• Title/Summary/Keyword: tidal flats

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Site Assessment Using Habitat Suitability Index for Manila Clam Ruditapes philippinarum in Geunso Bay Tidal Flats (서식지 적합지수를 이용한 근소만 갯벌 바지락(Ruditapes philippinarum)의 어장적지평가)

  • Choi, Yong-Hyeon;Hong, SokJin;Jeon, Seung-Ryul;Cho, Yoon-Sik
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.52 no.5
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    • pp.511-518
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    • 2019
  • Evaluating the habitat suitability of potential aquaculture sites for cultured species is critical to the sustainable use of tidal flats. This study evaluated the habitat suitability index (HSI) of 12 sites in a tidal flat aquaculture farm at Geunso Bay, Taean, in June 2016. The parameters used to model the suitability index were Growth (water temperature, chlorophyll ${\alpha}$, hydrodynamics), Survival (sediment-sand, mean size, air exposure), and Environment (DO, salinity). The HSI was calculated using weighted and No weighted geometric means. The results showed high habitat suitability at the bay's entrance (HIS; No weighted, 0.60-0.70; weighted, 0.60). Hydrodynamics, air exposure, sediment-sand and mean size are thought to have a significant impact on habitat selection by Manila clams Ruditapes philippinarum. This study explored the optimum habitat for Manila clams by calculating the HSI, providing basic data for tidal flat management.

Characteristics of Benthic Chlorophyll a and Sediment Properties in the Tidal Flats of Kwangyang Bay, Korea

  • Sin, Yong-Sik;Ryu, Sang-Ock;Song, Eun-Sook
    • ALGAE
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    • v.24 no.3
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    • pp.149-161
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    • 2009
  • Characteristics of benthic microalgae and sediment properties were investigated for the intertidal flats of Kwangyang Bay, Korea. Sampling stations were selected every 100 m in the intertidal flats from land-side to open ocean at two different sampling sites. Samples were collected in June 2004, July, September, November, February and May 2005. Sediments properties were measured including temperature, water contents, sediment bulk density, nutrient concentrations in porewater. Chlorophyll a concentrations in surface sediment (0.5 cm) were measured and relationships between the chlorophyll a and various sediment properties were analyzed to identify major mechanisms regulating biomass of benthic microalgae in the intertidal flats using simple linear regression analysis. Sediment chlorophyll a concentrations were maximum during winter and minimum during warm seasons ranging from 4.4 mg $m^{-2}\;to\;81.2\;mg\;m^{-2}$. No clear spatial variations were observed for the sediment chlorophyll a in the study sites. Results from regression analysis suggested that benthic microalgae biomass was affected by sediment temperature and nutrients especially ammonium and silicate. Grazing effect was estimated using chlorophyll: pheopigments ratio, indirect indicator of grazing activity, and the positive correlation of the ratio and chlorophyll a implied that microalgae biomass is affected by grazing of zoobenthos although direct measurement of grazing activity is required to determine the importance of top-down controls in the benthic microalgae dynamics.

Flood control analysis of the sea dike at estuary. (하구방조제의 홍수조절 해석)

  • 서승덕
    • Water for future
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    • v.10 no.2
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    • pp.113-124
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    • 1977
  • Alone the southwesten coast of Korean peninsula, the extensive available arable acreages suited for forming are found in the development of tidal flats in the geographically curved bays with a motable tidal emplitude. It was found that the developments of these tidal flats cover an estimated area more than 276,000ha. In this paper, a flood control system by Pul's Storage Indication Method and Pul's Graphical Method at Return Periods-50 yrs, design rainfall-267mm per 48hrs and design flood-926c.m.s. and at 0.2meter control height above the High Water Ordinary Spring Tide Level (+11.0m) was studied. At the result, the flood demage in the reservoir at Return Periods-50 yrs and the tidal level at H.W.O.S.T.L. were satisfied to the below E.L. 11.20m (Flood Level in the reservoir). Well skilled flood control technique and management and control of draining sluice gate should be required for the disaster prevention from the flood and tide damage.

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The Monitoring of Biogeochemical Interactions Between Sediment and Water: a Mesocosm Study

  • Yang, Jae-Sam;Kim, Yeong-Tae;Choi, Kang-Won
    • Journal of the korean society of oceanography
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    • v.39 no.1
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    • pp.107-118
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    • 2004
  • A series of mesocosm experiments has been conducted to investigate the effects of sediment on the qualities of superficial water over the tidal flats. The experiments involved two different kinds of sediments (Silt and Fine Sand) to mimic the natural habitats. Other environmental conditions in the mesocosm were kept as natural as possible. The mesocosm coincided with the annual patterns of the natural water qualities and was identical with the composition of benthic organisms of three reference sites of natural tidal flats. DIP has been leached out from sediment from June to October, but not for ammonium and DIN. The mesocosm was successfully able to simulate the environmental situations of natural tidal flat and will be a useful tool to assess the environmental impacts by human activities.

Age and Growth of the Crab Macrophthalmus japonicus from Tidal Flat of Bani Island, Jeollanamdo, Korea (전남 하의도 갯벌에 서식하는 칠게, Macrophthalmus japonicus의 연령과 성장)

  • Kwon, Dae-Hyeon;Choi, Ok-In;Ko, Byeong-Seol;Song, Jae-Hee;Jo, Young-Jo;Park, Ju-Nam
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.41 no.4
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    • pp.261-266
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    • 2008
  • The ocypodid crab, Macrophthalmus japonicus, commonly occurs in tidal flats in areas around Korea. We examined the age and growth of M. japonicus collected from the tidal flats of Haui Island in Jeollanamdo, Korea, from January to December 2006. According to variation in the monthly fatness index, the population spawned from June to August. To estimate parameters of growth, frequencies of monthly carapace lengths were analyzed using FiSAT II. The allometry of females differed from that of males. VBGE(von Bertalanffy growth equation) and seasonal VBGE were determined using monthly average carapace lengths for males and females, and an equation for estimating seasonal growth was calculated using regression coefficients.

Extraction of DEM in the Southern Tidal Flat of Kanghwa Island using Satellite Image (위성영상을 이용한 강화도 남단갯벌의 DEM 추출)

  • 박성우;정종철
    • Spatial Information Research
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    • v.11 no.1
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    • pp.13-22
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    • 2003
  • The study of geomorphology of tidal flat using remote sensing image has been considered useful because of it's ability to acquire data periodically. Especially, the Near Infrared band of satellite image has been used to divide between land and sea area. This study extracted a borderline of the tidal flat using Landsat-5 images and generated DEM(Digital elevation model) using tide level data as elevation value. DEM is a useful tool for three-dimensional survey of geomorphology and can be used for survey of tidal flat. This study divided 8 images of 1990's into two parts - before 1994 and after 1994 - and generated DEM respectively. In this work, the areas of tidal flats are calculated and it was revealed the area of tidal flat was decreased after 1994.

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The Generation of a Digital Elevatio Model in Tidal Flat Using Multitemporal Satellite Data (다시기 위성자료에 의한 조간대 수치지형모델의 작성)

  • 安忠鉉;梶原康司;建石降太郞;劉洪龍
    • Korean Journal of Remote Sensing
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    • v.8 no.2
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    • pp.131-145
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    • 1992
  • A low cost personal computer and image processing S/W were empolyed to derive Digtal Elevation Model(DEM) of tidal flat from multitemporal LANDSAT TM images, and to create three-dimensional(3D) perspective views of the tidel flat on Komso bay in west coasts of Korea. The method for generation of Digital Elevation Model(DEM) in tidal flat was considered by overlapping techniques of multitemporal LANDSAT TM images and interpolations. The boundary maps of tidal flat extracted from multitemporal images with different water high were digitally combined in x, y, z space with tide in formation and used as an inputcontour data to obtain an elevation model by interpolation using spline function. Elevation errors of less than $\pm$0.1m were achived using overlapping techniques and a spline interpolation approach, respectively. The derived DEM allows for the generation of a perspective grid and drape on the satellite image values to create a realistic terrain visualization model so that the tidal flat may be viewed from and desired direction. As the result of this study, we obtained elevation model of tidal flats which contribute to characterize of topography and monitoring of morphological evolution of tidal flats. Moreover, the modal generated here can be used for simulation of innudation according to tide and support other studies as a supplementary data set.

Fractal Analysis of Tidal Channel using High Resolution Satellite Image (고해상도 위성 영상을 이용한 조류로의 프랙털 분석)

  • Eom, Jin-Ah;Lee, Yoon-Kyung;Ryu, Joo-Hyung;Won, Joong-Sun
    • Korean Journal of Remote Sensing
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    • v.23 no.6
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    • pp.567-573
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    • 2007
  • Tidal channel development is influenced by sediment type, grain size, composition and tidal current. Tidal channels are usually characterized by channel formation, density and shape. Quantitative analysis of tidal channels using remotely sensed data have rarely been studied. The objective of this study is to quantify tidal channels in terms of fractal dimension and compare different inter-tidal channel patterns and compare with DEM (Digital Elevation Model). For the fractal analysis, we used box counting method which had been successfully applied to streams, coastlines and others linear features. For a study, the southern part of Ganghwado tidal flats was selected which know for high dynamics of tidal currents and vast tidal flats. This area has different widths and lengths of tidal channels. IKONOS was used for extracting tidal channels, and the box counting method was applied to obtain fractal dimensions (D) for each tidal channel. Yeochari area where channels showed less dense development and low DEM had low fractal dimenwion near $1.00{\sim}1.20$. Area (near Donggumdo and Yeongjongdo) of dendritic channel pattern and high DEM resulted in high fractal dimension near $1.20{\sim}1.35$. The difference of fractal dimensions according to channel development in tidal flats is relatively large enough to use as an index for tidal channel classification. Therefore we could conclude that fractal dimension, channel development and DEM in tidal channel has high correlation. Using fractal dimension, channel development and DEM, it would be possible to quantify the tidal channel development in association with surface characteristics.

Emergy Valuation of Tidal Flat Ecosystems in Korea: I. Characteristics of Environmental Emergy Inputs (에머지 방법론을 이용한 갯벌생태계의 가치 평가: I. 에머지 유입 특성)

  • NAM, JUNG HO;KANG, DAE SEOK
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.21 no.4
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    • pp.134-143
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    • 2016
  • This study analyzed the characteristics of emergy inputs from environmental sources that are essential in maintaining ecological processes and providing ecosystems services of the tidal flat ecosystems in Korea. Environmental sources provided a total of $4.98{\times}10^{21}sej/yr$ of emergy to the tidal flats of Korea. The emergy inputs from environmental sources were worth 1,141 billion ₩/yr. This is the value of environmental conditions that are the basis of ecosystem services provided by the tidal flat ecosystems. The emergy input per hectare to regional tidal flats decreased along the coastline from northwest to southeast, with the highest input in the Incheon-Gyeonggi area in the central western part of the Korean coast and the lowest input in the Busan area in the southeastern end. This reflects the general distribution pattern of the magnitude of tidal ranges along the Korean coast. There was no a clear-cut relationship between emergy inputs per unit area and fishery production(expressed in emergy quantity) per unit area. However, tidal flats in the west coast with higher emery inputs per unit area produced more fishery products than those in the south coast with lower emergy inputs, suggesting a possibility that the emergy inputs could be used for the rapid evaluation and comparison of the potential for ecosystem service provision by individual tidal flats.

Evaluating Changes in Blue Carbon Storage by Analyzing Tidal Flat Areas Using Multi-Temporal Satellite Data in the Nakdong River Estuary, South Korea (다중시기 위성자료 기반 낙동강 하구 지역 갯벌 면적 분석을 통한 블루카본 저장량 변화 평가)

  • Minju Kim;Jeongwoo Park;Chang-Uk Hyun
    • Korean Journal of Remote Sensing
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    • v.40 no.2
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    • pp.191-202
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    • 2024
  • Global warming is causing abnormal climates worldwide due to the increase in greenhouse gas concentrations in the atmosphere, negatively affecting ecosystems and humanity. In response, various countries are attempting to reduce greenhouse gas emissions in numerous ways, and interest in blue carbon, carbon absorbed by coastal ecosystems, is increasing. Known to absorb carbon up to 50 times faster than green carbon, blue carbon plays a vital role in responding to climate change. Particularly, the tidal flats of South Korea, one of the world's five largest tidal flats, are valued for their rich biodiversity and exceptional carbon absorption capabilities. While previous studies on blue carbon have focused on the carbon storage and annual carbon absorption rates of tidal flats, there is a lack of research linking tidal flat area changes detected using satellite data to carbon storage. This study applied the direct difference water index to high-resolution satellite data from PlanetScope and RapidEye to analyze the area and changes of the Nakdong River estuary tidal flats over six periods between 2013 and 2023, estimating the carbon storage for each period. The analysis showed that excluding the period in 2013 with a different tidal condition, the tidal flat area changed by up to approximately 5.4% annually, ranging from about 9.38 km2 (in 2022) to about 9.89 km2 (in 2021), with carbon storage estimated between approximately 30,230.0 Mg C and 31,893.7 Mg C.