• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.336-341
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• 2000

This study was conducted to clarify the habitat characteristics and distribution of seagrass. Zostera marina L. (Zosteraceae) in the brackish Hwajinpo Lake, Korea in June 1998 and July 2000. Z. marina beds were distributed along the sea-side cost of the lower lake mouth at 0.8 to 1.5m in death, and the seagrass bed area was about 3,200 m$^{2}$. Salinity, water temperature and pH were in the range of 8.0${\sim}$23.0$%_{o}$, 22.0${\sim}$23.7$^{\circ}C$ and 8.34${\sim}$8.62, respectively. Nutrient concentrations were generally now (TN: 24.34 ${\mu}$M, NH$_{4}$-N: 2.57 ${\mu}$M, NO$_{3}$-N: 0.56 ${\mu}$M, NO$_{2}$-N: 0.27 ${\mu}$M, TP: 2.08 ${\mu}$M, PO$_{4}$-P: 0.34 ${\mu}$M). Suspended particulate matters (SPM) concentration averaged 62.8 mg/l and particulate organic matter (POM) averaged 21.3 mg/l. Organic content of SPM averaged 33.9%. The beds substratum was composed of well-sorted, fine sand and its mean brain size was 3.13${\Phi}$. The Z. marina vegetation was almost submerged, and the morphological characteristics can be classified as steno-leaf phenotype by the shoot length, leaf width, and number of leaf vein. Shoot length and leaf width were 70.0${\sim}$126.5 cm and 5${\sim}$7 mm, respectively. Shoot densities ranged from 264 to 296/m$^{2}$, and the plants biomass was estimated at 332.6 to 373.0 g dw/m$^{2}$. Therefore, the habitats of Z. marina in Korea were recognized in a brackish lake, and morphological characteristics appeared to be variable.

• Journal of Ecology and Environment
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• v.41 no.3
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• pp.45-53
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• 2017

Background: There have been many studies on the growth conditions of Zostera marina and Zostera japonica, but few studies have examined how spatial and temporal factors affect growth in established seagrass beds or the distribution range and shoot density. This study aims to clarify the factors that determine the temporal and spatial distribution of Zostera marina and Zostera japonica in the Seto Inland Sea east of Yamaguchi Prefecture. Methods: The study site is in Hiroshima Bay of the Seto Inland Sea, along the east coast of Yamaguchi Prefecture, Japan. We monitored by diving observation to confirm shoot density, presence or absence of both species and observed water temperature, salinity by sensor in study sites. Results: The frequency of occurrence of Zostera marina was high in all seasons, even in water depths of D.L. + 1 to -5 m ($80{\pm}34%$ to $89{\pm}19%$; mean ${\pm}$ standard deviation), but lower (as low as $43{\pm}34%$) near the breakwall, where datum level was 1 to 2 m, and it was further reduced in datum level -5 m and deeper. The frequency of occurrence of Zostera japonica was highest in water with a datum level of +1 to 0 m. However, in datum level of 0 m or deeper, it became lower as the water depth became deeper. Datum level +1 m to 0 m was an optimal water depth for both species. The frequency of occurrence and the shoot density of both species showed no negative correlation. In 2011, the daily mean water temperature was $10^{\circ}C$ or less on more days than in other years and the feeding damage by S. fuscescens in the study sites caused damage at the tips. Conclusions: We considered that the relationship between these species at the optimal water depth was not competitive, but due to differences in spatial distribution, Zostera marina and Zostera japonica do not influence each other due to temperature conditions and feeding damage and other environmental conditions. Zostera japonica required light intensity than Zostera marina, and the water depth played an important role in the distribution of both species.

• Korean Journal of Ichthyology
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• v.28 no.2
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• pp.100-109
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• 2016

Species composition and distribution characteristics of fish were determined by monthly underwater visual census from September. 2013 to August, 2014 at Yeongunri off Tongyeong, Korea. The study area was divided into five habitat types by depth and substrate: (1) sand bottom as depth of 0~2 m, (2) seagrass bed of 2~5 m, (3) rocky outcrop of 0~2 m, (4) rocky bottom of 2~5 m, (5) sandy mud bottom of 5~8 m. A total of 1,673 individuals belonging to 43 species in 26 families were recorded during the study period. The number of species tended to decrease after October, 2013 and increase from March, 2014 showing the highest number in October (autumn), and lowest in January (winter). In terms of the number of species, Gobiidae was the most dominant family (7 species), followed by Scorpaenidae (4 species). Embiotocidae was the most abundant (26.1% in total number of individuals), followed by Scorpaenidae (19.9%) and Gobiidae (19.3%). The dominant species were Sebastes inermis (19.2%), Ditrema temminckii (13.1%), and Neoditrema ransonnetii (12.9%). The number of species and abundance were relatively high at the depth between 2 and 5 m on seagrass bed and rocky bottom, whereas they were lower at the depth between 0 and 2 m on the sand bottom, suggesting that seagrass beds and rocky bottoms provided the diverse habitats for various fish species in this sea.

• Journal of Wetlands Research
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• v.10 no.1
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• pp.49-57
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• 2008

Tidal flat, classified as wetland of coastal zone, is critical transitional zone connecting sea with land, and fulfills a variety of functions necessary for maintaining coastal ecosystem. Although it is critical to protect and strengthen its functions of coastal wetlands, tidal flat has been mainly viewed as areas for development in Korea. Therefore, this study provides with the effective mitigation measures so as to minimize adverse impacts of tidal flat reclamation projects on the proper environmental values. So far, coastal development has not considered as important the fact that development site consists of tidal flat in site selection. Therefore, large scale of tidal flats was abused. Problems were emerged only after tidal flat development was already planned. The original plan had to be revised. To rectify the problem, impacts of development on the environment need to be discussed based on the initial development planning. Particularly, sandy beaches, rocky shores and shallow areas, underwater forest including seagrass beds as well as the tidal flat in good condition should be excluded from development site.

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.23-36
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• 2010

The Cat Ba Islands in Hai Phong City, northern Vietnam, consist of a large limestone island with a maximum height of 322 m above sea level and 366 small limestone islets with a total area of about $180\;km^2$. The islands are relicts of karst limestone mountains that became submerged during the Holocene transgression 7000 - 8000 year ago. The combination of the longtime karst process and recent marine processes in the monsoonal tropical zone has created a very diversity landscape on the Cat Ba Islands that can be divided into 3 habitat types with 16 forms. The first habitat type is the karst mountains and hills, including karst mountains and hills, karst valleys and dolines, karst lakes, karst caves, and old marine terraces. The second habitat type is the limestone island coast, including beaches, mangrove marshes, tidal flats, rocky coasts, marine notch caves, marine karst lakes, and bights. The third habitat type is karst plains submerged by the sea, including karst cones (fengcong) and towers (fengling), bedrock exposed on the seabed, sandy mud seabed, and submerged channels. Like the landscape, the biodiversity is also high in ecosystems composed of scrub cover - bare hills, rainy tropical forests, paddy fields and gardens, swamps, caves, beaches, mangrove forests, tidal flats, rocky coasts, marine krast lakes, coral reefs, hard bottoms, seagrass beds and soft bottoms. The ecosystems on the Cat Ba Islands that support very high species biodiversity include tropical evergreen rainforests, soft bottoms; coral reefs, mangrove forests, and marine karst lakes. A total of 2,380 species have been recorded in the Cat Ba Islands, included 741 species of terrestrial plants; 282 species of terrestrial animals; 30 species of mangrove plants; 287 species of phytoplankton; 79 species of seaweed; 79 species of zooplankton; 196 species of marine fishes; 154 species of corals; and 538 species of zoobenthos. Many of these species are listed in the Red Book of Vietnam as endangered species, included the white-headed or Cat Ba langur (Trachypithecus poliocephalus), a famous endemic species. Human activities have resulted in significantly changes to the landscape end ecosytems of the Cat Ba islands; however, many natural aspects of the islandsd have been preserved. For this reason, the Cat Ba Islands were recognized as a Biological Reserved Area by UNESCO in 2004.

• Journal of Wetlands Research
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• v.26 no.1
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• pp.82-91
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• 2024

In this study, research cases related to blue carbon storage were collected and analyzed, and various definitions of blue carbon were considered in terms of spatiotemporal scope and scientific aspect. 444 papers were selected as research cases related to blue carbon storage, and analysis of the number of papers published by year/country and keywords was performed. Publication of papers related to blue carbon storage has continued to increase since 2011, and more than 50 papers have been published annually since 2018. The most publications by country were in Australia with more than 100 papers, and the United States and China also published more than 60 papers. Key terms related to "natural environment" and "storage characteristics" were analyzed in the sentences defined in the 23 papers that presented the definition of blue carbon. The natural environments where blue carbon was stored were mostly mangroves, salt marshes, and seagrass beds, and blue carbon repository included sediments and even plants themselves. The existing definition of blue carbon focused on the vegetation environment as the storage environment for blue carbon. However, since blue carbon is stored in the sediments of coastal wetlands, it would be appropriate to define the coastal ecosystem, including non-vegetated mudflats, as the storage environment for blue carbon.