독도 연안역 중형동물플랑크톤 군집의 계절과 경년 변이특성 = Seasonal and Interannual Variability of Mesozooplankton Community in the Coastal Waters of Dokdo

다국어 초록 (Multilingual Abstract)

Seasonal and interannual variability of mesozooplankton is closely linked to local hydro-climate conditions, which may be modulated by large-scale climate variability such as the Pacific Decadal Oscillation (PDO). The present study examines the seasonal and interannual dynamics of mesozooplankton in the coastal waters of Dokdo, East Sea, over a three-year period (2018–2020) and across the seasons. We examined species composition, abundance, and diversity in relation to hydroclimatic variables, including PDO, temperature, salinity, and chlorophyll-a concentration (hereafter chl-a). Results showed clear seasonal patterns, with copepods dominating during winter and spring, specifically Paracalanus spp. and Oithona spp. being particularly numerically abundant, summer communities had increased proportions of dinoflagellates Pyrocystis pseudonoctiluca and ctenophores. Fall samples exhibited higher taxonomic diversity with notable presence of gelatinous taxa, including appendicularians. The notable interannual differences in community composition and total abundance were observed, particularly after December 2019, when PDO shifted from a positive to a negative phase. During this period, increases in surface temperature and chl-a concentration coincided with elevated mesozooplankton abundance. Canonical correspondence analysis demonstrated that the observed community patterns were coherently structured along gradients of surface temperature, chl-a, and PDO, supporting the interpretation that seasonal and interannual variability was consistently aligned with concurrent environmental conditions. This study presents field-based evidence of how mesozooplankton communities in the coastal waters of Dokdo vary seasonally and interannually in relation to hydrographic conditions, contributing to a broader understanding of climate variability and its impact on ecosystem changes in this region.