Evidence for Hydrothermal Plume in Manus Basin, SW Pacific: Distribution of Transparency and Hydrogen Sulfide

남서태평양 열수해역의 화학적 환경특성을 이해하기 위하여 수온, 염분, 투명도, pH, 영양염 및 황화수소 등을 분석하였다. 시료는 마누스분지의 12개 정점에서 CTD를 이용하여 채취하였다. 열수작용은 해수 및 암석간의 순환작용에 의해 이들의 물리, 화학적 특성을 변화시키고, 주변의 해수와는 특성이 다른 열수가 plume을 형성하여 해양으로 공급된다. 본 연구에서는 남서태평양 PACMANUS 해역과 Susu Knolls 해역에서 투명도 및 황화수소를 이용하여 열수작용에 의한 plume을 확인하였다 특히, 열수환경을 지시하는 지화학적 추적자인 황화수소는 0 ∼ 3.31 μ M 범위와 평균 0.63 μ M을 보였다. 열수작용에 의한 plume의 높이, 분출량 및 활동도는 저층해류 순환 등의 영향을 받으며 수층의 등밀도면을 따라 주변 해수로 확산된다. 결과적으로 연구 해역에서의 황화수소 농도 이상치는 열수작용에 의한 영향으로 판단되고, 따라서 PACMANUS 해역의 남북방향에 가장 큰 공급원이 있을 것으로 보인다. To understand and investigate chemical characteristics of thermal environment in the southwestern Paciflc, we have measured hydrological and chemical parameters such as temperature, salinity, transparency, pH, nutrients and hydrogen sulfide (H 2 S). Samples were collected with CTD-casting at 12 station, in Manus Basin including PACMANUS, DESMOS and Susu Knolls, Hydrothermal systems consist of circulation zones where seawater interacts with rock, thereby changing chemical and physical characteristics of both the seawater and the rock. The altered seawater, called hydrothermal fluid, is injected back into the ocean from the hydrothermal vent fields and forms hydrothermal plumes. Consequently, we detected hydrothermal plume with transparency and sulfide anomalies at PACMANUS and Susu Knolls. Sulfide, as geochemical tracer of hydrothermal plume, ranged 0-3.31 μ M, and averaged 0.63 μ M in the study area. The height, flux and activity of the plume are affected by circulations in the deep water and the spread of plume follows along the isopycnal surface. Therefore the observed H 2 S anomaly can provide important clue for the source location and it appears that the targestsource in the PACMANUS is aligned in the north-south direction.33Nkciothe

Environment analysis of Kwangyang Bay after marine oil spill

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살아있는 세포와 동물에서 시냅스의 실시간 시각화를 위한 방법 개발

학위논문(박사) - 한국과학기술원 : 생명과학과, 2024.2,[iii, 66 p. :]The structural plasticity of synapses is a fundamental mechanism regulating brain functions. However, currently available methods, based on split fluorescent proteins (FPs), have been limited in assessing synaptic dynamics in vivo due to the irreversible binding of split FPs. Here, we develop ‘SynapShot’—a method for visualizing the structural dynamics of intact synapses by combining dimerization-dependent fluorescent proteins (ddFPs) with engineered synaptic adhesion molecules. SynapShot allows real-time monitoring of reversible and bi-directional changes of synaptic contacts under physiological stimulation. The application of green and red ddFPs in SynapShot enables the simultaneous visualization of two distinct populations of synapses. Notably, the red-shifted SynapShot is highly compatible with blue light-based optogenetic techniques, allowing for the visualization of synaptic dynamics while precisely controlling specific signaling pathways. Furthermore, we demonstrate that SynapShot enables real-time monitoring of structural changes in synaptic contacts in the mouse brain during both primitive and higher-order behaviors.한국과학기술원 :생명과학과

Studies of Geochemical Characteristics of Hydrothermal Particles: A new challenge in the Central Indian Ridge

KIOST (Korea Institute of Ocean Science and Technology) has been studying hydrothermal vent systems in the south Tonga arc and in the north Fiji basin, aiming to understand the nature of hydrothermal effluent, sinking particles, and the underlying mineral deposits. We plan to initiate a study of the Central Indian Ridge (CIR) that is less well studied. In this presentation, we briefly introduce the findings of our previous studies and our plan to study the CIR. In the south Tonga arc, we examined biogeochemical properties of sinking particles collected via short-term sediment trap deployments around a hydrothermal vent field. Contribution of non-biogenic materials was over 72 % with the concentrations of excess metals such as Fe, Mn, Cu, and Zn being very high. The elemental ratios of sinking particles in the Tonga arc were similar to those of the divergent plate boundary in the East Pacific Rise. In the north Fiji basin, we collected sinking particles deployed at four locations of increasing distance from an active hydrothermal vent site. The particle flux decreased with increasing distance. This trend was consistent with the results reported in the East Pacific Rise. Compositionand other geochemical characteristics of the sinking particles are being examined at the moment. A poorly understood region of the global hydrothermal system is the CIR. We have carried out rudimentary explorations to understand the nature1

북서태평양 해역에서 탄산염 화학종에 근거한 산성화 평가

북서태평양 마젤란 해저산 해역에서 탄산염 화학종(총알칼리도(TA), 용존무기탄소(DIC), pH 등)들의 분포 특성을 비교·분석하여 연구해역의 산성화 진행정도를 파악하였다. 현장 조사는 2014년 10월에 150.09°E 선상의 19.43°N∼20.17°N 사이에서 평균 16 km 간격으로 5개 정점을 선정해 진행되었다. 각 정점별로 최대 수심은 1778 m에서 3290 m로 관측되었다. 탄산염 화학종의 측정을 위해 사용된 방법은 개선된 one point titration으로, 채취된 시료는 현장 선상 실험실로 옮겨 분석하였다. 획득한 자료는 스크립스 해양연구소에서 제조한 CRM(Batch 132)을 분석해 보정하였다. 분석 결과, 연구 해역의 TA(최소 2223.06 μmol/kg, 최대 2426.44 μmol/kg) 및 DIC(최소 1839.91 μmol/kg, 최대 2395.93 μmol/kg) 농도는 저위도에서 고위도로, 표층에서 저층 방향으로 갈수록 증가하는 경향을 보였다. TA 농도의 최소값은 수심 약 500 m에서 나타났고, 최대값은 수심 약 2000 m에서 관측됐다. DIC의 농도는 표층에서 최소값이 확인되었으며, 수심 2200 m 정도에서 최대값을 보였다. △TA와 △DIC의 상관성을 통해 연구 해역의 총이산화탄소 변화를 제어하는 주요 요인을 확인한 결과, 표층에서는 생물에 의한 광합성/호흡이 우세하였고, 저층에서는 탄산칼슘(CaCO3)의 생성/용해 과정이 우세한 것으로 판단되었다. 위의 자료들을 종합하여 산석(aragonite)과 방해석(calcite)의 포화 수심(Ω=1)을 추정하였다. Aragonite의 포화 수심(Ωara)은 600∼700 m에서 확인되었고, Calcite의 포화 수심(Ωcal)은 전 수층에서 과포화된 상태를 보였다. 이는 기존 연구결과와 부합하는 것으로, 본 연구해역의 Aragonite 포화수심은 약 600 m, Calcite 6 km 간격으로 5개 정점을 선정해 진행되었다. 각 정점별로 최대 수심은 1778 m에서 3290 m로 관측되었다. 탄산염 화학종의 측정을 위해 사용된 방법은 개선된 one point titration으로, 채취된 시료는 현장 선상 실험실로 옮겨 분석하였다. 획득한 자료는 스크립스 해양연구소에서 제조한 CRM(Batch 132)을 분석해 보정하였다. 분석 결과, 연구 해역의 TA(최소 2223.06 μmol/kg, 최대 2426.44 μmol/kg) 및 DIC(최소 1839.91 μmol/kg, 최대 2395.93 μmol/kg) 농도는 저위도에서 고위도로, 표층에서 저층 방향으로 갈수록 증가하는 경향을 보였다. TA 농도의 최소값은 수심 약 500 m에서 나타났고, 최대값은 수심 약 2000 m에서 관측됐다. DIC의 농도는 표층에서 최소값이 확인되었으며, 수심 2200 m 정도에서 최대값을 보였다. △TA와 △DIC의 상관성을 통해 연구 해역의 총이산화탄소 변화를 제어하는 주요 요인을 확인한 결과, 표층에서는 생물에 의한 광합성/호흡이 우세하였고, 저층에서는 탄산칼슘(CaCO3)의 생성/용해 과정이 우세한 것으로 판단되었다. 위의 자료들을 종합하여 산석(aragonite)과 방해석(calcite)의 포화 수심(Ω=1)을 추정하였다. Aragonite의 포화 수심(Ωara)은 600∼700 m에서 확인되었고, Calcite의 포화 수심(Ωcal)은 전 수층에서 과포화된 상태를 보였다. 이는 기존 연구결과와 부합하는 것으로, 본 연구해역의 Aragonite 포화수심은 약 600 m, Calcite2

The axial valley morphology and related hydrothermal activities at the Central Spreading Ridge, the North Fiji Basin

Korea Institute of Ocean Science and Technology (KIOST) has conducted an expedition to delineate distribution patterns of seafloor massive sulfides and its geotectonic background over a spreading ridge (Central Spreading Ridge CSR) and a triple junction in North Fiji Basin for 52 days from 23 October to 13 December 2016. Based on the previous surveys, the exploration concentrated on the KF 2 and KF3 regions that had shown the high chance of seafloor hydrothermal activity among the three regional sites (KF 1, KF 2 and KF 3) in Fijian EEZ. KF2 is situated next triple junction to the south and KF3 is located along spreading center at the southern part of the CSR. High-resolution mappings over the KF2 reveal the high land that probably formed by the mass eruption of basaltic lava and the abyssal hills by tectonic extension, resulting in graben structure. The very next region of the triple junction is featured by pit crater of approximately 1.8 km in diameter. The pit crater is likely to be formed by disruption of the large basalt tube. The clear boundary of a crater and abyssal-hill fabric and their connectivity to the outer part of crater indicate the crater was developed after tectonic extension. Whereas the obvious abyssal hill fabric in KF3 is rarely traced but NS-trending lineaments are well observed instead, which corresponds to a set of fracture zones. The NS-trending fractures are characterized by a pull-apart riple junction in North Fiji Basin for 52 days from 23 October to 13 December 2016. Based on the previous surveys, the exploration concentrated on the KF 2 and KF3 regions that had shown the high chance of seafloor hydrothermal activity among the three regional sites (KF 1, KF 2 and KF 3) in Fijian EEZ. KF2 is situated next triple junction to the south and KF3 is located along spreading center at the southern part of the CSR. High-resolution mappings over the KF2 reveal the high land that probably formed by the mass eruption of basaltic lava and the abyssal hills by tectonic extension, resulting in graben structure. The very next region of the triple junction is featured by pit crater of approximately 1.8 km in diameter. The pit crater is likely to be formed by disruption of the large basalt tube. The clear boundary of a crater and abyssal-hill fabric and their connectivity to the outer part of crater indicate the crater was developed after tectonic extension. Whereas the obvious abyssal hill fabric in KF3 is rarely traced but NS-trending lineaments are well observed instead, which corresponds to a set of fracture zones. The NS-trending fractures are characterized by a pull-apart1

북동태평양 해역의 용존자유 아미노산 분포 및 조성연구

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Overview of Korean activities on seabed mineral resources and environmental impact assessments for mining

In the last few decades, there has been an increasing interest on the development of seabed mineral resources (such as polymetallic nodules, ferro-manganese crusts, and massive sulfides) due to limited land resources and rapidly increasing industrial demands. Therefore, international seabed authority has been issued more than 18 exploration licenses to the contractors (private companies or nations) for the last 5 years. Currently, Korean government has four exploration licenses: two in the international waters (each one in CCZ and Indian Ridge) and two licenses in the national jurisdiction waters (EEZ) (each one in the EEZ of Fiji and Tonga). At the same time, there are also growing concerns on the environmental impacts by the seabed mining. Thus, the environmental regulations have been getting tightened and strict. All contractors have to conduct Environmental Impact Assessments which are pre-requisite before applying for the exploitation license. We have also been carried out environmental studies including environmental baseline studies in our exploration contracted regions to better manage, mitigate, or/and minimize the mining impact on marine environments. The results of these environmental studies have been published in peer-reviewed journal and most of environmental data obtained from the international waters have been provided to ISA.2

Sediment magnetism and plaeo-depositional environment of deep-sea sediments from KODOS area in the northeastern equatorial Pacific

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Hydrothermal plume along the northern Central Indian Ridge, 8°S - 17°S: Magmatic and tectonic control on hydrothermal activity at slow-spreading ridge

CTD/MAPR profiles collected on 118 vertical casts on the slow-spreading Central Indian Ridge (8°S&#8211 17°S) reveal that hydrothermal plumes were most commonly associated with the asymmetric ridge sections where ultramafic massifs formed along one ridge flank near ridge-transform intersections or nontransform offsets (NTOs). The combined plume incidence for axial and valley wall casts, ph=0.30, is consistent with the existing global trend. This agreement confirms that thelong-term magmatic budget of the CIR is the primary control on the spatial frequency of hydrothermal venting at this slow spreading ridge. Because plume frequency was higher along asymmetrical than symmetrical ridge sections, permeability likely controls where venting is expressed. The occurrence of hydrothermal plumes at six locations on the axial flanks indicates that such cooling can also produce vent sites far off axis, perhaps fed by fluids channeled along detachment faults.ed along one ridge flank near ridge-transform intersections or nontransform offsets (NTOs). The combined plume incidence for axial and valley wall casts, ph=0.30, is consistent with the existing global trend. This agreement confirms that thelong-term magmatic budget of the CIR is the primary control on the spatial frequency of hydrothermal venting at this slow spreading ridge. Because plume frequency was higher along asymmetrical than symmetrical ridge sections, permeability likely controls where venting is expressed. The occurrence of hydrothermal plumes at six locations on the axial flanks indicates that such cooling can also produce vent sites far off axis, perhaps fed by fluids channeled along detachment faults.1