• Animal Systematics, Evolution and Diversity
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• no.spc9
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• pp.45-50
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• 2016

Freshwater benthic macroinvertebrates were investigated from five sampling sites on Jindo Island located in the southwestern end of the Korean Peninsula. A total of 47 species (average $14{\pm}3.16$ species per site, 40 species in lotic area, and 13 species in lentic area) belonging to 38 families, 14 orders, 5 classes, and 3 phyla were sampled. Coleoptera, Diptera, Ephemeroptera, and Trichoptera were the major groups of benthic macroinvertebrates with relatively high species richness. Species diversity indices (H') and richness indices (RI) of upper streams were relatively higher than those of lower streams, which were affected by agricultural effluent from the paddy fields.

• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.8-11
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• 2005

Carbon stable isotope ratios of producers varied in lake ecosystems. In tile present study, we tried to estimate the seasonal variations of carbon isotope ratios of phytoplankton and benthic diatoms in a strongly acidic lake ecosystem. Lake Katanuma is a volcanic, strongly acidic lake (average pH of 2.2), located in Miyagi, Japan. Only two algal species dominate in Lake Katanuma; Pinnularia acidojaponica as a benthic diatom, and Chlamydomonas acidophila as a green alga. Carbon isotope values of P. acidojaponica varied seasonally, while those of particulate organic matter, which were mainly composed of C. acidophila remained fairly stable. The differences suggested that $CO_2$ gas was more frequently limited for P. acidojaponica than C. acidophila, since high density patches of benthic diatoms were sometimes observed on the lake sediment. Generally, carbon concentration mechanisms (CCMs)of microalgae can fix bicarbonate in lakes, and affect the carbon isotope values of microalgae. While, in Lake Katanuma, CCMs of the microalgae may scarcely function because of high $CO_2$ gas concentration and low pH. This is the reason for low seasonal amplitude of carbon isotope values of phytoplankton relative to those in other lakes.

• Korean Journal of Ecology and Environment
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• v.57 no.2
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• pp.61-74
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• 2024

Daemadeung, located in the estuary of the Nakdong River, is formed by sand dunes and possesses well-developed intertidal flats. This study aimed to investigate the habitat of benthic microalgae, photosynthetic pigments, and photosynthetic efficiency in the intertidal flats of Daemadeung from January to December 2011. The inorganic nitrogen content in the sediment pore water was primarily composed of ammonium, while nitrate + nitrite was dominant in the upper layer water. The concentration of chlorophyll a and fucoxanthin in the sediment surface was significantly higher than the mean of all the sediment layer. The average Fv/Fm of benthic microalgae during the entire survey period was 0.52±0.03, with the highest value (0.61±0.08) observed in February. The rETR_max showed a seasonal trend, being high from spring to early autumn (April to October) and low from winter to early spring (January to March, November, December), with the highest value (153.05±2.30 µmol electrons m^-2 s^-1) in July and the lowest (38.49±5.17 µmol electrons m^-2 s^-1) in January. The average Fv/Fm of diurnal microalgae was 0.48±0.03, with the highest value (0.61±0.08) observed at noon. The rETR_max showed a highest peak at noon (54.24±11.35 µmol electrons m^-2 s^-1) and reached its lowest point at 16:00 (26.17±4.75 µmol electrons m^-2 s^-1). These findings suggest that the productivity of benthic microalgae varies significantly depending on the survey time and sediment depth. Therefore, to quantify the productivity of benthic microalgae using Diving-PAM, surveys should be conducted based on tidal conditions, and simultaneous pigment analysis of sediment layers should also be performed.

• Journal of Ecology and Environment
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• v.31 no.3
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• pp.233-241
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• 2008

Functional feeding groups (FFGs) of benthic macroinvertebrates are guilds of invertebrate taxa that obtain food in similar ways, regardless of their taxonomic affinities. They can represent a heterogeneous assemblage of benthic fauna and may indicate disturbances of their habitats. The proportion of different groups can change in response to disturbances that affect the food base of the system, thereby offering a means of assessing disruption of ecosystem functioning. In this study, we used benthic macroinvertebrate communities collected at 650 sites of 23 different water types in the province of Overijssel, The Netherlands. Physical and chemical environmental factors were measured at each sampling site. Each taxon was assigned to its corresponding FFG based on its food resources. A multilayer perceptron (MLP) using a backpropagation algorithm, a supervised artificial neural network, was applied to evaluate the influence of environmental variables to the FFGs of benthic macroinvertebrates through a sensitivity analysis. In the evaluation of input variables, the sensitivity analysis with partial derivatives demonstrates the relative importance of influential environmental variables on the FFG, showing that different variables influence the FFG in various ways. Collector-filterers and shredders were mainly influenced by $Ca^{2+}$ and width of the streams, and scrapers were influenced mostly with $Ca^{2+}$ and depth, and predators were by depth and pH. $Ca^{2+}$ and depth displayed relatively high influence on all four FFGs, while some variables such as pH, %gravel, %silt, and %bank affected specific groups. This approach can help to characterize community structure and to ecologically assess target ecosystems.

• Ocean and Polar Research
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• v.28 no.4
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• pp.369-383
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• 2006

The Saemangeum project is one of the biggest reclamation efforts in Korea and may cause coastal ecosystem change due to altered environments and habitat loss. Since February 2002, benthic environment and community structure in the Saemangeum studied area were studied to assess the influence of the project on macrofaunal community. The result of seasonal study from February, 2002 to August 2005 is reported here. Overall, changes of species numbers and dominant species of benthic animals in the periods before (1988) and after $(2002{\sim}2005)$ the Saemangeum dike construction were not evident both inside and outside the dike. However, local environmental and community change were noted The partial completion of Saemangeum dike $(4^{th}\;dike)$ in June 2003 altered water circulation and sediment deposition patterns both inside and outside the dike. Fine sediment was accumulated inside and outside the $4^{th}$ dike while coarse sediment dominated near the main channel (Sinsi gate). Benthic community resl)ended to the altered sediment type in these areas. Species number and diversity in both site was low compared to other sites. The dominant species in these areas were composed of the benthos that had not commonly occurred in the Saemangeum subtidal area.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.19-31
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• 2021

We investigated the distribution characteristics of mussels (Mytilus coruscus) growing in the Geomundo sea area by water depth. The research was also conducted to identify the surrounding benthic organisms. Mussels showed high density and low obesity in low water depths. The lower the density, the higher the obesity level appeared in deeper water. The morphological characteristics also appeared to increase as the water depth deepened. In addition, the shell length and total weight were more strongly correlated at a depth of 12 m than at 2 m. The total weight by the growth of the shell length and shell height was affected by the water depth. The analysis showed that the density and biomass of the algae inhabiting the surroundings decreased somewhat as the water depth increased. In benthic animals, the number of mussels tended to decrease slightly at the point where oysters dominated, at a depth of 2 m. Conversely, the number of oysters tended to decrease in deeper water dominated by mussels. Thus, the spatial competition between oysters and mussels was affected by the water depth. Also, mussels did not appear in areas where large algae flourished, suggesting that the survival of mussels was affected by the presence or absence of large algae.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.spc1
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• pp.142-150
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• 2006

We examined the effect of predation by observing the changes in macrobenthic communities in a tidal flat at Seonjae, Korea, following the exclusion of large predators such as birds, fishes and crustaceans using protective screens. We conducted two interference experiments in the field from April to November 2004: (1) Experiment 1 was conducted at a mid-tidal flat in the western part of Seonjae-do, Incheon, Korea, (2) Experiment 2 was set up at a low tidal flat in the eastern part of Seonjae-do. predator exclusion showed different effects in the two experiments. Both the number of species and density were reduced by 20% in Experiment 1. Whereas in Experiment 2, they increased by up to 13% and 69%, respectively. In Experiment 1, a high density of brachyuran crabs observed in the treatment may have caused the difference in community composition between the treatment and the control, and this probably resulted from active predation of macrofauna (e.g., small crabs) under protection from megafaunal predators such as birds and fishes. However, in Experiment 2, as typically observed in other predator exclusion experiments, a lower density of benthic predators and the subsequent reduction of over predation probably resulted in a more diverse and abundant benthic community in the treatment. We confirmed that predation was a contributing factor in the formation of the macrobenthic community. We also demonstrated relationships that exist among different trophic groups (large predators, macrobenthic predators and prey) and what effects and responses occur in each component of the tidal flats.

• Journal of Species Research
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• v.9 no.3
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• pp.191-197
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• 2020

Species belonging to the genus Tryblionella are important members of the diatom assemblages of benthic environments such as tidal flats. Their proper identification is thus of great importance in terms of taxonomy, ecology, as well as environmental sciences. However, many species of the genus have been neglected and/or misidentified during diatom studies of Korean tidal flats possibly due to the small size of the species. Lack of proper references for the identification of the species is also noted. To better understand the diversity of Tryblionella species, sediment samples were taken from various tidal flats of the Yellow Sea. Light microscope (LM) and scanning electron microscope (SEM) observations have shown the presence of Tryblionella adducta and T. hyalina, which have not been previously reported from Korean tidal flats. The former was found mostly from sand flats and the latter from mudflats. It is expected that the present study would contribute to a better understanding of the diversity and ecology of benthic diatoms of the Korean tidal flats.

• Korean Journal of Environment and Ecology
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• v.29 no.2
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• pp.210-220
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• 2015

We quantified temporal and spatial changes in the habitat for fish populations, the distribution of mandarin fish(Siniperca scherzeri) and an introduced species, largemouth bass(Micropterus salmoides) in Lake Paro and inflowing streams. The number of fish species identified in Lake Paro and the tributary streams included 10 families, 24 species and 10 families 30 species, respectively. The dominant fish species in Lake Paro were Zacco platypus, Hemibarbus labeo, Squalidus gracilis majimae, S. scherzeri and Tridentiger brevispinis, Z. platypus, Z. koreanus, and S. gracilis majimae in the inflowing streams. Although the habitat segregation for S. scherzeri and M. salmoides occurs, these two species showed the use of the fishes of the family Gobiidae as an important prey item based on IRI analysis. S. scherzeri and M. salmoides preyed mainly on T. brevispinis(67.4 %) and R. brunneus(84.0 %), respectively. The species preyed on by S. scherzeri and M. salmoides were benthic fishes that inhabit shallow water depths around the lake and have little swimming ability.

• Journal of Ecology and Environment
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• v.34 no.2
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• pp.175-191
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• 2011

Colonization patterns and community changes in benthic macroinvertebrates in the Cheonggye Stream, a functionally restored stream in downtown Seoul, Korea, were studied from November 2005 to November 2007. Benthic macroinvertebrates were quantitatively sampled 15 times from five sites in the stream section. Taxa richness (59 species in total) increased gradually over the first year, whereas the density revealed seasonal differences with significantly lower values in the winter season and after flood events. The benthic macroinvertebrate fauna may have drifted from the upstream reaches during floods and from the Han River, arrived aerially, or hitchhiked on artificially planted aquatic plants. Oligochaeta, Chironommidae, Psychodidae, and Hydropsychidae were identified as major community structure contributors in the stream. Swimmers and clingers colonized relatively earlier in the upper and middle reaches, whereas burrowers dominated particularly in the lower reaches. Collector-gatherers colonized at a relatively early period throughout the stream reaches, and collector-filterers, such as the net-spinning caddisfly (Cheumatopyche brevilineata), predominated in the upper and middle reaches after a 1-year time period. Cluster analyses and multi-response permutation procedures demonstrated that the Cheonggye Stream shares more similarities with the Jungnang Stream than with the Gapyeong Stream. Detrended correspondence analysis and nonmetric multidimensional scaling demonstrated that physical environmental factors (depth, current velocity, dissolved oxygen, and pH) as well as nutrients (total nitrogen and total phosphorous), water temperature, and conductivity could affect the distribution of benthic macroinvertebrates in the study streams.