• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.86-93
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• 2013

We monitored 32 wetlands in order to investigate the influence of aquatic plants on zooplankton density and diversity in the littoral zone in Gyeongsangnam-do from May to June in 2011. A total of 65 zooplankton species were identified in the study sites. Among them, the diversity of epiphytic zooplankton were higher (40 species) than planktonic zooplankton. Littoral zones of all wetlands were covered by various aquatic plants, and influenced the epiphytic zooplankton assemblages. Based on the data from $1{\times}1$ (m) quadrat sampling, epiphytic and planktonic rotifer density showed no significant relationships with macrophyte cover. However, the epiphytic cladocerans density significantly increased under high aquatic plant cover ($r^2=0.39$, p<0.05, n=32). Types of aquatic plants strongly influenced epiphytic zooplankton density. Upo and Jangcheok are locations which have well developed Phragmites communis and Ceratophyllum demersum communities in the littoral zone, and a higher density of epiphytic zooplankton was recorded on the surface of C. demersum. Especially, rotifers such as Lepadella, Monostyla and Testudinella showed obvious differences (One-way ANOVA, p<0.05 for all three species). This result suggests that epiphytic zooplankton have a substrate preference for larger surface areas, likely for adherence, on C. dimersum. In conclusion, the complex structure of the littoral plant community is expected to provide diverse refuge and microhabitats to epiphytic zooplankton.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.534-538
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• 2019

The distribution and characteristics of spawning beds of the Pacific herring Clupea pallasii, were observed by scuba diving in Jinhae Bay, Korea, with a focus on marine vegetation as adhesive substrates and egg density during the spawning season. In 2017, the fertilized eggs of C. pallasii were mainly found attached to the leaves of algae species Carpopeltis cornea, Gracilaria textorii, and Acrosrium polyneurum at the rocky shore in Wonpo-dong and Jeodo. The mean density of fertilized eggs in C. pallasii spawning beds was $153,776eggs/m^2$ off Wonpo-dong and $856,430eggs/m^2$ off Jeodo, giving an estimated total of $5.345{\times}10^9$ eggs in Wonpo-dong and $3.3074{\times}10^{10}$ eggs in Jeodo. We examined spawning beds with an area of $38,619m^2$ off Wonpo-dong and $34,760m^2$ off Jeodo. The choice of spawning bed may be affected by the composition of marine vegetation, such as the algal diversity of rocky shore environments, which could affect adhesive substrates and egg density during the spawning season. The results of the present study suggest that the spawning season of C. pallasii in Jinhae Bay is in January to mid-February.

• Journal of Ecology and Environment
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• v.37 no.2
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• pp.99-104
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• 2014

We estimated the influence of environmental factors on zooplankton communities at 25 reservoirs during winter (December 2010 to January 2011). Among zooplankton groups, Cyclops vicinus is more dominant during winter, and this is positively related to withered vegetation area and dissolved oxygen level. Therefore, the presence of withered vegetation might be considered as an important factor to determine C. vicinus distribution during winter. We considered that withered vegetation might be utilized as a habitat for C. vicinus, as well as provide an attachment substrate for periphytic algae. Abundance of periphytic algae can lead to high concentration of dissolved oxygen. Although copepods prefer high water temperatures for increasing their population growth, if Cyclops can overcome low temperature stress that leads to disruption of population, their population growth initiation in the next growing season (i.e. next spring) is possibly propelled by the winter population.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.3
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• pp.83-98
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• 2018

This study was conducted on rare plants distributed in Chungnam area from April, 2012 to November, 2017. The rare plant populations that are emerging are: Utricularia pilosa, Jeffersonia dubia, Iris ruthenica, Tipularia japonica, Calanthe discolor, Parasenecio pseudotaimingasa, Ranunculus kazusensis, Berchemia racemosa, Pogonia minor and Glehnia littoralis. According to the criteria of the International Union for Conservation of Nature (IUCN), plant resources in the rare species category were one important type (CR), three hazardous species (EN) and six vulnerable species (VU). As a result of analyzing characteristics of ecological environment and threats, five types of habitat types, two aquatic areas, two types of flatland and coastal sand dune distribution types were analyzed. The decreasing tendency of the rare plant populations in the surveyed area is judged to be artificial disturbance and habitat destruction rather than climate or environmental change. Considering the characteristics of habitat, conservation measures should be prepared for each population.

• Korean Journal of Ecology and Environment
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• v.42 no.4
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• pp.422-431
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• 2009

This study was to provide basic data for aquatic ecosystem research using fishes. Field sampling was carried out at five selected sites of Gap Stream, and fish samples, especially for a selection of sentinel species were collected three times in June, September, and October 2007. We analyzed total length distribution of Zacco platypus in relation with the season and the sampling sites, and then compared with total body weight, condition factor (K), and age distribution of the fish. The fish population data were compared with physico-chemical water quality, obtained from the Ministry of Environment, Korea. Water quality analysis showed a significant nutrient enrichment, based on total nitrogen (TN) and total phosphorus (TP), and organic matter pollution, based on biological oxygen demand (BOD) and chemical oxygen demand (COD) in the Site 5, which is directly influenced by wastewater disposal plant (WDP). Population analysis of the sentinel species showed that the total number of individuals, age distribution, and the population size-structure were influenced by the effluents from the WDP, and that reproductive failure of young-age population were evident in Site 5. According to the relation analysis of total weight to K, the disturbed population was mainly attributed to combined effects of habitat modifications and chemical degradations. Regression analysis of K values against water quality parameters showed significant (p<0.05) positive relations with nutrient and organic matter contents. Our data suggest that the population structure using a sentinel fish species reflected the ambient water quality in the stream and that diagnosis of aquatic ecosystem health using Z. platypus population may be practical for water resource and ecosystem conservations.

• Journal of People, Plants, and Environment
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• v.24 no.5
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• pp.469-483
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• 2021

Background and objective: If the Nelumbo nucifera spreads in a wetland at a high density, it can have considerable positive and negative ecological effects on habitats. For this reason, it is necessary to precisely investigate the impacts of its rapid proliferation. This study was conducted to propose the distribution and management of N. nucifera, which can cause the degradation of wildlife habitats due to the rapid spread of internal and external environmental factors that may affect the Junam wetland ecosystem. Methods: For the investigation and analysis of physical and ecological characteristics, factors of the abiotic environment such as general weather conditions, topography and water depth structure, and soil and water quality analysis, and bioenvironment characteristics such as changes in the N. nucifera community distribution were evaluated. To assess whether the differences in the soil depth and physicochemical characteristics between the N. nucifera community and the aquatic plant community are statistically significant, a One-way ANOVA was executed. Results: N. nucifera was presumably introduced in approximately 2007 and observed at a prevalence of only 0.8% in 2009, but had expanded to 11.1% in 2014. After that, the area was increased to 19.3% in 2015 and 40.0% in 2017, about twice that of the previous survey year. The rapid diffusion of an N. nucifera colony can have adverse effects on wildlife habitats and biodiversity at Junam Wetland. To solve these problems, four management methods can be proposed; water level management, mowing management, installation of posts and removal of lotus roots. Control of the N. nucifera community using these methods was judged to be suitable for cutting and water level management when considering expansion rate, water level variation, and wildlife habitat impacts. Conclusion: As the biotic and abiotic environmental factors are different for each wetland, it is necessary to determine the timing and method of management through a detailed investigation.

• Korean Journal of Plant Taxonomy
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• v.38 no.1
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• pp.69-77
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• 2008

We report Vallisneria spinulosa S. Z. Yan (Hydrocharitaceae) as an unrecorded species from the flora of Korea. This aquatic vascular plant occurs in reservoirs, streams, and ditches at Changnyeong, Changwon, and Gimhae which belong to Nakdong river basin. Vallisneria spinulosa is distinguishable from V. natans (Lour.) Hara already known to Korean flora by the presence of turion and hairs at base of stamen, adnation between pistil and staminodia, the number of stamen, and shape of fruit and seed. V. spinulosa is similar to V. desnseserrulata Makino in the viewpoint of distribution (Japan and southern China), but V. spinulosa has three to five epidermal wings on the surface of seed.

• ALGAE
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• v.27 no.4
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• pp.283-294
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• 2012

The physico-chemical and environmental factors of stoneworks were examined from March 2009 to October 2010, and aerial algae living on 24 stoneworks in Korea were identified. Fifty aerial algae were found in 24 stoneworks. Of the 50 taxa, 30 taxa were cyanophytes, 16 taxa were bacillariophytes, 3 taxa were chlorophytes, and 1 taxon was a xanthophyte. Nine species, including Aphanocapsa rivularis, which is known to only live in aquatic conditions, inhabited both aquatic and aerial environments. Synechococcus aeruginosus, Scytonema coactile var. thermalis, S. coactile var. minor, Stigonema ocellatum f. ocellatum, and Oscillatoria boryana were newly recorded in Korea. As a result of a correlation analysis between algae and the physico-chemical and ecological environmental factors, the taxa were divided into the bryophyte group, the humidity group, and the dry group. Although the bryophyte group was included within the humidity group, it was separated from the dry group. Taxa in the bryophyte group including Nostoc commune which was distributed in more humid areas than those in the humidity group. However, dry group taxa including Chroococcus pallidus were distributed in lower humidity than that of the two other groups. Correlations among other environmental factors were tested to identify other factors that could substitute for humidity and light intensity. As a result, tree distance, water distance, and plant coverage were replaceable environmental factors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.85-94
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• 2011

The species composition and distributions of benthic marine plants on the East Coast of Korea were studied. We examined all species found in the intertidal and subtidal zones at four sites seasonally from August 2006 to May 2009. Of the 148 species identified, 92 were rhodophytes, 39 were phaeophytes, 16 were chlorophytes, and 1 was a seagrass. The most species (125) were found at Jukbyeon, while the fewest (99) were found at Chuksan. Overall, the numbers of species were highest during the spring and lowest in autumn. Seventy-five species (50 rhodophytes, 15 phaeophytes, 9 chlorophytes, and 1 seagrass) were found at all four sites. The dominant species providing cover were melobesioidean algae, Sargassum spp., Phyllospadix japonica, and Corallina pilulifera. The vertical distribution of benthic marine plants was characterized by C. pilulifera, Sargassum spp., Hizikia fusiformis, Grateloupia elliptica, Symphyocladia latiuscula, Grateloupia lanceolata, Ulva pertusa, and Chondria crassicaulis in the intertidal zone; Sargassum spp., P. japonica, Prionitis cornea, C. pilulifera, and Acrosorium polyneurum at 1 m depth; Sargassum spp., P. japonica, and melobesioidean algae at 5 m depth; and melobesioidean algae at 10 m depth. There was variation among the sites, presumably due to differences in the local conditions.

• Mycobiology
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• v.50 no.5
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• pp.326-344
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• 2022

The fungal-like family Saprolegniaceae (Oomycota), also called "water mold," includes mostly aquatic saprophytes as well as notorious aquatic animal pathogens. Most studies on Saprolegniaceae have been biased toward pathogenic species that are important to aquaculture rather than saprotrophic species, despite the latter's crucial roles in carbon cycling of freshwater ecosystems. Few attempts have been made to study the diversity and ecology of Saprolegniaceae; thus, their ecological role is not well-known. During a survey of oomycetes between 2016 and 2021, we investigated the diversity and distribution of culturable Saprolegniaceae species in freshwater ecosystems of Korea. In the present study, members of Saprolegniaceae were isolated and identified at species level based on their cultural, morphological, and molecular phylogenetic analyses. Furthermore, substrate preference and seasonal dynamics for each were examined. Most of the species were previously reported as animal pathogens; however, in the present study, they were often isolated from other freshwater substrates, such as plant debris, algae, water, and soil sediment. The relative abundance of Saprolegniaceae was higher in the cold to cool season than that in the warm to hot season of Korea. This study enhances our understanding of the diversity and ecological attributes of Saprolegniaceae in freshwater ecosystems.