• 생태와환경
• /
• 제37권3호통권108호
• /
• pp.272-281
• /
• 2004

팔당호의 유기물 수지 산정을 위해 팔당호내 일차생산력을 측정하고 유입하천의 유입유기물량 및 방류유기물량을 측정하여 유기물부하에서 내부생성유기물의 기여도를 평가하였다. 식물플랑크톤에 의한 일차생산력은 지점과 시기에 따라 큰 차이를 보여 3회 조사결과 $101{\sim}2701\;mgC\;m^{-2}day{-1}$의 범위로 나타났으며, 체류시간이 길고, 수체내 클로로필 a농도가 높았던 6월에 모든 지점에서 높은 생산력을 보였다. 빈번한 강우로 체류시간이 짧고 조류현존량이 적었던 4월과 8월의 조사에서는 총 유기물유입량에서 내부생성유기물량은 약 7%를 차지하였고 이중 식물플랑크톤에 의한 내부생산기여도는 약 5%로 매우 낮았다. 그러나 조사일 전후로 강우가 없어 수체가 안정되었고 외부유입유기물량이 적었던 6월 조사에서는 식물플랑크톤에 의한 내부생산 기여도가 29.0%를 보였다.

• 생태와환경
• /
• 제34권3호통권95호
• /
• pp.166-174
• /
• 2001

소양호로 유입되는 유기탄소량을 측정하였으며, 유기탄소 부하량에 대한 유기물 기원의 기여도를 계산하기위해서 내부생성유기탄소와 외부기원유기탄소를 측정하였다. 내부생성유기탄소는 EOC를 고려한 식물플랑크톤의 1차생산력으로부터 계산하였으며, 외부기원유기탄소는 유입수의 유기탄소 농도와 양어장의 유기탄소 배출량으로부터 구하였다. 1차생산력은 가두리 양식장이 설치된 1987견부터 증가하여 1995견가지 높은 분포를 보였으며 가두리가 철거된 1998년 이후 급격히 감소하였다. 내부생성유기탄소와 외부기원유기탄소의 부하는 여름철에 집중되었으며, 7${\sim}$9월에 연간 부하량의 43.2%와 71.7%가 각각 유입되었다. 1차생산력은 여름철에 $1,000\;mgC\;m^{-2}\;d^{-1}$ 이상으로 증가하였으며 겨울철에 비교적낮았다. 식물플랑크톤의 EOC배출율도 1차생산이 증가하여 수체의 DOC농도가 높은 여름철에 높았다. 전체조사기간동안 내부생성과 외부기원유기물의 평균적인 기여도는 각각 총부하량의 53.6%와 46.4%를 차지하였다. EOC 배출율은 1차생산력의 4.4${\sim}$21.2%를 차지하였으며, 1차생산력 산정에서 식물플랑크톤의 EOC 배출율이 고려되어야 할 것으로 보인다.

• 한국물환경학회지
• /
• 제36권4호
• /
• pp.284-299
• /
• 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.

• 환경위생공학
• /
• 제12권3호
• /
• pp.31-39
• /
• 1997

The seasonal and spatial changes in dissolved organic carbon(DOC) in Lake Kasumigaura, a shallow and eutrophic lake, were analyzed from October 1992 to October 1995. The proportion of T-DOC was classified by labile(L-DOC) and refractory DOC(R-DOC) on the basis of long-term incubation, fractionated the molecular weight of T-DOC by ultrafiltration. The porewater DOC were measured at sedimental surface of the central basin in order to evaluate the DOC released from the sediment. The proportion of L-DOC and R-DOC were accounted for about 15% and 85% of T-DOC in the central basin, respectively. The molecular weight(MW) distribution occupied some 60% of the low and medium MW. The horizontal variation of T-DOC concentrations trended to higher in the central basin than in the inlet of influent rivers, because of contribution by autochthonous organic carbon loading. The seasonal variation of T-DOC showed to higher summer than winter in the inlet of influent, but at the central basin it fluctuated little seasonally. During the high increase of porewater DOC in 1994 evaluated the high release possibility from the sediment surface (10cm). The present study suggests that autochthonous organic carbon loading must be controlled for improving the water quality of the eutrophic lakes.

• Journal of the korean society of oceanography
• /
• 제35권2호
• /
• pp.124-127
• /
• 2000

The analysis of stable carbon isotope ratios for benthic fauna was applied to identify the source of carbon in benthic food webs in Youngil Bay, Korea. The ${\delta}^{13}$C values of 9 invertebrate species collected in this area showed a narrow range between -20.5 and -16.3%$_o$ with a mean of-18.1 (${\pm}$1.1)"%$_o$. The results suggest that the major source of organic carbon for the benthic fauna of the lower estuarine reaches and the oceanic sites is autochthonous marine particulate organic matter. The contribution of organic matter from terrestrial and riverine sources to the diet of the benthic fauna in this area appears to be minor, despite the considerable inflow of riverine waters.

• 한국물환경학회지
• /
• 제29권1호
• /
• pp.81-87
• /
• 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.

• 한국환경과학회지
• /
• 제8권1호
• /
• pp.101-106
• /
• 1999

The relationship between primary productivity and changes in water quality was investigated at Mulgum station, a site downstream of the Nakdong River, Korea. Phytoplankton production was characterized by blooms of Microcystis aeruginosa during the summer and Stephanodiscus hantzschii during the winter. Primary production and secondary production by bacterioplankton ranged from 1.5~53.5 mg-C/ι day and 0.1~0.3 mg-C/ι day, respectively. Distribution of total organic carbon appeared to be highly correlated with phytoplankton biomass, especially during blooms of M. aeruginosa, when particulate organic carbon was 81% of total organic carbon and the main source of organic materials supplied into the water. The correlation coefficient between chlorophyll-a and BOD was 0.86. Thus it was concluded that autochthonous phytoplankton mostly affected the BOD level. Total bacterial numbers were also highly correlated with chlorophyll-a ($r^2$= 0.84) and the bacterial community appears to be regulated by phytoplankton biomass in this area.

• 한국환경과학회지
• /
• 제29권5호
• /
• pp.531-539
• /
• 2020

To understand the composition, quantity, and quality of Suspended Particulate Organic Matter (SPOM) in the Gangneung Namdae Stream, Korea, we examined spatiotemporal variations in water temperature, salinity, chlorophlly a (Chl a), Particulate Organic Carbon (POC) and nitrogen (PON), and carbon stable isotope (δ¹³C) of SPOM at six stations in June (pre-monsoon), July (monsoon), and September (post-monsoon) 2017. With increasing precipitation, the average POC and C/N values increased significantly in July than in June. In September, the values decreased with decreasing precipitation. The δ¹³C values showed irregular spatiotemporal fluctuations among the stations and periods, thereby suggesting a greater contribution of autochthonous organic matter to the pool of SPOM than that of allochthonous organic matter derived from upstream. In addition, the large and irregular changes in POC, C/N ratio, C:Chl a, and δ¹³C compared to that of PON were observed for all periods among the stations, indicating a serial discontinuity of the stream. Our results suggest that the Gangneung Namdae Stream is significantly influenced by the increase in freshwater discharge caused by heavy rainfalls during the summer monsoon and post-monsoon periods.

• 생태와환경
• /
• 제34권4호통권96호
• /
• pp.267-276
• /
• 2001

수도권의 중심부를 가로지르는 한강의 하류수역은 조수의 영향을 받을 수 있는 하구의 상단부에 위치해 있다. 한강 하류수역은 한강종합개발사업의 일환으로 이루어진 준설과 수중보 건설에 의해서 강물이 정체되었으며, 또한 지천으로부터 유입되는 많은 오염물질에 의해서 식물플랑크톤의 대량 발생을 촉진할 수 있는 환경으로 변화되었다. 본 연구에서는 부영양한 한강 하류수역에서 식물플랑크톤의 1차생산을 측정하였으며, 더불어 내부생성유기물과 외부기원유기물을 산정하였다. 1차생산력은 C-14 uptake법과 P-I 모델법으로 측정하였다. 1차생산력의 범위는 $140{\sim}4,890\;mgC\;m^{-2}\;d^{-1}$ (중앙값 $1,865\;mgC\;m^{-2}\;d^{-1}$)이었으며, 국내의 부영양한 호수와 유사한 수준이었다. 식물플랑크톤의 생물량 변동은 봄철에 최대치를 보였으며, 유량의 변화와 관련이 있는 것으로 나타났다. 외부기원유기물은 여름철 흥수기를 제외한 연중 내내 지천을 통하여 유입되는 오염물질에 의해서 좌우되었다. 총 유기물 부하량에 대하여 식물플랑크톤의 1차생산이 차지하는 기여도는 40.9%로서, 유수 생태계로서는 높은 수준이었다.

• Ocean and Polar Research
• /
• 제45권3호
• /
• pp.103-111
• /
• 2023

To evaluate the impact of effluents from land-based fish farms on the coastal ocean of Wando, Korea, we analyzed inorganic nutrients, particulate organic carbon (POC), dissolved organic carbon (DOC), and colored dissolved organic matter (CDOM) in the effluent and influent of land-based fish farms during the summer (July) of 2021. The average concentrations of nutrients (Dissolved inorganic nitrogen, phosphorus, and silicate; DIN, DIP, and DSi, respectively) in the effluents of this study area were 17±3.7 μM, 1.4±0.7 μM, and 14±1.6 μM, respectively. The average concentrations of POC and DOC were 37±22 μM and 81±13 μM, respectively, with POC accounting for about 30% for total organic carbon in effluents. The Reduced Dissolved Inorganic Nitrogen/Total Dissolved Inorganic Nitrogen ratio (0.7), potential short-period index, indicates that the discharge of nutrients excreted by the fish and unconsumed feed into coastal water results in such nutrients being deposited and accumulated in the sediment. Subsequently, this continuous accumulation triggers the release of ammonium ions during organic matter decomposition, and the ammonium-enriched waters that encroach on fish farms as influent seem to be due to the diffusion of high concentrations of ammonium from bottom sediment. Furthermore, we used fluorescence indices to examine the characteristics of organic matter sources, obtaining mean values of 1.54±0.19, 1.06±0.06, and 1.56±0.06 for the humification index, biological index, and fluorescence index, respectively, in the effluent. These results indicate that the organic matters had an autochthonous origin that resulted from microbial decomposition, and such organic matters were rapidly generated and removed by biological activity, likely supplied from the sediment. Our results suggest that the effluent from land-based fish farms could be a potential source of deoxygenation occurrence in coastal areas.