Rapid change of zooplankton composition in the South Sea ecosystem during a three day period revealed by DNA metabarcoding

Abstract

Assessment of the biodiversity and temporal change of the zooplankton community structure comprises a fundamental element for understanding the marine ecosystem health. Although species identification is the first step forward such an assessment, it have difficult in traditional morphological method. DNA barcoding coupled with high-throughput next generation sequencing technology allows considerably large number of species to be identified from the mixed bulk samples within a relatively short time. In the preset study we made an attempt to investigate the short-term change of zooplankton community such as hourly, and day and night changes. Zooplankton sampling was carried out at a fixed station near Tong-Yeong, the southern coast of Korea at every two hours for a period of 72 hours by filtering the pumped-up water from 2m depth with a 200㎛ net in June and July 2013. DNA was extracted from the zooplankton assemblage, DNA barcode - mitochondrial COI gene - was amplified by PCR and the sequences obtained by pyrosequencing. A total of 120 species belonging to 9 phyla were identified from the samples, indicating a high level of species diversity appears in early summer. It was notable that the occurrences of 29 species showed significant differentiation between day and night times. The dominant species, Acartia hudsonica, usually appeared at night times while Euphausia pacifica during the day times in both months. The hsment, it have difficult in traditional morphological method. DNA barcoding coupled with high-throughput next generation sequencing technology allows considerably large number of species to be identified from the mixed bulk samples within a relatively short time. In the preset study we made an attempt to investigate the short-term change of zooplankton community such as hourly, and day and night changes. Zooplankton sampling was carried out at a fixed station near Tong-Yeong, the southern coast of Korea at every two hours for a period of 72 hours by filtering the pumped-up water from 2m depth with a 200㎛ net in June and July 2013. DNA was extracted from the zooplankton assemblage, DNA barcode - mitochondrial COI gene - was amplified by PCR and the sequences obtained by pyrosequencing. A total of 120 species belonging to 9 phyla were identified from the samples, indicating a high level of species diversity appears in early summer. It was notable that the occurrences of 29 species showed significant differentiation between day and night times. The dominant species, Acartia hudsonica, usually appeared at night times while Euphausia pacifica during the day times in both months. The h