Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 12 2 2008 10.5194/hess-12-363-2008 http://www.hydrol-earth-syst-sci.net/12/363/2008/ http://www.hydrol-earth-syst-sci.net/12/363/2008/hess-12-363-2008.html http://www.hydrol-earth-syst-sci.net/12/363/2008/hess-12-363-2008.pdf 363 370 2008-03-05 Recovery from episodic acidification delayed by drought and high sea salt deposition H. Laudon hjalmar.laudon@emg.umu.se Department of Ecology and Environmental Sciences, Umeå University, 901 87 Umeå, Sweden For the prediction of episodic acidification large uncertainties are connected to climatic variability and its effect on drought conditions and sea-salt episodes. In this study data on 342 hydrological episodes in 25 Swedish streams, sampled over 10 years, have been analyzed using a recently developed episode model. The results demonstrate that drought is the most important factor modulating the magnitude of the anthropogenic influence on pH and ANC during episodes. These modulating effects are especially pronounced in southern and central Sweden, where the historically high acid deposition has resulted in significant S pools in catchment soils. The results also suggest that the effects of episodic acidification are becoming less severe in many streams, but this amelioration is less clear in coastal streams subject to high levels of sea-salt deposition. Concurrently with the amelioration of the effects of episodic acidification, regional climate models predict that temperatures will increase in Sweden during the coming decades, accompanied by reductions in summer precipitation and more frequent storms during fall and winter in large areas of the country. If these predictions are realized delays in streams' recovery from episodic acidification events can be expected. Alewell, C., Mitchell, M. J., Likens, G. E., and Krouse, H. R.: Sources of stream sulfate at the Hubbard Brook Experimental Forest: Long-term analyses using stable isotopes, Biogeochemistry, 44, 281–299, 1999. Baker, J. P., VanSickle, J., Gagen, C. J., DeWalle, D. R., Sharpe, W. E., Carline, R. F., Baldigo, B. P., Murdoch, P. S., Bath, D. W., Kretser, W. A., Simonin, H. A., and Wigington, P. J.: Episodic acidification of small streams in the northeastern United States: Effects on fish populations, Ecol. Appl., 6, 422–437, 1996. Bishop, K. H., Laudon, H., and Köhler, S.: Separating the natural and anthropogenic components of spring flood pH decline: A method for areas that are not chronically acidified, Water Resour. Res., 30, 1873–1889, 2000. Christophersen, N., Dymbe, L. H., Johannssen, M., and Seip, H. M.: A Model for Sulphate in Streamwater at Stogama, Southern Norway, Ecol. Model., 21, 35–61, 1983. Devito, K. J., Hill, A. R., and Dillon, P. J.: Episodic sulphate export from wetlands in acidified headwater catchments: prediction at the landscape scale, Biogeochemistry, 44, 187–203, 1999. Eimers, M. C., Dillon, P. J., and Schiff, S. L.: Sulphate flux from an upland forested catchment in South-Central Ontario, Canada, Water Air Soil Poll., 152, 3–21, 2004a. Eimers, M. C., Dillon, P. J., and Watmough, S. A.: Long-term (18-year) changes in sulphate concentrations in two Ontario headwater lakes and their inflows in response to decreasing deposition and climate variations, Hydrol. Process., 18, 2617–2630, 2004b. Evans, C. D., Monteith, D. T., and Harriman, R.: Long-term variability in the deposition of marine ions at west coast sites in the UK Acid Waters Monitoring Network: impacts on surface water chemistry and significance for trend determination, Sci. Total Environ., 265, 115–129, 2001. Fölster, J., Bishop, K., Kram, P., Kvarnas, H., and Wilander, A.: Time series of long-term annual fluxes in the streamwater of nine forest catchments from the Swedish environmental monitoring program (PMK 5), Sci. Total Environ., 310, 113–120, 2003. Fölster, J. and Wilander, A.: Recovery from acidification in Swedish forest streams, Environ. Pollut., 117, 379–389, 2002. Heath, R. H., Kahl, J. S., Norton, S. A., and Fernandez, I. J.: Episodic stream acidification caused by atmospheric deposition of sea salts at Acadia National Park, Maine, United States, Water Resour. Res., 28, 1081–1088, 1992. Hindar, A., Henrikssen, A., Torseth, K., and Semb, A.: Acid water and fish death, Nature, 372, 327–328, 1994. Hindar, A., Torseth, K., Henriksen, A., and Orsolini, Y.: The significance of the North Atlantic Oscillation (NAO) for sea-salt episodes and acidification-related effects in Norwegian rivers, Environ. Sci. Technol., 38, 26–33, 2004. Jeffries, D. S., Semkin, R. G., Beall, F. D., and Franklyn, J.: Temporal trends in water chemistry in the Turkey Lakes watershed, Ontario, Canada, 1982–1999, Water Air Soil Poll., Focus, 2, 5–22, 2002. Kindbom, K., Sjöberg, K., Munthe, J., Peterson, K., Persson, C., Roos, E., and Bergström, R.: Nationell miljöövervakning av nederbördskemi, IVL (Swedish Environmental Research Institute), 35 pp., (in Swedish), 1998. Kjellström, E.: Recent and future signatures of climate change in Europe. Ambio, 33, 193–198, 2004. Kowalik, R. A. and Ormerod, S. J.: Intensive sampling and transplantation experiments reveal continued effects of episodic acidification on sensitive stream invertebrates, Freshwater Biol., 51, 180–191, 2006. Laudon, H. and Bishop, K.: Episodic stream water decline during autumn storms following a summer drought, Hydrol. Process., 16, 1725–1733, 2002. Laudon, H., Clair, T. A., and Hemond, H. F.: Long-term response in episodic acidification to declining SO42- deposition in two streams in Nova Scotia, Hydrol. Earth Syst. Sci., 6, 773–781, 2002. Laudon, H., Dillon, P. J., Eimers, M. C., Semkin, R. G., and Jeffries, D. S.: Climate-induced episodic acidification of streams in central Ontario, Environ. Sci. Technol., 38, 6009–6015, 2004. Laudon, H. and Hemond, H. F.: Recovery of streams from episodic acidification in northern Sweden, Environ. Sci. Technol., 36, 921–928, 2002. Laudon, H., Westling, O., Lofgren, S., and Bishop, K.: Modeling preindustrial ANC and pH during the spring flood in northern Sweden, Biogeochemistry, 54, 171–195, 2001. Lawrence, G. B.: Persistent episodic acidification of streams linked to acid rain effects on soil, Atmos. Environ., 36, 1589–1598, 2002. Lepori, F., Barbieri, A., and Ormerod, S. J.: Effects of episodic acidification on macroinvertebrate assemblages in Swiss Alpine streams, Freshwater Biol., 48, 1873–1885, 2003. Mylona, S.: Sulphur dioxide emissions in Europe 1880–1991 and their effect on sulphur concentrations and depositions, Tellus B, 48, 662–689, 1996. Neal, C. and Kirchner, J. W.: Sodium and chloride levels in rainfall, mist, streamwater and groundwater at the Plynlimon catchments, mid-Wales: inferences on hydrological and chemical controls, Hydrol. Earth Syst. Sci., 4, 295–310, 2000. Posch, M., Hettelingh, J.-P., de Smet, P. A. M., and Downing, R. T.: Calculation and mapping of critical thresholds in Europe: Status Report 1997, 259101007, RIVM, 1997. Raddum, G. G., Fjellheim, A., and Skjelkvale, B. L.: Improvements in water quality and aquatic ecosystems due to reduction in sulphur deposition in Norway, Water Air Soil Pollut., 130, 87–98, 2001. Schiff, S. L., Spoelstra, J., Semkin, R. G., and Jeffries, D. S.: Drought induced pulses of SO42- from a Canadian shield wetland: use of delta S-34 and delta O-18 in SO42- to determine sources of sulfur, Appl. Geochem., 20, 691–700, 2005. Skjelkvåle, B. L., Mannio, J., Wilander, A., and Andersen, T.: Recovery from acidification of lakes in Finland, Norway and Sweden 1990–1999, Hydrol. Earth Syst. Sci., 5, 327–337, 2001. Stoddard, J. L., Jeffries, D. S., Lukewille, A., Clair, T. A., Dillon, P. J., Driscoll, C. T., Forsius, M., Johannessen, M., Kahl, J. S., Kellogg, J. H., Kemp, A., Mannio, J., Monteith, D. T., Murdoch, P. S., Patrick, S., Rebsdorf, A., Skjelkvåle, B. L., Stainton, M. P., Traaen, T., van Dam, H., Webster, K. E., Wieting, J., and Wilander, A.: Regional trends in aquatic recovery from acidification in North America and Europe, Nature, 401, 575–578, 1999. Warfvinge, P. and Bertills, U.: Recovery from Acidification, Swedish Environmental Protection Agency report 5034, Stockholm, 96 pp., 2000. Wigington, P. J., Baker, J. P., DeWalle, D. R., Kretser, W. A., Murdoch, P. S., Simonin, H. A., VanSickle, J., McDowell, M. K., Peck, D. V., and Barchet, W. R.: Episodic acidification of small streams in the northeastern United States: Episodic Response Project, Ecol. Appl. Issn, 6, 374–388, 1996. Wilander, A., Johnson, R. K., Goedkoop, W., and Lundin, L.: Riksinventeringen 1995, Swedish Environmental Protection Agency report 4813, Stockholm, 210 pp., (in Swedish with English summary), 1998. Yan, N. D., Girard, R., Heneberry, J. H., Keller, W. B., Gunn, J. M., and Dillon, P. J.: Recovery of copepod, but not cladoceran, zooplankton from severe and chronic effects of multiple stressors, Ecol. Lett., 7, 452–460, 2004. Yue, S., Pilon, P., and Cavadias, G.: Power of the Mann-Kendall and Spearman's rho tests for detecting monotonic trends in hydrological series, J. Hydrol., 259, 254–271, 2002.