• Article

    Predictability of Sea Surface Temperature in the Northwestern Pacific simulated by an Ocean Mid-range Prediction System (OMIDAS): Seasonal Difference

    북서태평양 중기해양예측모형(OMIDAS) 해면수온 예측성능: 계절적인 차이

    Heeseok Jung, Yong Sun Kim, Ho-Jeong Shin, and Chan Joo Jang

    정희석, 김용선, 신호정, 장찬주

    Changes in a marine environment have a broad socioeconomic implication on fisheries and their relevant industries so that there has been a ... + READ MORE
    Changes in a marine environment have a broad socioeconomic implication on fisheries and their relevant industries so that there has been a growing demand for the medium-range (months to years) prediction of the marine environment Using a medium-range ocean prediction model (Ocean Mid-range prediction System, OMIDAS) for the northwest Pacific, this study attempted to assess seasonal difference in the mid-range predictability of the sea surface temperature (SST), focusing on the Korea seas characterized as a complex marine system. A three-month re-forecast experiment was conducted for each of the four seasons in 2016 starting from January, forced with Climate Forecast System version 2 (CFSv2) forecast data. The assessment using relative root-mean-square-error was taken for the last month SST of each experiment. Compared to the CFSv2, the OMIDAS revealed a better prediction skill for the Korea seas SST, particularly in the Yellow sea mainly due to a more realistic representation of the topography and current systems. Seasonally, the OMIDAS showed better predictability in the warm seasons (spring and summer) than in the cold seasons (fall and winter), suggesting seasonal dependency in predictability of the Korea seas. In addition, the mid-range predictability for the Korea seas significantly varies depending on regions: the predictability was higher in the East Sea than in the Yellow Sea. The improvement in the seasonal predictability for the Korea seas by OMIDAS highlights the importance of a regional ocean modeling system for a medium-range marine prediction. - COLLAPSE
    June 2021
  • Article

    Evaluation of the Possibility of Developing Organic Matter Indicators in Coastal Environments: Utilization of Dissolved Organic Carbon and Fluorescent Dissolved Organic Matter

    연안환경에서 유기물 지표 개발을 위한 가능성 평가: 용존유기탄소와 형광용존유기물질 활용

    Min-Young Lee, Kyungsun Yang, Sunchan Kim, and Tae-Hoon Kim

    이민영, 양경선, 김순찬, 김태훈

    In order to evaluate the dissolved organic carbon (DOC) and fluorescent dissolved organic matter (FDOM), as indicators of organic matter in the ... + READ MORE
    In order to evaluate the dissolved organic carbon (DOC) and fluorescent dissolved organic matter (FDOM), as indicators of organic matter in the coastal environments, we measured the concentrations of DOC, FDOM, and chemical oxygen demand (COD) in saline groundwater (Woljeong, Pyoseon, and Hwasun beaches) and coastal seawater (Haengwon, Gwideok, Pyoseon, and Yeongnak) in Jeju, Korea. The highest concentrations of DOC and COD in groundwater were found in Woljeong and Pyoseon, and those in coastal water were observed in Haengwon and Pyoseon, indicating that the higher concentrations of DOC and COD seem to be associated with saline groundwater-driven dissolved organic matter (DOM) and/or biogeochemical processes. According to origin and optical properties of DOM using FDOM as a tracer, proportion of humic-like FDOM, more refractory DOM, was relatively greater in the groundwater than in the coastal water. With regard to this result, there was no relationship between DOC and COD in groundwater, while DOC showed a good positive correlation (r2 = 0.66) with COD in coastal water. This result indicates that COD as an indicator of assessment of DOM has a limitation in which it is difficult to quantify refractory DOM. Although DOC is a potential alternative to COD in the coastal environments, particulate organic carbon cannot be negligible due to relatively higher concentration compared to the open ocean. Therefore, the use of total organic carbon (TOC) as a replacement of COD in the coastal ocean is important, and the evaluation criterion of the TOC is necessary in order to evaluate of organic matter indicator in the various coastal environments. - COLLAPSE
    June 2021
  • Article

    Community Structure and Health Status of Macrobenthic Animals in the Nakdong River Estuary, Busan, Korea

    낙동강 하구역에 서식하는 대형저서동물의 군집구조와 건강도

    Seok Hyun Youn, Jin Woo Lee, Chul Woong Oh, Byoung-Mi Choi, Kon-Tak Yoon, Jong-Hun Na, and In-Soo Seo

    윤석현, 이진우, 오철웅, 최병미, 윤건탁, 나종헌, 서인수

    The community structure and health status of macrobenthos assemblages were investigated in the subtidal area of the Nakdong River estuary, Southern Coast ... + READ MORE
    The community structure and health status of macrobenthos assemblages were investigated in the subtidal area of the Nakdong River estuary, Southern Coast of Korea. Benthic fauna samples were collected seasonally at 8 stations in the subtidal area of the Nakdong River estuary from February 2013 to October 2015. During the survey, a total of 380 species and 4,603 ind./m2 of macrobenthos in all sampling areas were collected. The major dominant species were the polychaetes Minuspio japonica, Pseudopolydora kempi, Heteromastus filifomis, Capitella capitata, the amphipod Grandidierella japonica and the bivalvia Arcuatula senhousia. Some species of polychaetes found in the study area consisted of opportunistic species that showed high densities when habitat condition was poor. On the other hand, macrobenthos assemblages in the study area were divided into brackish water and marine groups. Abundance was high in the brackish group, while the number of species and diversity index were high in the oceanic group. The three indices (AMBI, M-AMBI, and BHI) in the assessment of health levels based on the ecological characteristics and number of species in macrobenthic were commonly shown to be in good condition in the group of oceanic stations, while relatively poor conditions were reflected in the group of brackish stations. Compared to other indices, the M-AMBI index of the three indices for health assessment was considered to be a relatively more suitable one to assess benthic ecological conditions. - COLLAPSE
    June 2021
  • Article

    Growth and Production of Pholis nebulosa (Temminck & Schlegel, 1845) in a Seagrass (Zostera marina) Bed of Southern Korea
    Joo Myun Park, Ha Won Kim, Seok Nam Kwak, and Ralf Riedel
    The seagrass habitats are a highly productive marine ecosystem which provides nursery ground and shelter for many fish and invertebrate species. Pholis ... + READ MORE
    The seagrass habitats are a highly productive marine ecosystem which provides nursery ground and shelter for many fish and invertebrate species. Pholis nebulosa (Temminck & Schlegel, 1845) is one of the most abundant seagrass fishes in the coastal waters of Korea. The estimation of fish production is key for devising conservation measures and ensuring fish resources sustainability. A total 894 P. nebulosa ranging from 3.83 to 26.5 cm total length (TL) were collected monthly in 2006 with a small beam trawl in a seagrass bed of southern Korea. Growth parameters of P. nebulosa were estimated using the von Bertalanffy growth model, and production was estimated using a general equation which relates daily fish production to ash-free dry weight (AFDW), biomass, and water temperature. The von Bertalanffy's growth equation was estimated as: Lt = 28.3823(1-e-0.7835(t+0.9864)). The densities, biomass, daily, annual production, and P/B ratio were 0.069±0.061/m-2, 1.022±0.621 g/m2, 0.005±0.004 g AFDW/m2/day, 1.676 g AFDW/m2/yr, and 1.641, respectively. Monthly variation in production of P. nebulosa peaked during March and April 2006 (0.0139 and 0.0111 g AFDW/m2/day), whereas the lowest value of 0.0005 g AFDW/m2/day was in December. Monthly change in production of P. nebulosa was positively correlated with biomass and condition factor. Our results will contribute to the conservation of seagrass ecosystems, which are still undisturbed in the study area. - COLLAPSE
    June 2021