The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY (한국해양학회지:바다)

The Korean Society of Oceanography (한국해양학회)
권호 표지
DOI QR코드

DOI QR Code

Effect of Freshwater Discharge on the Seawater Quality (Nutrients, Organic Materials and Trace Metals) in Cheonsu Bay

여름철 천수만 해수에서 담수 대량 방류에 따른 영양염, 유기물 및 미량금속의 변화

  • LEE, JI-YOON (Korea Environmental Science & Technology Institute Inc.) ;
  • CHOI, MAN-SIK (Department of Marine Environmental Science, Chungnam National University) ;
  • SONG, YUNHO (Korea Marineaid Co., Ltd.)
  • Received : 2019.06.07
  • Accepted : 2019.10.18
  • Published : 2019.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

When the fresh water from the artificial lakes (Ganwolho and Bunamho) were discharged to Cheonsu Bay in summer to prevent the flood over the reclaimed farmland near the lakes, the impact on water qualities (nutrients, organic matters, trace metals) within the bay was investigated through four surveys (June, July, August and October, 2011). Dissolved inorganic nitrogen (DIN) increased about as much as 3-4 times over the whole water column when the freshwater was discharged. And the main species composition of DIN changed from ammonia to nitrate. Dissolved inorganic phosphorus (DIP) decreased as much as 2 times in surface waters, but increased as much as 1.5 times in deep waters, and also silicate concentrations increased as much as 3-4 times in deep waters of the inner bay. The N/P ratios in Chunsu bay seawaters were much higher (2 to 7 times) than the Redfield ratio when the freshwaters were discharged, which indicated the phosphorus limiting in the phytoplankton growth. Dissolved organic carbon (DOC) and nitrogen (DON) increased as much as about 2 times. In addition, particulate organic matters (POC, PON, POP, Bio-Si) increased as much as above 2 times in the surface waters of the inner bay. Trace metals (Fe, Mn, Co, Ni, Cu) increased in the surface waters of the inner bay, but dissolved Cd concentrations decreased as much as 2 times. Therefore, when the contaminated fresh waters from the artificial lakes were discharged into the bay, nutrients, organic matters and trace metals generally increased compared to normal period. Since the phytoplankton bloom occurred in the surface waters of the inner bay, dissolved oxygens at the surface waters were oversaturated and hence hypoxic in the deep waters. Highly enriched nutrients concentrations were found in deep waters of the inner bay, which was accompanied with the hypoxic condition. Finally, the water quality in the inner bay of the Chunsu bay was deteriorated from less than grade 3 in normal periods to grade 5 when the freshwaters from the artificial lakes were discharged in summer.

여름철 인공호수(간월호, 부남호)로 부터의 담수방류시 천수만 수질(영양염, 유기물, 미량금속)에 미치는 영향을 평가하기 위해 2011년 6, 7, 8, 10월에 평상시와 담수방류 시기 각 2회씩의 해수를 채취하였다. 담수가 방류되면 용존 무기 질소(DIN)의 농도가 만내의 모든 수층에서 약 3-4배 증가하였고, 평상시 암모니아성 질소(NH4+-N)가 우세하다가 담수방류시 질산성 질소(NO3--N)가 우세하였다. 용존 무기인(DIP)의 경우 내만 표층에서 절반으로 감소하였고 저층에서는 1.5배 증가하였으며 규산염(Si(OH)4)은 내만 저층에서 2배 증가하는 모습을 보였다. Redfield ratio는 담수 방류시 인 제한 환경으로 바뀌었다. 용존 유기 탄소(DOC) 및 질소(DON)는 약 2배 증가하였고, 입자상 유기 탄소(POC), 질소(PON), 인(POP) 및 생물기원 규소(Bio-SiO2)는 내만 표층에서 약 2배 이상 증가했다. 용존 금속(Fe, Co, Ni, Cu)은 내만의 표층에서 증가하였으나, 용존 Cd의 경우 만의 표층에서 절반으로 감소하였다. 이와 같은 결과로 미루어 볼 때 영양염, 유기물 및 금속 농도가 높은 인공호수의 물이 만으로 유입되면, 천수만 내의 영양염 및 용존 유기물, 금속농도가 증가하고, 식물플랑크톤 대증식이 발생하여 표층에서 산소 과포화, 저층에서 빈산소를 발생시킨다. 빈산소와 함께 내만의 저층에서는 매우 높은 농도의 영양염(DIN, DIP, Si(OH)4) 농도가 존재하였다. 수질 평가 지수값을 통해 천수만의 부영양화 정도를 평가한 결과, 평상시에는 3등급 이하로 나타나다가 방류시 5등급으로 바뀌게 됨을 알 수 있었다.

Keywords

References

  1. Berger, C.J.M., S.M. Lippiatt, M.G. Lawrence and K.W. Bruland, 2008. Application of a chemical leach technique for estimating labile particulate aluminum, iron, and manganese in the Columbia River plume and coastal waters off Oregon and Washington. Journal of Geophysical Research-Oceans, 113(C00B01): 1-16.
  2. Boyle, E.A., S.S. Huested and B. Grant, 1982. The Chemical Mass Balance of the Amazon Plume. 2. Copper, Nickel, and Cadmium. Deep Sea Research, Part 1: Oceanographic Research Papers, 29(11): 1355-1364. https://doi.org/10.1016/0198-0149(82)90013-9
  3. Brzezinski, M.A., 1985. The Si:C:N ratio of marine diatoms: interspecific variablity and the effect of some environmental variables. Journal of Phycology, 21: 347-357. https://doi.org/10.1111/j.0022-3646.1985.00347.x
  4. Choi, Y.S., J.H. Song, S.P. Yoon, S.O. Chung, K.H. An and K.J. Park, 2014. The environmental characteristics and factors on the cultured manila clam (Ruditapes philippinarum) at Hwangdo and Jeongsanpo of Taean in the west coast of Korea. The Korean Journal of Malacology, 30(2): 117-126. https://doi.org/10.9710/kjm.2014.30.2.117
  5. Edmond, J.M., A. Spivack, B.C. Grant, H. Ming-Hui, C. Zexiam, C. Sung, and Z. Xiushau, 1985. Chemical dynamics of the Changjiang estuary. Continental Shelf Research, 4: 17-36 https://doi.org/10.1016/0278-4343(85)90019-6
  6. Froelich, P.N., L.W. Kaul, J.T. Byrd, M.O. Andreae and K.K. Roe. 1985. Arsenic, barium, germanium, tin, dimethylsulfide and nutrient biogeochemistry. Estuarine Coastal and shelf Science, 21: 239-264.
  7. Head, P.C., 1985. Practical Estuarine Chemistry. Cambrige Univ. Press, 337 pp
  8. Hecky, R.E., and P. Kilham, 1988. Nutrient limitation of phytoplankton biomass in in freshwater and marine environments: A review of recent evidence on the effects of enrichment. Limnology and Oceanography, 33: 796-822. https://doi.org/10.4319/lo.1988.33.4part2.0796
  9. Hydes, D.J. and P.S. Liss, 1977. The behaviour of dissolved aluminium in estuarine and coastal waters. Esuarine and Coastal Marine Science, 5: 755-769 https://doi.org/10.1016/0302-3524(77)90047-0
  10. Jung, K.Y., Y.J. Ro, Y.H. Choi and B.J. Kim, 2015. Hypoxia in a transient estuary caused by summer lake-water discharge from artificial dykes into Chunsu Bay, Korea. Marine Pollution Bulletin, 95: 47-62. https://doi.org/10.1016/j.marpolbul.2015.04.043
  11. Kaplan, W.A., 1983. Nitrification. In: Nitrogen In Marine Environment, edited by Carpenter, E.J. and D.C. Capone, Academic Press, New york, pp. 139-190.
  12. Kim, D.S., D.I. Lim, S.K. Jeon and H.S. Jung, 2005. Chemical characteristics and eutrophication in Cheonsu Bay, west coast of Korea. Ocean and Polar Research, 27(1): 45-58. https://doi.org/10.4217/OPR.2005.27.1.045
  13. Lee, D.K., K.H. Kim and J.S. Lee, 2016. Hypoxia and characteristics of nutrient distribution at the bottom water of Cheonsu Bay due to the discharge of eutrophicated artificial lake water. Jounal of the Korean Society of Marine Environment & Safety. 22(7): 854-862. https://doi.org/10.7837/kosomes.2016.22.7.854
  14. Lee, J.K., C. Park, D.B. Lee and S.W. Lee, 2012. Variations in plankton assemblage in a semi-closed Cheonsu Bay, Korea. The Sea, 17(2): 95-111. https://doi.org/10.7850/jkso.2012.17.2.095
  15. Lee, S.W., C. Park, D.B. Lee and J.K. Lee, 2014. Effects of frashwater discharge on plankton in Cheonsu Bay, Korea during rainy season. The Sea, 19(1): 41-52. https://doi.org/10.7850/jkso.2014.19.1.41
  16. Lee, T.W., 1996. Change in species composition of fish in Chonsu Bay. 1. Demersal fish. Journal of Korean Fishery Society, 29(1): 71-83.
  17. Moon, C.H., C. Park and S.Y. Lee, 1993. Nutrients and particulate organic matter in Asan Bay. Bulletin of Korean Fishery Society., 26(2): 173-181.
  18. Nixon, S.W. and M.E. Pilson, 1983. Nitrogen in Estuaries and Coastal Marine System. In:Nitrogen In Marine Environment, edited by Carpenter, E.J. and D.C. Capone, Academic Press, New york, pp. 565-638
  19. Paasche, E. and I. Ostergren, 1980. The annual cycle of plankton diatom growth and silica production in the inner Oslofjord. Limnology and Oceanography, 25: 481-494. https://doi.org/10.4319/lo.1980.25.3.0481
  20. Park, S.Y., G.S. Park, H.C. Kim, P.J. Kim, J.P. Kim, J.H. Park and S.Y. Kim, 2006. Long-term changes and variational characteristics of water quality in the Cheonsu Bay of the Yellow Sea, Korea. Journal of the Environmental Sciences. 15(5): 447-459. https://doi.org/10.5322/JES.2006.15.5.447
  21. Ragueneau, O., N. Savoye, Y. Del Amo, J. Cotten, B. Tardiveau and A. Leynaert, 2005. A new method for the measurement of biogenic silica in suspended matter of coastal waters: using Si : Al ratios to correct for the mineral interference. Continental Shelf Research, 25(5-6): 697-710. https://doi.org/10.1016/j.csr.2004.09.017
  22. Redfield, A.C., 1958. The biological control of chemical factors in the environment. American Science, 46: 205-221.
  23. Rho, T.G., T.S. Lee, S.R. Lee, M.S. Choi, C. Park, J.H. Lee, J.Y. Lee and S.S. Kim, 2012. Reference values and water quality assessment based on the regional environmental characteristics. The Sea 17(2): 45-58. https://doi.org/10.7850/jkso.2012.17.2.045
  24. Shim, J.H and W.H. Lee, 1979. On phytoplankton of the Cheonsu Bay, west coast. Journal of the Oceanological Society of Korea, 14(1): 6-14.
  25. Shim, J.H. and H.G. Yeo, 1988. Spatial and temporal variations of phytoplankton in Chŏnsu Bay. Journal of the Oceanological Society of Korea, 23(3): 130-145.
  26. Shim, J.H. and K.H. Yoon, 1990. Seasonal variation and production of zooplankton in Chonsu Bay, Korea. Journal of the Oceanological Society of Korea, 25(4): 229-239.
  27. Shim, J.H. and Y.K. Shin, 1989. Biomass of primary producer in the Chŏnsu Bay - relationships between phytoplankton carbon, dell number and chlorophyll. Journal of the Oceanological Society of Korea, 24(4): 194-205.
  28. Shin, Y.K., J.H. Shim, J.S. Jo and Y.C. Park, 1990. Relative significance of nanoplankton in Chonsu Bay: Species composition, abundance, chlorophyll and primary productivity. Journal of the Oceanological Society of Korea. 25(4): 217-228.
  29. Sohrin, Y., S. Urushihara, S. Nakatsuka, T. Kono, E. Higo, T. Minami, K. Norisuye and S. Umetani, 2008. Multielemental determination of GEOTRACES key trace metals in seawater by ICPMS after preconcentration using an ethylenediaminetriacetic acid chelating resin. Analytical Chemistry, 80(16): 6267-6273. https://doi.org/10.1021/ac800500f
  30. Song, Y.H. M.S. Choi and Y.W. Ahn, 2011. Trace metals in Chun-su Bay sediments. The Sea, 16(4): 169-179. https://doi.org/10.7850/jkso.2011.16.4.169
  31. Sugimura, Y. and Y. Suzuki, 1988. A high-temperature catalytic-oxidation method for the determination of non-volatile dissolved organic carbon in seawater by direct injection of a liquid sample. Marine Chemistry, 24(2): 105-131. https://doi.org/10.1016/0304-4203(88)90043-6
  32. Windom, H.L., R.G. Smith and C. Rawlinson., 1989. Particulate trace metal composition and flux across the southeastern U.S. continental shelf. Marine Chemistry, 27(3-4): 283-297. https://doi.org/10.1016/0304-4203(89)90052-2
  33. Zeitzschel B., 1970. The quantity, composition and distribution of suspended particulate matter in the gulf of California. Marine Biology, 7(4): 305-318. https://doi.org/10.1007/BF00750823