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Article
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Changes of Phytoplankton Community and Oceanic Physicochemical Properties of Jeju Coast in Spring and Summer Seasons, 2022
2022년 춘계에서 하계 제주 연안의 해양 물리화학적 특성 및 식물플랑크톤 출현 변동
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Ji Yeon Jang, Joo-Hwan Kim, Do Yun Jeong, Su-Min Kang, Xu Wang, Yun Hyeong Choi, Joon-Baek Lee, Young Kyun Lim, Seung Ho Baek, Jin Ho Kim
장지연, 김주환, 정도윤, 강수민, 왕욱, 최윤형, 이준백, 임영균, 백승호, 김진호
- Phytoplankton, as key primary producers, play a critical role in the dynamics of marine ecosystems. This study explores the variation in phytoplankton …
- Phytoplankton, as key primary producers, play a critical role in the dynamics of marine ecosystems. This study explores the variation in phytoplankton species appearance along the Jeju coast from spring to summer 2022, emphasizing the stratification and changes in nutrient dynamics. Through extensive field surveys at twelve points around Jeju Island, we measured a range of physical and chemical oceanographic parameters. Monthly average stratification indices displayed an abrupt increase from 22 in May to 3,196 in August, highlighting intense stratification, significantly influenced by the influx of Changjiang River Diluted Water during the summer months. Concurrently, nutrient concentrations exhibited a downward trend, with nitrate and nitrite levels decreasing from 6.7 µM in March to 1.3 µM in July, and phosphate levels declining from 0.31 µM to 0.02 µM during the same period, while silicate concentrations, ranging from 6.8 to 9.8 µM, remained consistently high throughout the study. Similarly, a reduction in monthly average phytoplankton biomass was observed, with concentrations peaking in the spring (April and May) at 406,053 to 409,139 cells L-1 and declining to 45,546 to 118,214 cells L-1 by summer (June to August). Diatoms (Chaetoceros spp. and Skeletonema spp.) dominated the phytoplankton community throughout the period; however, an increased proportion of dinoflagellates (Gyrodinium spp. and Heterocapsa spp.) was observed during the summer months, when stratification was most pronounced. This study confirms that variations in currents and water masses impacting the Jeju coast can significantly influence phytoplankton community dynamics, emphasizing the need for ongoing monitoring in this region. - COLLAPSE
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Changes of Phytoplankton Community and Oceanic Physicochemical Properties of Jeju Coast in Spring and Summer Seasons, 2022
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Note
- Morphological and molecular investigation of Melosira octogona Schmidt (Melosirales, Bacillariophyta) isolated from the Jeju Island
- Sung Min An, Kichul Cho, Grace Choi
- Melosira octogona Schmidt has been documented primarily through illustrations and light microscopy photographs, resulting in incomplete morphological descriptions. In this study, the …
- Melosira octogona Schmidt has been documented primarily through illustrations and light microscopy photographs, resulting in incomplete morphological descriptions. In this study, the morphological characteristics of M. octogona were investigated using scanning electron microscopy, and the small subunit rDNA of the strain isolated from the coast of Jeju Island, South Korea, was analyzed for the first time. The cells were organized in short chains, with the frustules taking on an octagonal shape in the girdle view because of the straight, obliquely oriented valve margin. The cells were joined together in specific pairs by a cingulum. Imaging analysis via SEM revealed the presence of a hemispherical valve with a well-developed corona on the valve face, along with stellate thickening and rimoportulae. The epicingulum was composed of six ligulate bands punctuated by rows of circular to elongated pores. Genetic analysis of the 18S rDNA sequence suggested a close relationship between M. octogona and Melosira sp. (KJ961704), demonstrating a high degree of similarity. Meanwhile, it exhibited comparatively low similarity (99.0 %) to Melosira cf. octogona (AY485518). The results of our analysis can enhance the precise recognition of M. octogona and enrich our understanding of its phylogenetic position within the order Melosirales. - COLLAPSE
Ocean and Polar Research
