**Comparison of Water Sampling between Environmental DNA Metabarcoding and Conventional Microscopic Identification: A Case Study in Gwangyang Bay, South Korea**

### **Dong-Kyun Kim 1, Kiyun Park 1, Hyunbin Jo 1 and Ihn-Sil Kwak 1,2,\***


**\*** Correspondence: iskwak@chonnam.ac.kr; Tel.: +82-61-659-7148

Received: 2 July 2019; Accepted: 7 August 2019; Published: 9 August 2019

**Abstract:** Our study focuses on methodological comparison of plankton community composition in relation to ecological monitoring and assessment with data sampling. Recently, along with the advancement of monitoring techniques, metabarcoding has been widely used in the context of environmental DNA (eDNA). We examine the applicability of eDNA metabarcoding for effective monitoring and assessment of community composition, compared with conventional observation using microscopic identification in a coastal ecosystem, Gwangynag Bay in South Korea. Our analysis is based primarily on two surveys at a total of 15 study sites in early and late summer (June and September) of the year 2018. The results of our study demonstrate the similarity and dissimilarity of biological communities in composition, richness and diversity between eDNA metabarcoding and conventional microscopic identification. It is found that, overall, eDNA metabarcoding appears to provide a wider variety of species composition, while conventional microscopic identification depicts more distinct plankton communities in sites. Finally, we sugges<sup>t</sup> that eDNA metabarcoding is a practically useful method and can be potentially considered as a valuable alternative for biological monitoring and diversity assessments.

**Keywords:** coastal ecosystem; eDNA; metabarcoding; microscopy; monitoring and assessment
