• Title/Summary/Keyword: Geosphere

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Distribution of Carex nakasimae Ohwi, a Korean endemic sedge (Cyperaceae)

  • CHUNG, Kyong-Sook;IM, Hyoung-Tak;MASAKI, Tomomi;HOSHINO, Takuji;LEE, Chang-Shook
    • Korean Journal of Plant Taxonomy
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    • v.50 no.2
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    • pp.239-246
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    • 2020
  • Carex nakasimae Ohwi (Cyperaceae) is an endemic species on the Korean peninsula. This study reports a new locality of the species, updating the distribution map. A new population of the species was found during field surveys in 2014 in a small swamp in Haman-gun, Gyeongsangnam-do province, located in the southeastern part of the Korean peninsula. In the flowering and fruiting periods of the species, the population is associated with ca. 91 vascular plant taxa from 40 families. To conserve the endemic species, maintaining the habitat is critical. Furthermore, taxonomic and phylogenetic positions of the species should be clarified to establish biological conservation strategies for the rare, endemic C. nakasimae.

Effect of land use and urbanization on groundwater recharge in metropolitan area: time series analysis of groundwater level data

  • Chae, Gi-Tak;Yun, Seong-Taek;Kim, Dong-Seung;Choi, Hyeon-Su
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.09a
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    • pp.113-114
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    • 2004
  • In order to classify the groundwater recharge characteristics in an urban area, a time series analysis of groundwater level data was performed. For this study, the daily groundwater level data from 35 monitoring wells were collected for 3 years (Fig. 1). The use of the cross-correlation function (CCF), one of the time series analysis, showed both the close relationship between rainfall and groundwater level change and the lag time (delay time) of groundwater level fluctuation after a rainfall event. Based on the result of CCF, monitored wells were classified into two major groups. Group I wells (n=10) showed a fast response of groundwater level change to rainfall event, with a delay time of maximum correlation between rainfall and groundwater level near 1 to 7 days. On the other hand, the delay time of 17-68 days was observed from Group II wells (n=25) (Fig. 1). The fast response in Group I wells is possibly caused by the change of hydraulic pressure of bedrock aquifer due to the rainfall recharge, rather than the direct response to rainfall recharge.

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Hydrogeochemical processes and behavior of nitrate in an dlluvial aquifer: A preliminary result from Cheonan area, Korea

  • Kim, Kyoung-Ho;Yun, Seong-Taek;Choi, Byoung-Young;Kim, Kang-Joo
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.04a
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    • pp.97-99
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    • 2004
  • To understand the geochemical processes controlling the distribution of nitrate and other agricultural constituents in an alluvial aquifer, hydrogeological and hydro geochemical studies were carried out in an agricultural area within Cheonan. In this selected field, nitrate concentrations were very wide in range but was locally attenuated significantly down to very low levels (<1.0 mg/L). Abrupt removal of nitrate coincided with the pattern of redox change and thus indicated that geochemical processes occurring during and after recharge events control the behavior and distribution of nitrate and other redox-sensitive chemical species.

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