Ecological Characteristics of Epilithic Diatom Communities in the Estuary of Korean Peninsula

Abstract

Ecological characteristics of epilithic diatom communities in the 193 sampling sites from estuaries of Korean peninsula were studied with environmental variables between 2015 and 2016. Totally 394 taxa belong to 13 families were classified from the study, and Naviculaceae was the dominant family of Korean peninsula. In view of diatom abundance, Nitzschia perminuta (19.6%) and Nitzschia inconspicua (14.0%) were the most dominant species, while Bacillariaceae was the largest family. Based on the cluster analysis with number and abundance of the diatom species appeared, the epilithic diatom communities of estuaries in Korean peninsula were largely divided into four groups (G1–G4). Ecological characteristics of diatom community in each group were as follows; (1) G1, mainly from estuaries of the East Sea, was characterized by high forest land–use, high dissolved oxygen, and low concentration of nutrients. The dominant and subdominant species were Fragilaria elliptica (14.8%) and Nitzschia perminuta (11.2%), respectively. (2) G2, mainly from the eastern part of the South Sea, was characterized by the good water quality, such as low turbidity, and low concentration of nutrients. The dominant and subdominant species were Nitzschia perminuta (36.2%) and Nitzschia inconspicua (12.0%), respectively. (3) G3, mainly from the western part of the South Sea and the southern part of the Yellow Sea, was characterized by high agriculture land–use, low electric conductivity and low salinity. The dominant and subdominant species were Nitzschia inconspicua (20.9%) and Navicula gregaria (9.9%), respectively. (4) G4, mainly from the northern part of the Yellow Sea, was characterized by poor water quality, high concentration of nutrients. The dominant and subdominant species were Cyclotella atomus (8.6%) and Nitzschia ovalis (8.3%), respectively. The environmental factors strongly impacted on the distribution of epilithic diatoms in each group; total nitrogen (TN) to G1, turbidity to G2, agriculture to G3, and total phosphorus (TP) to G4, respectively. Moreover, the most important environmental factors affecting the occurrence of indicator species were as follows; forest land–use for Fragilaria construens f. venter of G1, turbidity for Rhoicosphenia abbreviate of G2, urban land-use and TP for Bacillaria paradoxa and Hantzschia amphioxys of G3, and TP and turbidity for Nitzschia ovalis and Stephanodiscus invistatus of G4, respectively. In conclusion, the distribution of epilithic diatom communities of estuaries in Korean peninsula were spatially grouped by the geochemical features like the development of tidal mudflats and land-use. Of environmental variables, turbidity, TN and TP are more essential to the appearance of diatom species over the estuary.