but interpretation and application of the relevant provisions differ, and the views expressed on them still leave ample room to be unilaterally interpreted and applied. So, it is undeniable that conflicts over ocean waters among the concerned countries are serious and difficult to overcome. To solve these problems, the UNCLOS calls for the countries concerned to make every effort to enter into provisional arrangements of a practical nature. Korea and Japan have maritime boundary problems in the waters surrounding the Korean peninsula, and so, in order to solve those problems, both nations established a joint development zone (JDZ) in the East China Sea in 1974. The zone can be terminated in 2028. Therefore, this study examines and analyzes the impact of the JDZ agreement between Korea and Japan over the East China Sea as to the delimitations of the continental shelf/EEZ

We conducted a field survey from 2018 to 2020 to analyze the spatial distribution of phytoplankton communities at 13 stations in the East Sea. The diatom Chaetoceros curvisetus appeared as the dominant species in winter, and small flagellates less than 20 μm prevailed in all seasons except winter. The seasonal average range of the micro (>20 μm), nano (20 μm≥Chl-a>3 μm), and picophytoplankton (≤3 μm) was 20.6-26.2%, 27.1-35.9%, and 40.8-49.0%, respectively. The composition ratio of nano and picophytoplankton was high at the surface mixed layer from spring to autumn when the water columns were strongly stratified. Especially, the stability of the water mass was increased when the summer surface water temperature was higher than that of the previous year. As a result, the nutrient inflow from the lower layer to the surface was reduced as the ocean stratification layer was strengthened. Therefore, the composition ratio of nano and picophytoplankton was the highest at 77.9% at the surface mixed layer. In conclusion, the structure of the phytoplankton community in the East Sea has been miniaturized, which is expected to form a complex microbial food web structure and lower the carbon transfer rate to the upper consumer stage.

이 논문은 울릉도, 독도를 포함하는 동해 울릉분지 해저 화산그룹(가칭: 울릉도-독도 화산그룹)의 분화사를 복원 하고 미래 분화 가능성을 평가하기 위해 진행중인 육상-해양 복합 다중스케일 화산연구의 개념과 지금까지의 결과를 소개하는데 목적을 둔다. 다중채널 탄성파반사자료 해석을 통해 유추되는 울릉도-독도 화산그룹의 주 활동 시기는 대략 5-2.5 Ma로, 동쪽 끝의 이사부평정해산에서 처음 시작되어 서쪽의 울릉도로 전파된 것으로 해석된다. 울릉도의 육상부 는 5단계에 걸쳐 생성되었으며 최종 단계에 접어들어 폭발성 분화를 통해 폭 약 3 km의 칼데라 지형과 그 내부에 화 산돔을 형성하였다. 울릉도의 마지막 분화 산물인 알봉 화산돔과 그 하부의 수증기마그마성 분화로부터 기원된 층단위 N-1 화산쇄설층은 기존 포놀라이트질 마그마방으로 유입된 보다 염기성의 새로운 마그마의 분화로부터 생성되었다. 층 단위 N-1과 알봉 분석이 갖는 조면안산암질 전암조성은 기존 포놀라이트질 마그마방 하부에 존재한 고철질 집적암이 새로 주입된 마그마를 오염시킨 결과로, 그 자체가 마그마의 조성을 지시하지는 않는다. 층단위 N-1과 알봉 화산돔에서 확인되는 새로운 마그마 주입의 증거들은 최근 밝혀진 울릉도의 높은 지온구배 및 분화주기와 더불어 울릉도가 여전히 작동중인 마그마 배관체계를 갖는 활화산임을 암시한다.

Benthic harpacticoids were collected from the East Sea of Korea. Specimen were identified as members of the genus Robertgurneya Apostolov & Marinov, 1988 based on the following characteristics: the fourth segment of antennule with aesthetasc, antenna with three-segmented exopod, shape of mandible, and P1-P4 armature formula. Robertgurneya donghaensis sp. nov. is morphologically most closely related to R. simulans (Norman & Scott T., 1905) and R. similis similis (Scott A., 1896). However, R. donghaensis is characterized by the rostrum with a pointed tip, caudal rami about as board as the length of its inner edge, the first segment of the P1 endopod much longer than entire exopod, and the P5 exopod with five setae in male. The genus Robertgurneya is reported from Korean waters for the first time.

A new free-living marine nematode species of the genus Pseudosteineria Wieser, 1956 affiliated with the family Xyalidae is described based on specimens collected from the sediment of a subtidal benthic environmental habitat in the East Sea, Korea. Pseudosteineria varisetis sp. nov differed from its congeners by the combination of the following characteristics: a relatively long body (1,628-1,691 μm long in males), a circular amphideal fovea situated behind the subcephalic setae, the presence of lateral cuticular alae starting from behind the nerve ring, the presence of eight groups of long subcephalic setae, the presence of irregularly distributed variable lengths of somatic setae on the body, solid spicules (43.2-43.9 μm long) with a cephalated proximal end, a long tubular shaped gubernaculum with dorsal swelling, and a conico-cylindrical tail with two to four terminal setae. In this report, we provide a taxonomic description and illustrations of a new species of the genus Pseudosteineria by differential interference contrast microscopy.

Henricia specimen was collected from the East Sea of Korea using fishing nets. The specimen was identified as Henricia hayashii (Djakonov 1961), belonging to the family Echinasteridae of the order Spinulosida. This species can be distinguished from other Henricia species by slender arms (R/r=7.4), constricted arm base, six to thirtyfive slender spinelets, open-meshed, reticulated abactinal skeleton comprising semitriangular, rod-like form, and small ossicles present inside the papular areas. This species superficially resembles H. reniossa in terms of its body size but differs in the shape and arrangement of the abactinal and actinal plates. To date, two genera of Echinasteridae, Aleutihenricia and Henricia, including a total of 14 species, have been reported in Korea. Herein, the morphological characteristics of H. hayashii are described, and photographs are provided.

This study provides comprehensive assessment results for the most recent high-resolution regional climatology in the East/Japan Sea by comparing with the various existing climatologies. This new high-resolution climatology is generated based on the Optimal Interpolation (OI) method with individual profiles from the World Ocean Database and gridded World Ocean Atlas provided by the National Centers for Environmental Information (NCEI). It was generated from the recent previous study which had a primary focus to solve the abnormal horizontal gradient problem appearing in the other high-resolution climatology version of NCEI. This study showed that this new OI field simulates well the mesoscale features including closed-curve temperature spatial distribution associated with eddy formation. Quantitative spatial variability was compared to the other four different climatologies and significant variability at 160 km was presented through a wavelet spectrum analysis. In addition, the general improvement of the new OI field except for warm bias in the coastal area was confirmed from the comparison with serial observation data provided by the National Fisheries Research and Development Institute’s Korean Oceanic Data Center.

We determined the composition of water and sediment bacterial assemblages from the East Sea using 16S rRNA gene sequencing. Total bacterial reads were greater in surface waters (<100 m) than in deep seawaters (>500 m) and sediments. However, total OTUs, bacterial diversity, and evenness were greater in deep seawaters than in surface waters with those in the sediment comparable to the deep sea waters. Proteobacteria was the most dominant bacterial phylum comprising 67.3% of the total sequence reads followed by Bacteriodetes (15.8%). Planctomycetes, Verrucomicrobia, and Actinobacteria followed all together consisting of only 8.1% of the total sequence. Candidatus Pelagibacter ubique considered oligotrophic bacteria, and Planctomycetes copiotrophic bacteria showed an opposite distribution in the surface waters, suggesting a potentially direct competition for available resources by these bacteria with different traits. The bacterial community in the warm surface waters were well separated from the other deep cold seawater and sediment samples. The bacteria exclusively associated with deep sea waters was Actinobacteriacea, known to be prevalent in the deep photic zone. The bacterial group Chromatiales and Lutibacter were those exclusively associated with the sediment samples. The overall bacterial community showed similarities in the horizontal rather than vertical direction in the East Sea.

국내 및 국외에서 인간에 영향을 줄 수 있는 미세플라스틱에 대한 다양한 연구가 진행되고 있으며, 특히 가장 기초자료로 제공 될 수 있는 해양환경 중 미세플라스틱의 분포에 대해 연구가 많이 진행되고 있다. 국내에서도 해양환경의 분포 특성에 대한 연구가 진행 되었으나, 연안에 대한 연구만 국한 되어 연구가 진행되고 있다. 따라서 본 연구에서는 쿠로시 오해류 및 중국의 양쯔강 유입수의 영향이 다분할 것으로 판단되는 제주도 남서측 동중국 개방 해역에서 2020년 8월에 23 개 정점을 선정하여 표층해수 중에 환경자료인 수온 및 염분과 미세플라스틱의 풍도(abundance), 성상(재질), 형태, 크기를 분석하여 표층 해수에서 존재하는 미세플라스틱의 분포특성을 밝혀 해양환경 중 미세플라스틱의 기초자료를 제공하고자 하였다. 연구 지역에서 미세플라스틱의 풍도(abundance)는 0.17~1.37 (평균 0.46) particles/L를 나타내었으며, 성상(재질), 형태, 크기에서 PP 재질과 PE 재질이 작은 크기의 0.02~0.3 mm 분류군에서 조각(fragment) 형태로 우세하고, 이들 재질 다음으로 Alkyd 재질과 polyester 재질이 1.0~5.0 mm 분류군에서 섬유(Fiber) 형태로 우세하였다. 환경자료인 수온 및 염분을 이용하여 미세플라스틱의 분포 특성을 살펴보았는데, 여름철 강하게 발생하는 황해연안해류와 한국연안해류로 저 수온 및 저 염분이 유입되고, 여름철 강하게 발생하는 대만 난류와 쓰시마 난류의 영향으로 고 수온 및 고 염분이 유입되어 복합적으로 발생하는 지역으로 수온과 PE 재질, 0.02~0.3 mm 크기 분류군, 조각(Fragment) 형태에서 음의 상관성(PE : p <0.01, 0.02~0.03 mm : p <0.05, 조각(Fragment) : p <0.05)을 보여 0.02~0.3 mm의 조각(fragment) 형태인 PE 재질이 황해연안해류와 한국연안해류를 통해 유입될 가능성이 높은 것으로 판단되며, 염분과 PP, Polyester 재질에서 양의 상관성(PP : p <0.05, Polyester : p <0.05)을 보여 1.0~5.0 mm의 섬유(Fiber) 형태인 Polyester 재질이 대만난류 및 쓰시마 난류를 통해 유입될 가능성이 높은 것으로 판단 된다.

한반도는 삼면이 바다로 둘러싸여 있으며, 많은 강과 하천이 바다와 연결되어 있기 때문에 육상에서의 쓰레기 유입이 되기 쉽다. 또한 해상에서는 활발한 수산업 활동과 다양한 레저 활동으로 인해 쓰레기 유입이 많다. 바다에 유입된 쓰레기는 시간이 지남에 따라 무게가 가해져 가라앉아 해저에 침적하게 되며, 해저에 산재되어 있기 때문에 직접 확인이 불가능하고 수거에 어려움이 있다. 수거되지 못한 해양침적쓰레기는 해저 생태계 및 수질에 영향을 미치게 되며, 특히 폐그물로프와 폐어구로 인한 유령어업과 선박사고가 발생할 수 있다는 점이 있다. 따라서 해당 성상의 쓰레기들(폐그물로프와 폐어구)은 우선적으로 수거가 이루어져야하기 때문에 분포 특성을 파악할 필요가 있다. 그 일환으로 본 연구에서는 국내 39개 항을 대상으로 해양에 침적되어 있는 쓰레기 조사를 실시했다. 그 중 동해에 대해서 GIS 기반의 공간 분석을 통해 해양침적쓰레기 성상별 분포 지도를 작성하고, 분포 특성을 파악하였다. 결과적으로 동해에서 폐타이어가 58 %로 구성되었고, 방파제 및 선박 접안 시설에 분포가 밀집되었다. 그리고 폐합성수지가 26 %로 구성되어 항외에도 분포가 있었다. 각 성상별 뚜렷한 분포 특성을 파악하기는 어려웠지만 폐합성수지가 다른 성상들과 비교해 항외에 분포되는 특성이 있었다. 본 연구는 이와 같은 분포 특성을 통해서 해양침적쓰레기 수거에 도움이 될 기초 자료로 제공될 수 있다.

This study aims to face common threats from the depletion of fish resources, the decline of production and employment as well as the increase of life risk in East Sea Rim countries, North Korea, South Korea, Japan and Russia due to the Chinese fishing fleets entering East Sea. The recent competition in fishing among fishing vessels and fleets of national origin operating in the East Sea has induced a significant change in the ecological landscape of the fishing fleets cluster while having influenced production and employment in the fishing industries of South Korea and Japan as well as life threat on the fishermen in North Korea. It seems that the population organizational ecological theory can be applied to this change. It can be seen as the isomorphism of the selection process over the exclusive economic zone (EEZ) to avoid the environment in which these North Korean fishing vessels are pushed against the Chinese fleet in the North Korean part of the East Sea. To resolve the fishery disputes or conflict in the common waters in East Sea, first of all, Chinese fishing fleets will be required to put international pressure so as to solve the unfairness of the illegal fishing and overfishing by the International Fishery Organization or the UN violations of the sanctions against North Korea selling fishing rights to China. Although it is not easy for South Korea to cooperate with North Korea in the short term, South Korea will be able to support the fishery infrastructure in North Korea in the mid- to the long-term to prevent the loss of innocent lives for their fishermen and to raise their incomes.

A new free-living marine nematode species of the genus Belbolla Andrássy, 1973 belonging to the family Enchelidiidae is described based on specimens collected from the sediment of a subtidal benthic environmental habitat in the East Sea, Korea. Belbolla wonkimi sp. nov. differs from its congeners by the combination of the following characteristics: a relatively long body (3263-3396 μm), the absence of ocelli, nine oesophageal bulbs in the posterior pharynx, well-developed two winged precloacal supplements, longer spicule length (115-130 μm, 1.6-1.8 anal body diameter long), and a triangle-shaped shorter gubernacular apophysis (17-18 μm). Comparative tables on the biogeographical and morphological characteristics of Belbolla species are presented. A DIC (differential interference contrast) photomicrograph of the new species is also provided. This is the first taxonomic report on the genus Belbolla from Korean waters.

Henricia specimens were collected using fishing nets from the East Sea of Korea. The specimens were identified as Henricia oculata Pennant, 1777, belonging to the family Echinasteridae of the order Spinulosida. This species can be distinguished from other Henricia species by broad arms (R/r=4-4.1), rough skin, a thick arm base, three to nine minute delicate abactinal spines, and inferomarginal plates reniform in shape. This species superficially resembles H. pachyderma in its body size and wide papular areas but differs mainly in the number of papulae and abactinal spines, and the shape and arrangement of the inferomarginal plates. To date, two genera of Echinasteridae, Aleutihenricia and Henricia, with a total of 13 species, have been reported in Korea. The morphological characteristics of H. oculata are described, and photographs are provided.