DSpace Collection:

Wind-Induced Topographic Rossby Waves in the Southwestern Slope of the Chukchi Abyssal Plain

2026-01-14T07:39:20Z

Title: Wind-Induced Topographic Rossby Waves in the Southwestern Slope of the Chukchi Abyssal Plain Authors: Ku Ahyoung; Donohue Kathleen A.; Watts D. Randolph; Kim Kiduk; Song Hajin; Jeon Chanhyung; Park, Taewook; Cho, Kyoung-Ho; Peacock Thomas; Park Jae-Hun Abstract: Near-bottom currents collected over 1 year (August 2021-22) using a current- and pressure-recording inverted echo sounder (CPIES) at a depth of 1060 m showed fluctuations within a frequency band between 2 and 6.5 days near the southwestern slope of the Chukchi Abyssal Plain. The amplitude of the fluctuations was approximately 8 cm s21 on average during the summer months and weakened to approximately 3 cm s21 between February and June 2022. Similar fluctuations were reproduced by the data-assimilated Hybrid Coordinate Ocean Model (HYCOM), confirming that they were bottom intensified. Calculations of the bottom-trapping scale using HYCOM revealed that these fluctuations could be attributed to topographic Rossby waves (TRWs) with a length scale of approximately 50 km. The spatial distributions of TRWs in HYCOM and ray-tracing results suggest that TRWs likely propagated from the west-southwest. It is suggested that these TRWs were triggered by nonlocal wind stress curl (WSC), 220 km to the west along the continental slope, as the coherence in the TRW frequency band between the TRWs and WSC was significant. The weaker TRW signal from February to June 2022 was related to weaker WSC and higher sea ice concentration in the study area. The stronger TRWs from July to October occurred when the WSC was stronger and the sea ice concentration was lower in the study area. Our findings imply that changes in the Arctic WSC field or a longer sea ice-free season could trigger more energetic and frequent TRWs, observable down to 1000-m depth around the southwestern slope of the Chukchi Abyssal Plain.

Determining horizontal and vertical distributions of polar cod (Boreogadus saida) in the Bering Sea and western Arctic Ocean using traditional sampling and environmental DNA metabarcoding

2026-02-10T04:36:32Z

Title: Determining horizontal and vertical distributions of polar cod (Boreogadus saida) in the Bering Sea and western Arctic Ocean using traditional sampling and environmental DNA metabarcoding Authors: Gwak Woo-Seok; Kim, Jee-Hoon; Cho, Kyoung-Ho; Yang, Eun Jin Abstract: Boreogadus saida, commonly known as polar cod, is a key species in Arctic marine ecosystems that is also an indicator of environmental change. This study examined the spatial distribution of B. saida, which typically inhabits circumpolar waters ranging in temperature from-2 to 8 degrees C. Age classification based on size was performed on fish samples collected using ring nets, frame trawl nets, and hand nets. The results demonstrated that most individuals collected by ring and frame trawl nets in the southern Chukchi Sea (SCS) and East Siberian Sea (ESS) during late July and early August were age-0, while those collected in mid-August were age-1 and age-2. The individuals collected by hand net in the surface of the ESS and the northern Chukchi Sea (NCS) were all in age-1 and age-2 +. Smaller larvae collected in the ESS suggested local spawning grounds. Environmental factors, particularly temperature and prey availability, were found to influence habitat selection. To complement traditional sampling methods, environmental DNA (eDNA) metabarcoding using MiFish primers was conducted at various horizontal and vertical sites across the Bering Sea (BS), Chukchi Sea (CS), and ESS. B. saida eDNA was detected from surface waters to a maximum depth of 1804 mat temperatures ranging from-1.6 to 4.4 degrees C, which demonstrated the utility of eDNA for mapping both horizontal and vertical distributions. These findings highlight the value of integrating eDNA metabarcoding with conventional techniques to clarify B. saida's distribution and life history. They also emphasize the broader potential of eDNA monitoring as a sensitive, non-invasive framework for Arctic biodiversity assessment. Taken together, our results underscore not only the current distribution of B. saida but also the promise of eDNA as a foundation for long-term, ecosystem-wide monitoring in a rapidly changing Arctic.

Environmental and Ecosystem Changes in the Western Arctic Ocean: A Research Overview

2026-01-15T06:37:47Z

Title: Environmental and Ecosystem Changes in the Western Arctic Ocean: A Research Overview Authors: Yang, Eun Jin Abstract: 현재 북극은 전 지구에서 가장 빠른 속도로 온난화가 진행되면서 해빙이 급속히 소멸하고 있으며, 이는 기후 시스템과 해양환경, 생태계 전반에 중대한 영향을 미치고 있다. 이러한 변화는 단순한 환경 문제가 아니라 기후변화, 수산자원, 북극항로, 자원개발, 국제 지정학 등과 밀접하게 연관된 복합적 이슈로서, 전 지구 기후 안정성에 직접적인 영향을 미친다. 본 종설 논문은 쇄빙연구선 아라온을 활용한 서북극해 장기 현장관측, 해양계류장비, 퇴적물 트랩, eDNA 분석, 위성자료, 모델링 등 다중자료를 기반으로 북극 온난화가 초래한 서북극해의 해양환경？생태계 변화를 통합적으로 정리하였다. 연구를 통해 북극해의 대서양화가 서북극해 동시베리아까지 확장되었으며, 대서양수 확장이 해빙소멸을 가속화할수 있는 핵심 메커니즘임을 세계 최초로 확인하였다. 서북극해 식물플랑크톤은 규조류 중심에서 소형 편모조류 중심 구조로 전환되고 있었으며, 해빙하 대번성과 엽록소 최대층이 실제 일차 생산에 크게 기여함을 규명하였고, 해빙하 생태계가 북극해 탄소플럭스에 중요한 역할을 함을 제시하였다. 또한 조사해역에서 저산소？고산성화 수괴 등 새로운 생지화학적 이상 현상을 세계 최초로 규명하였으며, 대서양수 유입？담수화？해빙 감소 변화가 복합적으로 작용하여 서북극해 산성화가 빠르게 심화되고 있음을 확인하였다. 이러한 결과는 북극해가 물리？화학？생태계가 동시에 변화하는 전환기에 있음을 보여주고 있다. 향후 연구는 북극해 장기 모니터링 체계의 고도화, 국제공동연구 강화, 데이터 상호운용성 확보를 통해 예측 기반을 확립하고, 2029년 건조 예정인 차세대 쇄빙연구선을 활용한 집중 탐사를 통해 지속가능한 북극해 관리와 기후변화 대응을 선도하는 과학적 기반을 마련할 것이다.

Role of sea ice, stratification, and near-inertial oscillations in shaping the upper Siberian Arctic Ocean currents

2026-02-10T04:08:26Z

Title: Role of sea ice, stratification, and near-inertial oscillations in shaping the upper Siberian Arctic Ocean currents Authors: I.V. Polyakov; A.V. Pnyushkov; E.C. Carmack; M. Charette; Cho, Kyoung-Ho; S. Dykstra; J. Haapala; Jung, Jinyoung; L. Kipp; Yang, Eun Jin; S. Molodtsov Abstract: The Siberian Arctic Ocean (SAO) is the largest integrator and redistributor of Siberian freshwater resources and acts to significantly influence the Arctic climate system. Moreover, the SAO is experiencing some of the most notable climate changes in the Arctic, and advection of anomalous Atlantic-(atlantification) and Pacific-origin (pacification) inflow waters and biota continue to play a major role in reshaping the SAO in recent decades. In this study, we use a large collection of mooring data to create a coherent picture of the spatiotemporal patterns and variability of currents and shear in the upper SAO during the past decade. Although there was no noticeable trend in the upper SAO’s current speed and shear from 2013 to 2023, their seasonal cycle has significantly strengthened. The cycle reveals a strong relationship between upper ocean currents and their shear with sea ice conditions ？ particularly during transitional seasons ？ evidenced by a strong negative correlation (？0.94) between seasonal sea ice concentration and current shear. In the shallow (<20？30 m) summer surface mixed layer, currents have increased because strong stratification prevents wind energy from propagating into the deeper layers. In this case, strong near-inertial currents account for more than half of the summertime current speed and shear. In the winter, a thicker surface layer is created by deep upper SAO ventilation due to atlantification, which distributes wind energy to far deeper (>100 m) layers. These findings are critical to understanding the ramifications for mixing and halocline weakening, as well as the rate of atlantification in the region.