Benthic Diatom Communities in Korean Estuaries: Species Appearances in Relation to Environmental Variables.

Kim Kim,Hwang Hwang,Cho Cho

doi:10.3390/ijerph16152681

Kim Kim, Hwang Hwang + Show 1 more

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https://doi.org/10.3390/ijerph16152681

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Abstract

In the Korean Peninsula’s southern estuaries, the distributive characteristics of epilithic diatoms and the important environmental factors predicting species occurrence were examined. The collection of diatoms and measurements of water quality and land-use were performed every May between 2009 and 2016, with no influence from the Asian monsoon and snow. Throughout the study, 564 diatoms were classified with first and second dominant species of Nitzschia inconspicua and N. perminuta. Based on diatom appearance and standing crops, the 512 sampling stations were divided into four groups by cluster analysis, and two regions, namely the West and East Sea. Geographically, G1, G2, G3, and G4 were located in the East Sea, Southeast Sea, West Sea, and Southwest Sea, respectively. Canonical correspondence analysis (CCA) results indicated that environmental factors, such as turbidity, electric conductivity (EC), and total phosphorus (TP), significantly influenced the distribution of epilithic diatoms. A random forest model showed that major environmental factors influencing the diatom species appearance included EC, salinity, turbidity, and total nitrogen. This study demonstrated that the spatial distribution of epilithic diatoms in the southern estuaries of the Korean Peninsula was determined by several factors, including a geographically higher tidal current-driven turbidity increase and higher industrial or anthropogenic nutrient-loading.

Highlights

An estuary is a transition zone where seawater and freshwater meet, and it is a dynamic ecosystem with a diverse composition of living organisms due to significant physicochemical changes, such as water temperature, salinity, and nutrients [1,2,3]
The sites were selected based on the 2008 Guide of Ministry of Environment (MOE)/National Institute of Environmental Research (NIER) [36], as sites that form a boundary with the ocean and areas affected by the ocean in an upstream direction of the river
Between 2009 and 2016 during May, we assessed the feasibility of applying diatom indices previously studied to assess the biological integrity of estuaries, while predicting the importance of environmental factors and species appearance of epilithic diatoms in the southern part of the

Summary

Introduction

An estuary is a transition zone where seawater and freshwater meet, and it is a dynamic ecosystem with a diverse composition of living organisms due to significant physicochemical changes, such as water temperature, salinity, and nutrients [1,2,3]. Despite the fact that estuaries have various functions, including providing habitat, purifying water quality, and producing marine products, they are being destroyed by development projects concentrated in these regions [4]. Only 235 estuaries are able to maintain estuarine circulation, whereas the estuarine circulation of the remaining estuaries is cut off by estuarine dams or sea dikes, which limit the formation of a brackish water zone that constitutes an estuarine ecosystem [6]. Development projects concentrated in estuarine regions destroy the various functions of estuarine wetlands, including providing habitat, purifying water quality, and producing marine products [4].

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