Upo Wetland Research Articles

우포늪의 부영양화도 및 유기물 오염도 평가

우포늪의 부영양화도 및 유기물 오염도 평가

A 2000-year environmental history of the Upo Wetland on the Korean Peninsula

The Upo Wetland was designated an internationally important wetland by the Ramsar Convention and is the largest inland wetland on the Korean Peninsula. This study was conducted to reveal the environmental history of the wetland and its surroundings, and to evaluate the influence of human activities on the ecosystem. We used information from historical documents and sediment records to investigate the wetland. A 40-cm sediment core was collected and dated using 210Pb and 14C. Physical and chemical variables in the core were measured and pollen was analyzed. The environmental history of the Upo Wetland over the last 2,000 years was divided into three phases. Seawater may have entered the wetland around 2,000 years ago. Upo was probably a riverine wetland with a floodplain that experienced relatively rapid water flow and erosion until about AD 870. Thereafter, Upo became a palustrine wetland with lacustrine characteristics during an unstable environmental phase until some time between 870 and 1880 AD, when water flow decreased and both the water retention time and the area of flooding within the wetland increased. Construction of artificial levees within the wetland during the twentieth century constituted an anthropogenic impact superimposed on natural changes, and Upo became a shallow lake. Inputs of nutrients and other pollutants from the catchment continue to threaten the Upo ecosystem despite the establishment of policies intended to protect this important ecosystem.

An Observational Study on the Differences in Thermal Characteristics of the Upo Wetland and Converted Areas from Wetland to Paddy Field

This study intended to collect data for evaluating the meteorological value of Upo Wetland which is the largest wetland in the downstream of Nakdong River. The observations were conducted in summer at the Upo Wetland and its surrounding paddy field that is the converted areas from a wetland to a paddy field. The following results are obtained: 1) The temperature of Upo Wetland area was <TEX>$1^{\circ}C$</TEX> lower than the surrounding area during the day while it was a little higher during the night.; 2) The maximum wind speed in the Upo Wetland area was 3.5 m/s which is stronger than 1.6 m/s of its surrounding area. The south wind was observed in the farmland for most of the day while north winds and south winds alternated between day and night in Upo Wetland.; 3) In heat budget analysis, Upo Wetland was wasted in the form of latent heat rather than sensible heat in daytime.

Heavy Metal Accumulation in Oxyloma hirasei from the Upo Wetland

Human activities have enhanced the influx of heavy metals to aquatic ecosystem and hanged the abiotic environment such as the sediments supporting benthic organisms. The levels of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the benthic gastropod Oxyloma hirasei and the sediments around their habitat were investigated to examine heavy metal levels and the potential of the gastropod as a bioindicator. We detected different levels of heavy metals in the sediments of two wetland areas, Upo and Mokpo, in the relatively well-conserved Upo wetland, Ramsar Convention Area. Oxyloma hirasei had higher concentrations of heavy metals except Cr and Ni in their soft tissues than in their shells (Cd: <TEX>$2.10{\sim}3.16$</TEX>, Cu: <TEX>$19.73{\sim}28.66$</TEX>, Pb: <TEX>$0.67{\sim}1.17$</TEX>, Zn: <TEX>$216.1{\sim}285.7\;{\mu}g/g$</TEX> dry weight in the soft tissues; Cr: <TEX>$1.19{\sim}2.58$</TEX>, Ni: <TEX>$0.47{\sim}1.16\;{\mu}g/g$</TEX> dry weight in the shells). Differences in the Cd, Cu, Ni and Pb concentrations in O. hirasei soft tissues reflected differences in heavy metal concentrations in the sediments at the sampling sites. The coefficients of variation for Cd, Cu and Pb were lower than those for other metals in the soft tissues. Levels of Cd in the tissues of O. hirasei were the highest among the metals examined in this study. Therefore, the soft tissue of O. hirasei appears to be a promising bioindicator particularly for Cd.

Heavy Metal Concentrations in the Mollusc Gastropod, Cipangopaludina chinensis malleata from Upo Wetland Reflect the Level of Heavy Metals in the Sediments

Upo wetland is the largest inland wetland in Korea as Ramsar Convention Area. The purposes of the study were to investigate the levels of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in the sediment and Cipangopaludina chinensis malleata from three sites of the wetland and to assess the potential of the gastropod as a bioindicator for heavy metal levels. The gastropods were dissected into shell and soft tissue without the digestive and excretive organs. The levels of Cd, Cu and Pb were below the guideline of Soil Environment Conservation Act and the heavy metals except Cr were slightly different among the sites. Cd was higher in Upo site (0.32 μg/g) than Sajipo site (0.28 μg/g). Cu and Zn showed the highest value in Sajipo as 43.5 μg/g and 39.8 μg/g, respectively while the concentrations of Pb and Zn were the highest in Upstream as 58.8 μg/g and 138 μg/g, respectively. In the soft tissues and shells of the gastropod, the overall common trend in the concentrations of the heavy metals was revealed with the following order: Zn > Cu > Cr > Ni > Pb > Cd and Ni > Zn > Cr > Cu > Pb > Cd, respectively. Although the soft tissues exhibited higher concentrations of the heavy metals except Ni than the shell in the gastropod, the levels of Cd and Pb in the gastropod were generally below the restrictive values set up by Korea Food & Drug Administration. From Duncan's Multiple Range Test (DMRT) results, the concentrations of Pb and Zn in the sediments among the sites were reflected on the soft tissue (Pb) and the shell (Pb and Zn) of the gastropod in the same order. The lower value of coefficient of variation (CV) in Pb concentration of the shell than in that of the soft tissue supports the usefulness of the shell as a bioindicator for Pb pollution. Although the CV value in the shell was a little higher than in the soft tissue, DMRT results and the stability of incorporated Zn into the shell support the use of the shell of the gastropod as a potential bioindicator for long-term contamination of Zn.

Ecotourism of Upo Wetland and Perceptions of Stakeholders

The purposes of this study were to investigate ecotourism goals of conservation and increasing residents' benefits based on perceptions from the stakeholders of the Upo wetland. The stakeholders are residents, five villages' reprensentatives, people who were residents but now live out of the area, civil officals, and environmental NGO staffs of he Upo wetland. The results of this study were as follows: While the perceptions of environmental conservation among interviewees were positive, the residents' perceptions about residents' benefits were very negative in the Upo wetland. People who used to reside and then moves out had pride about the Upo and they wanted to return to live in the Upo wetland area. Even though the wetland is named as one of the most well known ecotourism sites by the Ministry of Environment and Korean National Ecotourism Organization(KNTO), the Upo wetland area is not an ecotourism site yet based on the definition of ecotourism goals which seek generating conservation and residents' benefits in this study. There are suggestions for this wetland area. The conservation policy with the residents' benefits are strongly recommended.

Holocene paleosols of the Upo wetland, Korea: Their implications for wetland formation

A 4.490 m long core UP-1 was recovered from the marginal part of the Upo wetland. The wetland is a typical riverine wetland in Korea and has been designated as a Protected Wetland in accordance with the International Ramsar Treaty. We studied the Holocene environmental changes of the Upo wetland and the depositional conditions under which the Upo wetland formed. The core is divided into four units on the basis of grain size distribution, abundance of mottles and vertical color variation. Unit 1 has undergone pedogenic processes, resulting in variably weak to moderate soil profile development. Unit 1 paleosols are regarded as synsedimentary soils of floodplain origin, and the radiocarbon data suggest that the whole paleosol profile spans the last 5790 years. The boundaries between the soil horizons are not clear-cut, probably due to a repeated cycle of accumulation, denudation and soil-forming processes. The recurrence of these processes initiated the development of the Upo wetland. The lower boundary of Unit 2 lies at about 2300 14C yr BP, the beginning of the Subatlantic age in Korea. The lack of intense soil formation and abundant clay content in Unit 2 indicate that the geomorphologically stable wetland was developed around the coring site at that time. This means that the depositional environment changed from a floodplain to a stable, continuously submerging wetland setting. An abrupt change in sediment textures was detected in Unit 3, which commenced formation around 1000–900 14C yr BP, indicative of geological events such as inundations or inflows of slope-wash sediments. Anthropogenic deforestation and plowing around the Upo wetland area might have started at that time.