosphorus was estimated to be $110m\;d^{-1}$. The critical hydraulic load that determines the usability of phosphorus for algal production appeared to be about $2.0m\;d^{-1}$. When a hydraulic load was larger than the critical value, the concentrations of chlorophyll ${\alpha}$ ($Chl.{\alpha}$), chemical oxygen demand (COD), and 5-day biochemical oxygen demand BOD in the reservoir water became insensitive to internal algal reactions. The model analysis showed that the allochthonous COD continued to increase while the allochthonous BOD slightly decreased after 1999. The decrease of allochthonous BOD is due to the expansion of sewage and wastewater treatment plants in the watershed. The increase of allochthonous COD seems to result from the increase in anthropogenic non-point sources as well as the increase in the discharge of natural organic matters due to climate change. Organic matter of algal origin continued to increase until the mid-2000s, but recently it has decreased as the phosphorus concentration has decreased. The COD and BOD of algal origin increased from 35 % and 27 % during 1988 ~ 1994 to 43 % and 40 % during 2000 ~ 2010, respectively, and then decreased to 25 % and 28 % during 2011 ~ 2017.

Characteristics of Dissolved Organic Matter(DOM) Based on Molecular Weight Fractions and Fluorescence Properties in the Downstream Nakdong River (낙동강 하류 수역에서 분자량 크기 및 형광특성을 고려한 용존유기물질 특성)

  • Ji, Hwaseong;Kim, Mihee;Lee, Youjung;Son, Heejong
    • Journal of Korean Society on Water Environment
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    • v.36 no.3
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    • pp.194-205
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    • 2020
  • The characteristics and behavior of dissolved organic matter (DOM) were determined by analyzing the molecular weight fractions and fluorescence properties of water samples in the downstream Nakdong River. Biogeochemical water quality parameters and fluorescent dissolved organic matter (FDOM) were analyzed at five sampling points in the downstream area of the Nakdong River January-August 2019. The molecular weight fractions of the DOM were separated by the Liquid Chromatography-Organic Carbon Detection (LC-OCD). The DOM predominantly comprised humic substances, followed by the building blocks, low molecular weight neutrals and biopolymers. The hydrophobic (aromatic) and hydrophilic properties were shown as coexisting, as most of the SUVA254nm values were under four. The FDOM was characterized as humic-like (FDOMH) with allochthonous origin and protein-like (FDOMP) with autochthonous origin; the FDOMH with autochthonous origin was also identified. The FDOMH relies on the aromaticity of the allochthonous organic matter and increases during summer. The FDOMH and FDOMP, which depend on the biodegradable dissolved organic matter from phytoplankton, were highly fluorescent in winter. The allochthonous organic matter was the dominant factor contributing to the behavior of the DOM, externally introduced to the river by rainfall. The FDOM only minimally contributed to the behavior of the DOM. It can be explained as the seasonal characteristics of the DOM, varied by the source of the organic matter.

Organic Matter Sources in a Reservoir (Lake Soyang); Primary Production of Phytoplankton and DOC, and External Loading (식물플랑크톤의 세포외배출유기물을 고려한 소양호의 1차생산과 유기물 부하)

  • Nam, Kung-Hyun;Hwang, Gil-Son;Choi, Kwang-Soon;Kim, Chul-Goo;Kim, Bom-Chul
    • Korean Journal of Ecology and Environment
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    • v.34 no.3 s.95
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    • pp.166-174
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    • 2001
  • The autochthonous and allochthonous organic carbon loading were measured in Lake Soyang, to estimate the amount of carbon loading into the lake and the contribution of their sources to tile lake's carbon loading. Autochthonous carbon loading was estimated from phytoplankton primary production with the extracellular organic carbon (EOC). Allochthonous loading was determined by measuring dissolved organic carbon (DOC) and particulate organic carbon (POC) concentration in the main inflowing Soyang River. Both autochthonous and allochthonous organic carbon loading were high during the svmmer, from July to September, and accounted for 43.2% and 71.7% of the annual loading, respectively. Primary productivity was elevated up to $1,000\;mgC\;m^{-2}\;d^{-1}$ during summer and lowest in winter. EOC production from phytoplankton was also large in summer, resulting in a high DOC concentration in the lake water. Primary production of phytoplankton and allochthonous organic matter loading from the watershed contributed to 53.6% and 46.4% of total loading, respectively. The EOC production accounted far $4.4{\sim}21.2%$ of POC primary production, implying that EOC production of phytolankton must be considered in estimation of primary production.

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Analysis of Organic Carbon Cycle and Mass Balance in Daecheong Reservoir using Three-dimensional Hydrodynamic and Water Quality Model (3차원 수리·수질 모델을 이용한 대청호 유기탄소 순환 및 물질수지 해석)

  • An, Inkyung;Park, Hyungseok;Chung, Sewoong;Ryu, Ingu;Choi, Jungkyu;Kim, Jiwon
    • Journal of Korean Society on Water Environment
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    • v.36 no.4
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    • pp.284-299
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    • 2020
  • Dam reservoirs play a particularly crucial role in processing the allochthonous and the autochthonous dissolved (DOC) and the particulate (POC) organic carbon and in the budget of global carbon cycle. However, the complex physical and biogeochemical processes make it difficult to capture the temporal and spatial dynamics of the DOC and the POC in reservoirs. The purpose of this study was to simulate the dynamics of the DOC and the POC in Daecheong Reservoir using the 3-D hydrodynamics and water quality model (AEM3D), and to quantify the mass balance through the source and sink fluxes analysis. The AEM3D model was calibrated using field data collected in 2017 and showed reasonable performance in the water temperature and the water quality simulations. The results showed that the allochthonous and autochthonous proportions of the annual total organic carbon (TOC) loads in the reservoir were 55.5% and 44.5%, respectively. In season, the allochthonous loading was the highest (72.7%) in summer, while in autumn, the autochthonous loading was the majority (77.1%) because of the basal metabolism of the phytoplankton. The amount of the DOC discharged to downstream of the dam was similar to the allochthonous load into the reservoir. However, the POC was removed by approximately 96.6% in the reservoir mainly by the sedimentation. The POC sedimentation flux was 36.21 g-C/㎡/yr. In terms of space, the contribution rate of the autochthonous organic carbon loading was high in order of the riverine zone, the transitional zone, and the lacustrine zone. The results of the study provide important information on the TOC management in the watersheds with extensive stagnant water, such as dam reservoirs and weir pools.

Rapid climate change during the deglaciation of Lake Hovsgol, Mongolia

  • Chun, Jong-Hwa;Cheong, Dae-Kyo
    • Proceedings of the Korean Quaternary Association Conference
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    • 2005.10a
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    • pp.34-39
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    • 2005
  • A 120-cm core recovered from Lake Hovsgol, the northern Mongolia provides evidence for climate variability since the Marine Isotope Stage 3, representing a sharp lithological change. The lowermost part of the core consists of diatom-barren calcareous silty clay without coarse sands, framboidal pyrite, and biogenic components deposited during the MIS 3. Following the last glacial maximum, in-situ moss is included in the sediments, as lake-level was retreated by cold and dry environment with low precipitation. The AMS radiocarbon ages of the plant fragments match a marked lithologic boundary between 14,060 and 14,325 $^{14}C$ yr BP. The contents of coarse sands abruptly increase, indicating probably wind-derived sandy dust or coarse grains contributed from floating icebergs. And abundant framboidal pyrite grains were deposited in an anoxic environment, as reflected by high accumulation of organic matters at a low lake stand. During the deglaciation, quantities of coarse sands, ostracod, shell fragments, framboidal pyrite, and diatom markedly varies by regional and global scale climate regimes. Some allochthonous coarse sands were probably ice-rafted debris derived from floating icebergs. A rapid increase in diatom productivity probably marked the onset of Bolling-Allerodwarming. Subsequent high concentration of framboidal pyrite probably represents a dry and cold condition, such as Younger Drays events. Consistent warm period with high precipitation at Holocene is documented by diatomaceous clayey ooze without framboidal pyrite, coarse sands, and ostracod.

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Organic Matters Budget and Movement Characteristic in Lake Hoengseong (횡성호의 유기물 수지 및 거동 특성)

  • Joung, Seung-Hyun;Park, Hae-Kyung;Yun, Seok-Hwan
    • Journal of Korean Society on Water Environment
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    • v.28 no.2
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    • pp.238-246
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    • 2012
  • Organic matters budget in Lake Hoengseong were monthly investigated from April 2009 to November 2009. The intense rainfall occurred at between July and August and the hydrological factors were highly varied during the rainfall season. By the concentrated rainfall, the elevation, influx and efflux were sharply increased and the turbid water was also flowed into the middle water column in Lake. The inflow of turbid water increased the nutrient concentrations in water body and this appears to stimulate of phytoplankton regard as the primary productivity of influx of organic matter. Monthly average concentration of dissolved organic carbon (DOC) was generally higher than the particulate organic carbon (POC) concentration in Lake, but Temporal and spatial variation of POC concentration was higher than DOC and the maximum POC concentration was recorded in surface water in August, had the highest phytoplankton biomass. Organic carbon concentration in inflow site was rarely changed during the dry season, but the concentration was rapidly increased by the initial intense rainfall. In organic matters budget, the most of the organic matters was inflowed from the inflow site at rainfall season. Especially, the influx of allochthonous organic matters during the intense rainfall was 72.4% in the total influx organic matters.

Changes in the Concentrations and the Characteristics of Organic Carbon After Entrance into Dam Reservoirs (댐저수지 유입 후 유기탄소 농도 및 성상 변화)

  • Shin, Jae-Won;Lee, Bo-Mi;Hur, Jin;Park, Ji-Hyung
    • Journal of Korean Society on Water Environment
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    • v.29 no.1
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    • pp.81-87
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    • 2013
  • Changes of organic carbon after the entrance into dam reservoirs were investigated using water samples collected in May, September, and October in 2010 from the inflow sites and the outlets of four selected dam reservoirs-Soyang, Chungju, Chungju regulation, and Uiam. Increase of refractory dissolved organic carbon (R-DOC) was observed only for large dam reservoirs with long residence times whereas the trend was not found for relatively small reservoirs. The effects of residence times on organic carbon changes were further confirmed by significant positive correlations between monthly residence times and the relative increase of either dissolved organic carbon (DOC) or R-DOC concentrations. Comparison of spectroscopic characteristics of DOC revealed that the changes in the large reservoirs in May might result from in-lake processes. The inflow of terrestrial sources of DOM during storms appears to largely affect the DOC quality of the large reservoirs for the rest of the sampling periods. The mechanism, however, did not fully explain the behaviors of DOC for the small sized reservoirs. Our combined results suggested that both residence time and the input of allochthonous carbon sources might substantially influence the quantity of DOC as well as its quality in dam reservoirs.