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Choi, J.U.; Lee, Y.G.; Jeong, D.U.; Choi, Y.H., and Woo, H.J., 2018. Effects of Abalone Farming Cage Removal on the Benthic Foraminiferal Assemblages. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 321–325. Coconut Creek (Florida), ISSN 0749-0208. To improve the aquaculture environment of an abalone farm near the Bogil Island, relocation was executed via the partial relocation of cages. The surface sediments were collected from nine stations to analyze the grain size, geochemical characteristics, and benthic foraminiferal assemblages in May (before) and August (after) 2015. Although no distinct environmental changes in the cage area were observed, the relocation area had an increased sand content caused by water circulation. In addition, despite the increase in the sediment temperature, the ignition loss decreased while the dissolved oxygen in the se...

Jeong, D.U.; Lee, Y.G.; Kang, J.; Woo, H.J., and Choi, Y.H., 2020. Sediment geochemistry and benthic foraminiferal response to fish farming after conversion from a red laver (seaweed) farm. Journal of Coastal Research, 36(3), 559–574. Coconut Creek (Florida), ISSN 0749-0208.To understand the effects of biodeposits discharged from a fish farm (which was previously a red laver farm) on geochemistry of the sediment and benthic ecology, trace metals and element analyses, 210Pb dating, and benthic foraminiferal analyses were conducted on sediment cores collected below the fish farm cages. Sediment core sampling was also carried out at a control plot (160 m away) to understand the spreading of biodeposits. The geochemical effect of fish farming is pronounced. There was an increase in silt content and sedimentation fluxes of Znex (Zn in excess fractions), Cuex, Asex, and TPex (total phosphorus in excess fractions) after red laver farming. The silt content increased from 45.01% to 50.07%, with a sediment accumulation rate of ∼0.61 cm/y, on average. TPex, with 0.15% ± 0.06% on average, showed that the fish farming effects increased by 0.22% ± 0.07%. Znex, Cuex, Cdex, and Asex showed a positive relationship with TPex increase: 19.92 ± 1.79, 10.23 ± 3.99, 0.57 ± 0.19, and 0.92 ± 0.04 µg/cm2/y, respectively. The high sedimentation fluxes of Znex and Asex in the control plot may signify an expansion of influence of the fish farm by tidal currents. Seven benthic foraminifera appeared during the fish and red laver farming periods, with the dominant species being Cribroelphidium excavatum; however, they were characterized by a high similarity index of 88.1% and very low frequency of abundance, indicating bad habitat conditions. Among them, the C. excavatum–Ammonia beccarii–Ammonia ketienziensis–Cribroelphidium subarcticum assemblage ranged from 21 cm depth to the uppermost layer, characterized by increases in A. beccarii. This increase may have been caused by the accumulation of organic matter discharged from the fish farm after red laver farming, rather than from an increase in the trace metals. A. beccarii may be a species tolerant to fish farming.

Choi, Y.H.; Jeong, D.U.; Lee, Y.G.; Choi, J.U.; Kim, S., and Lee, J.S., 2019. Opportunistic species and seasonal variation in epiphytic foraminiferal assemblages in abalone farm nets. Jour...

This study investigated concentration of metal ions in sediment and intersexuality in Polymesoda erosa and Lutraria lutraria . Samples were collected from five areas of Ha Long Bay in October, 2012. The concentration of metal ions showed that Al (37390.0 ± 11816.5 mg/kg) was highest and Mn (360.4 ± 101.4 mg/kg) was second high concentration. Cd (0.04 ± 0.05 mg/kg) was lowest. The intersexuality was 14.3% in P. erosa and 9.1% in L. lutraria that observed only in female. Key words: Ha Long Bay, bivalves, heavy metal, intersexuality 서 론 수서생태계에서 생물에게 미치는 화학적 스트레스 요인 가운데 중금속은 생물 체내 축적성이 강하고 대사, 생화학, 생리학 및 조직학적 반응의 변화를 유도한다 (Stasiūnaitė, 1999). 중금속 가운데 Cd, Pb, Hg, Zn은 생식 등의 내분비계 장애기능을 유발하는 기능을 가지고 있다 (WWF, 2006; Ju et al ., 2009). 해양의 중금속은 퇴적물과 쉽게 결합하며, 해수보다 퇴적물에 매우 높은 농도로 분포한다 (Martin and Whitifield, 1983). 이매패류는 주로 해양저질에 서식하며, 여과섭식을 하며 이동성이 낮아 일생동안 서식범위가 국한되어 있어서 특정 지역의 오염상태를 알아보기 위한 지표종으로 많이 사용되고 있다 (Marin et al ., 2006; Schintu et al ., 2008; Husmann et al ., 2012). 환경요인으로 인해 생물이 받는 위해도를 평가하는 방법은 위험성 확인 (hazard identification), 노출평가 (exposure assessment), 용량-반응 평가 (dose-response assessment) 및 위해도 결정 (risk characterization) 의 주요 4단계이다 (NRC, 1983). 다양한 생물지표 가운데 생식생물학 및 조직학적 지표들은 개체 또는 개체군 수준에서 독성물질에 의한 장기적이고 지속적인 영향을 평가하는데 중요하게 이용되는 항목이다 (Huggett

Lee, Y.G.; Kim, S.; Jeong, D.U.; Kim, J.K., and Woo, H.J., 2013. Effects of heavy rainfall on sedimentation in the tidal salt marsh of Suncheon Bay, South Korea. Tide observations, geographic surveys, sediment composition, and sediment accretion rate monitoring were conducted to investigate the relationship between general pattern changes and control factors of the accretion rate at 10 localities of the tidal salt marsh of Suncheon Bay over 2 years (June 2007–May 2009). The substrate sediments of the tidal salt marshes that are distributed between the mean sea level and the high water of ordinary spring tide are mainly composed of silt (37.98%) and clay (60.45%) and have a high average annual accretion rate of 28.88 mm/y. The high substrate sedimentation of tidal salt marshes is caused by: (1) a high concentrated suspended sediment supply from the tidal flat; (2) considerable marsh grass vegetation; (3) undeveloped tidal salt marsh creek; and (4) marsh elevation distributed between the mean sea l...

The shape and microscopic structure of the foot of the equilateral venus, Gomphina Veneriformis are described by light and electron microscopy along with the substrate conditions of their habitat. The habitat sediment of G. veneriformis is composed of sand (2 - 0.063 mm in diameter), mainly. The foot is wedge-shaped with multiple vertical furrows on the surface. Although the foot is composed of an epithelial layer, a connective tissue layer and a muscular layer, the boundary between the connective tissue and muscular layer is not clear. The epithelial layer was composed mostly of ciliated columnar epithelia and secretory cells. Epithelial cells forming the apical region of the fold were long columnar, while cells of the interfold were mostly short columnar. The cilia and microvilli were commonly observed on the free surface of epithelial cells, while tight junctions of apico-lateral aspect and membrane interdigitations were found between the epithelial cells. Secretory cells were found to contain acidic mucopolysaccharide, and were classified into two types in accordance with the shapes and ultrastructures of secretory granules. The muscle fibers were composed of thin and thick microfilaments, the proportions of which were 81.3% and 18.7%, respectively. It was determined that such morphology and structural characteristics of the foot of G. veneriformis would present advantageous conditions for borrowing into substrate and mobility.

School of Construction Engineering, Pukyong National University, Busan 608-737, KoreaTo predict changes in the marine environment of the Beolgyo Stream Estuary in Jeonnam Province, South Korea, where cohesive tidal flats cover a broad area and a large bridge is under construction, this study conducted numerical simulations involving tidal flow and cohesive sediment transport. A wetting and drying (WAD) technique for tidal flats from the Princeton Ocean Model (POM) was applied to a large-scale-grid hydrodynamic module capable of evaluating the flow resistance of structures. Derivation of the eddy viscosity coefficient for wakes created by structures was accomplished through the explicit use of shear velocity and Chezy’s average velocity. Furthermore, various field observations, including of tide, tidal flow, suspended sediment concentrations, bottom sediments, and water depth, were performed to verify the model and obtain input data for it. In particular, geologic parameters related to the evaluation of settling velocity and critical shear stresses for erosion and deposition were observed, and numerical tests for the representation of suspended sediment concentrations were performed to determine proper values for the empirical coefficients in the sediment transport module. According to the simulation results, the velocity variation was particularly prominent around the piers in the tidal channel. Erosion occurred mainly along the tidal channels near the piers, where bridge structures reduced the flow cross section, creating strong flow. In contrast, in the rear area of the structure, where the flow was relatively weak due to the formation of eddies, deposition and moderated erosion were predicted. In estuaries and coastal waters, changes in the flow environment caused by artificial structures can produce changes in the sedimentary environment, which in turn can affect the local marine ecosystem. The numerical model proposed in this study will enable systematic prediction of changes to flow and sedimentary environments caused by the construction of artificial structures. Key words: Beolgyo Stream Estuary, Cohesive sediment transport, Erosion and deposition, Flow resistance of structures, Numerical simulation, Tide and tidal flow

In the four sedimentary cores from Yeoja Bay, the analyses of grain size, benthic foraminiferal species compositions, assemblages and statistics were carried out to investigate the effects of late Holocene sea-level change on benthic foraminifera. The core sediments were mainly composed of fine-grained silt and clay. The benthic foraminifera were classified into 27 species of 16 genera, 30 species of 21 genera, 50 species of 29 genera and 52 species of 29 genera in Core YC-1 to 4, respectively. In the result of cluster analysis, it seemed that Group 1 (Core YC-1 and 2) of representative A. beccarii assemblages was deposited in upper bay environment and Group 2 (Core YC-3 and 4) of representative E. clavatum-A. beccarii assemblages was deposited in inner bay environment affected by offshore water. In the result of species composition analysis, the production frequency of A. beccarii was gradually decreased from low layer to upper layer, whereas production frequency of E. clavatum and P.F./T.F. was gradually increased to upward. These change patterns appeared in benthic and planktonic foraminifera seemed to reflect the late Holocene sea-level rise in Yeoja Bay.

大韓民国南東部浦項地域に分布する中新統の古環境を, 底生有孔虫群集に基づき解析した.Qモード主成分分析の結果, 第1主成分は各底生有孔虫種の産出頻度, 第2主成分は海水の炭酸カルシウム濃度, 第3主成分は沿岸水の影響の程度, 第4主成分は中層水と深層水, 第5主成分は寒流系水塊の影響, 第6主成分は中層水と表層水に関係している.主成分分析の結果と現在の西南日本沖太平洋の海洋環境から, 中新統の堆積環境を推定した.北部地域のHeunghae層は中部漸深海帯下部で堆積した.中部地域のCheongogsa層中部の堆積深度は上部漸深海帯から中部漸深海帯上部であった.Cheongogsa層最上部は中部漸深海帯下部に, Hagjeon層は上部漸深海帯から中部漸深海帯上部で堆積した.Duho層下部の古水深は上部漸深海帯から中部漸深海帯下部である.南部地域に分布するHagjeon層は上部漸深海帯から中部漸深海帯上部にて堆積し, 中部漸深海帯下部まで深くなったこともあった.Cheongogsa層中部(N 8帯)以降, 寒流系水塊の影響が認められた.