• Journal of Korean Society on Water Environment
• /
• v.34 no.6
• /
• pp.579-590
• /
• 2018

The lakes' metabolism bears important information for the assessment of the carbon budget due to the accumulation or loss of carbon in the lake as well as the dynamics of the food webs through primary production. A lake-scale metabolism is evaluated by Gross Primary Production (GPP), Ecosystem Respiration (R), and Net Ecosystem Production (NEP), which is the difference between the first two values. Methods for estimating GPP and R are based on the levels carbon and oxygen. Estimation of carbon is expensive because of the use of radioactive materials which requires a high degree of proficiency. The purpose of this study was to estimate Lake Daecheong ecosystem metabolism using high frequency water temperature data and DO measurement sensor, widely utilized in the field of water quality monitoring, and to evaluate the possibility of using the application method. High frequency data was collected at intervals of 10 minutes from September to December 2017 by installing a thermistor chain and a DO sensor in downstream of Daechung Dam. The data was then used to estimate GPP, R and NEP using the R public program LakeMetabolizer, and other metabolism models (mle, ols, kalman, bookkeep). Calculations of gas exchange coefficient methods (cole, crusius, heiskanen, macIntyre, read, soloviev, vachon) were compared. According to the result, Lake Daecheong has some deviation based on the application method, but it was generally estimated that the NEP value is negative and acts as a source of atmospheric carbon in a heterotrophic system. Although the high frequency sensor data used in this study had negative and positive GPP and R values during the physical mixing process, they can be used to monitor real-time metabolic changes in the ecosystem if these problems are solved.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2002.10a
• /
• pp.441-444
• /
• 2002

In recent, industrialization increases the level of pollution load in sea areas, and the inflows of pollutants to public sea areas cause sudden and wide-range of influence to the water quality and the ecosystem. To prepare for these kinds of unpredictable water pollution issues, the necessity is emerging to build an automatic water quality monitoring system, which can monitor and alarm the water quality changes of the subject sea areas. For the ongoing installation plan of the automatic water quality monitoring system around the Saemankeum sea area, this report compares and analyzes its installation conditions as well as the physical and chemical characteristics of the in-situ type and the water-sampling type of the automatic water quality monitoring equipments, and subjects to provide elementary data for the system installation in the Saemankeum.

• Ocean and Polar Research
• /
• v.30 no.1
• /
• pp.109-117
• /
• 2008

Application of biomarkers for assessing marine environmental health risk is a relatively new field. According to the National Research Council and the World Health Organization, biomarkers can be divided into three classes: biomarkers of exposure, biomarkers of effect, and biomarkers of susceptibility. In order to assess exposure to or effect of the environmental pollutants on marine ecosystem, the following set of biomarkers can be examined: detoxification, oxidative stress, biotransformation products, stress responses, apoptosis, physiological metabolisms, neuromuscular responses, reproductions, steroid hormones, antioxidants, genetic modifications. Since early 1990s, several biomarker research groups have developed health indices of marine organisms to be used for assessing the state of the marine environment. Biomarker indices can be used to interpret data obtained from monitoring biological effects. In this review, we will summarize Health assessment Index, Biomarker Index, Bioeffect Assessment Index and Generalized Linear Model. Measurements of biomarker responses and development of biomarker index in marine organisms from contaminated sites offer great a lot of information, which can be used in environmental monitoring programs, designed for various aspects of ecosystem risk assessment.

• Korean Journal of Ecology and Environment
• /
• v.56 no.3
• /
• pp.196-206
• /
• 2023

Benthic attached diatoms (BADs), a major primary producer in lotic stream and river ecosystems are micro-sized organisms and require a highly magnified microscopic technique in the observation work. Thus, it is often not easy to ensure accuracy and precision in both qualitative and quantitative analyses. This study proposed a new technique applicable to improve quality control of aquatic ecosystem monitoring and assessment using BADs. In order to meet the purpose of quality control, we developed a permanent mounting slide technique which can be used for both qualitative and quantitative analyses simultaneously. We designed specimens with the combination of grid on both cover and slide glasses and compared their efficiency. As a result of observation and counting of BADs, the slide glass designed with the color-lined grid showed the highest efficiency compared to other test conditions. We expect that the method developed in this study could be effectively used to analyze BADs and contributed to improve the quality control in aquatic ecosystem health monitoring and assessment.

• Journal of Fisheries and Marine Sciences Education
• /
• v.27 no.1
• /
• pp.253-261
• /
• 2015

The chemical water quality and fish assemblage of Dong Stream to assessment of environmental improvement after discharge seawater were investigated from July to December 2013. BOD and DO were significantly different between before and after discharge seawater, while pH and SS did not significant. A total of 11 fish species, 218 individuals and 10,525.1g were collected. Dominant fish species were Mugil cephalus, Konosirus punctatus, Acanthogobius flavimanus and Leiognathus nuchalis which account for 77.5% of total individuals collected, and they were estuarian species. Peak number of species and individuals, and biomass occurred in September, whereas diversity index were highest in November. The water ecosystem of Dong Stream have been changed estuarian environment. As a result of stream assessment on water quality and ecosystem, water quality have been improved as 'III' grade. These results suggested that stream restoration policies such as drain pipes maintenance, management of pollution sources and riverbed dredging to improve environment and recover habitate of Dong Stream were need for set up and establishment of regular monitoring system.

• Journal of Wetlands Research
• /
• v.3 no.2
• /
• pp.133-142
• /
• 2001

Growth of cities and an increase in population result in the development-oriented policy, urban streams to lose their natural characteristics and functions by channelization, parking lot construction, and so forth. The streams fall into urban drains, which is the current status of urban streams. Recently, the interest in the stream environment and the ecosystem has been increased, and the efforts have been made to improve the traditional maintenance program for small streams. These efforts lead to the application of the natural recovery systems. This study applied the 240-meter model reach along the Oncheon stream, which locates in Dongrae-gu, Busan city. to analyze the natural recovery system. The efficiency of each system has been analyzed and the future improvements for the systems are presented. The results show that the stream maintenance program should consider the ecological environment. thereby minimizing the environmental effects. When the changes are inevitable, the maintenance program should adopt the methods. which closely simulate the original environmental elements. or are more favorable to the ecosystem.

• Korean Journal of Ecology and Environment
• /
• v.42 no.4
• /
• pp.487-494
• /
• 2009

We compared spatial and temporal variations of water chemistry between high-flow year ($HF_y$) and low-flow year ($LF_y$) in an artificial lentic ecosystem of Daechung Reservoir. The differences in the rainfall distributions explained the variation of the annual inflow and determined flow characteristics and water residence time and modified chemical and biological conditions, based on TP, suspended solids, and chlorophylla, resulting in changes of ecological functions. The intense rainfall and inflow from the watershed resulted in partial disruption of thermal structure in the metalimnion depth, ionic dilution, high TP, and high suspended solids. This condition produced a reduced chlorophyll-a in the headwaters due to low light availability and rapid flushing. In contrast, reduced inflow and low rainfall by drought resulted in strong thermal difference between the epilimnion and hypolimnion, low inorganic solids, high total dissolved solids, and low phosphorus in the ambient water. The riverine conditions dominated the hydrology in the monsoon of $HF_y$ and lacustrine conditions dominated in the $HF_y$. Overall data suggest that effective managements of the flow from the watershed may have an important role in the eutrophication processes.

• Food Science and Biotechnology
• /
• v.15 no.4
• /
• pp.595-598
• /
• 2006

Semi-quantitative monitoring of Lactobacillus sake and Lactobacillus plantarum, major and minor microorganisms in kimchi, respectively, and Lactobacillus paraplantarum, recently shown to be present in kimchi, was carried out by real-time polymerase chain reaction (PCR). Changes in the 3 species during kimchi fermentation were monitored by the threshold cycle ($C_T$) of real-time PCR. As fermentation proceeded at $15^{\circ}C$, the number of L. sake increased dramatically compared to those of L. plantarum and L. paraplantarum. During fermentation at $4^{\circ}C$, the growth rates of the 3 species decreased, but the proportions of L. plantarum and L. paraplantarum in the microbial ecosystem were almost constant. Considering the $C_T$ values of the first samples and the change in the $C_T$ value, the number of L. sake is no doubt greater than those of L. plantarum and L. paraplantarum in the kimchi ecosystem. L. sake seems to be one of the major microorganisms involved in kimchi fermentation, but there is insufficient evidence to suggest that L. plantarum is the primary acidifying bacterium.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.11
• /
• pp.1939-1946
• /
• 2008

The Oceanic ecosystem destruction caused by Water-Bloom, Jellyfish development, and Oil contamination in nation's waters becomes serious problem. For these reasons, the oceanic conditions are observed in air and on the water using helicopters and vessels. But, employing helicopters and vessels are limitted on a budget, and weather conditions. To overcome these problems, an unattended automated monitoring system not only gather all sorts of the oceanic condition in spite of bad weather, but save labor and oil costs. For each sensor connected in network and radiodetermination, location of sensors are verified in the tidal water to improve gathering informations.

• Journal of Environmental Science International
• /
• v.28 no.8
• /
• pp.645-654
• /
• 2019

This study was conducted in two breeding seasons in 2017 to identify nesting habits and breeding biology of barn swallows in Daejang-dong village, Bucheon city, suburban Seoul. Among the 77 barn swallow nests studied, there were 34 breeding nests -27 in the first and 12 in the second. The reuse rate of old nests was 51.6%. In addition to tile-roofed houses (20.6%), breeding nests were most common in brick houses (38.2%) and in slate-roofed houses (26.5%). Most breeding nests were in eaves (58.8%) and front doors (32.3%). The average clutch size was $4.8{\pm}0.9$ in the first and $4.3{\pm}0.5$ in the second. The breeding success rate was 75.0% in the first and 58.1% in the second, considering the hatching rate and the fledgling rate. It was found that the rainy season was affected by a lack of food. At least 27 pairs of nestling barn swallows and 127 young barn swallows successfully fledged were estimated to be 181. These results show that Daejang-dong village is an important suburban habitat of the Seoul metropolitan area, and that it can be used to verify the environmental conservation value of rice fields of in the Seoul metropolitan area.