An Effect of Ph and Water Hardness on The Growth of Heterocypris incongruens (Ostracoda)

Yongeun Kim,Yun-sik Lee,Myeong seob Kim,Hyoung-ho Mo,Kijong Cho 한국응용곤충학회 2012 한국응용곤충학회 학술대회논문집 Vol.2012 No.05

We evaluated the effect of water pH (6, 7, 8 and 9) and hardness (40mg/L and 160mg/L as CaCO3) on the growth of H. incongruens. Both water pH and hardness affected the growth parameter of H. incongruens such as head capsule width and maturity time. The head capsule width of the adults in the highest ph condition was 9.7% increased compared to the lowest ph condition. The maximum difference of the maturity time was 192 hours among the test conditions. Overall, as water ph level increase makes head capsule size of the test animal large, the inter-molt period and maturity time become shorter significantly. The effect of water hardness increasing showed a similar tendency with ph level. Especially, the difference of the growth parameter among the test conditions was increased by growing test animal. There are strong correlation between available amount of intake calcium and growth parameters of test animal. These results indicate that because of calcium demand for growth, water pH level and hardness are the important effect factor in life-cycle of the H. incongruens..

Ecotoxicological evaluation for contaminated abandoned mine soils using Daphnia magna

Myeong seob Kim,Jino Son,Hyoung-ho Mo,Yongeun Kim,Yun-Sik Lee,Kijong Cho 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.05

Sedimentation of soil particles in water is perhaps the most significant pathway to contamination of aquatic ecosystems. In this scenario, the use of freshwater organisms for assessing sediment toxicity will be considered more ecologically relevant than tests that use aqueous soil extracts. To evaluate the toxicity of soils sampled in the vicinity of the abandoned mine located in the Gyeonggi province, Daphnia magna were exposed to a 1:4 of soil to water which soil samples were serially two-fold serially diluted with clean sand to concentrations ranging from 6.25 to 100 % % (w/w) for 24- and 48-h. Irrespective of exposure time, the survival of D. magna for reference soil was not decreased, while the survival of D. magna showed high sensitivity to the soils with moderate as well as high metal concentrations. Moreover, the heavy metal concentrations in the water samples increased with increasing the heavy metal concentrations in the soils, which indicates the increased sensitivity is the consequences of the bioavailable fraction of contaminants in soils. These results clearly showed that the freshwater organism D. magna can be used as test species to assess the potential impact of soil contaminants into aquatic ecosystems.

Effect of teflubenzuron (chitin synthesis inhibitor) on biological trait of Paranura rosea (Collembola)

Yun-Sik Lee,Jino Son,Yongeun Kim,Myeong seob Kim,Kijong Cho 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.05

The use of insect growth regulators (IGRs) has been gaining popularity as an environmentally friendly option to improve existing integrated pest management (IPM) strategies. Although IGRs have a selective effect on target organisms, they may exert a more selective effect on non-target organisms. In this study, the toxic effects of teflubenzuron on biological traits of P. rosea, Collembola, were assessed in the OECD artificial soil under two different exposure conditions, one was exposed in the bulk soil, and the other was exposed in the compacted soil which unidirectional force was applied to the soil surface. After 28 days of exposure, the toxicity of teflubenzuron on the survival and juvenile production of P. rosea in the bulk system was more toxic than that of the compact system. Moreover, not only the egg production but also the hatching rate and molting frequency of P. roseas was decreased in a concentration dependent manner. These results suggest that the IGRs teflubenzuron exhibit significant impacts on the biological traits of non-target organisms P. rosea and its toxic effects are differently assessed depending on the exposure conditions.

Effects of cadmium concentration and exposure time on avoidance behavior of soil collembolan (Paronychiurs kimi)

Yun-Sik Lee,Jino Son,Yongeun Kim,Myung-seob Kim,Kijong Cho 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.10

In recent, the ISO has suggested a new guideline by using an avoidance behavior of soil invertebrates for the use of screening tools in the evaluation of soil contamination. In this study, we used a collembolan, Paronychiurus kimi which is native to Korea, as a test species because of its ecological relevance to Korean soil. The objectives of this study were to evaluate whether the exposure time (24, 48, 72, 96 and 120 h) and cadmium concentration (50, 100, 200 and 400 mg/kg of dry soil) affect the avoidance behavior of P. kimi. Twenty collembolans were introduced to the center of the soil which divided into two sections; cadmium untreated soil was placed in one of the section, and the cadmium treated soil was placed in the opposite section. To minimize soil structural effect on the avoidance behavior, the both soils were compacted by applying unidirectional force to the soil surface. The avoidance behaviors of P. kimi were not significantly affected by cadmium concentrations after 24 and 48 h of exposure, but were significant after 72-120 h. There results showed that avoidance behavior appears to be a good endpoint for the use in evaluation of soil contamination with 72 h of exposure duration.

Effect of fenoxycarb (juvenile hormone agonist) on biological traits of Paranura rosea (Collembola)

Yun-Sik Lee,Jino Son,Yongeun Kim,Myung-seob Kim,Kijong Cho 한국응용곤충학회 2011 한국응용곤충학회 학술대회논문집 Vol.2011 No.10

In this study, the toxic effects of fenoxycarb on biological traits of nontarger arthropod P. rosea, Collembola. The tests were assessed in the OECD artificial soil under two different exposure condtions, one was exposed in the bulk soil, and the other was exposed in the compacted soil which unidirectional force was applied to the soil surface. In the bulk system, survived adults and hatched juveniles were counted after 28-day exposures, and in the compact system, survived adults, eggs, hatched juveniles and molts were counted everyday until no more hatching. The toxic effect of fenoxycarb on survival and juvenile production of P. rosea in the bulk system was more toxic than that of the compact system. Juveniles and eggs were seriously affected as compared with toxic effect for adults. Particularly, toxic effect on hatching rate (3.75 mg/kg EC50juvenile) were very higher than that on oviposition (200.868 mg/kg EC50egg) or survival rate of adults ( >1200 mg/kg LC50). The molting freauency of P. rosea was decreased in a concentration dependent manner. These results suggest that the IGRs fenoxycarb exhibit significant impacts on the biological traits of non-target organisms P. rosea and its toxic effects are differently assessed depending on the exposure conditions.

Integration of an individual-oriented model into a system dynamics model: An application to a multi-species system

Kim, Yongeun,Son, Jino,Lee, Yun-Sik,Lee, Minyoung,Hong, Jinsol,Cho, Kijong Elsevier 2019 Environmental modelling & software Vol.112 No.-

<P><B>Abstract</B></P> <P>Although the system dynamics (SD) modeling approach has been used frequently to model various systems, there is little research on the development of hybrid SD–individual-oriented (IO) modeling. The aim of this study is to demonstrate the use of an array variable for the hybrid SD–IO modeling approach using the SD platform, and to provide a detailed modeling process of an algae–daphnid system consisting of two freshwater algal species and <I>Daphnia</I>. Our study showed that the array variable in the SD approach is useful for modeling multiple individuals and as a function to control the switch and integration variable for the hybrid modeling approach. The proposed method can improve the usability of hybrid modeling by enabling hybrid SD–IO modeling without requiring extensive knowledge of programming. Given the ongoing development and advancement of the SD modeling approach, this modeling technique will be a useful method to study complex systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The method for hybrid system dynamics (SD)–individual-oriented (IO) approach using the SD platform was demonstrated. </LI> <LI> For IO modeling in the SD approach, multiple individuals were modeled using array variables. </LI> <LI> To implement the proposed method, the algae–daphnid system was chosen as the subject of the case study. </LI> <LI> The results showed that the method can be a useful approach for combining SD and IO models in a single modeling platform. </LI> </UL> </P>

Mathematical modeling to simulate the adsorption and internalization of copper in two freshwater algae species, Pseudokirchneriella subcapitata and Chlorella vulgaris

Kim, Yongeun,Lee, Minyoung,Hong, Jinsol,Cho, Kijong Korean Society of Environmental Biology 2021 환경생물 : 환경생물학회지 Vol.39 No.3

Prediction of the behavior of heavy metals over time is important to evaluate the heavy metal toxicity in algae species. Various modeling studies have been well established, but there is a need for an improved model for predicting the chronic effects of metals on algae species to combine the metal kinetics and biological response of algal cells. In this study, a kinetic dynamics model was developed to predict the copper behavior(5 ㎍ L^-1, 10 ㎍ L^-1, and 15 ㎍ L^-1) for two freshwater algae (Pseudokirchneriella subcapitata and Chlorella vulgaris) in the chronic exposure experiments (8 d and 21 d). In the experimental observations, the rapid change in copper mass between the solutions, extracellular and intracellular sites occurred within initial exposure periods, and then it was slower although the algal density changed with time. Our model showed a good agreement with the measured copper mass in each part for all tested conditions with an elapsed time (R² for P. subcapitata: 0.928, R² for C. vulgaris: 0.943). This study provides a novel kinetic dynamics model that is compromised between practical simplicity and realistic complexity, and it can be used to investigate the chronic effects of heavy metals on the algal population.

Process-based modeling to access the nutrient removal efficiency of hydrophytes based on a multiple-quotas approach

Yongeun Kim,Yun-Sik Lee,June Wee,Jinsol Hong,Minyoung Lee,Kijong Cho 한국환경생물학회 2020 한국환경생물학회 학술대회 Vol.2020 No.11

The Use of the Dynamic Model to Improve Mechanistic Understanding of Organism Response to Stress: A Case Study on Daphnia magna

Yongeun Kim,Hyoung-ho Mo,Yun-sik Lee,June Wee,Kijong Cho 한국응용곤충학회 2014 한국응용곤충학회 학술대회논문집 Vol.2014 No.04

Environmental risk assessment aims to estimate the impacts of various stressors on populations and communities in the environment. However, most of the exposure tests conducted under the laboratory level. This gap between the controlled condition of the experiments and the complexity of the field situation can lead to irrelevant estimation of stress effects. For this reason, dynamic model approach in ecology that including integrated mechanistic understanding has become important. The dynamic models at the individual level can be used to interpret the individual’s response to stress, extrapolate which response to untested conditions, and predict the impacts on the higher ecological level. The overall objective of this case study was to simulate the chronic toxicity of copper on Daphnia magna using dynamic energy budget theory with the improved toxicity module component. The model system was constructed and evaluated, using the PowersimⓇ software. The toxicity model system was integrated with toxic effects on allocation of reserve, structure, and maturity energy of D. magna into improved toxicity module. The model was calibrated and verified by actual data sets where obtained from a laboratory experiment including growth, maturity and survival measurement of D. magna during copper exposure. The simulation results showed that the response of D. magna under copper exposure was well estimated by model system.

Modeling Approach to Understand Mechanism of Aquatic Organism Exposed to Copper using Daphnia magna

Yongeun Kim,Hyoung-ho Mo,Yun-sik Lee,June Wee,Kijong Cho 한국응용곤충학회 2014 한국응용곤충학회 학술대회논문집 Vol.2014 No.10

Understanding how species will respond to projected future climate change has become important. However, the impacts of climate change on the ecosystem are very complex and uncertain, we need a reliable tool for approaching it. Mechanistic modeling can be one of the solution for handling the various factors and responses of test organisms in regard to climate change. We introduce the case study on the copper toxicity on D. magna and show the applicability of these mechanistic model approaches. The overall objective of this case study was to simulate the chronic toxicity of copper on Daphnia magna using dynamic energy budget theory with the improved toxicity module component. The toxicity module includes toxic effects on allocation of reserve, structure, and maturity energy in the D. magna. Model calibration and verification were performed using data sets obtained from a laboratory experiment that include growth, maturity and survival measurement data of D. magna during copper exposure. The simulation results show that the response of D. magna under copper exposure was well estimated by toxicity module. Overall, the results show the dynamics model based on DEB theory can be used for estimating long-term metal toxicity on D. magna. Thus, mechanistic modeling can be utilized as a approach tool for evaluating the impacts of climate change on the ecosystem with more mechanistic description.