• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.232-241
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• 2012

The seasonal changes in phytoplankton species composition, standing crops, dominant species, species diversity and physico-chemical characteristics in the Unmun dam were studied, from August, 2009 to April, 2010. The phytoplanktons of a total of 121 taxa were identified, the composition of phytoplankton community was characterized by a green algae and diatoms, and the quantity composition of standing crops was dominated by diatoms and dinophyceae. The diatoms Aulacoseria granulata and blue-green alga Anabaena planktonica in Summer, Peridinium voltzii in Autumn and Asterionella formosa in Winter to Spring were, especially, prominent. The seasonal changes of the biomass varied from 578 cells $mL^{-1}$ to 12,938 cells $mL^{-1}$, and the maximum algal density was observed in April, Asterionells formosa contributed to 88% of the total cell numbers. The species diversity and richness were highest during autumn, and dominance index was highest in the spring season.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.58-65
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• 2011

This study aims to investigate the settling velocity of aggregates of cohesive sediment (floc) and its relationship with sediment size, density and fractal dimension. A system of commercial camera and macro-lens is used for the experiment. Through the image-analysis technique, the image taken by the camera system is analyzed. For the experiment, kaolinite and a natural sediment sampled at Lake Apopka in Florida have been tested. From this study, it is known that kaolinite and Lake Apopka sediments show different behaviors mainly depending on the organic matter content. Samples of kaolinite with less organic contents show a more definite trend to follow a fractal theory and relatively strong relationships between the settling velocity, density, fractal dimension and floc size compared to the Lake Apopka sediments rich in organics.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.242-251
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• 2012

To investigate foodweb of aquatic ecosystem in the Tamjin River, carbon and nitrogen stable isotopes ratios of aquatic organisms, as well as environmental indicators based on the water, were determined in this study. Various organisms such as fishes (Coreoperca kawamebari, Zacco platypus, Cobitis lutheri, and Pungtungia herzi) and periphyton (epilithon and epiphyte), and particulate- and coarse particulate organic matters (POM and CPOM) were collected in upper (Tamjin River, Yuchi Stream, and Omcheon Stream) and lower (TJ-1~TJ-5) reaches of Jangheung Dam. The nitrate concentration and ${\delta}^{15}N$ signature of POM and organisms (invertebrates and fish) were found to be more enriched toward the downstream section of the river. It was determined that allochthonous matter occurring from a tributary alters the chemical character of water, as well as the isotopic signature of organisms contained therein. Attached algae (ephilithon) were identified as a base component of the benthic foodchain further downstream.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.42-57
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• 2011

We described the above-ground plant species composition and measured a range of soil physico-chemical properties and the composition and size of the soil seed bank in the remnant natural vegetations on the flood plains of the Han River within Seoul, South Korea. We used analysis of variance and multivariate analyses to analyse the data and S${\o}$rensen's similarity index to compare the composition of the vegetation and seed banks. The soils were circum-neutral and composed of mainly sand and silt fractions with a very limited clay component; a gradient based on sand/clay proportions was identified. The soil seed banks varied markedly between- and within-sites and had much greater species diversity than the above-ground vegetation. Two of the major dominants in the vegetation (Miscanthus saccariflorus and Phragmites australis) were found at very low densities in the seed bank. The site differences appeared to be correlated with the sand-clay gradient, suggesting that the soil properties differentially affected seed inputs into the soil, or that the processes than controlled sediment deposition during floods was also important in differentially affecting seed deposition. Lastly, there was relatively little similarity between the vegetation, dominated mainly by perennials, and the seed bank which contained a relatively large proportion of annuals and biennials. This result suggests that after disturbance caused by flooding there is the potential for many other species to colonize. This may impinge on the regeneration potential of the sites and cause concern for the future conservation of these important remnants of natural vegetation.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.22-30
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• 2011

This study was purposed to develop an effective LC/MS/MS method for simultaneously determining five pre-treated cyanotoxins (anatoxin-a, microcystins-RR, -YR, -LR and -LA) of cyanobacteria blooms. Cyanobacterial bloom samples were collected from 11 major lakes and three downstream areas of river around Korea during 2005~2009. Cyanotoxins were identified in 38 samples from the lakes. The validity of the method was evaluated and the recovery rates were found ranging from 83~87%. The MDL turned out to be $0.046\;{\mu}g\;L^{-1}$ for anatoxin-a and $0.066\;{\mu}g\;L^{-1}$ for microcystins (RR, YR, LR and LA), which indicates that the method has high sensitivity and accuracy. The most dominant genus of the cyanobacterial blooms was Microcystis, which accounted for 71% of the analysed samples. Microcystis also contained the largest amount of microcystins ($398.5\;{\mu}g\;gDW^{-1}$) among the analyzed cyanobacteria. The analysis of the five cyanotoxins showed that anatoxin-a ranged between $0{\sim}41.833\;{\mu}g\;gDW^{-1}$ and microcystins ranged between $6.311{\sim}2,148.786\;{\mu}g\;gDW^{-1}$. Among the microcystins, micocystin-RR took up 58.3%, the largest portion. Anatoxin-a was found to account for 77.8% of the samples. This study has its significance in that it allowed the establishment of toxin criteria appropriate for the Korean water systems. Further studies may be necessary to conduct for improving water treatment methods.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.95-101
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• 2011

Present study aimed to investigate morphological change and gene expression in the gill of Cyprinus carpio after exposure against muddy water caused by riverbed disturbance with various rearing condition. The gill of C. carpio showed abnormal shapes in its secondary lamellae and a rough surface with impure debris after exposed to muddy water for 80 days. In addition, the gills showed the edema, the exfoliation of epithelial cell, and the fusion of the secondary lamellae. Using 20 ACPs, 24 differentially expressed genes (DEGs) exposed to muddy water for 80 days were identified. 17 genes among them were up-regulated, while 7 genes were down-regulated in preterm deliveries. A BLAST searches revealed that 3 genes were revealed known genes as calcium transporter 1 (TRPV6) mRNA, macha mRNA for putative puroindoline b protein, and Efnb3 protein-like. Therefore, it is considered that Efnb3 gene from gill would be a useful indicator for neurobehavioral changes in fish influenced by muddy water.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.10-17
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• 2013

History of Instream Flow Incremental Methodology (IFIM) Following the large reservoir and water development era of the mid-twentieth century in North America, resource agencies became concerned over the loss of many miles of riverine fish and wildlife resources in the arid western United States. Consequently, several western states began issuing rules for protecting existing stream resources from future depletions caused by accelerated water development. Many assessment methods appeared during the 1960's and early 1970's. These techniques were based on hydrologic analysis of the water supply and hydraulic considerations of critical stream channel segments, coupled with empirical observations of habitat quality and an understanding of riverine fish ecology. Following enactment of the National Environmental Policy Act (NEPA) of 1970, attention was shifted from minimum flows to the evaluation of alternative designs and operations of federally funded water projects. Methods capable of quantifying the effect of incremental changes in stream flow to evaluate a series of possible alternative development schemes were needed. This need led to the development of habitat versus discharge functions developed from life stage-specific relations for selected species, that is, fish passage, spawning, and rearing habitat versus flow for trout or salmon. During the late 1970's and early 1980's, an era of small hydropower development began. Hundreds of proposed hydropower sites in the Pacific Northwest and New England regions of the United States came under intensive examination by state and federal fishery management interests. During this transition period from evaluating large federal reservoirs to evaluating license applications for small hydropower, the Instream Flow Incremental Methodology (IFIM) was developed under the guidance of the U.S. Fish and Wildlife Service (USFWS).

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.1-9
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• 2013

Algal blooms in potable water supplies are becoming an increasingly prevalent and serious water quality problem around the world. In addition to precipitating taste and odor problems, blooms damage the environment, and some classes like cyanobacteria (blue-green algae) release toxins that can threaten human health, even causing death. There is a recognized need in the water industry for models that can accurately forecast in real-time algal bloom events for planning and mitigation purposes. In this study, using data for an interconnected system of rivers and reservoirs operated by a New Jersey water utility, various ANN models, including both discrete prediction and classification models, were developed and tested for forecasting counts of three different algal classes for one-week and two-weeks ahead periods. Predictor model inputs included physical, meteorological, chemical, and biological variables, and two different temporal schemes for processing inputs relative to the prediction event were used. Despite relatively limited historical data, the discrete prediction ANN models generally performed well during validation, achieving relatively high correlation coefficients, and often predicting the formation and dissipation of high algae count periods. The ANN classification models also performed well, with average classification percentages averaging 94 percent accuracy. Despite relatively limited data events, this study demonstrates that with adequate data collection, both in terms of the number of historical events and availability of important predictor variables, ANNs can provide accurate real-time forecasts of algal population counts, as well as foster increased understanding of important cause and effect relationships, which can be used to both improve monitoring programs and forecasting efforts.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.128-134
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• 2013

In the summer season (June~August) during the study period of Lake Doam, average concentrations of major water quality parameters, COD, SS, TN, and TP were 4.0, 16.2, 3.129 and $0.077mg\;L^{-1}$, respectively, and Chl-a was $11.8mg\;m^{-3}$. The result has indicated that Lake Doam was a meso-eutrotrophic lake. Lake Doam data from the summer season (June~August), precipitation from 2001 to 2012, and water quality (COD, SS, TN, TP, Chl-a etc.) of seven years (2001, 2002, 2004 and 2009~2012), were statistically analyzed for long-term trends by Mann-Kendall test and Sen's slope estimator methods. The statistical results showed that precipitation, SD, COD, TN, $NO_3-N$, $NH_3-N$ and Chl-a had decreasing trends, and EC, turbidity, SS, TP and DIP had increasing trends. Suspended solids and total phosphorus were directly affected by precipitation. In the case of suspended solids, more aggressive and constructive plans need to be implemented than the current turbidity reduction project to achieve the targeted water quality ($5mg\;L^{-1}$ of SS) in Lake Doam. In particular, we need to specify a project that considers the steep topographic characteristics of high, land farming areas and precipitation conditions of the Lake Doam watershed, which can increase the efficiency of a turbidity reduction project.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.25-32
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• 2013

This study examined the status of the vegetation around Gangcheonsan provincial park located in Sunchang-gun in Jeollabuk-do and Damyang-gun in Jeollanam-do from June 4 to October 12, 2011. Gangcheonsan vegetation was arranged 9 plant communities in accordance with data of 28 releves. Major forest vegetation included Quercus variabilis communityand Quercus variabilis-Quercus serrata community, Pinus densiflora community, and Pinus densiflora-Quercus variabilis community (evergreen coniferous forest in all), and Phyllostachys nigra var. henonis community (plantation). Wetland vegetation included Salix gracilistyla community (riverbank forests), Phragmites japonica community, and Polygonia thunbergii community. Gangcheonsan Provincial Park has beautiful scenery that is in harmony with fantastically-shaped rocks, waterfalls, and valleys and conserves a specific plant community habitat distributed through the forest wetlands including its valleys. It is necessary to conduct long-term monitoring with its focus on Pinus densiflora community, Lycoris koreana community, and Lycoris squamigera community in the provincial park to grasp the characteristics of ecological inhabit changes in major communities and provide active methods for conservation, restoration, and publicity.