• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.253-258
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• 2018

Phytoplankton community was studied in relation to a typhoon at Bok-gyo Bridge area in Juam Lake, Korea. In August 31, 2000, a typhoon (Prapiroon) was passed by Juam Lake with great power enough to destroy summer stratification of Juam Lake. Destratification resulted in temporal mixing of the whole water column and changed the physical and chemical properties of water bodies, and caused the changes of the biological properties. The transparency decreased from 195 cm before the typhoon to 84 cm after the typhoon with the resuspension of the bottom sediment. In the vertical distribution of the phytoplankton population, the maximum population was measured at depth of 2 m before the typhoon. However, immediately after the typhoon, the population distributed evenly throughout the entire water layers. The carbon biomass of the phytoplankton was also highest at the depth of 2 m before the typhoon, but immediately after the typhoon, it was uniformly distributed throughout the whole water layers. The vertical profiles of the concentrations of chlorophyll a, however, did not show a significant difference before and after the typhoon. The typhoon induced destratification and restratification altered the taxa of the phytoplankton. The major dominant phytoplankton taxa before the typhoon was diatoms including Aulacoseira granulata, but the green algae overwhelmed the diatoms in cell number and biomass after the typhoon. The chlorophycean dominance was replaced by cyanophycean dominance with the heavy rain and descent of water temperture at the end of September.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.1
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• pp.11-23
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• 2016

An ecological study on subtidal macrobenthic fauna was conducted off the Namhaedo Island, south coast of Korea from July 2012 to April 2013. A total of 247 species of macrobenthos occurred with a mean density of $1,027ind./m^2$ and a mean biomass of $148.7g/m^2$. Polychaetes was the richest and most abundant faunal group that comprised 37% in both total species number and density whereas echinoderms were biomass-dominant faunal group that accounted for 44% of the mean biomass. There was a seasonal variation in the species richness and abundance of macrobenthos with more species in winter and higher density in spring. Mean faunal density was relatively high at the stations near Namhaedo Island, but gradually decreased toward offshore stations. The most dominant species in terms of density was an amphipod species, Eriopisella sechellensis which occurred as a top ranker during three seasons except spring recorded the fourth rank. E. sechellensis showed its high density at the near shore stations of Namhaedo Island, but this species did not occur around the entrance of Gwangyang and Saryang Bays where Theora fragilis and Lumbrineris longifolia showed high densities. In particular, Tharyx sp., recorded high density between Gwangyang Bay entrance and offshore after Sea Prince oil spill, did not occur in the same area during this study period. The bottom temperature and sorting value of the surface sediments were highly correlated to the spatial distribution of macrobenthic fauna from the Bio-Env analysis. From the cluster analysis, the study area has five station groups with more similar faunal affinities from inner area toward offshore area. Based on the SIMPER analysis T. fragilis, Magelona japonica, E. sechellensis, L. longifolia and Paraprionospio cordifolia were mainly contributed to the classification of station groups. From the BPI, benthic communities in the entrance of Gwangyang Bay and Saryang Bay were considered to be in a slightly polluted condition in contrast to the normal healthy community at the offshore of Namhaedo Island. These results suggested that the benthic community of this area should be regularly monitored to assess the health status of this benthic ecosystem.