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Magnetic and Geochemical Evidence of Late Pleistocene Oceanographic Shifts in the Ross Sea Continental Margin
No full textThe Antarctic continental margin preserves essential sedimentary archives of ice-ocean interactions in response to climate variability. This study combines sedimentological, geochemical, and magnetic proxies to investigate late Pleistocene oceanographic changes in the western Ross Sea. Magnetic and geochemical data indicate magnetite and manganese depletion under reducing conditions below ~365 cm core depth, evidenced by lower magnetic concentration and Mn/Fe, and higher Fe/magnetic susceptibility ratios. The magnetite dissolution significantly debilitated remanent magnetization intensity, underscoring the need for caution in paleomagnetic reconstructions in the Antarctic margin; this may also be the case in sediments straddling the redox boundary. Sedimentary features within the reducing interval include laminated contourites with elevated organic carbon content and C/N ratios, along with enhanced carbonate preservation, suggesting reworked shelf sediment deposition by stronger cross-slope currents and weakened Dense Shelf Water (DSW) outflows during ice sheet expansions. By contrast, the upper core section exhibits widespread oxic conditions, characterized by maghemitization and manganese precipitation, and diamictite facies with abundant ice-rafted debris. These findings suggest a significant transition in oceanographic conditions during the late Brunhes (~300 ka), driven by extensive retreat of the Ross Sea ice sheet and intensified DSW export.1
외우지 않아도 괜찮아 지구과학
No full text교과서 속 핵심 개념과 원리를 쉽고 재미있게 풀어내 지구과학의 기초를 탄탄하게 다지도록 돕는다. 국내 최초로 해양, 대기, 지질 각 분야의 전문가가 꼭 필요한 지식을 엄선하여 더욱 정확하고 신뢰할 수 있다는 것이 이 책의 특징이자 강점이다. 여기에 흥미진진한 스토리와 과학으로 꽉 찬 100여 컷의 사이언티픽 일러스트가 더해져, 누구나 가볍게 손에 들고 지구과학 공부를 시작할 수 있다.
* 《외우지 않아도 괜찮아 지구과학》은 ‘물화생지 문해력 기르기’ 시리즈의 첫 권이며 ‘생물학’, ‘물리학’, ‘화학’이 출간 예정이다.Part 1 해양
바닷물은 왜 짤까? | 해수의 특성
러버덕이 세계 여행을 할 수 있었던 이유 | 해류와 해양 순환
우리가 마시는 해양심층수는 진짜일까? | 심층수와 동해 수괴
바닷속은 고요하지 않다 | 해양 내부파와 해양 혼합
바다에 도사린 위험 | 지진해일
바다가 따뜻해지면 | 해양 온난화
바다의 탄소순환이 기후를 좌우한다고? | 해양 탄소순환과 생물 펌프
먼바다에서만 일어나는 일인 줄 알았는데 | 인도양 쌍극진동
미래 기후의 힌트를 찾아서 | 고수온 복원과 고기후
해양학자의 임무 | 블루카본
모두의 관심이 필요한 바다 | 해양오염
해양에서 일어나는 일을 이해하려는 노력 | 현장 해양관측, 우리나라 해양사
Part 2 대기
둥근 모양으로 기울어져 자전하는 일이 만들어낸 것 | 날씨, 기후
대기의 상태와 운동 | 수치모델
기상청 vs. 윈디 | 예보
더욱 중요해지는 기상관측 | 관측, 자료동화
태풍이 많이 생기는 곳 | 북서태평양 태풍 활동 특성
적도 태평양을 모니터링하는 이유 | 엘니뇨와 라니냐
지구온난화와 자연 변동성의 합작 | 자연 변동성과 인간 활동의 복합적 영향
변동성 증가와 우리의 대응 | 기상재해
Part 3 지질
그때 그 흙 먹던 아이는 | 토양
돌 보기를 돌같이 | 광물과 암석
돌, 돌 무슨 돌 | 화성암과 광물 관찰
공룡은 판 이동속도에 미끄러져 익사했나요 | 판의 이동
감자지구설 | 지오이드
땅속에 치는 파도 | 변성작용
티끌 모아 태산 | 쇄설성 퇴적암
바다가 만든 돌 | 탄산염 퇴적암
라떼는 말이야 | 지질시대 대홍수
푸르른 초원의 사하라 | 기후변화
용어 설명 | 참고 자료 및 그림 출처 | 찾아보
Evaluation of the parameters of size distribution of emitted aerosols for simulation of radionuclides atmospheric transport following Fukushima accident using FLEXPART model
No full textIn this study, the FLEXPART atmospheric transport model was used to simulate the atmospheric transport of Cs-137 following the Fukushima NPP accident in March 2011, using the source term estimation described in [1]. The simulation results were compared with airborne concentration measurements conducted in Japan and globally. It was shown that FLEXPART results as compared to Fukushima are highly sensitive to assumptions regarding size distribution of the radioactivity in the source. Based on our study, 'conventional' assumptions regarding the mean aerodynamic diameter (MAD) of particles, which are typically reported in the range of 0.2 to 0.7 μm in various
studies, yielded reasonable agreement between simulated and observed concentrations within Japan. However, at greater distances from the source (e.g., across Eurasia), our results showed that the calculated concentrations were significantly overestimated. As discussed in our study, the size distribution of particles in the plume evolves over time. Therefore, measurements of AMAD conducted in Europe [2], which report a similar range of AMAD values, may not be representative enough to determine the initial AMAD at the source. To address this, we curve-fitted the observed size distribution of emitted particles measured in Japan shortly after the accident, as presented in
[3]. This approach resulted in the following estimates for the size distribution: AMAD ≈ 2.5 μm and geometric standard deviation (GSD) ≈ 1.8. Simulations conducted with these updated size distribution parameters showed significant improvement in the agreement between calculated and observed airborne concentrations, as compared to using conventional assumptions.1
이어도 해양과학기지 20년 장기 관측 자료로 본 동중국해 기후변화
No full text동중국해는 가속화된 온난화와 다양한 해양-대기 현상이 나타나는 기후민감 해역으로 실시간 모니터링이 필수적이다. 2003년 설립된 이어도 해양과학기지(I-ORS)는 OceanSITES에 등록된 최초의 대륙붕 관측 플랫폼으로서 20년간 해양환경 변화를 지속적으로 관측 중이다. I-ORS에서 측정된 표층 수온은 전지구 평균(10년당 0.25°C)의 2배인 10년당 0.5°C씩 상승하고 있다. 또한 해양열파는 2021년 이후 빈도와 강도가 급증하여, 2024년에는 관측 이래 최다인 63일간의 심각 수준 해양열파를 기록했다. 따라서 I-ORS의 20년 관측 자료는 동중국해의 기후변화 민감성을 명확히 보여주며, 이 해역의 미래 기후 영향을 이해하고 대응하기 위해 지속적인 모니터링이 중요함을 강조한다.2
Seasonal and interannual variations in material transport in the Korea Strait originating from the Taiwan Strait
No full textUnderstanding the variability in material transport from the Taiwan Strait (TS) to the Korean Strait (KS) is crucial for predicting ecological changes and the spread of marine debris in the East Asian Marginal Seas (EAMS). However, the dynamic variability of this transport remains poorly understood. In this study, we investigated the dynamic variability of material transport from the TS to the KS, using a Lagrangian particle-tracking system coupled with a three-dimensional numerical model. The model results showed that particles originating from the TS most frequently passed through the KS in August, with distinct interannual variability. Our findings indicate that southerly winds enhance the sea surface height (SSH) gradient in the southwestern East China Sea (ECS) shelf region through surface Ekman transport, weakening cross-shelf offshore currents and preventing particles from being transported offshore. The interannual variability of southerly winds is associated with variations in SSH in the southwestern shelf region, thereby modulating material transport from the TS to the KS. Furthermore, southerly winds over the EAMS are found to strengthen during negative phases of the Pacific Decadal Oscillation, suggesting a potential linkage between material connectivity in the EAMS and large-scale climate indices. These findings reveal how physical processes govern material transport in the EAMS, offering valuable insights into the prediction of nutrient fluxes and pollutant dispersion.11Ysciescopu
LC-MS-Guided Isolation of Triterpene Glycosides from Holothuria atra: Structural Features Governing TRPA1 Inhibition
No full textThe LC-MS-guided separation of the extract from the sea cucumber Holothuria atra led to the isolation of 16 triterpene glycosides (1–16), including seven previously unreported derivatives consisting of three sulfated (1, 3, 5) and four nonsulfated congeners (12, 13, 15, and 16). Notably, compounds 15 and 16 feature a new aglycone structure bearing an 8(9),11(12)-diene scaffold. All isolates were evaluated for their inhibitory activity toward transient receptor potential ankyrin 1 (TRPA1). In addition, to investigate the structural features governing the activity based on wider chemical diversity, desulfated derivatives (17–19) and sapogenins (20–22) were obtained through the chemical modifications of natural saponins and evaluated for their activity. The tetracyclic aglycone scaffold and the structure of the side branch attached to C-20 were critical for activity, with sulfated glycoside 6, containing a 9(11)-holostene-3β, 12α, 17α-triol with a side branch bearing a 22-hydroxy group, being the most potent (IC50 1.4 μM). The findings of this study may provide valuable insights into designing TRPA1 antagonists based on saponins.11Nsciescopu
Examining Acoustic Characteristics of Bluefin Gurnard Chelidonichthys kumu Sounds with Passive Acoustic Monitoring (PAM)
No full text22Nkc
A dipole pattern bias in marine heatwave intensity in the Kuroshio Extension simulated by the CMIP6 models: a role of northward shift of the Kuroshio Current
No full textClimate models are essential for investigating and predicting marine heatwaves (MHWs), but their inherent biases pose challenges for accurately analyzing and projecting MHWs. As global warming intensifies, MHWs are expected to become more extreme, emphasizing the need for precise model evaluations and deeper understanding of the underlying causes of bias to improve MHW simulations. In this study, we evaluated the MHW intensity simulated by 30 Coupled Model Intercomparison Project Phase 6 (CMIP6) models in the North Pacific Ocean by comparing them with the optimum interpolation sea surface temperature (OISST) dataset over a 33 year period (1982-2014). Over 80% of the CMIP6 models showed a dipole-pattern bias in the mean MHW intensity over the Kuroshio Extension, characterized by overestimation to the north and underestimation to the south. Hierarchical clustering based on the spatial pattern of the intensity bias in the Kuroshio Extension identifies four distinct clusters: two showing a dipole-pattern bias with slightly different magnitudes and the other two showing weaker or stronger intensity. The separation latitude based on the maximum surface current revealed that the models with the dipole bias pattern simulated the northward overshooting of the Kuroshio Current. This northward overshooting likely enhanced the transport of warmer sea surface temperatures to higher latitudes, thereby intensifying the MHWs. These findings highlight the critical role of ocean currents in the simulation of MHW in the western boundary current regions, including the Kuroshio region.11Ysciescopu