• Korean Journal of Ecology and Environment
• /
• v.49 no.2
• /
• pp.147-152
• /
• 2016

This study was conducted to develop a technique of ecosystem health assessment on Korea National Parks. The purpose of natural resource monitoring in national parks is to develop scientific information on the current status and long term trends in the composition, structure, and function of park ecosystems, and to determine how well current management practices are sustaining those ecosystems. The evaluation results will reflect in the park conservation and polices and promote the effect and functions of assessment program to the people. Health assessment steps were performed in order the establishing monitoring goals and objectives, development of the conceptual model, frame establishment, determination of indicators, standard and classification and health assessment. Health Indicators were selected the 13 with common, choice and climate indicators. We developed a pictogram and was separated into five colors to health condition, it was divided into three shape for comparison with the past state. Seoraksan, Odaesan National Park has been rated highly but Bukhansan, Kyeryongsan National Park has been underestimated.

• Korean Journal of Ecology and Environment
• /
• v.49 no.2
• /
• pp.67-79
• /
• 2016

Cyanotoxins in aquatic ecosystems have been investigated by many researchers worldwide. Cyanotoxins can be classified according to toxicity as neurotoxins (anatoxin-a, anatoxin-a(s), saxitoxins) or hepatotoxins (microcystins, nodularin, cylindrospermopsin). Microcystins are generally present within cyanobacterial cells and are released by damage to the cell membrane. Cyanotoxins have been reported to cause adverse effects and to accumulate in aquatic organisms in lakes, rivers and oceans. Possible pathways of microcystins in Lake Suwa, Japan, have been investigated from five perspectives: production, adsorption, physiochemical decomposition, bioaccumulation and biodegradation. In this study, temporal variability in microcystins in Lake Suwa were investigated over 25 years (1991~2015). In nature, microcystins are removed by biodegradation of microorganisms and/or feeding of predators. However, during water treatment, the use of copper sulfate to remove algal cells causes extraction of a mess of microcystins. Cyanotoxins are removed by physical, chemical and biological methods, and the reduction of nutrients inflow is a basic method to prevent cyanobacterial bloom formation. However, this method is not effective for eutrophic lakes because nutrients are already present. The presence of a cyanotoxins can be a potential threat and therefore must be considered during water treatment. A complete understanding of the mechanism of cyanotoxins degradation in the ecosystem requires more intensive study, including a quantitative enumeration of cyanotoxin degrading microbes. This should be done in conjunction with an investigation of the microbial ecological mechanism of cyanobacteria degradation.

• Korean Journal of Ecology and Environment
• /
• v.40 no.4
• /
• pp.576-580
• /
• 2007

Phytoplankton community dynamics were studied from 2004 to 2006 with two and four weeks interval at mid to lower part of the Nakdong River (Waegwan: RK 194, Goryeong: RK 157, Jukpo: RK 112, Namji: RK 75 and Hanam: RK 63: RK: distance from the Estuarine Barrage), South Korea. Annual averages of water temperature was about $16^{\circ}C$, and dissolved oxygen was ranged between 10.0 and 11.5 mg $L^{-1}$ (percent saturation, 106.5 to 112.8%). Diatoms were dominant group with over 60% of phytoplankton abundance in all study sites (Waegwan: 64%, Goryeong: 69%, Jukpo: 73%, Namji: 79%, and Hanam: 83%). However, the occasional dominances of other groups such as green algae and blue-green algae were observed from March to October. Stephanodiscus hantzschii was dominant species and the relative abundances were highat all study sites (48-72%). The ratio of S. hantzschiiltotal phytoplankton abundance were showed a clear increasing tendency toward the estuarine barrage: i.e. 0.31 at Waegwan, 0.39: Goryeong, 0.50: Jukpo, 0.56: Namji, 0.60: Hanam. The results of this study provide the information that the phytoplankton community structure in a regulated river system is basically affected by the physical properties such as water velocity and retention time, resulting in single species dominance by the stagnancy of river flow.

• Korean Journal of Ecology and Environment
• /
• v.40 no.4
• /
• pp.527-536
• /
• 2007

In this study, we applied 10-metric health assessment model, based on the Index of Biological Integrity (IBI) during 2006 in the Changwon Stream, which is located in the Changwon city, Gyeongnam province, S. Korea, and then compared with water quality data. The Index of Biological Integrity (IBI) in the Changwon Stream varied from 18 to 38 in the watershed depending on the sampling location and averaged 30.3 (n=6) during the study. Analysis of tolerance guilds showed that the proportion of sensitive species was 13%, but tolerant and intermediate species were 34% and 53%, respectively. Qualitative Habitat Evaluation Index (QHEI) averaged 43.3 (range: 65-104, n=6) indicating non-supporting condition, based on the criteria of U.S. EPA (1993). Values of QHEI showed a typical longitudinal decreases from the headwater reach to the downstream location, except for Site 1 with a low QHEI value by artificial habitat by concrete construction. Minimum QHEI was found in Site 4 where fish diversity was minimal. Conductivity increased continuously along the gradients and especially showed abrupt increases in the downstream sites along with turbidity. Stream ecosystem health of IBI matched to the values of QHEI except for S6. Low IBI values in the sites 4 and 5 was considered to be a result of combined effects of chemical pollutions and habitat degradations. Our results support the hypotheses of Plafkin et ai. (1989) that physical habitat quality directly influences the trophic structure and species richness, and is closely associated with IBI values.

• Korean Journal of Ecology and Environment
• /
• v.40 no.4
• /
• pp.569-575
• /
• 2007

This study was carried out to determine bioaccumulation levels of total mercury on various fish tissues in two streams (Banseok and Hasin Stream) and one lake (Yeongsan Lake) during April-May 2007. We also determined natural background levels of total mercury bioaccumulation to evaluate relative individual impacts of fish and compared the levels with reference sites as a preliminary study to evaluate heavy metal stressor using fish. For the study, we collected fishes in the sampling sites and analyzed the concentrations of total mercury in the liver, kidney, gill, vertebral column, and muscle tissues using Direct Mercury Analyzer (DMA-80, US EPA Method 7473). The levels varied depending on the types of waterbody and tissues used. Concentrations of total mercury ranged between 5.1${\mu}g$ $kg^{-1}$ and 108.6 ${\mu}g$ $kg^{-1}$ in the streams and between 5.3${\mu}g$ $kg^{-1}$ and 87.3 ${\mu}g$ $kg^{-1}$ in the reservoir, and the values were highest in the muscle tissues. Levels of natural background levels of total mercury, even though the sampling number was few, averaged 23.6 ${\mu}g$ $kg^{-1}$ in the study sites. The individual and mean values in each system was not so high in terms of US EPA criteria of fish health and human health, indicating that the impact was minor in the study site. Further studies should be done for the determination of mercury levels in the systems.

• Korean Journal of Ecology and Environment
• /
• v.40 no.4
• /
• pp.560-568
• /
• 2007

The objectives of this study were to analyze ecological effects on effluents from the Sagok Stream (Chonnam province) as an abandoned mine drainage through necropsy-based health assessments and fish exposure tests, and to conduct In situ field pilot tests for restoration of stream water. Also, we analyzed water quality including general parameters and heavy metals. The tests were performed three times on April 2005, April 2006, and April 2007. Also, we constructed a reactor facility in the outflowing point of the abandoned mine for the remediation of AMD wastewater. In lab test, death rates in all three treatments were ${\geq}50%$ in the experiments. Necropsybased fish tissue assessments using the Health Assessment Index (HAI), indicated that the most frequently damaged tissue was liver (average: 20.8). Values of Health Assessment Index were lower in the control than any other treatments of T1, T2, and T3 and three treatments showed a distinct toxicity impacts by the AMD. In situ lethal test, concentration of Fe, Al and Zn decreased particularly by 85%, 99% and 94%, respectively through the disposal facility. Values of pH, ranged from 3.1 to 7.0, increased by 2.3 fold (mean=5.1) along with the reduction of metal contents. All fishes in P1 cage died 100% on 3 days later after the experimental setting, while all fishes in the P6 died 100% on 9 days later. Overall, these results evidently provide a key methodology for pilot test using the disposal facility and also clarify the toxicity of AMD once again, so this approach used in the pilot facilities here may reduce the acidic and toxic effects in the abandoned mining drainage.

• Korean Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.1-10
• /
• 2012

The Jinwi stream, which is located in the Gyeonggi Province, shows a large variation in water quality from the upper stream to downstream. Therefore the Jinwi stream is suitable for assessing changes to the benthic macroinvertebrate community structure according to saprobity. This study was conducted to find out the applicability of biotic indices for water quality pollution through an analysis of the correlation between water quality and benthic macroinvertebrate indices for the Jinwi stream. Along with the pollution of water, the species composition of Ephemeroptera decreased, while that of Annelida increased. The ecological score for the benthic macroinvertebrate community (ESB) showed more significant correlations than any other biotic index (H', DI, R1, J, EPT and KSI) with the water quality items.

• Korean Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.82-92
• /
• 2012

In this study, we identified spatial and temporal patterns of reservoir trophic state within Keum-river watershed and analyzed correlations between chlorophyll-$a$ (Chl-$a$) and water quality parameters including conductivity and total phosphorus (TP). The reservoirs were separated into three trophic categories by the criteria of TP: 2 oligotrophic (9.3~9.4 ${\mu}g\;L^{-1}$), 15 mesotrophic (10.3~19.2 ${\mu}g\;L^{-1}$), and 14 eutrophic reservoirs (38.9~117.1 ${\mu}g\;L^{-1}$). Water quality parameters such as conductivity, TP, and Chl-$a$ reflected rainfall patterns, and the patters of annual mean TP were similar to the variation of annual mean Chl-$a$. Empirical models of Chl-$a$ against TP in reservoirs showed that statistical significance ($p$ <0.05) occurred in only some seasons and the trophic relations were modified by a washing-out effect or high non-algal light attenuation.

• Korean Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.62-71
• /
• 2012

Lake Doam watershed was surveyed to evaluate non-point source discharge characteristics and discharge load including several water quality parameters in Song Stream from July 2009 to July 2011. Concentrations of water pollutants were high during the rainfall period, especially, SS, TP and COD showed increasing tendencies toward cumulative water discharge but TN did not show much difference. SS, TP and COD had an initial flush effect of over 50 mm rainfall event but there was no clear tendency for rainfalls below that level. Event mean concentration (EMC) regarding the rainy and dry period showed large differences. Especially rainy season EMC (SS, TP, COD) demonstrated an increasingly high tendency. EMCs of COD, SS, TN and TP measured for twelve rain events were as high as 26.1, 866.0, 4.68 and 0.605 mg $L^{-1}$, respectively. COD, SS, TN and TP loadings from the highland agricultural region of the Song Stream watershed were 34,263, 1,250,254, 2,673 and 933 kg $yr^{-1}\;km^{-2}$, respectively, which were relatively higher than the results of other stream systems. Therefore, it is strongly recommended that long-term monitoring and non-point pollution reduction programs for the highland agricultural area to continue. Furthermore, this non-point source pollution loading research acquired from the highland agricultural area could be the base for reassessment.

• Korean Journal of Ecology and Environment
• /
• v.45 no.1
• /
• pp.34-41
• /
• 2012

The variation of dissolved oxygen (DO) was monitored with high frequency by an automatic data-logging sensor in a eutrophic urban stream (the Anyang Stream) located in a metropolitan area of Seoul, South Korea. In general, DO showed the diel variation of increase in daytime and decrease at night, implying that primary production is a major mechanism of oxygen supply in this ecosystem. The fluctuation of oxygen was determined by rainfall. DO depletion was most obvious after a rainfall resulting in an anoxic condition for a day, which is thought to be caused by scouring of periphyton and organic ooze at the stream bottom. Seasonally DO was higher in winter and frequently depleted in warm seasons. DO depletion was often at a dangerous level for fish survival. Fish survey showed that little fish was living at the study site and oxygen depletion may be the major stress factor for aquatic animals. From the results it can be suggested that a high frequency monitoring of oxygen should be established for the proper assessment of aquatic habitats and better management strategy.