• Ocean and Polar Research
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• v.29 no.2
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• pp.123-134
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• 2007

Distribution patterns of sandy bottom macrobenthic communities were studied around the Hupo coastal area. The seasonal surveys were conducted at 15 chosen sites within a depth range of 10 to 50 m along 10 km of the coastline using a Smith-McIntyre grab $(0.05\;m^2)$ in 2005. Overall depth distribution following the direction of the offshore become deeper parallel to the coastline. A total of 319 macrobenthic species were sampled with a mean density of $1,972\;ind./m^2$, and mean biomass was 82.5 wet-weight $g/m^2$. The major individual-dominant species were three polychaetes Spiophanes bombyx ($436\;ind./m^2$), Scoletoma longifolia ($250\;ind./m^2$) and Magelona japonica ($170\;ind./m^2$), and bivalve Adontorhina subquadrata ($73\;ind./m^2$). Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray-Curtis similarity identified 2 major station groups which corresponded to macrobenthic faunal assemblages and their characteristic species. In addition, environmental conditions were significantly different between station groups. Group I contained mostly 20 and 50 m deep sites and was associated with sandy mud. Group I was characterized by high abundance of S. bombyx, S. longifolia, A. subquadrata. It was divided into two sub-groups (I-I and I-II) in relation to depth. Sub-group I-I was associated with deeper sites than sub-group I-II. Group II included mostly inshore area shallower than 15 m and was associated with coarse and medium sand. Group II was characterized by Lumbrinerides hayashii and Urothoe grimaldii japonica.

• Ocean and Polar Research
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• v.34 no.1
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• pp.1-18
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• 2012

We investigated seasonal changes in the mesozooplankton community structure in November 2006 and February, May, and August 2007 at 12 stations in the semi-enclosed Muan Bay, Korea. Forty taxa were sampled, with an average abundance ranging from 1,459 to 20,078 indiv. $m^{-3}$; the highest abundance was detected in August 2007, and the lowest in February 2007. Acartia omorii, A. hudsonica, A. ohtsukai, Bestiolina coreana, Calanopia sp., Paracalanus parvus s. l., Cirripedia larvae, Decapoda larvae, and Gastropoda larvae were the most abundant taxa detected. The species diversity of the mesozooplankton was high around the inner regions in August 2007 but it was relatively low in November 2006. Non-metric multidimensional scaling (nMDS) revealed significant differences in the structure of mesozooplankton community among the seasons. Canonical correspondence analysis (CCA), performed to examine the relationships among dominant taxa, stations, and environmental variables, showed that most species of copepods were positively correlated with temperature, salinity, chlorophyll a, and COD concentration. Our results suggested that the mesozooplankton community structure observed in this study might be affected partly by the seasonal changes in environmental variables, such as the status of the sluice gates (i.e., open or closed) and the in situ production of resting eggs by major copepods.

• Ocean and Polar Research
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• v.32 no.4
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• pp.411-426
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• 2010

The seasonal variations in the zooplankton community of the southern coastal waters of Korea were investigated seasonally in May, August, November 2005, and February 2006. A total of 74 taxa were sampled, with an average abundance ranging from 2,426~23,793 indiv./$m^3$, among which Noctiluca scintillans predominated. Noctiluca scintillans, Acartia omorii, Acartia erythraea, Paracalanus parvus s. l., Centropages abdominalis, Tortanus forcipatus, and Pseudevadne tergestina were the most abundant species detected. Zooplankton diversity was high around the inner regions during the summer, but it was relatively low in the stations located in the outer regions in the autumn. Non-metric multidimensional scaling (nMDS) revealed significant differences in the structures of the zooplankton community among the three regions. Our results showed that the seasonal variations in zooplankton communities in the southern coastal waters of Korea were attributable to seasonal changes in temperature, salinity, chlorophyll a concentrations, and N. scintillans blooms; additionally, this particularly study area might have been specifically influenced by the appearance of the Tsushima Warm Current.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.1 no.1
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• pp.41-51
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• 2020

Ground beetle fauna of Wangpi-cheon watershed in Yeongyang-gun to Uljin-gun, Gyeongsangbuk-do was investigated from May to October in 2012. Ground beetles were collected by pitfall trapping. A total of 38 species of 20 genera belonging to 8 subfamilies were identified from 2,486 collected ground beetles. Species richness was high in Pterostichinae (16 species), Carabinae (8 species), Harpalinae (5 species), Callistinae (3 species), Nebriinae (3 species) and others (1 species). Dominant species were Synuchus cycloderus (1,025 individuals) and Aulonocarabus seishinensis seishinensis (332 individuals), Pristosia vigil (133 individuals), and Coptolabrus smaragdinus branickii (117 individuals) in order. Monthly changes in abundance of upper dominante genera Pterostichus, Aulonocarabus, Coptolabrus species and Synuchus, Pristosia, Colpodes species showed that the former had the highest number in August whereas the latter increased in June and September. The genus Pterostichus species were preferred in deciduous forest in Wangpi-cheon watershed, while the genus Synuchus species were collected in mixes forest adjacent to farmland and recreation facilities and the genera Chlaenius, Harpalus species were collected in mixes forest adjacent to farmland nearby stream. Non-metric multidimensional scaling (NMDS), ground beetles and sites could be divided into two distinct groups: St. 1, St. 2, St. 3 group and St. 4 group. Some species such as Pterostichus orientalis orientalis, P. vicinus and P. bellatrix were particularly abundant at St. 4.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.154-170
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• 2022

The zooplankton composition, abundance, community structure, and species diversity in the major commercial fishery species spawning grounds in the southern coast of Korea were investigated in this study. A total of 80 taxa were sampled, with the mean abundance range of 5,612-11,720 ind. m^-3 and the mean biomass range of 41.6-1,086.8 mg m^-3. The dominant species were Paracalanus copepodites, Paracalanus parvus s. l., Oithona copepodites, Paracalanus nauplii, Noctiluca scintillans, Oithona similis, and Ditrichocorycaeus affinis. The species diversity indices were highest in August, suggesting that diversity is influenced by neritic and oceanic warm-water species. A cluster analysis with non-metric multidimensional scaling (nMDS) revealed three groups of zooplankton communities. The April and May samples clustered into Group A, having the highest mean total zooplankton abundance and lowest species diversity, consisting mainly of temperate species located in the middle region of the southern coast of Korea. Cluster Group B was from the early summer season (June) and contained the highest species diversity with some oceanic and neritic zooplankton species. Cluster Group C from the summer season (July and August) mainly comprised P. parvus s. l. and O. similis. The redundancy analysis (RDA) indicated that abundance is positively correlated with salinity, and chlorophyll-a concentrations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.54-65
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• 2023

Effect of environmental factors on the seasonal variations of zooplankton communities was investigated in the semi-closed Yeoja Bay, Korea from February, April to August, and November 2021. Out of a total 49 species of zooplankton were collected with a predominant of neritic copepods (mainly Paracalanus orientalis, Acartia omorii, Acartia ohtsukai, Centropages abdominalis, Ditrichocorycaeus affinis, and Oithona sp.), accounting for 58.9% of the total abundance of zooplankton. The diversity indices indicated a relatively highest in July, suggesting that diversity is influenced by seasonal temperature, N. scintillans, and neritic copepods species. A cluster analysis with non-metric multidimensional scaling revealed four groups of zooplankton communities. The February sample clustered into Group A, having the lowest mean total abundance and species diversity of zooplankton, consisting mainly of N. scintillans located the whole region. Cluster Group B from the spring season (April to May) and contained the species diversity with some neritic copepods. Cluster Group C from the summer season (June to August) mainly comprised P. orientalis, A. ohtsukai, Oithona sp., and hydromedusae. Cluster Group D from the autumn season (November) mainly comprised P. orientalis, Temora discaudata. Redundancy analysis indicated that abundance is positively correlated with temperature, salinity, and pico chlorophyll-a concentrations. This study showed that planktonic larvae (such as branchyura larvae) and some copepods (including A. omorii, A. ohtsukai, C. sinicus, and C. abdominalis) were significantly vulnerable to zooplankton community of temperature, salinity, and pico chlorophyll-a concentrations.

• Journal of Korean Society on Water Environment
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• v.39 no.2
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• pp.181-193
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• 2023

Distribution changes in microalgae communities were studied in the Nakdonggang River at two sampling stations (St.1 Gyeongcheongyo Bridge (GB) and St.2 Daedong Wharf (DW)) at monthly intervals from January 2021 to November 2021. A total of 83 taxa included 82 species, 1 forma, belonging to 49 genera, 32 families, 21 orders, and 8 classes. The most important groups were Bacillariophyta and Chlorophyta. The number of species ranged from 5 to 24 in GB, and from 9 to 21 taxa in DW. The contribution of Bacillariophyta to the total species richness was the highest during all survey periods, and Chlorophyta yielded the next highest value in the study area. The dominant taxa were Aulacoseira ambigua, A. ambigua f. japonica, and Ulnaria acus in this study. Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray- Curtis similarity identified 4 major groups, which corresponded to microalgae assemblages and their characteristic species. Correlation was analyzed through the CCA analysis. It was found that there was a correlation between the microalgae and environmental factors. It was revealed that the divided groups were distinguished because of the differences by the survey period. Therefore, seasonal change was judged as a major factor affecting the distribution of microalgae communities.

• Journal of Ecology and Environment
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• v.47 no.1
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• pp.1-13
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• 2023

Background: The positive effects of Arctic plants on the soil environment and plant-species co-occurrence patterns are known to be particularly important in physically harsh environments. Although three dominant plants (Cassiope tetragona, Dryas octopetala, and Silene acaulis) are abundant in the Arctic ecosystem at Ny-Ålesund, Svalbard, few studies have examined their occurrence patterns with other species and their buffering effect on soil-temperature and soil-moisture fluctuation. To quantify the plant-species co-occurrence patterns and their positive effects on soil environments, I surveyed the vegetation cover, analyzed the soil-chemical properties (total carbon, total nitrogen, pH, and soil organic matter) from 101 open plots, and measured the daily soil-temperature and soil-moisture content under three dominant plant patches and bare soil. Results: The Cassiope tetragona and Dryas octopetala communities increased the soil-temperature stability; however, the three dominant plant communities did not significantly affect the soil-moisture stability. Non-metric multidimensional scaling separated the sampling sites into three groups based on the different vegetation compositions. The three dominant plants occurred randomly with other species; however, the vegetation composition of two positive co-occurring species pairs (Oxyria digyna-Cerastium acrticum and Luzula confusa-Salix polaris) was examined. The plant species richness did not significantly differ in the three plant communities. Conclusions: The three plant communities showed distinctive vegetation compositions; however, the three dominant plants were randomly and widely distributed throughout the study sites. Although the facilitative effects of the three Arctic plants on increases in the soil-moisture fluctuation and richness were not quantified, this research enables a deeper understanding of plant co-occurrence patterns in Arctic ecosystems and thereby contributes to predicting the shift in vegetation composition and coexistence in response to climate warming. This research highlights the need to better understand plant-plant interactions within tundra communities.

• Animal Bioscience
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• v.36 no.1
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• pp.63-74
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• 2023

Objective: The objective of this study was to investigate the effects of feeding active dry yeast (ADY) and yeast culture (YC) on fecal bacterial community in finishing bulls fed high-concentrate diets in the same experimental environment. Methods: Forty-five healthy finishing cattle (Simmental×Chinese Luxi yellow bulls; 24 months; 505±29 kg) were randomly divided into three groups: i) CON group (control group, only fed basal diet), ii) ADY group (fed basal diet + active dry yeast), and iii) YC group (fed basal diet + yeast culture). At the end of the trial, nine rectum fecal samples were randomly selected from each group for bacterial DNA sequencing. Results: There was no difference among groups about alpha diversity indices (all p>0.05), including ACE, Chao 1, Shannon, and Simpson indices. Principal component analysis and non-metric multidimensional scaling analysis showed a high similarity among three groups. Compared with CON group, ADY and YC groups had greater relative abundance of c_Clostridia, o_Oscillospirales, and f_Oscillospiraceae, but lesser relative abundance of g_Megasphaera, and s_Megasphaera_elsdenii (all p<0.01). And, the relative abundances of p_Firmicutes (p = 0.03), s_Prevotella_sp (p = 0.03), o_Clostridiales (p<0.01), g_Clostridium (p<0.01), f_Caloramatoraceae (p<0.01), and f_Ruminococcaceae (p = 0.04) were increased in the ADY group. The PICRUSt2 prediction results showed that the metabolic pathways had no significant differences among groups (p>0.05). Besides, the relative abundance of c_Clostridia (r = 0.42), and f_Oscillospiraceae (r = 0.40) were positively correlated to average daily gain of finishing bulls (p<0.05). Conclusion: Both of ADY and YC had no effect on diversity of fecal bacteria in finishing bulls, but the supplementation of ADY and YC can improve the large intestinal function in finishing bulls by increasing the abundance of cellulolytic bacteria and altering the abundance of lactic acid-utilizing bacteria.

• Ocean and Polar Research
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• v.31 no.2
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• pp.199-212
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• 2009

The community structure of meiofauna was surveyed from six stations in sand mining area near around Sungapdo, Taean five times from April-December, 2007. Ten meiofaunal taxa in total, comprising 5-9 taxa per station were recovered. Nematodes were dominant from four stations in April and from five stations in May. In June, copepods were dominant from all stations except station two, from which sarcomastigophorans were predominant. Copepods were also dominant from three stations in October and four stations in December. The mean density of meiofauna per $10\;cm^{-2}$ was the highest in October (130 individuals) and lowest (68 individuals) in April. Meiofauna mean biomass per $100\;cm^{-2}$ was $3.80-75.26{\mu}gC$ from each station, with the monthly mean biomass being lowest in April ($11.97{\mu}gC$) and highest in October ($39.50{\mu}gC$). The highest biomass was recorded at station five in October ($75.26{\mu}gC$). Eleven families of harpacticoid copepods occurred Ameiridae and Ectinosomatidae were the most frequent. The mean diversity index was 1.21 from all the stations, 1.22 from the sand mining stations, and 1.19 from the reference stations. The nematode:copepod (N/C) ratio was 1.57 from the sand mining stations and 1.37 from the reference stations. Non-metric multidimensional scaling analysis divided the community into group A (station one, non-sand mining and reference area) and groups B and C in the sand mining area. The present study reports similar numbers of taxa but lower density and biomass of meiofauna compared to previous studies in Korean waters. The variability of the diversity index and N/C ratio may indicate large fluctuation of meiofauna depending on temporal and spatial conditions of the environment in the study area.