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Interactions Among Tuna Catches, Prey Organisms, and Marine Environment in the Southwestern Indian Ocean
No full textAmong tropical oceans, the western Indian Ocean experiences the highest summer phytoplankton blooms due to strong monsoon winds. These winds drive upwelling, enriching surface waters with nutrients and light, fueling phytoplankton growth that supports marine ecosystems and increases large fish biomass. Tuna catches in this region are the second most economically valuable. A key oceanic feature is the presence of persistent sound scattering layers (SSL), composed of small pelagic organisms (1-20 cm). This study examined the interactions among tuna catches, SSL prey, and the marine environment. Data were collected from May 15 to June 7, 2023, using the EK80 (38 kHz) onboard KIOST’s Isabu and multi-net sampling (1 m × 1 m; 200 μm mesh) at 65°E longitude across 19°S, 8°S, and 2°N. Environmental data (30°S-15°N, 45-80°E) were obtained from the Copernicus Marine Service. Results showed a moderate positive correlation between prey (MVBS) and tuna catch (Spearman’s ρ = 0.270). Multiple regression analysis revealed that temperature negatively affected tuna catch, while salinity, DO, and chlorophyll had positive effects (F(4,13342) = 310.56, p < 0.001). This short-term study provides initial insights into tuna-prey-environment interactions. Future research should investigate long-term trends under climate change.1
Development of a Synonymous Codon Screening System Using Visual Reporters to select enhanced Marine Protein Expression
No full text2
Supply of Aged Organic Carbon on the Arctic Chukchi Sea Slope
No full textTo better understand the carbon cycling dynamics in the Arctic Ocean, which is undergoing rapid declines in sea ice extent and increasing temperatures, we examined sinking particles collected by bottom-tethered sediment traps deployed on the Chukchi Sea slope in the Pacific sector of the Arctic Ocean from 2017 to 2021. Sinking particle flux was high during the summer (June–September) and low during the winter (October–May), reflecting the characteristic seasonal variation in primary production. Additionally, two notable phenomena were observed: (a) substantial interannual variations in summertime particle flux and (b) a continuous supply of aged carbon throughout the year. The pronounced interannual variations in summertime particle flux were plausibly associated with the timing of sea ice retreat, subsequent ice-free periods, and associated biogeochemical processes. Aged particulate organic carbon, likely supplied by sediment resuspension and lateral transport, accounted for a considerable fraction of total carbon flux throughout the year, as evidenced by depleted radiocarbon isotopic compositions and relatively high contents of lithogenic material.11Nsciescopu
Impact of Different tidal Current Velocity Evaluation Methods on Tidal Energy Production Estimates in the Uldolmok Strait
No full textAccurate assessment of tidal current energy resources is essential for the design and feasibility evaluation of tidal energy farms, and this requires reliable calculation of current velocity. In this study, field measurements were conducted at three sites in Uldolmok, a candidate area for tidal energy development in Korea, using a bottom-mounted Acoustic Doppler Current Profiler (ADCP) to obtain layered tidal current data. Based on these data, the Instantaneous power-weighted tidal current velocity recommended in IEC TS 62600-200 was applied to estimate the
current velocity. This method calculates the average by cubing the tidal current velocity at each vertical bin within the turbine blade swept area and applying weighting according to the relative area of each layer. For comparison, two non-standard approaches were also applied, namely the all depth averaged current velocity and the simple average within the blade-swept region. Using the current velocities derived from these three methods, annual energy production (AEP) and capacity factor (CF) were estimated by applying two commercially available tidal turbines, namely MCT 1200 (1.2 MW) and HS 1000 (1.085 MW). Based on the site where the current velocity and AEP were highest among the three sites, the Instantaneous power-weighted tidal current velocity was up to 31.3% higher than the depth-averaged current velocity and 3.0% higher than the blade-averaged current velocity. For the MCT 1200 turbine, the AEP calculated using the non-standard methods were 892.22 MWh and 916.15 MWh, while the standard method yielded 921.63 MWh. The corresponding capacity factors were 66.03%, 67.80%, and 68.21%. Therefore, instead of relying on simple averaging methods, it is recommended to apply a more rational and theoretically valid approach for calculating the current velocity to ensure the economic viability and design reliability of tidal energy farms.
Keyword : Tidal current energy, Uldolmok, Tidal currernt velocity Corresponding Author. : Uk-Jae LEE ( [email protected] )1
Clay minerals and elemental composition of smectites in the marine sediment from the southwest Ross Sea and implication for their provenance and sediment input changes after the last glacial period
No full textSmectite in detrital sediments can be composed of various proportions of Al, Mg, and Fe, indicating the sediment sources derived from the bedrock or from the sedimentary strata. Comparing the elemental composition of smectites can help to define sediment provenance in relation to paleo-environmental changes, especially glacier retreat. However, few studies of mineralogical and geochemical properties of clay minerals in marine sediment from the southwest Ross Sea have been conducted. Here, this study investigates the clay mineralogy and elemental composition of smectites during the last glacial period to the latest Holocene sediment in cores RS15-GC16B (southern Drygalski Trough), RS15-GC78 (offshore of Mawson Glacier), and RS15-GC80 (Mackay Glacier front) deposited in the southwest Ross Sea sector. It might be necessary to understand variabilities and distribution of elemental compositions in smectites in the southwest Ross Sea and their provenance, and to reconstruct sediment transport through the glacier changes. Indeed, two types of smectite (Al-rich and Al–Fe rich) were identified in core RS15-GC16B from the southern Drygalski Trough, indicating that some sediments were supplied from glaciogenic debris containing Al–Fe rich smectite by the northward advance of the East Antarctic glacier during the glacial period. In contrast, only Al-rich smectite in core RS15-GC16B (the southern Drygalski Trough) were identified during the deglacial period. Al-rich smectite is probably originated from subglacial erosion of sedimentary strata from the David Glacier. This finding implies different sources during glacial and deglacial period deposited at core RS15-GC16B, although that show only minor difference in smectite contents. Overall, these results highlight importance of analysis of the elemental composition of smectites in tracing sediment sources and their transport pathways during the East Antarctic glacier retreat.11Ysciescopu
Feeding Habits of Starry Flounder, Platichthys stellatus in the Middle Coastal Waters off East Sea, Korea
No full text강도다리의 섭식생태를 위하여 2011년 3월부터 2012년 2월까지 동해 중부연안에서 총 366개체의 강도다리를 채집하였다. 강도다리의 전장 (Total length, TL)은 16.5~48.5 cm TL의 범위였다. 강도다리는 거미불가사리류 (Ophiuroidea), 어류 (Teleostei), 집게류 (Anomura), 갯지렁이류 (Polychaeta)를 주로 섭식하는 저서육식성어류였다. 그리고 이매패류 (Bivalvia), 게류 (Brachyura), 곤쟁이류 (Mysidacea)도 소량 섭식하였다. 강도다리는 성장과 계절에 따라서 주요 먹이생물이 변하였는데, 작은 개체들은 곤쟁이류와 갯지렁이류를 주로 섭식하였으나, 성장함에 따라 곤쟁이류와 갯지렁이류의 비율은 감소하였고, 어류와 거미불가사리류가 차지하는 비율이 증가하였다. 계절에 따라 봄에는 집게류의 비율이 높았고 여름과 가을에는 거미불가사리류의 비율이 높았으며, 겨울에는 어류의 비율이 높았다. 다변량분석 결과 강도다리의 위내용물 조성은 체장과 계절에 따라 유의한 차이를 보였다. 어류는 큰 체장군의 위내용물 조성에서 기여도가 높았지만 갯지렁이류와 곤쟁이류는 작은 체장군에서 높은 비율을 보여 큰 체장군과의 차이를 보여주는 특징적인 먹이생물이었다. Dietary breadth index는 성장함에 따라서 감소하였고, 여름에 높게 나타났다.22Nkc
Continuous culture methods of microorganism and their system using bubble removal reaction unit
No full text본 발명은 써모코커스 온누리누스 균주를 연속 배양하는 방법으로서, 상기 써모코커스 온누리누스 균주를 배양기에서 배양하는 단계 상기 배양기에서 생산된 배양액 중 상기 써모코커스 온누리누스 균주가 포함되거나 제거된 재순환액을 배양액순환용기를 거쳐서 상기 배양기에 투여하여 재순환시키는 단계 및 상기 배양기로부터 응축기를 통과한 거품을 버퍼탱크로 회수하여, 상기 버퍼탱크에서 배출되는 배양액을 상기 배양액순환용기에 공급하는 단계 를 포함하는, 거품 제거 반응부를 이용하는 연속 배양 방법과 이와 관련되는 시스템에 관한 것이다.
본 발명에 의하면, 써모코커스 온누리누스 균주에 대한 연속배양에서 거품이 일정시간 사라질 수 있도록 정치해 놓아서 자연스럽게 거품이 제거된 배양액이 배양조로 재공급되도록 함으로써, 소포제의 사용없이도 거품의 제거를 가능하도록 하고, 운전 비용을 감소시킴과 아울러, 경제성을 높일 수 있으며, 배지의 공급량을 낮춘 상태에서 안정적인 운전이 가능하도록 하는 효과를 가진다
Distribution, abundance and grazing impact of Salpa fusiformis, with response to environmental conditions and their effects on other zooplankton species in Korean waters
No full textThe highly abundant pelagic tunicate Salpa fusiformis blooms in the Korean Peninsula. In this study, we examined the composition of mesozooplankton species and the environmental parameters in the S. fusiformis bloom areas in the East China Sea, the East Sea and the South Sea to understand the possible reasons behind this bloom. Salps abundance ranged from 0 to 547 ind. m−3 in the East China Sea, 0 to 161 ind. m−3 in the East Sea and 0 to 124 ind. m−3 in the South Sea. High salp abundance was associated with elevated chlorophyll a concentration and a shallow thermocline, particularly in regions where chlorophyll a concentrations did not exceed 1.5 μgL−1. Other mesozooplankton abundance was negatively correlated to salp abundance. Salp clearance rate estimated from Chl a concentration of the water ranged from 0.74 to 2.1 L ind.−1 h−1, and the grazing impact of salps was as high as 68.7% of the primary production at station J3 with moderate to high salp abundance in the South Sea. Salp ingestion rate positively correlated with both salp length and volume. The results suggest that episodic blooms of the salps can play a significant role in shaping the distribution of the plankton community and potentially carbon flux in this region.11Nsciescopu
Water column correction for coral reef habitat mapping using high spatial resolution remote sensing image technology
No full textCoral reefs play a significant role in marine ecosystems, but are increasingly facing degradation, primarily due to ocean warming. Effective monitoring and management methods are crucial for the conservation and rehabilitation of these ecosystems, and accurate mapping is essential for monitoring and conserving coral reef ecosystems. Utilizing remote sensing data is an effective approach to achieve high-quality maps. However, water column interference can disturb the reflected signal in remote sensing data. In this study, depth-invariant index (DII) transformation was applied to perform water column correction on high-resolution multispectral data from the QuickBird sensor, focusing on the coral reefs around Weno Island, Micronesia. Habitat classification was performed using an object-based image analysis method with additional in-situ measurements. The classification performance was evaluated using error matrices and kappa statistics.1
The potential of Spirulina maxima extract-treated conditioned medium from adipose-derived mesenchymal stem cells for hair growth promoting effect on human dermal papilla cells
No full textIntroduction: Therapeutic applications using adipose-derived mesenchymal stem cells (ADMSCs) have been highlighted as an attractive option to treat multiple diseases. It is widely accepted that ADMSCs exhibit their curative effects on hair loss via diverse secretory factors which promote hair follicle growth and remodeling of hair growth cycle. Recently, further studies using marine resources have been carried out to stimulate ADMSCs, enhancing both the quantitative and qualitative secretion to obtain more effective ADMSCs-derived conditioned medium (ACM). Methods: Our study investigated the effects of Spirulina maxima on cell proliferation in ADMSCs and determined optimal treatment condition. Human growth factor array was performed to evaluate the effects of S. maxima treatment on the alterations of growth factors secretion in ADMSCs. Subsequently, we examined the effects of S. maxima-treated ACM (SACM) on cell proliferation and alkaline phosphatase (ALP) activity in human dermal papilla cells (HDPCs). The underlying mechanisms of hair growth promotion effect of SACM was illustrated by confirming the expression levels of proteins related to mTOR/Akt and Wnt/β-catenin signaling pathway. Results: S. maxima extract promoted cell proliferation in ADMSCs and stimulated the secretion of fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF). SACM treatment also increased cell proliferation and ALP activity in HDPCs, similar with those of ACM treatment. Furthermore, SACM significantly enhanced in vitro hair growth promotion by activating mTOR/Akt and Wnt/β-catenin signaling pathway. Conclusion: SACM could be a more effective regenerative therapy for the promotion of hair growth and might have the potential to utilizing in pharmaceutical and cosmeceutical industries compared to non-treated ACM, suggesting the potential of S. maxima as an ADMSCs-preconditioning agent. © 2025 The Author(s)11Ysciescopu