• Title, Summary, Keyword: southwestern Pacific

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DNA Barcoding of Isaacsicalanus paucisetus (Copepoda: Calanoida: Spinocalanidae) from the Hydrothermal Vent in the North Fiji Basin, Southwestern Pacific Ocean

  • Park, Chailinn;Lee, Won-Kyung;Kim, Se-Joo;Ju, Se-Jong
    • Animal Systematics, Evolution and Diversity
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    • v.36 no.2
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    • pp.182-184
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    • 2020
  • Isaacsicalanus paucisetus Fleminger, 1983, a monotypic species of the family Spinocalanidae Vervoort, 1951, was first reported from a hydrothermal vent field in the East Pacific Rise off the mouth of the Gulf of California. The mitochondrial cytochrome oxidase I(mtCOI) DNA barcodes are considered a useful tool to assist traditional taxonomy and species discrimination in calanoid copepods. However, the mtCOI DNA barcodes of I. paucisetus have not been reported due to the species rarity and the difficulty of sampling. In this study, we firstly determined the mtCOI DNA barcodes of the I. paucisetus newly collected from a hydrothermal vent in the North Fiji Basin of the southwestern Pacific. All mtCOI DNA barcodes of I. paucisetus were identical and intraspecies variations of spinocalanid species were 0.0-3.0%. Interspecies and intergeneric variations were 13.4-25.2% and 16.7-24.1%, respectively. The DNA barcodes of I. paucisetus obtained in the present study would be helpful for understanding taxonomic relationships of widespread spinocalanid species.

Variations in species composition of fishes caught by trawl survey in the northwestern East Sea of Russian EEZ and southwestern East Sea of Korean EEZ (러시아측 동해 북서부 해역과 한국측 동해 남서부 해역 트롤 조사에 어획된 어류의 종조성 및 양적변동)

  • SOHN, Myoung Ho;YOON, Sang Chul;LEE, Sung Il;YOON, Byung Sun;CHA, Hyung Kee;KIM, Jong Bin;Kalchugin, Pavel;Solomatov, Sergey
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.3
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    • pp.355-369
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    • 2015
  • To examine species composition, abundance and biomass of fishes in the northwestern East Sea of Russian EEZ, trawl survey were conducted at 31 sampling stations from 2006 to 2008. Also, trawl survey were conducted at 21 sampling stations in the southwestern East Sea of Korean EEZ from 2006 to 2008. A total of 67 fishes were collected in the northwestern East Sea of Russian EEZ, a total of 39 fishes were collected in the southwestern East Sea of Korean EEZ. Among them, a total of 53 fishes were collected in the northwestern East Sea of Russian EEZ only, and a total of 25 fishes were collected in the southwestern East Sea of Korean EEZ only. Mean abundance per area which caught by trawl survey in the northwestern East Sea ranged from a high of $116,478inds./km^2$ in 2008 to a low of $19,737inds./km^2$ in 2006. And mean abundance per area in the southwestern East Sea ranged from a high of $89,129inds./km^2$ in 2006 to a low of $8,234inds./km^2$ in 2008. Mean biomass per area which caught by trawl survey in the northwestern East Sea ranged from a high of $11,333kg/km^2$ in 2008 to a low of $2,439kg/km^2$ in 2006. And mean biomass per area in the southwestern East Sea ranged from a high of $6,273kg/km^2$ in 2006 to a low of $1,062 kg/km^2$ in 2008. Cluster analysis, based on a Bray-Curtis similarity matrix of fourth root transformed data of number of species and individuals per area, showed division into three different groups by depth in the northwestern and southwestern East Sea.

DNA Barcoding for the Hydrothermal Vent Crab Austinograea Species (Crustacea: Bythograeidae) from the North Fiji Basin, Southwestern Pacific Ocean

  • Lee, Won-Kyung;Ju, Se-Jong;Hou, Bo Kyeng;Kim, Se-Joo
    • Animal Systematics, Evolution and Diversity
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    • v.35 no.1
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    • pp.30-32
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    • 2019
  • The brachyuran crab Bythograeidae Williams, 1980 is common in hydrothermal vent fields worldwide and has recorded to sixteen species of six genera. In this study, we firstly determined the cytochrome c oxidase subunit 1 (CO1) DNA barcodes for the fifth species of Austinograea, A. hourdezi, from hydrothermal vent regions of the North Fiji Basin in southwestern Pacific Ocean. All CO1 DNA barcodes of A. hourdezi were identical. The interspecies variations of three bythograeid genera were 10.9-13.3% for Austinograea, 6.6-15.7% for Bythograea, and 9.7% for Gandalfus. These results would be helpful to understand taxonomy of brachyuran crabs living in hydrothermal vent fields using CO1 DNA barcodes.

Distribution of Dissolved Organic Carbon (DOC) in the Southwestern East Sea in Summer

  • Kim, Tae-Hoon;Kim, Gue-Buem
    • Ocean and Polar Research
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    • v.32 no.3
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    • pp.291-297
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    • 2010
  • In the summer of 2008 (August 4-14), vertical and horizontal distributions of inorganic nutrients and dissolved organic carbon (DOC) were measured in the southwestern East Sea. Concentrations of DOC were determined for the first time in the southwestern East Sea using the high-temperature combustion oxidation (HTCO) method, and results were compared with those measured by another laboratory. Concentrations of DOC ranged from 58 to 104 ${\mu}M$ in the upper 200 m, showing a typical decreasing pattern with depth. Generally, concentrations of DOC were relatively lower, with higher nutrient concentrations, in the upper layer of the coastal upwelling zone. Concentrations of DOC ranged from 54 to 64 ${\mu}M$ in the deep Ulleung Basin (200-1500 m), and were higher than those in the Pacific and Atlantic oceans. In association with rapid vertical ventilation of the euphotic, this difference indicates a larger accumulation of semi-labile DOC in the deep East Sea than in the major oceans. A correlation between apparent oxygen utilization (AOU) and DOC in the deep ocean of the East Sea revealed that only a small portion (<10%) of the sinking DOC, relative to the sinking particulate organic carbon (POC), contributes to microbial degradation. Our results present an important data set of DOC in the East Sea, which plays a critical role in carbon cycle modeling and sequestration.

Change of Coastal Upwelling Index along the Southeastern Coast of Korea (동해 남부 연안용승지수의 변화)

  • SHIN, CHANG-WOONG
    • The Sea
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    • v.24 no.1
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    • pp.79-91
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    • 2019
  • Long-term trends and recent variations of upwelling index (UI), which affects significantly ecosystem in southwestern part of the East Sea, were investigated. The UI was calculated with the NCEP/NCAR reanalysis data from January 1948 to September 2018. The mean UI has positive value that causes upwelling in April to August with a peak in July. The long-term reducing trend of UI was in statistically significant in June and July, and the sum of UI in May, June and July also showed same result. Through the atmospheric pressure analysis around the Korean peninsula, it was found that the trend of the UI was the influence of the pressure change trend in the northwestern region ($35-50^{\circ}N$, $114-129^{\circ}E$) of the southwestern part of the East Sea. Investigating UI in recent 7 years from 2012 to 2018, it was revealed that the UI was bigger than 3 times of standard deviation in July 2013. This was result from the sea level pressure difference became larger in the southwestern part of the East Sea than normal year due to the lowered air pressure in the northeastern region of China and the strengthened high air pressure of western peripheral of the North Pacific High. On the other hand, the UI in July 2018 was negative when the impact of the North Pacific High and the low air pressure in the northeastern China was weak. Due to the decreasing trend of UI and its large year-to-year variation in southwestern part of the East Sea, continuous monitoring is necessary to know the influence of coastal upwelling on the ecosystem.

Redescription of Desmotimmia mirabilis (Timm, 1961) (Nematoda, Desmoscolecida, Desmoscolecidae) from South Korea

  • Chang, Cheon-Young
    • Animal Systematics, Evolution and Diversity
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    • v.24 no.2
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    • pp.199-203
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    • 2008
  • Desmotimmia mirabilis (Timm), a rarely known desmoscolecid nematode species, was discovered for the first time from the Yellow Sea off southwestern coast of Korea. This is the third record of the species, and the first report from the northwestern Pacific region. Redescription is prepared on the basis of a male specimen from South Korea.

Paleomagnetism of Deep-sea Core Sediment in Southwestern Pacific (남서태평양 심해분지 주상퇴적물의 지자기 층서 연구)

  • Moon, Jai-Woon;Kim, Ki-Hyune;Chi, Sang-Bum;Lee, Gun-Chang;Doh, Seong-Jae;Park, Cheong-Kee
    • The Sea
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    • v.6 no.3
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    • pp.135-141
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    • 2001
  • A paleomagnetic investigation was carried out to analyze magnetostratigraphic information and to evaluate the relationship between paleoenvironment and magnetic properties in sedimentary sequences of piston cores recovered from the abyssal basin of the southwestern Pacific. Pateomagnetic results revealed that the sediments had a stable remanent magnetization and recorded both normal and reversal polarities. The age of sediments was from late Pliocene and Pleistocene determined by matching the polarities with the geomagnetic time scale. The sedimentation rates were in the range of 0.63-1.85 mm/$10^3$ year which were extremely low rates. The results of the paleomagnetic analyses indicated that intervals of the magnetically stable layers as well as high value of susceptibility were significantly affected by the input changes which resulted input of large-quantity materials of relatively stable magnetic carriers.

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Geographic Distribution and Epidemiology of Lung Cancer During 2011 in Zhejiang Province of China

  • Lin, Xia-Lu;Chen, Yan;Gong, Wei-Wei;Wu, Zhao-Fan;Zou, Bao-Bo;Zhao, Jin-Shun;Gu, Hua;Jiang, Jian-Min
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.13
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    • pp.5299-5303
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    • 2014
  • Background: To explore etiology for providing scientific clues for the prevention of lung cancer. Materials and Methods: Data for lung cancer incidence and meteorological geographic factors from 25 counties in Zhejiang province of China during 2011 were studied. Stepwise multiple regression and correlation analysis were performed to analyze the geographic distribution and epidemiology of lung cancer. Results: 8,291 new cases (5,998 in males and 2,293 females) of lung cancer during 2011 in Zhejiang province were reported in the 25 studied counties. Reported and standardized incidence rates for lung cancer were 58.0 and 47.0 per 100,000 population, respectively. The incidence of lung cancer increased with age. Geographic distribution analysis shows that the standardized incidence rates of lung cancer in northeastern Zhejiang province were higher than in the southwestern part, such as in Nanhu, Fuyang, Wuxing and Yuyao counties, where the rates were more than 50 per 100,000 population. In the southwestern Zhejiang province, for instance, in Yueqing, Xianju and Jiande counties, the standardized incidence rates of lung cancer were lower than 37 per 100,000 population. Spearman correlation tests showed that forest coverage rate, air quality index (AQI), and annual precipitation level are associated with the incidence of lung cancer. Conclusions: Lung cancer in Zhejiang province shows obvious regional differences. High incidence appears associated with low forest coverage rate, poor air quality and low annual precipitation. Therefore, increasing the forest coverage rate and controlling air pollution may play an important role in lung cancer prevention.

Comparison of Biological Characteristics of Pacific Cod Gadus microcephalus between the East and Yellow Seas, Korea (동해와 황해 대구(Gadus macrocephalus)의 생물학적 특성 비교)

  • Lee, Kyunghwan;Cha, Hyung Kee;Kim, Yeonghye;Lee, Jeong-Yong;Jung, Sukgeun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.4
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    • pp.499-508
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    • 2016
  • We investigated regional differences in the growth and maturation rate of Pacific cod in the East and Yellow Seas. Significant regional differences were detected in the von Bertalanffy growth equation and mean length at maturity (L50). Cod in the East Sea grew at a faster rate than those in the Yellow Sea, with females growing faster than males in both populations. Cod of both sexes matured earlier in the Yellow Sea (age of maturity: 2.3 years for males, 2.6 years for females) than in the East Sea (age of maturity: 3.9 years for males, 4 years for females). These regional differences suggest that Pacific cod in the Yellow Sea, which is at the southwestern extremity of global cod distribution and thus likely to be an inhospitable habitat for this species, have adapted to their environment by developing earlier maturation and slower growth than cod in the East Sea or the Korea Strait. These regional differences must be taken into account when setting biological reference points for management of the Pacific cod fishery in Korean waters.

A Study of Three-dimensional Magnetization Vector Inversion (MVI) Modeling Using Bathymetry Data and Magnetic Data of TA (Tofua Arc) 12 Seamount in Tonga Arc, Southwestern Pacific (남서태평양 통가열도 TA (Tofua Arc) 12 해저산의 해저지형과 자력자료를 이용한 3차원 자화벡터역산 모델 연구)

  • Choi, Soon Young;Kim, Chang Hwan;Park, Chan Hong;Kim, Hyung Rae
    • Geophysics and Geophysical Exploration
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    • v.23 no.1
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    • pp.22-37
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    • 2020
  • We analyze the comprehensive three-dimensional (3D) magnetic structure characteristics from the seafloor to the deep layer of the Tofua Arc (TA) 12 seamount in the Tonga Arc, Southwestern Pacific, using bathymetric and geomagnetic data, and magnetization vector inversion (MVI) results. The seafloor features surrounding TA 12 highlight a NW-SE-oriented elliptical caldera at the summit of the seamount, two small cones in the depressed area. A large-scale sea valley is present on the western flank of the seamount, extending from these caldera cones to the southwestern base of the seamount. TA 12 seamount exhibits a low magnetic anomaly in the caldera depression, whereas a high magnetic anomaly is observed surrounding the low magnetic anomaly across the caldera summit. It is therefore presumed that there may be a strong magnetic material distribution or magma intrusion in the caldera. The 3D MVI results show that the high anomaly zones are mainly present in the surrounding slopes of the seamount from the seafloor to the -3,000 m (below the seafloor) level, with the magnetic susceptibility intensity increasing as the seafloor level increases at the caldera depression. However, small high anomaly zones are present across the study area near the seafloor level. Therefore, we expect that the magma ascent in TA 12 seamount migrated from the flanks to the depression area. Furthermore, we assume that the complex magnetic distribution near the seafloor is due to the remnant magnetization.