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  Subjects -> GEOGRAPHY (Total: 493 journals)
Showing 1 - 200 of 277 Journals sorted by number of followers
Geophysical Research Letters     Full-text available via subscription   (Followers: 177)
Journal of Geophysical Research : Space Physics     Full-text available via subscription   (Followers: 155)
Journal of Geophysical Research : Atmospheres     Partially Free   (Followers: 143)
Journal of Geophysical Research : Planets     Full-text available via subscription   (Followers: 136)
Remote Sensing of Environment     Hybrid Journal   (Followers: 96)
Antipode     Hybrid Journal   (Followers: 65)
Journal of Geophysical Research : Earth Surface     Partially Free   (Followers: 60)
Journal of Geophysical Research : Oceans     Partially Free   (Followers: 60)
Progress in Human Geography     Hybrid Journal   (Followers: 59)
Journal of Geophysical Research : Solid Earth     Full-text available via subscription   (Followers: 58)
International Journal of Geographical Information Science     Hybrid Journal   (Followers: 55)
GIScience & Remote Sensing     Open Access   (Followers: 53)
Journal of Water and Climate Change     Open Access   (Followers: 53)
Climate Change Economics     Hybrid Journal   (Followers: 50)
Reviews of Geophysics     Full-text available via subscription   (Followers: 49)
Remote Sensing Letters     Hybrid Journal   (Followers: 46)
Annals of the American Association of Geographers     Hybrid Journal   (Followers: 43)
Economic Geography     Hybrid Journal   (Followers: 40)
Applied Geography     Hybrid Journal   (Followers: 38)
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (Followers: 35)
Urban Geography     Hybrid Journal   (Followers: 34)
Journal of Geophysical Research : Biogeosciences     Full-text available via subscription   (Followers: 34)
Climate and Development     Hybrid Journal   (Followers: 33)
Journal of Coastal Research     Hybrid Journal   (Followers: 31)
Annals of GIS     Open Access   (Followers: 31)
Cartography and Geographic Information Science     Hybrid Journal   (Followers: 31)
GPS Solutions     Hybrid Journal   (Followers: 28)
Transactions of the Institute of British Geographers     Hybrid Journal   (Followers: 27)
Journal of Urbanism: International Research on Placemaking and Urban Sustainability     Hybrid Journal   (Followers: 24)
Journal of the Middle East and Africa     Hybrid Journal   (Followers: 22)
China : An International Journal     Full-text available via subscription   (Followers: 20)
Urban Research & Practice     Hybrid Journal   (Followers: 20)
Dialogues in Human Geography     Hybrid Journal   (Followers: 20)
Imago Mundi: The International Journal for the History of Cartography     Hybrid Journal   (Followers: 20)
Atmospheric Measurement Techniques (AMT)     Open Access   (Followers: 19)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 19)
Water International     Hybrid Journal   (Followers: 19)
Journal of the American Planning Association     Hybrid Journal   (Followers: 19)
Journal of Cultural Geography     Hybrid Journal   (Followers: 18)
Geography Compass     Hybrid Journal   (Followers: 18)
Professional Geographer     Hybrid Journal   (Followers: 17)
International Geology Review     Hybrid Journal   (Followers: 17)
Cartographica : The International Journal for Geographic Information and Geovisualization     Full-text available via subscription   (Followers: 17)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Africa Insight     Full-text available via subscription   (Followers: 16)
The Geographical Journal     Hybrid Journal   (Followers: 16)
Crossings : Journal of Migration & Culture     Hybrid Journal   (Followers: 16)
Tectonics     Full-text available via subscription   (Followers: 15)
American Journal of Geographic Information System     Open Access   (Followers: 14)
Geographical Review     Hybrid Journal   (Followers: 13)
Buildings & Landscapes: Journal of the Vernacular Architecture Forum     Full-text available via subscription   (Followers: 13)
Geomatics, Natural Hazards and Risk     Open Access   (Followers: 13)
International Indigenous Policy Journal     Open Access   (Followers: 13)
Annual Review of Marine Science     Full-text available via subscription   (Followers: 13)
Progress in Physical Geography     Hybrid Journal   (Followers: 13)
American Journal of Human Ecology     Open Access   (Followers: 11)
Bulletin of Geosciences     Open Access   (Followers: 11)
Geographical Research     Hybrid Journal   (Followers: 11)
Geographical Analysis     Hybrid Journal   (Followers: 11)
Canadian Journal of Soil Science     Full-text available via subscription   (Followers: 11)
Geosciences Journal     Hybrid Journal   (Followers: 10)
GeoJournal     Hybrid Journal   (Followers: 10)
Journal of Geography     Hybrid Journal   (Followers: 10)
European Spatial Research and Policy     Open Access   (Followers: 9)
Cartographic Journal     Hybrid Journal   (Followers: 9)
Atmospheric Measurement Techniques Discussions (AMTD)     Open Access   (Followers: 9)
Journal of Borderlands Studies     Hybrid Journal   (Followers: 8)
Geography and Natural Resources     Hybrid Journal   (Followers: 8)
Physical Geography     Hybrid Journal   (Followers: 8)
Natural Science     Open Access   (Followers: 8)
Middle East Development Journal     Hybrid Journal   (Followers: 8)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 8)
Journal of Iberian and Latin American Research     Hybrid Journal   (Followers: 8)
Geo-spatial Information Science     Open Access   (Followers: 7)
Nordic Journal of Migration Research     Open Access   (Followers: 7)
Social Geography Discussions (SGD)     Open Access   (Followers: 7)
California Italian Studies Journal     Full-text available via subscription   (Followers: 7)
Journal of Latin American Geography     Full-text available via subscription   (Followers: 7)
Urban History Review / Revue d'histoire urbaine     Full-text available via subscription   (Followers: 7)
GeoInformatica     Hybrid Journal   (Followers: 7)
International Journal of Health Geographics     Open Access   (Followers: 7)
Northern Scotland     Hybrid Journal   (Followers: 6)
Journal of Geographical Systems     Hybrid Journal   (Followers: 6)
Asia Policy     Full-text available via subscription   (Followers: 6)
Singapore Journal of Tropical Geography     Hybrid Journal   (Followers: 6)
The Canadian Geographer/le Geographe Canadien     Hybrid Journal   (Followers: 6)
Australian Geographer     Hybrid Journal   (Followers: 6)
Ocean Science Journal     Hybrid Journal   (Followers: 6)
Journal of Maps     Open Access   (Followers: 6)
Globe, The     Full-text available via subscription   (Followers: 5)
ISPRS International Journal of Geo-Information     Open Access   (Followers: 5)
Journal of Developmental Entrepreneurship     Hybrid Journal   (Followers: 5)
Current Research in Geoscience     Open Access   (Followers: 5)
Creativity Studies     Open Access   (Followers: 5)
Focus on Geography     Partially Free   (Followers: 5)
Journal of Map & Geography Libraries     Hybrid Journal   (Followers: 5)
Australian Antarctic Magazine     Free   (Followers: 5)
Asian Geographer     Hybrid Journal   (Followers: 5)
Journal of Australian Studies     Hybrid Journal   (Followers: 5)
Bulletin of the Ecological Society of America     Open Access   (Followers: 4)
Geografiska Annaler, Series A : Physical Geography     Hybrid Journal   (Followers: 4)
Journal of Sedimentary Research     Hybrid Journal   (Followers: 4)
Genre & histoire     Open Access   (Followers: 4)
Latinoamérica. Revista de estudios Latinoamericanos     Open Access   (Followers: 4)
Applied Geomatics     Hybrid Journal   (Followers: 4)
Transmodernity : Journal of Peripheral Cultural Production of the Luso-Hispanic World     Open Access   (Followers: 4)
Journal of Western Archives     Open Access   (Followers: 3)
Interaction     Full-text available via subscription   (Followers: 3)
Limnological Review     Open Access   (Followers: 3)
Bulletin of Geography. Socio-economic Series     Open Access   (Followers: 3)
Southeastern Europe     Hybrid Journal   (Followers: 3)
New Zealand Journal of Geography     Hybrid Journal   (Followers: 3)
International Journal of Image and Data Fusion     Hybrid Journal   (Followers: 3)
Économie rurale     Open Access   (Followers: 3)
Polar Research     Open Access   (Followers: 3)
South Asian Diaspora     Hybrid Journal   (Followers: 3)
Journal of Burma Studies     Full-text available via subscription   (Followers: 3)
Social Dynamics: A journal of African studies     Hybrid Journal   (Followers: 3)
All Earth     Open Access   (Followers: 3)
Geodesy and Cartography     Open Access   (Followers: 2)
Pastoralism : Research, Policy and Practice     Open Access   (Followers: 2)
Maine Policy Review     Open Access   (Followers: 2)
The South Asianist     Open Access   (Followers: 2)
Provincial China     Hybrid Journal   (Followers: 2)
Regions and Cohesion     Open Access   (Followers: 2)
Polar Journal     Hybrid Journal   (Followers: 2)
Regional Science Policy & Practice     Hybrid Journal   (Followers: 2)
History of Geo- and Space Sciences     Open Access   (Followers: 2)
Mineralogia     Open Access   (Followers: 2)
Eastern European Countryside     Open Access   (Followers: 2)
Lithosphere     Open Access   (Followers: 2)
Geosphere     Open Access   (Followers: 2)
Journal of Earthquake and Tsunami     Hybrid Journal   (Followers: 2)
Cahiers franco-canadiens de l'Ouest     Full-text available via subscription   (Followers: 2)
Norois     Open Access   (Followers: 2)
Standort - Zeitschrift für angewandte Geographie     Hybrid Journal   (Followers: 2)
Études rurales     Open Access   (Followers: 2)
Polar Geography     Hybrid Journal   (Followers: 2)
Scottish Geographical Journal     Hybrid Journal   (Followers: 2)
Norsk Geografisk Tidsskrift - Norwegian Journal of Geography     Hybrid Journal   (Followers: 2)
Southeastern Geographer     Full-text available via subscription   (Followers: 2)
Yearbook of the Association of Pacific Coast Geographers     Full-text available via subscription   (Followers: 2)
BioRisk     Open Access   (Followers: 2)
Geographical Education     Full-text available via subscription   (Followers: 2)
Cahiers Balkaniques     Open Access   (Followers: 2)
Reflets : revue d'intervention sociale et communautaire     Full-text available via subscription   (Followers: 2)
Études internationales     Full-text available via subscription   (Followers: 1)
GEM - International Journal on Geomathematics     Hybrid Journal   (Followers: 1)
Recherches sociographiques     Full-text available via subscription   (Followers: 1)
Estudios Geográficos     Open Access   (Followers: 1)
Terrae Incognitae     Hybrid Journal   (Followers: 1)
Geoforum Perspektiv     Open Access   (Followers: 1)
Newfoundland and Labrador Studies     Full-text available via subscription   (Followers: 1)
South African Geographical Journal     Hybrid Journal   (Followers: 1)
Geochronometria     Open Access   (Followers: 1)
Amerika     Open Access   (Followers: 1)
Journal de la Société des Océanistes     Open Access   (Followers: 1)
Les Cahiers d'Outre-Mer     Open Access   (Followers: 1)
Revue archéologique du Centre de la France     Open Access   (Followers: 1)
Journal of Terrestrial Observation     Open Access   (Followers: 1)
PRISM : A Journal of Regional Engagement     Open Access   (Followers: 1)
Physio-Géo     Open Access   (Followers: 1)
Méditerranée     Open Access   (Followers: 1)
Indiana     Open Access   (Followers: 1)
Revista de Geografía Norte Grande     Open Access   (Followers: 1)
L'Année du Maghreb     Open Access   (Followers: 1)
European Countryside     Open Access   (Followers: 1)
Norteamérica     Open Access   (Followers: 1)
International Journal of Bahamian Studies     Open Access   (Followers: 1)
Journal of the Southwest     Full-text available via subscription   (Followers: 1)
PSC Discussion Papers Series     Open Access  
Anales de Geografía de la Universidad Complutense     Open Access  
International Journal of River Basin Management     Hybrid Journal  
Revista Geográfica de América Central     Open Access  
Multiciencias     Open Access  
Investigaciones Geográficas (Esp)     Open Access  
Sociedade & Natureza     Open Access  
Región y Sociedad     Open Access  
Migración y Desarrollo     Open Access  
Migraciones Internacionales     Open Access  
Investigaciones Geográficas     Open Access  
Frontera Norte     Open Access  
Cuadernos de Desarrollo Rural     Open Access  
Territoire en Mouvement     Open Access  
Quaestiones Geographicae     Open Access  
Limes. Cultural Regionalistics     Open Access  
GEOMATICA     Hybrid Journal  
Preview     Hybrid Journal  
Cuadernos de Geografía : Revista Colombiana de Geografía     Open Access  
Studia Universitatis Babes-Bolyai, Geologia     Open Access  
Recherches amérindiennes au Québec     Full-text available via subscription  
Rabaska : revue d'ethnologie de l'Amérique française     Full-text available via subscription  
Port Acadie : revue interdisciplinaire en études acadiennes / Port Acadie: An Interdisciplinary Review in Acadian Studies     Full-text available via subscription  
Études/Inuit/Studies     Full-text available via subscription  
Aurora Journal     Full-text available via subscription  
Revista de la Asociacion Geologica Argentina     Open Access  
San Francisco Estuary and Watershed Science     Open Access  
Journal of Alpine Research : Revue de géographie alpine     Open Access  
Géocarrefour     Open Access  
Confins     Open Access  

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Ocean Science Journal
Journal Prestige (SJR): 0.262
Citation Impact (citeScore): 1
Number of Followers: 6  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1738-5261 - ISSN (Online) 2005-7172
Published by Springer-Verlag Homepage  [2469 journals]
  • Estimation of Potential Habitats for Three Species of Bivalves Using the
           Habitat Variables in Gomso Bay Tidal Flat, Korea

    • Free pre-print version: Loading...

      Abstract: Abstract The gradual changes in the habitat of Gomso Bay negative impacted the intertidal flat aquaculture of the Manila clam Ruditapes philippinarum. The habitat evaluation of the Manila clam in Gomso Bay tidal flat that should be preceded to identify this negative impact in clam culture was conducted using the habitat variables chlorophyll-a, hydrodynamics, sediment sand, exposure time, dissolved oxygen, and salinity. Additionally, to utilize the unsuitable sites of Manila clam culture, we used the habitat suitability index by subdividing substrate variables (sorting coefficient, silt content, and mean grain size) for two species (Cyclina sinensis and Mactra veneriformis). As a result, the lower flat was chosen as the optimal habitat for Manila clam, with a habitat suitability index mean score of 0.62 and the upper flat was deemed to be the potential habitat for C. sinensis, while the middle flat was chosen for M. veneriformis. Therefore, the possibility of using unsuitable sites for Manila clam farming as alternative species was identified. These findings can be used as a reference for optimal site selection for the diversification of commercial species and decentralization of clam culture farms in the Gomso Bay tidal flat.
      PubDate: 2022-08-04
       
  • Comparing Environmental DNA Metabarcoding and Underwater Visual Census to
           Monitor Korean Coastal Fish Community

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      Abstract: Abstract This study conducted underwater visual census (UVC) and eDNA metabarcoding to survey fish fauna in the coastal waters off Busan (Cheongsapo) and Ulsan (Bangeojin), Southeast sea of Korea, after which the two survey methods were compared. A total of 49 species were identified in Cheongsapo (eDNA metabarcoding: 29 species; UVC: 29 species) and 60 were identified in Bangeojin (eDNA metabarcoding: 43 species; UVC: 30 species), which accounted for 70 species in both areas. Except for 13 species without GenBank sequence data, 80% of the species detected using UVC were detected through eDNA metabarcoding. In addition, eDNA metabarcoding enabled the detection of 33 species that were otherwise not detected by UVC. Thus, eDNA can be used to conduct fast and wide fish diversity surveys and is applicable to microhabitats in coastal areas. Therefore, eDNA could become an important complement to traditional surveys for monitoring marine biodiversity.
      PubDate: 2022-08-01
       
  • Spatio-Temporal Variation of the M2 Tidal Current from Field Observations
           in the Jeju Strait

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      Abstract: Abstract The variability in the tidal current in the Jeju Strait was investigated based on sea surface current fields observed by a high-frequency (HF) radar and vertical current profiles observed by three bottom-moored acoustic Doppler current profilers (ADCPs). The monthly M2 tidal current, the most dominant constituent in the study area, had significant temporal variability, and there were spatial changes in the temporal variation trend. While the semi-major axis of the M2 tidal current in winter was stronger than that in summer in some parts of the HF radar observation range, the summertime semi-major axis was stronger than that in wintertime in other parts of the observation range. Both opposite trend areas coexisted within the HF radar coverage area of several tens of kilometers. The vertical structure of the tidal currents in winter was similar to the theoretical structure in which Ekman dynamics was applied under depth-independent vertical eddy viscosity, and the year-to-year change was weak. In contrast, the vertical structure of the tidal currents in summer significantly varies over depth and years. Furthermore, the seasonal variation patterns at the three ADCP stations differed spatially. The temporal and spatial variability of tidal currents could be explained as a result of the strengthening stratification and, consequently, semidiurnal internal tides in summer. In summer, an internal tide with a wavelength of tens of kilometers could be generated in the vicinity of and propagate into the study area. The overlapping and offsetting of the barotropic and internal tidal components within the HF radar observation range caused complex spatial variations.
      PubDate: 2022-08-01
       
  • Effects of Light, Salinity and Temperature on Germination Characteristics
           of Surfgrass, Phyllospadix japonicus and P. iwatensis Seeds

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      Abstract: Abstract Surfgrass (Phyllospadix spp.) is a marine flowering plant that attaches to the bedrock of the Pacific Ocean, where the tide is fast and the waves are strong. In Korea, two species of surfgrass are mainly found on the east coast. Phyllospadix japonicus is present throughout the east coast, whereas P. iwatensis is mainly present on the central east coast. The germination requirements of these two surfgrass species were studied in relation to the light, salinity, and temperature treatments. In the light test, both species showed significantly higher percentage germination (PG), faster daily germination rate (DGR), and shorter mean time-to-germinate (MTG) under light conditions than those under dark conditions. In the salinity and temperature experiments, the highest PGs for P. japonicus and P. iwatensis were 95.6 ± 4.4% and 82.2 ± 1.1%, respectively, at 30 psu and 7 °C. The maximum DGRs of P. japonicus and P. iwatensis were 1.95 ± 0.04 seeds d−1 and 1.43 ± 0.05 seeds d−1, respectively, at 15 psu and 17 °C. MTGs of both species were the shortest at 15 psu at all temperatures, and increased as salinity increased. The two surfgrass species showed a similar germination tendency, but P. japonicus showed a higher PG, faster DGR, and shorter MTG than P. iwatensis. Owing to these differences in germination characteristics, P. japonicus may have an advantage for occupying a wider bedrock area in the East Sea coast of the Korean Peninsula.
      PubDate: 2022-07-29
       
  • Monsoon-Driven Geomorphological Changes Along the West Coast of Sri Lanka:
           A Combined Approach Utilizing ‘CoastSat’ and Google Earth Engine

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      Abstract: Abstract Long-term field monitoring of shoreline changes is time-consuming, expensive, and labor-intensive. Instead, satellite images can be used as an alternative method to collect field data. The time-series satellite images are available at any location in the world that can be processed with the Google Earth Engine cloud environment. This study primarily focuses on shoreline change detection and describing the coastal geomorphology of three urban beaches on the west coast of Sri Lanka. The study extended from 2015 to 2021 during which large-scale coastal development projects were carried out in the study area. The ‘CoastSat’ toolkit was used to extract the time-series of shoreline positions. Time-series shoreline position obtained through ‘CoastSat’ was compared with the field measurements carried out using the Global Navigation Satellite System technique with a horizontal accuracy of 7 mm. The results indicate that the average horizontal difference of shoreline positions obtained by ‘CoastSat’ and field observation was 7.5 ± 1 m in Agulana-Ratmalana on 19 August 2019, and was 8.3 ± 1 m in Kalutara on 29 July 2020. The extracted shoreline changes show erosion and deposition patterns affected by monsoon seasonality and anthropogenic events. The results further show that North of Mount Lavinia Beach was accreted from 18 to 27 m, while South of Mount Lavinia Beach was eroded from 12 to 17 m. Accretion was mainly due to sand nourishment in the area during the 1st quarter of 2020. Furthermore, Agulana-Ratmalana Beach predominantly accreted from 22 to 30 m, while the northernmost transect (AR1) had a steady-state beach condition. This was again due to nourished sand during the 1st quarter of 2020. In contrast, accretion and erosion trends in Kalutara Beach are mainly due to the breakup of the river mouth sand bar to control flooding by the artificial cutting open of the sand spit bar in 2017. The transect (KL2) near the broken sand spit bar at the north of Kalutara shows severe erosion (56 m), since northward longshore transport of sediment has stopped with the breakage of the sand spit bar. In contrast, Kalutara south transects show an accretion to steady-state condition due to the existing hard engineering structures. Consequently, the study suggests that the CoastSat: A Google Earth Engine-enabled Python toolkit can be used to extract shoreline positions and to detect medium-to-large-scale coastline changes with appropriate tidal corrections, when and where there are no long-term coastal field measurements available. This method could be adapted to any coastal area in the world for acceptable shoreline detection that would be very useful for planning and evaluating coastal management strategies.
      PubDate: 2022-07-07
       
  • Progress in the Industry-University-Institute Cooperative Use of Research
           Vessels

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      Abstract: Abstract With the support of the Ministry of Oceans and Fisheries of Korea, the Korea Institute of Ocean Science and Technology (KIOST) promoted ‘The study for the industry-university-institute cooperative use of research vessels’, which was an opportunity to advance domestic ocean research to the next level, in line with the launch of the R/V Isabu in 2017. A brief history in relation to the project is described in Lee (Ocean Sci J 57(2), 2022) in this issue. Celebrating the 5th year of the project, KIOST (Marine scientists on a boat, KIOST Korea Institute of Ocean Science and Technology, Busan, 2021) has published a resource book on the progress of the project excluding scientific papers. In this special issue, some of the scientific results from the project are grouped together and introduced. The joint use of research vessels started with large research vessels and gradually expanded to small research vessels. Thus, the target area of the study also included from the open ocean to the coastal waters (KIOST, in Marine scientists on a boat, KIOST Korea Institute of Ocean Science and Technology, Busan, 2021) as shown in the papers featured in this issue.
      PubDate: 2022-06-22
       
  • Multi-proxy Stratigraphy and Paleoceanographic Variations in Sediment from
           the Korea Plateau, East Sea (Japan Sea), Over the Last 500 kyr

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      Abstract: Abstract High-resolution geochemical measurements were performed on core E09-08, which was taken from the top flat area of the Korea Plateau in the East Sea (Japan Sea). Based on analyses of sedimentary lamination, high-resolution oxygen isotopes, alkenone sea surface temperature (SST) variations, and comparison with previous results from the eastern part of the East Sea, a detailed multi-proxy-based stratigraphy was reconstructed. The results demonstrated that the core bottom dates approximately 500 kyr in the late marine isotope stage (MIS) 13, and provides high-resolution data on the paleoceanographic regime in the study area. Biogenic components of total organic carbon (TOC), carbon and nitrogen isotopes of organic matter (δ13Corg and δ15Norg), and alkenone concentrations indicate a paleoceanographic regime shift within the last 500 kyr. The excursion of proxies of δ18O, δ13Corg and δ15Norg and alkenone-based SST indicate two modes of oceanographic conditions: strong negative coupled mode (SNCM) during MIS 2, 10, and 12, and normal oceanographic decoupled mode (NODM) during other MIS. These two modes were interpreted as the terrestrial organic matter source domain and high-productivity oceanographic domain, respectively. The SNCM is characterized by relatively low δ13Corg and δ15Norg, and a high C/N ratio (> 12), whereas the NODM is characterized by relatively high δ13Corg and high δ15Norg, implying that larger amounts of terrestrial material were supplied during MIS 2, 10 and 12, with enhanced productivity during other MIS. The SNCM and NODM mode are also strongly associated with eustatic sea-level changes. The δ13Corg and δ15Norg values and alkenone-based SST excursions over glacial-interglacial periods were generally consistent with global-scale paleoclimate variation, as well as local paleoclimate. This study employed multi-proxy-based stratigraphy to demonstrate dramatic oceanographic variations since MIS 13, indicating that the local oceanographic setting was superimposed on global glacial-interglacial variations.
      PubDate: 2022-06-14
       
  • Seasonal Growth Dynamics of Posidonia oceanica in a Pristine Mediterranean
           Gulf

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      Abstract: Abstract Seasonal growth dynamics and ecology of Posidonia oceanica were studied in a space alongshore a pristine Mediterranean gulf in 2011–2012. About one-third of the present study surface area was occupied meadows where only calcite rocks were found on bottoms between 0.5 and 29 m. Shoot density was not significantly different among seasons, and was above 364 ± 27 shoots m−2, but was different among the depths. The density variables decreased along the bottom depth gradient along which the number of leaves per shoot, inter shoot distance and the morphometrical variables tended to increase. Inferring the dynamics of biometrics (length and width of leaf, orthotropic rhizomes and leaf sheath) and density (LAI, leaf biomass and the number of leaves per shoot), the biometrics of the meadow grew seasonally between growth by March and mortality by August–September, regardless of the coverage area. Mortality occurred due to the highest annual salinity in late summer. A transition depth in space and month in time was assessed as 15 m and as August for variation of the biometrics, respectively. Rhizome related-biometrics (length, thickness, weight, sheath length and width) were dynamically initialized mainly by water nitrogen content which was high by winter-spring. A PAR in the range of 10–32%, and surface water temperature up to 28.8–29.3 °C corresponding to up to ~ 40 PSU were critical limiting factors for P. oceanica to survive in space. Water physics, chemistry, and optical properties governed the annual course of biometrics. Total organic carbon was also negatively affecting the seasonal dynamics of the rhizome.
      PubDate: 2022-06-13
       
  • New Opportunities in Global Ocean Research for Academia and Industry

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      Abstract: Abstract Since 2017, requesting ship time has become possible for university researchers and businesses on research vessels. They include Isabu and Onnuri of the Korea Institute of Ocean Science and Technology (KIOST) and the icebreaking research vessel Araon of the Korea Polar Research Institute (KOPRI). There was no regulation barring the chartering of the significant national scientific infrastructure in the first place, but the exorbitant cost of ship time had made their usage virtually impossible. Shared Use Committee (SUC) was set up to handle applications and coordinate the cruises. A modest amount of research funds is also granted. Currently, the KIOST vessels conduct surveys in the Pacific and the central Indian Ocean annually. The KOPRI vessel routinely operates around Antarctica during the austral summer and in the Arctic seas during the boreal summer. Other government-supported institutions are likely to follow this shared used example. Here I provide a brief historical background leading to the shared use of research and information for potential applicants. The description is given from the perspective of geological oceanography, and thus some accounts may differ in other fields of study. A case study is given where a team of international university scientists successfully conducted a joint experiment to investigate the upper mantle structure by deploying ocean bottom instruments and recovering them one year later in the Pacific using Korean research vessels. Finally, some long and short-term recommendations are made to improve the system further.
      PubDate: 2022-06-10
       
  • Current Structure and Volume Transport in the Jeju Strait Observed for a
           Year with Multiple ADCP Moorings

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      Abstract: Abstract The seasonal and spatial variation of the current structure and volume transport across the Jeju Strait (JS) is described based on an analysis of the data from five bottom mounted acoustic Doppler current profilers from February 13, 2020 to February 23, 2021. The current was weak and the mixed layer was well developed in winter, so the vertical current shear was not large. Whereas in summer, the inflow of high-temperature and low-salinity surface water built up the stratification, and the surface current velocity increased, resulting in a large vertical current shear. One salient feature to be found was that a westward flowing counter current in the lower layer appeared from June to December near the bottom trough of the JS. We named this seasonal counter current in the lower layer the Jeju Strait Under Current. The eastward net volume transport passing through the JS was large in summer–autumn and small in winter-spring, but did not follow a simple sinusoidal pattern. The annual mean net volume transport was 0.48 Sv (Sv ≡ 106 m3 s−1), with a minimum (0.27 Sv) in December and a maximum (0.79 Sv) in October 2020. When there were strong northerly winds in winter, a net volume transport to the west was temporarily caused by Ekman transport, but the direction reverted to the east as soon as the northerly winds lessened. When there were strong northwesterly (southeasterly) winds due to typhoons, the volume transport decreased (increased) sharply and then recovered rapidly.
      PubDate: 2022-06-08
       
  • Bioaccumulation of Trace Metals in Sabellaria alveolata (Annelida:
           Polychaeta) and Their Controlling Factors Along the Essaouira Protected
           Coastal Area (Atlantic Coast of Morocco)

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      Abstract: Abstract This study assessed, for the first time, the bioaccumulation of trace metals in the tissues of Sabellaria alveolata (Annelida: Polychaeta) collected from the Essaouira protected coastal area (Atlantic coast of Morocco), and examined the relationships between metal contents and some physico-chemical parameters of seawater. The biogenic reefs of S. alveolata were seasonally collected from April 2017 to February 2018, and physico-chemical parameters of seawater were measured. In the laboratory, dried and mineralized samples of S. alveolata were analysed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The physico-chemical parameters of seawater are within acceptable limits for survival, growth and metabolic activity of aquatic organisms, and metal concentrations in the tissues of S. alveolata showed decreasing levels in the order Fe > Al > Zn > Cu > Cd > Cr > Pb > Ag. Concentrations were lower than levels reported in other species of polychaetes in other Moroccan and world regions except for Al and Fe. Spatial and seasonal variations of metals were highly significant, with two essential periods of high concentrations: winter and summer. Cluster analysis showed that the studied sites, urbanized and non-urbanized, were similar except for one site (SK) that differs slightly from the others, probably due to the absence of real industrial activity coupled with the dilution of metals under the influence of hydrodynamic factors in this area. The analysis also showed that Al and Fe are derived from the same source, most likely related to continental inputs, and that Cd, Cr and Cu are derived from another source which is more urban than continental while Zn maintains a dual origin, both continental and urban. Assessment of the pollution gradient, via calculation of metal contamination index (IcSx), revealed that the Essaouira protected coastal area is less polluted compared with other coastal areas of Morocco.
      PubDate: 2022-06-01
       
  • Origin of the Holocene Sediments in the Ninetyeast Ridge of the Equatorial
           Indian Ocean

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      Abstract: Abstract The long-term evolution of the South Asian monsoon system and its influence on the Bay of Bengal (BOB) is of great interest to climate scientists. A number of climate forcings trigger the changes of the Indian summer monsoon (ISM) precipitation centroid, while the ISM rainfall projected by climate models shows a large discrepancy in local precipitation patterns. Moreover, the continuous recovery of paleoceanographic records in the BOB is often a struggle due to the presence of the fan-dominated depositional regime of the Bengal Fan. In this study, we present multi-proxy records of the last 13 kyrs from a sediment core (HI1710-MC1) at the Ninetyeast Ridge (NER) in the southern BOB, which is prevented from turbidite deposition. Our result suggests that the surface ocean environment and detrital provenance at the NER have not responded sensitively to the ISM variation and largely remained stable for the last 13 kyrs. The biogenic fraction (CaCO3, total organic carbon, and total nitrogen contents) has remained relatively constant regardless of the Indian monsoon variability during the Holocene. The radiogenic isotope (εNd and 87Sr/86Sr) and clay mineral compositions of the detrital sediments indicate that the two major sources (the Himalaya through the Ganges–Brahmaputra–Meghna River system with a minor contribution from the Indo-Burma Ranges via the Irrawaddy-Salween River system) have played a primary role in delivering sediments to the study site. Our results imply that the longer sediment records preserved at the NER can be used to reconstruct the relative changes of runoff in the two major river systems. The Holocene record at the NER, thus, provides a basis for the study of the Late Quaternary variability in the Indian monsoon precipitation patterns and resultant runoff to the BOB.
      PubDate: 2022-06-01
       
  • Enhancement of Sea Surface Chlorophyll a Concentration by Interaction of
           Winds and Currents in a Cyclonic Eddy in the Japan/East Sea

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      Abstract: Abstract Chlorophyll a concentration (Chl-a), wind, and water temperature were measured at a buoy moored near Dok-Do in the Japan/East Sea (JES). Short-term (1–3 day) enhancements of Chl-a associated with the surface layer cooling observed in spring (May–June) and autumn (Oct-Nov) were found to be correlated with the Ekman pumping induced by the interaction of the eddy current and wind, separable into components due to the wind stress and the lateral gradient in vertical vorticity. In the spring, surface Chl-a increases in conjunction with upwelling due to the lateral gradient in vorticity and the curl of the wind stress. However, in fall, positive Chl-a anomalies are only correlated with upwelling due to the curl of relative wind stress, which arises from the difference between the wind and the ocean surface current. The observed response time of the upwelling induced by wind-current interaction was very short (less than a day) compared to most theoretical studies which are driven by steady winds of more than 3 days. Our analysis suggests that as the mixed layer deepens, Chl-a at the surface is enhanced by the turbulent mixing of the underlying mixed layer water with high Chl-a and nutrients. However, the upwelling is a necessary condition for it to occur.
      PubDate: 2022-06-01
       
  • Evaluation of Sea Surface Temperature-Dependent Whitecap Coverage
           Parameterizations Using In Situ Data

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      Abstract: Abstract This study aims to evaluate previous parameterizations of whitecap coverage (W) based on in-situ observational datasets. Ten-meter wind speed measurements over the sea surface (U10) have been the most traditional and effective method of estimating W. A secondary variable—sea surface temperature (Tw)—is considered for better parameterization of W. A non-monotonic relationship is found between the W and Tw because all the coefficients and exponent in the W-U10 power-law fit are Tw-dependent. Therefore, replacing the fixed slope variable of the power-law fit with the positively or negatively Tw-dependent function does not result in significant improvements. When the Tw-dependent coefficients and exponent are embedded in the W parameterization, a better estimation of W is obtained. Tw related parameter of wind-sea Reynolds number contains wavefield information, which is also related to Tw, making wind-sea Reynolds number an optional parameter for estimating W. We suggest that further improvement of W (U10, Tw) parameterization requires consideration of more wavefield information.
      PubDate: 2022-06-01
       
  • Seasonal Fluctuations in the Abundance of Marine Tardigrades
           (Heterotardigrada: Echiniscoides sigismundi, Styraconyx haploceros)
           Inhabiting Fistulobalanus albicostatus, an Intertidal Barnacle on the West
           Coast of Korea

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      Abstract: Abstract The purpose of this study was to further clarify marine tardigrade ecology; in particular, the monthly density fluctuations of Echiniscoides sigismundi and Styraconyx haploceros inhabiting the barnacle Fistulobalanus albicostatus in the intertidal zone. Both species were observed in all months, and the monthly body length distributions did not show a clear pattern, indicating these species breed throughout the year. However, the density of both species was higher in fall/winter than in spring/summer. The two species showed different prevalence and density distributions in the upper and lower parts of a barnacle bedrock in the intertidal zone. S. haploceros was found only in the lower part, where it dominated over E. sigismundi in most months. E. sigismundi was found in both parts, but its occurrence rate and density were higher in the lower part of the intertidal zone. The density of both species was significantly higher on the external surface of the barnacles than internally. No significant differences in tardigrade density were detected among different sizes of barnacles, living or dead, except for a significant difference in the density of E. sigismundi between dead and large live barnacles. Our findings suggest that E. sigismundi and S. haploceros are well adapted to inhabiting intertidal barnacles, and the fall/winter season is more favorable than spring/summer for marine tardigrades in temperate regions. E. sigismundi appears to tolerate the upper part of the barnacle bedrock in the intertidal zone, which may be an extremely harsh environment, better than S. haploceros.
      PubDate: 2022-06-01
       
  • Influence of Sea Surface Fluctuation on Internal Waves’ Vertical
           Structures in a Two-Layer Model

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      Abstract: Abstract Using a two-layer linear ocean wave model that is quasi-incompressible and two-dimensional, we studied the relationships between surface fluctuation and ocean internal waves (IWs). The main conclusions were as follows. In a two-layer ocean, the analytical solution of IW was obtained by solving a homogeneous ordinary differential equation with constant coefficients according to the frequency, wave number (wavelength), and vertical velocity amplitude of the ocean surface fluctuation. The vertical structure and characteristics of IW in the ocean were analyzed under the conditions of different stratification parameters and background currents. Once the surface fluctuations were determined, the features of IW showed different shapes, which indicated the indeterminacy of the solution. Such indeterminacy reflects the characteristics of the inverse problem. To obtain a definite solution, the constraint conditions of the inverse problem should be provided—that is, the environmental parameters of the two layers, such as the background flow, stratification parameters, thickness of the two layers, and geostrophic parameters. If the environmental parameters are fixed, four situations of solutions can be determined. The first three solutions have IWs, and the fourth solution only has an external wave. For certain environmental parameters, the wave number and natural frequency (characteristic frequency) of the first three situations of IWs were determined in this study. We showed that a resonance phenomenon will occur and cause very severe ocean internal waves when the wave number and frequency of the surface fluctuation are analogous or equivalent to the natural wave number and natural frequency.
      PubDate: 2022-05-31
       
  • Application of a Length-Based Stock Assessment Model for the Chub Mackerel
           (Scomber japonicus) in Korean Waters

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      Abstract: Abstract We modified Quinn’s size-based model for the assessment of chub mackerel (Scomber japonicus) stock in Korean waters, using annual data about body lengths (fork lengths), fishery catches, and catch-per-unit-effort. One of the strengths of Quinn’s size-based model is the construction of an imaginary age structure for a fish population, allowing the estimation of year- and age-based population sizes. Our modification was twofold. First, we applied a likelihood theory for numerical optimization, instead of the least squares method that Quinn et al. (1998) used. Second, we not only made point estimates of parameters, but also measured their uncertainties, using ADMB (automatic differentiation model builder) software. Estimates of annual biomass from 2001 to 2017 ranged from 1.01 × 106 to 2.15 × 106 MT, and estimates of annual fishing mortality from 1996 to 2017 ranged from 0.11 to 0.32 per year. Using a sensitivity analysis, we obtained the natural mortality of the stock, which was 0.1 per year.
      PubDate: 2022-05-09
      DOI: 10.1007/s12601-022-00067-x
       
  • Effect of Different pCO2 Concentrations in Seawater on Meiofauna:
           Abundance of Communities in Sediment and Survival Rate of Harpacticoid
           Copepods

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      Abstract: Abstract The amount of CO2 dissolved in the ocean has been increasing continuously, and the results using climate change models show that the CO2 concentration of the ocean will increase by over 1000 ppm by 2100. Ocean acidification is expected to have a considerable impact on marine ecosystems. To find out about the impacts of ocean acidification on meiofaunal communities and copepod groups, we analyzed the differences in the abundance of meiofauna communities in sediment and the survival rate of harpacticoid copepod assemblages separated from the sediment, between 400 and 1000 ppm pCO2 for a short period of 5 days. In experiments with communities in sediments exposed to different pCO2 concentrations, there was no significant difference in the abundance of total meiofauna and nematodes. However, the abundance of the harpacticoid copepod community was significantly lower at 1000 ppm than that at 400 ppm pCO2. On the other hand, in experiments with assemblages of harpacticoid copepods directly exposed to seawater, there was no significant difference in their survival rates between the two concentrations. Our findings suggest that a CO2 concentration of 1000 ppm in seawater can cause changes in the abundance of specific taxa such as harpacticoid copepods among the meiofauna communities in sediments.
      PubDate: 2022-05-06
      DOI: 10.1007/s12601-022-00066-y
       
  • Optimized Metavirome Analysis of Marine DNA Virus Communities for
           Taxonomic Profiling

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      Abstract: Abstract Recent advances in metavirome technology have provided new insights into viral diversity and function. The bioinformatic process of metavirome study is generally divided into two (or three) steps: assembly and taxonomic profiling including nucleotide alignment. Moreover, k-mer size and contig length are known to considerably affect the results of the assembly and consequently those of taxonomic profiling; however, the optimal k-mer size and contig length have not been established. In the present study, we analyzed marine virus DNA datasets with three different k-mer sizes using different assemblers: 1 k-mer (20) in the CLC Genomics Workbench, and 4 (21, 33, 55, and 77) and 5 (21, 33, 55, 77, and 99) k-mers in metaSPAdes. The use of large k-mers had the advantage of resolving more repeat regions, with higher N50 values and average contig lengths. The contig length helps reduce the error of continuous sequences and determine the number of viral operational taxonomic units. Our analysis suggested that 300 bp may be an appropriate minimum contig length, depending on the characteristics of viral samples. Based on the assembly result using metaSPAdes, we analyzed the DNA virus community using three taxonomic profiling tools: MG-RAST online server, the taxonomic profiling tools function in the CLC microbial module, and customized taxonomic assignment coding (CUTAXAC) using RStudio based on the BLASTn analysis. CUTAXAC showed the most diverse viral composition at the family and species levels along with the highest Shannon diversity index and fastest analysis time.
      PubDate: 2022-05-02
      DOI: 10.1007/s12601-022-00064-0
       
  • Temporal Variations in the Antifouling Activity of Extract of the Soft
           Coral Sarcophyton trocheliophorum Collected from the Red Sea

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      Abstract: Abstract Soft corals are considered as a prospective resource for the isolation of natural product antifoulants. In this study, the temporal variations in the antifouling activity of the crude extract of the soft coral Sarcophyton trocheliophorum samples collected from the Jeddah coast of Saudi Arabia during summer (June–August 2018) and winter seasons (December 2018–February 2019) were assessed using laboratory tests. The crude extract was tested against biofilm-forming bacteria and barnacle larvae in the laboratory. The results indicated significant variations (P < 0.001) in the antifouling activity of the extracts between the samples collected during the summer and winter seasons. The extract of the soft coral samples collected during the summer season showed higher inhibitory activity against the fouling bacteria and barnacle larva. In addition, the surface-associated bacteria abundance on the soft corals were analysed and the results showed higher abundance on winter season samples. Further, GC–MS analysis indicated differences in the metabolite composition with the abundance of compounds such as cis-z-a-Bisabolene epoxide and caryophyllene oxide being high in summer samples and Isoaromadendrene epoxide and β-cembrenediol showing a higher peak area percentage in winter samples. Overall, this study revealed temporal variations in the antifouling activity and metabolite composition of the Red Sea soft corals.
      PubDate: 2022-03-16
      DOI: 10.1007/s12601-022-00062-2
       
 
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