ISSN : 2287-8327
Background: Previous numerous studies on watershed scale demonstrated that the constructions of upper dams may influence the below dams due to modifications of flow regime and nutrient inputs. Little is known about how the dam constructions influence the downstream lakes or reservoirs in the regional scale. This study demonstrates how the construction of upper dam (i.e., Yongdam Dam) influences nutrient regime, trophic relations, and empirical models in Daechung Reservoir (DR). Yongdam Dam was constructed at the upstream region of DR in year 2000. Results: The analysis of hydrological variables showed that inflow and discharge in the DR were largely reduced after the year 2000. The construction of upper dam construction also resulted in increases of water temperature, pH and conductivity (as an indicator of ionic content) in the DR. Empirical models of TP-CHL and N:P ratio-CHL suggested that stronger responses of CHL to the phosphorus were evident after the upper dam construction, indicating that algal production at a unit phosphorus increased after the upper dam construction. Mann-Kendall tests on the relations of N:P ratios to TN showed weak or no relations (tau = −0.143, z = −0.371, p = 0.7105) before the dam construction, while the relation of N:P ratios to TP showed strong in the periods of before- (tau = −0714, z = −2.351, p = 0.0187) and after the construction (tau = −0.868, z = −4.270, p = 0.0000). This outcome indicates that TP is key determinant on N:P ratios in the reservoir. Scatter Plots on Trophic State Index Deviations (TSIDs) of “TSI(SD) - TSI(CHL)” against “TSI(TP) - TSI(CHL)” showed that the dominance of clay turbidity or light limitation was evident before the upper dam construction [TSI(TP) - TSI(CHL) > 0 and TSI(SD) - TSI(CHL) > 0] and phosphorus limitation became stronger after the dam construction [(TSI(TP) - TSI(CHL) < 0 and TSI(SD) - TSI(CHL) > 0]. Conclusions: Overall, our analysis suggests that the upper dam construction modified the response of trophic components (phytoplankton) to the nutrients or nutrient ratios through the alteration of flow regime, resulting in modifications of ecological functions and trophic relations in the low trophic levels.
An, K. G., & Jones, J. R. (2000). Factors regulating bluegreen dominance in a reservoir directly influenced by the Asian monsoon. Hydrobiologia, 432, 37–48.
An, K. G., & Park, S. S. (2002). Indirect influence of summer monsoon on Chlorophyll-total phosphorous models in reservoirs: a case study. Ecological Modelling, 152, 192–203.
Canfield, D. J., & Bachmann, R. W. (1981). Prediction of total phosphorus concentration, chlorophyll-a and Secchi depths in natural and artificial lakes. Canadian Journal of Fisheries and Aquatic Sciences, 38, 414–423.
Carlson, R. E. (1977). A trophic state index for lake. Limnology and Oceanography, 22, 361–369.
Cole, T. M., Hannan, H. H., et al. (1990). Dissolved oxygen dynamics. Chapter 4. In K. W. Thornton (Ed.), Reservoir Limnology: ecological perspectives. New York:Wiley.
Correll, D. L. (1999). Phosphorus: A rate limiting nutrient in surface waters. Poultry Science, 78, 674–682.
Havens, K. E., James, R. T., East, T. L., & Smith, V. H. (2003). N:P ratios, light limitation and cyanobacterial dominance in a subtropical lake impacted by non-point source nutrient pollution. Environmental Pollution, 122, 379–390.
Irigoien, X., & Castel, J. (1997). Light Limitation and Distribution of Chlorophyll Pigments in a Highly Turbid Estuary: the Gironde (SW France). Estuarine, Coastal and Shelf Science, 44, 507–517.
Kennedy, R. H., Thornton, K. W., & Gunkel, R. C. (1982). The establishment of water quality gradients in reservoirs. Canadian Water Resources Journal, 7, 71–87.
Kennedy, R. H., Thornton, K. W., & Ford, D. (1985). Characterization of the reservoir ecosystem. In D. Gunnison (Ed.), Microbial processes in reservoirs. Boston: Dr. W. Junk Publishers.
Kimmel, B.L. and A.W. Groeger. 1984. Factors controlling primary production in lakes and reservoirs; A perspective. In: Lake and Reservoir Management. U.S. EPA-440/5-84-001. Pp. 277-281.
Kimmel, B. L., Lind, O. T., & Paulson, L. H. (1990). Reservoir primary production. Chapter 6. In K. W. Thornton et al. (Eds.), Reservoir Limnology: Ecological Perspectives. New York: Wiley.
Lehman, P. W., Sommer, T., & Rivard, L. (2007). The influence of floodplain habitat on quantity and quality of riverine phytoplankton carbon produced during the flood season in San Francisco Estuary. Aquatic Ecology, 42, 363–378.
Moss, B. R. (1998). Ionic contents in the lake water were diluted by the rainwater and most pronounced in the riverine zone by high flow. Ecology of Fresh Waters: Man and Medium, Past to Future. By, school of biological sciences, university of Liverpool. UK: Blackwell Publishing.
Oberholster, P. J., Dabrowski, J., & Botha, A. M. (2013). Using modified multiple phosphorus sensitivity indices for mitigation and management of phosphorus loads on a catchment level. Fundamental and Applied Limnology/Archiv für Hydrobiologie, 182, 1–16.
O'Boyle, S., Wilkes, R., McDermott, G., Longphuirt, S. N., & Murray, C. (2015). Factors affecting the accumulation of phytoplankton biomass in Irish estuaries and nearshore coastal waters: A conceptual model. Estuarine,Coastal and Shelf Science, 155, 75–88.
Oh, H. M., Lee, S. J., Kim, J. H., Kim, H. S., & Yoon, B. D. (2001). Seasonal Variation and Indirect Monitoring of Microcystin Concentrations in Daechung Reservoir, Korea. Applied Environmental Microbiology, 67, 1484–1489.
Park, J. H., Duan, L., Kim, B., Mitchell, M. J., & Shibata, H. (2010). Potential effects of climate change and variability on watershed biogeochemical processes and water quality in Northeast Asia. Japan Environment International, 36, 212–225.
Prepas, E. E., & Rigler, F. A. (1982). Improvements in qualifying the phosphorus concentration in lake water. Canadian Journal of Fisheries and Aquatic Sciences, 39, 822–829.
Puckridge, J. T., Walker, K. R., & Costelloe, J. F. (2000). Hydrological persistence and the ecology of dryland rivers. Regulated Rivers: Research & Management, 16, 385–402.
Sartory, D. P., & Grobbelaar, J. U. (1984). Extraction of chlorophyll-a from freshwater phytoplankton for spectrophotometric analysis. Hydrobiologia, 114, 177–187.
Sedell, J. R., Reeves, G. H., Hauer, F. R., Stanford, J. A., & Hawkins, C. P. (1990). Role of refugia in recovery from disturbances: Modern fragmented and disconnected river systems. Section 4. Ecosystem and Landscape Constraints on Lotic Community Recovery Environmental Management, 14, 711–724.
Sterner, R. W. (2008). On the Phosphorus Limitation Paradigm for Lakes. International Review of Hydrobiology, 93, 433–445.
Straskraba, M. (1996). Lake and reservoir management. Verhandlungen des Internationalen Verein Limnologie, 26, 193–209.
Ward, J.V. and J.A. Stanford (1983). The serial discontinuity concept of lotic ecosystem. . In (eds, T.D. Fontaine and S.M. Bartel), Dynamics of lotic ecosystems (pp 29–42). Ann Arbor, Michigan, USA.
Wetzel RG (2001). Limnology: lake and river ecosystems 3rd Edition, ISBN: 978-0-12-744760-5.