Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 12 2 2008 10.5194/hess-12-437-2008 http://www.hydrol-earth-syst-sci.net/12/437/2008/ http://www.hydrol-earth-syst-sci.net/12/437/2008/hess-12-437-2008.html http://www.hydrol-earth-syst-sci.net/12/437/2008/hess-12-437-2008.pdf 437 447 2008-03-05 Modelling the effects of climate on long-term patterns of dissolved organic carbon concentrations in the surface waters of a boreal catchment M. N. Futter m.futter@macaulay.ac.uk M. Starr M. Forsius M. Holmberg Watershed Ecosystems Graduate Program, Trent University, Peterborough, K9J 7B8, Canada Department of Forest Ecology, University of Helsinki, P.O. Box 27, 00014 Helsinki, Finland Finnish Environment Institute, P.O. Box 140, 00251 Helsinki, Finland now at: Macaulay Land Use Research Institute, Craigiebuckler, AB15 8QH, UK Dissolved organic carbon concentrations ([DOC]) in surface waters are increasing in many regions of Europe and North America. These increases are likely driven by a combination of changing climate, recovery from acidification and change in severity of winter storms in coastal areas. INCA-C, a process-based model of climate effects on surface water [DOC], was used to explore the mechanisms by which changing climate controls seasonal to inter-annual patterns of [DOC] in the lake and outflow stream of a small Finnish catchment between 1990 and 2003. Both production in the catchment and mineralization in the lake controlled [DOC] in the lake. Concentrations in the catchment outflow were controlled by rates of DOC production in the surrounding organic soils. The INCA-C simulation results were compared to those obtained using artificial neural networks (ANN). In general, "black box" ANN models provide better fits to observed data but process-based models can identify the mechanism responsible for the observed pattern. A statistically significant increase was observed in both INCA-C modelled and measured annual average [DOC] in the lake. This suggests that some of the observed increase in surface water [DOC] is caused by climate-related processes operating in the lake and catchment. However, a full understanding of surface water [DOC] dynamics can only come from catchment-scale process-based models linking the effects of changing climate and deposition on aquatic and terrestrial environments. Bergström, I., Mäkelä, K., and Starr, M. (Eds.): Integrated Monitoring Programme in Finland, First National Report, Ministry of the Environment, Environmental Policy Department, Report 1. 1995, Ministry of the Environment, p. 138 (+7 appendices), 1995. Burns, D. A., McHale, M. R., Driscoll, C. T., and Roy, K. M.: Response of surface water chemistry to reduced levels of acid precipitation: comparison of trends in two regions of New York, USA, Hydrol. Processes, 20, 1611–1627, 2006. Chow, A. T., Tanji, K. K., and Gao, S.: Production of dissolved organic carbon (DOC) and trihalomethane precursor (THM) from peat soils, Water Res., 37, 4475–4485, 2003. Christ, M. J. and David, M. B.: Temperature and moisture effects on the production of dissolved organic carbon in a spodosol, Soil Biol. Biochem., 28, 1191–1199, 1996. Clair, T. A., Pollock, T. L., and Ehrman, J. M.: Exports of carbon and nitrogen from river basins in Canada's Atlantic provinces, Global Biogeochem. Cy., 8, 441–450, 1994. Clair, T. A., Ehrman, J. M., and Higuchi, K.: Changes in freshwater carbon exports from Canadian terrestrial basins to lake and estuaries under a 2XCO₂ atmospheric scenario, Global Biogeochem. Cy., 13, 1091–1097, 1999. De Wit, H. A., Kotowski, M., and Mulder, J.: Modeling aluminum and organic matter solubility in the forest floor using WHAM, Soil Sci. Soc. Am. J., 63, 1141–1148, 1999. Dillon, P. J. and Molot, L.: Dissolved organic and inorganic carbon mass-balances in central Ontario lakes, Biogeochemistry, 36, 29–42, 1997. Evans, C. D.: Modelling the effects of climate change on an acidic upland stream, Biogeochemistry, 74, 21–46, 2005. Evans, C. D., Monteith, D. T., and Cooper, D. M.: Long-term increases in surface water dissolved organic carbon: Observations, possible causes and environmental impacts, Environ. Pollut., 137, 55–71, 2005. Freeman, C., Ostle, N., and Kang, H.: An enzymatic `latch' on a global carbon store, Nature, 409, p. 149, 2001. Freeman, C., Fenner, N., Ostle, N. J., Kang, H., Dowrick, D. J., Reynolds, B., Lock, M. A., Sleep, D., Hughes, S., and Hudson, J.: Export of dissolved organic carbon from peatlands under elevated carbon dioxide levels, Nature, 430, 195–198, 2004. Forsius, M., Kleemola, S., Starr, M., and Ruoho-Airola, T.: Ion mass budgets for small forested catchments in Finland, Water Air Soil Poll., 79, 19–38, 1995. Futter, M. N., Butterfield, D., Cosby, B. J., Dillon, P. J., Wade, A. J., and Whitehead, P. G.: Modeling the mechanisms that control in-stream dissolved organic carbon dynamics in upland and forested catchments, Water Resour. Res., 43, W02424, doi:10.1029/2006WR004960, 2007. Futter, M. N. and de Wit, H.: What controls dissolved organic carbon concentrations in streams: a comparison of empirical and process-based models, Sci. Total Environ., in press, 2008. Gennings, C., Molot, L. A., and Dillon, P. J.: Enhanced photochemical loss of organic carbon in acidic waters, Biogeochemistry, 52, 339–354, 2001. Holmberg, M., Forsius, M., Starr, M., and Huttunen, M.: An application of artificial neural networks to carbon, nitrogen and phosphorus concentrations in three boreal streams and impacts of climate change, Ecol. Modell., 195, 51–60, 2006. Hongve, D., Riise, G., and Kristiansen, J. F.: Increased colour and organic acid concentrations in Norwegian forest lakes and drinking water: a result of increased precipitation?, Aquatic Sci., 66, 231–238, 2004. Kalbitz, K., Solinger, S., Park, J.-H., Michalzik, B., and Matzner, E.: Controls on the dynamics of dissolved organic matter in soils: A review, Soil Sci., 165, 277–304, 2000. Keskitalo, J., Salonen, K., and Holopainen, A.-L.: Long-term fluctuations in environmental conditions, plankton and macrophytes in a humic lake, Valkea-Kotinen, Bor. Environ. Res., 3, 251–262, 1998. Kortelainen, P. and Saukkonen, S.: Leaching of nutrients, organic carbon and iron from Finnish forestry land, Water Air Soil Poll., 105, 239–250, 1998. Kurka, A.-M., Starr, M., Heikinheimo, M., and Salkinoja-Salonen, M.: Decomposition of cellulose strips in relation to climate, litterfall nitrogen, phosphorus and C/N ratio in natural boreal forests, Plant. Soil, 219, 91–101, 2000. Lennon, J. T.: Experimental evidence that terrestrial carbon subsidies increase CO₂ flux from lake ecosystems, Oecologia, 138, 584–591, 2004. Lischeid, G. and Langusch, J.: Comparative simulation of the nitrogen dynamics using the INCA model and a neural network analysis: implications for improved nitrogen modelling, Hydrol. Earth Syst. Sci., 8, 742–750, 2004. Liski, J., Palosuo, T., Peltoniemi, M., and Sievänen, R.: Carbon and decomposition model Yasso for forest soils, Ecol. Modell., 189, 168–182, 2005. Michalzik, B., Tipping, E., Mulder, J., Gallardo Lancho, J. F., Matzner, E., Bryant, C. L., Clarke, N., Lofts, S., and Vincente Esteban, M. A.: Modelling the production and transport of dissolved organic carbon in forest soils, Biogeochemistry, 66, 241–264, 2003. Nash, J. E. and Sutcliffe, J. V.: River flow forecasting through conceptual models Part I – a discussion of principles, J. Hydrol., 10, 282–290, 1970. Neff, J. C. and Asner, G. P.: Dissolved organic carbon in terrestrial systems: synthesis and a model, Ecosystems, 4, 29–48, 2001. Rankinen, K., Karvonen, T., and Butterfield, D.: A simple model for predicting soil temperature in snow-covered and seasonally frozen soil: model description and testing, Hydrol. Earth Syst. Sci., 8, 706–716, 2004. Ravichandran, M.: Interactions between mercury and dissolved organic matter – a review, Chemosphere, 55, 319–331, 2004. Salonen, K., Arvola, L., Tulonen, T., Hammar, T., Metsälä, T.-R., Kankaala, P., and Münster, U.: Planktonic food chains of a highly humic lake. I. A mesocosm experiment during the spring primary production maximum, Hydrobiologia, 229, 125–142, 1992. Salonen, K. and Vähätalo, A.: Photochemical mineralisation of dissolved organic matter in lake Skjervatjern, Environ. Int., 20, 307–312, 1994. Salthun, N. R.: The "Nordic" HBV Model. Description and documentation of the model version developed for the project Climate Change and Energy Production, NVE Publication 7, Norwegian Water Resources and Energy Administration, Oslo, 26 pp., 1996. Schindler, D. W., Curtis, P. J., Bayley, S. E., Parker, B. R., Beaty, K. G., and Stainton, M. P.: Climate-induced changes in the dissolved organic carbon budgets of boreal lakes, Biogeochemistry, 36, 9–28, 1997. Schlesinger, W. H.: Biogeochemistry: an analysis of global change, Academic Press, 1991. Seibert, J. and McDonnell, J. J.: On the dialog between modeler and experimentalist in catchment hydrology: use of soft data for multi-criteria model calibration, Water Resour. Res., 38, 1241, doi:10.1029/2001WR000978, 2002. Skjelkvåle, B. L., Stoddard, J. L., Jeffries, D. S., Tørseth, K., Hogasen, T., Bowman, J., Mannio, J., Monteith, D. T., Mosello, R., Rogora, M., Rzychon, D., Vesely, J., Wieting, J., Wilander, A., and Worsztynowicz, A.: Regional scale evidence for improvements in surface water chemistry 1990–2001, Environ. Pollut., 137, 165–176, 2005. Starr, M. and Ukonmaanaho, L.: Levels and characteristics of TOC in throughfall, forest floor leachate and soil solution in undisturbed boreal forest ecosystems, Water Air Soil Poll. Focus, 4, 715–729, 2004. Starr, M. and Ukonmaanaho, L.: Results from the first round of the integrated monitoring soil chemistry subprogramme, in: Forest Condition in Finland, edited by: Ukonmaanaho, L. and Raitio, H., National Report 2000, Finnish Forest Research Institute, Helsinki, Research Papers 824, 140–157, 2001. Starr, M., Vanhala, P., and Forsius, M.: Progress report on calculation of carbon and nitrogen budgets for Finnish ICP IM catchments, in: 14th Annual Report 2005, edited by: Kleemola, S. and Forsius, M., UN ECE ICP Integrated Monitoring, Finnish Environment Institute, Helsinki, Finland, The Finnish Environment, 788, 44–49, 2005. Ukonmaanaho, L., Starr, M., and Ruoho-Airola, T.: Trends in sulphate, base cations and H$^+$ concentrations in bulk precipitation and throuhgfall at integrated monitoring sites in Finland 1989–1995, Water Air Soil Poll., 105, 353–363, 1998. Vähätalo, A. V.: Role of photochemical reactions in the biogeochemical cycling of detrital carbon in aquatic ecosystems, Academic Dissertation in Microbiology, University of Helsinki, Finland, 2000. Vähätalo, A. V. and Wetzel, R. G.: Photochemical and microbial decomposition of chromophoric dissolved organic matter during long (months – years) exposure, Mar. Chem., 89, 313–326, 2004. Vähätalo, A. V., Salonen, K., Münster, U., Järvinen, M., and Wetzel, R. G.: Photochemical transformation of allochthonous organic matter provides bioavailable nutrients in a humic lake Arch, Hydrobiol., 156, 287–314, 2003. Vähätalo, A. V., Salkinoja-Salonen, M., Taalas, P., and Salonen, K.: Spectrum of the quantum yield for photochemical mineralization of dissolved organic carbon in a humic lake, Limnol. Oceanogr., 45, 664–676, 2000. Vuorenmaa, J., Forsius, M., and Mannio, J.: Increasing trends of total organic carbon concentrations in small forest lakes in Finland from 1987 to 2003, Sci. Total Environ., 365, 47–65, 2006. Wade, A. J., Durand, P., Beaujouan, V., Wessel, W. W., Raat, K. J., Whitehead, P. G., Butterfield, D., Rankinen, K., and Lepistö, A.: A nitrogen model for European catchments: INCA, new model structure and equations, Hydrol. Earth Syst. Sci., 6, 559–582, 2002. Wright, R. F., Aherne, J., Bishop, K., Camarero, L., Cosby, B. J., Erlandsson, M., Evans, C. D., Forsius, M., Hardekopf, D. W., Helliwell, R., Hruska, J., Jenkins, A., Kopáček, J., Moldan, F., Posch, M., and Rogora, M.: Modelling the effect of climate change on recovery of acidified freshwaters: relative sensitivity of individual processes in the MAGIC model, Sci. Total Environ., 365, 154–166, 2006. Worrall, F., Harriman, R., Evans, C. D., Watts, C. D., Adamson, J., Neal, C., Tipping, E., Burt, T., Grieve, I., Monteith, D., Naden, P. S., Nisbet, T., Reynolds, B., and Stevens, P.: Review of riverine DOC trends in the UK, Biogeochemistry, 70, 369–402, 2004.