Effects of Atmospheric Nitrogen Deposition on Remote Freshwater Ecosystems
- 514 Downloads
- 13 Citations
Abstract
We review known and hypothesized effects of nitrogen (N) deposition owing to human activities on the chemistry, organisms, and ecosystem processes of remote oligotrophic freshwaters. Acidification is the best-known effect of N deposition on water chemistry, but additional effects include increased nutrient availability and alteration of the balance between N and other nutrients. Our synthesis of the literature, framed in a comprehensive model for the effects of N deposition on natural ecosystems, shows that all these effects can reduce biological diversity and alter ecosystem processes in remote freshwaters. N deposition is projected to grow worldwide in the near future and will interact with other global changes. Present effects on these fragile ecosystems may be only early signs of more radical impacts ahead.
Keywords
Acidification Atmospheric deposition Global change Mountain ecosystems N:P ratio Nutrient limitationNotes
Acknowledgments
We thank Sibel Şatıroğlu, Florian Mermillod-Blondin, and three anonymous reviewers for providing comments on this manuscript.
References
- Aber, J.D., K.J. Nadelhoffer, P. Steudler, and J.M. Melillo. 1989. Nitrogen saturation in northern forest ecosystems. BioScience 39: 378–386.CrossRefGoogle Scholar
- Aber, J.D., C.L. Goodale, S.V. Ollinger, M.-L. Smith, A.H. Magill, M.E. Martin, R.A. Hallett, and J.L. Stoddard. 2003. Is nitrogen deposition altering the nitrogen status of northeastern forests? BioScience 53: 375–389.CrossRefGoogle Scholar
- Baker, J.P., J. Van Sickle, C.J. Gagen, D.R. DeWalle, W.E. Sharpe, R.F. Carline, B.P. Baldigo, P.S. Murdoch, et al. 1996. Episodic acidification of small streams in the northeastern United States: Effects on fish populations. Ecological Applications 6: 422–437.CrossRefGoogle Scholar
- Baldigo, B.P., G.B. Lawrence, R.W. Bode, H.A. Simonin, K.M. Roy, and A.J. Smith. 2009. Impacts of acidification on macroinvertebrate communities in streams of the western Adirondack Mountains, New York, USA. Ecological Indicators 9: 226–239.CrossRefGoogle Scholar
- Baron, J.S., H.M. Rueth, A.M. Wolfe, K.R. Nydick, E.J. Allstott, J.T. Minear, and B. Moraska. 2000. Ecosystem responses to nitrogen deposition in the Colorado Front Range. Ecosystems 3: 352–368.CrossRefGoogle Scholar
- Baron, J.S., C.T. Driscoll, J.L. Stoddard, and E.E. Richer. 2011. Empirical critical loads of atmospheric nitrogen deposition for nutrient enrichment and acidification of sensitive US lakes. BioScience 61: 602–613.CrossRefGoogle Scholar
- Bergström, A.-K. 2010. The use of TN:TP and DIN:TP ratios as indicators for phytoplankton nutrient limitation in oligotrophic lakes affected by N deposition. Aquatic Sciences 72: 277–281.CrossRefGoogle Scholar
- Bergström, A.-K., and M. Jansson. 2006. Atmospheric nitrogen deposition has caused nitrogen enrichment and eutrophication of lakes in the northern hemisphere. Global Change Biology 12: 635–643.CrossRefGoogle Scholar
- Bergström, A.-K., P. Blomqvist, and M. Jansson. 2005. Effects of atmospheric nitrogen deposition on nutrient limitation and phytoplankton biomass in unproductive Swedish lakes. Limnology and Oceanography 50: 987–994.CrossRefGoogle Scholar
- Bergström, A.-K., A. Jonsson, and M. Jansson. 2008. Phytoplankton responses to nitrogen and phosphorus enrichment in unproductive Swedish lakes along a gradient of atmospheric nitrogen deposition. Aquatic Biology 4: 55–64.CrossRefGoogle Scholar
- Bobbink, R., K. Hicks, J. Galloway, T. Spranger, R. Alkemade, M. Ashmore, M. Bustamante, S. Cinderby, et al. 2010. Global assessment of nitrogen deposition effects on terrestrial plant diversity: A synthesis. Ecological Applications 20: 30–59.CrossRefGoogle Scholar
- Bothwell, M.L. 1989. Phosphorus-limited growth dynamics of lotic periphytic diatom communities: Aerial biomass and cellular growth rate responses. Canadian Journal of Fisheries and Aquatic Sciences 46: 1293–1301.CrossRefGoogle Scholar
- Brown, L.E., A.M. Milner, and D.M. Hannah. 2007. Hydroecology of alpine rivers. In Hydroecology and ecohydrology: Past, present and future, ed. P.J. Wood, D.M. Hannah, and J.P. Sadler, 339–360. Chichester: Wiley.Google Scholar
- Bulgakov, N.G., and A.P. Levich. 1999. The nitrogen:phosphorus ratio as a factor regulating phytoplankton community structure. Archiv für Hydrobiologie 146: 3–22.Google Scholar
- Campbell, J.L., J.W. Hornbeck, M.J. Mitchell, M.B. Adams, M.S. Castro, C.T. Driscoll, J.S. Kahl, J.N. Kochenderfer, et al. 2004. Input-output budgets of inorganic nitrogen for 24 forest watersheds in the Northeastern United States: a review. Water, Air, and Soil pollution 151: 373–396.CrossRefGoogle Scholar
- Chadwick, M.A., and A.D. Huryn. 2003. Effect of a whole-catchment N addition on stream detritus processing. Journal of the North American Benthological Society 22: 194–206.CrossRefGoogle Scholar
- Davies, T.D., M. Tranter, P.J. Wigington Jr, and K.N. Eshleman. 1992. ‘Acidic episodes’ in surface waters in Europe. Journal of Hydrology 132: 25–69.CrossRefGoogle Scholar
- Dentener, F., J. Drevet, J.F. Lamarque, I. Bey, B. Eickhout, A.M. Fiore, D. Hauglustaine, and L.W. Horowitz, et al. 2006. Nitrogen and sulfur deposition on regional and global scales: A multimodel evaluation. Global Biogeochemical Cycles 20:GB4003. doi: 10.1029/2005GB002672.
- Dillon, P.J., and L.A. Molot. 1990. The role of ammonium and nitrate retention in the acidification of lakes and forested catchments. Biogeochemistry 11: 23–43.CrossRefGoogle Scholar
- Dise, N.B., and R.F. Wright. 1995. Nitrogen leaching from European forests in relation to nitrogen deposition. Forest Ecology and Management 71: 153–162.CrossRefGoogle Scholar
- Dodds, W.K., and E. Welch. 2000. Establishing nutrient criteria in streams. Journal of the North American Benthological Society 19: 186–196.CrossRefGoogle Scholar
- Driscoll, C.T., and W.D. Schecher. 1990. The chemistry of aluminum in the environment. Environmental Health Perspectives 12: 28–49.Google Scholar
- Driscoll, C.T., G.B. Lawrence, A.J. Bulger, T.J. Butler, C.S. Cronan, C. Eagar, K.F. Lambert, G.E. Likens, et al. 2001. Acidic deposition in the Northeastern United States: Sources and inputs, ecosystem effects, and management strategies. BioScience 51: 180–198.CrossRefGoogle Scholar
- Driscoll, C.T., K.M. Driscoll, M.J. Mitchell, and D.J. Raynal. 2003. Effects of acidic deposition on forest and aquatic ecosystems in New York State. Environmental Pollution 123: 327–336.CrossRefGoogle Scholar
- Dudgeon, D., A.H. Arthington, M.O. Gessner, Z.-I. Kawabata, M.O. Gessner, D.J. Knowler, C. Lévêque, R.J. Naiman, et al. 2006. Freshwater biodiversity: Importance, threats, status and conservation challenges. Biological Reviews 81: 163–182.CrossRefGoogle Scholar
- Eisenreich, S.J., ed. 2005. Climate change and the European Water Dimension. Joint Research Centre of the European Commission, EU Report No. 21553, Ispra, Italy.Google Scholar
- Elser, J.J., and J. Urabe. 1999. The stoichiometry of consumer-driven nutrient recycling: Theory, observations, and consequences. Ecology 80: 745–751.CrossRefGoogle Scholar
- Elser, J.J., M.E.S. Bracken, E.E. Cleland, D.S. Gruner, W.S. Harpole, H. Hillebrand, J.T. Ngai, E.W. Seabloom, et al. 2007. Global analysis of nitrogen and phosphorus limitation of primary production in freshwater, marine, and terrestrial ecosystems. Ecology Letters 10: 1135–1142.CrossRefGoogle Scholar
- Elser, J.J., M. Kyle, L. Steger, K.R. Nydick, and J.S. Baron. 2009a. Nutrient availability and phytoplankton nutrient limitation across a gradient of atmospheric nitrogen deposition. Ecology 90: 3062–3073.CrossRefGoogle Scholar
- Elser, J.J., T. Andersen, J.S. Baron, A.-K. Bergström, M. Jansson, M. Kyle, K.R. Nydick, L. Steger, et al. 2009b. Shifts in lake N:P stoichiometry and nutrient limitation driven by atmospheric nitrogen deposition. Science 326: 835–837.CrossRefGoogle Scholar
- Elser, J.J., A.L. Peace, M. Kyle, M. Wojewodzic, M.L. McCrackin, T. Andersen, and D.O. Hessen. 2010. Atmospheric nitrogen deposition is associated with elevated phosphorus limitation of lake zooplankton. Ecology Letters 13: 1256–1261.CrossRefGoogle Scholar
- Fay, J.A., D. Golomb, and K. Subramanyam. 1987. Anthropogenic nitrogen oxide transport and deposition in eastern North America. Atmospheric Environment 21: 61–68.CrossRefGoogle Scholar
- Felten, V., and F. Guérold. 2006. Short-term physiological responses to a severe acid stress in three macroinvertebrate species: A comparative study. Chemosphere 63: 1427–1435.CrossRefGoogle Scholar
- Fenn, M.E., and M.A. Poth. 1999. Temporal and spatial trends in streamwater nitrate concentrations in the San Bernardino Mountains, Southern California. Journal of Environmental Quality 28: 822–836.CrossRefGoogle Scholar
- Fenn, M.E., J.S. Baron, E.B. Allen, H.M. Rueth, K.R. Nydick, L. Geiser, W.D. Bowman, J.O. Sickman, et al. 2003. Ecological effects of nitrogen deposition in the western United States. BioScience 53: 404–420.CrossRefGoogle Scholar
- Fischer, R., V. Mues, E. Ulrich, G. Becher, and M. Lorenz. 2007. Monitoring of atmospheric deposition in European forests and an overview on its implication on forest condition. Applied Geochemistry 22: 1129–1139.CrossRefGoogle Scholar
- Galloway, J.N., F.J. Dentener, D.G. Capone, E.W. Boyer, R.W. Howarth, S.P. Seitzinger, G.P. Asner, C.C. Cleveland, et al. 2004. Nitrogen cycles: Past, present, and future. Biogeochemistry 70: 153–226.CrossRefGoogle Scholar
- Goldman, C.R. 1988. Primary productivity, nutrients, and transparency during the early onset of eutrophication in ultra-oligotrophic Lake Tahoe, California-Nevada. Limnology and Oceanography 33: 1321–1333.CrossRefGoogle Scholar
- Heathwaite, A.L., P.J. Johnes, and N.E. Peters. 1996. Trends in nutrients and water quality. Hydrological Processes 10: 263–293.CrossRefGoogle Scholar
- Henriksen, A., and D.F. Brakke. 1988. Increasing contributions of nitrogen to the acidity of surface waters in Norway. Water, Air, and Soil pollution 42: 183–201.CrossRefGoogle Scholar
- Henriksen, A., J. Kämäri, M. Posch, and A. Wilander. 1992. Critical loads in Nordic countries. Ambio 21: 356–363.Google Scholar
- Hobbs, W.O., R.J. Telford, H.J.B. Birks, J.E. Saros, R.R.O. Hazewinkel, B.B. Perren, É. Saulnier-Talbot, and A.P. Wolfe. 2010. Quantifying recent ecological changes in remote lakes of North America and Greenland using sediment diatom assemblages. PLoS ONE 5: e10026. doi: 10.1371/journal.pone.0010026.CrossRefGoogle Scholar
- Holmgren, S.U., C. Bigler, Ó. Ingólfsson, and A.P. Wolfe. 2010. The Holocene–Anthropocene transition in lakes of western Spitsbergen, Svalbard (Norwegian High Arctic): Climate change and nitrogen deposition. Journal of Paleolimnology 43: 393–412.CrossRefGoogle Scholar
- Howarth, R.W., D.P. Swaney, E.W. Boyer, R. Marino, N. Jaworski, and C. Goodale. 2006. The influence of climate on average nitrogen export from large watersheds in the Northeastern United States. Biogeochemistry 79: 163–186.CrossRefGoogle Scholar
- Karlsson, J., P. Byström, J. Ask, P. Ask, L. Persson, and M. Jansson. 2009. Light limitation of nutrient-poor lake ecosystems. Nature 460: 506–509.CrossRefGoogle Scholar
- Kopáček, J., L. Procházková, E. Stuchlík, and P. Blažka. 1995. The nitrogen–phosphorus relationship in mountain lakes: Influence of atmospheric input, watershed, and pH. Limnology and Oceanography 40: 930–937.CrossRefGoogle Scholar
- Kroeze, C., and S.P. Seitzinger. 1998. Nitrogen inputs to rivers, estuaries, and continental shelves and related nitrous oxide emissions in 1990 and 2050: A global model. Nutrient Cycling in Agroecosystems 52: 195–212.CrossRefGoogle Scholar
- Lafrancois, B.M., K.R. Nydick, B.M. Johnson, and J.S. Baron. 2004. Cumulative effects of nutrients and pH on the plankton of two mountain lakes. Canadian Journal of Fisheries and Aquatic Sciences 61: 1153–1165.CrossRefGoogle Scholar
- Lepori, F., and S.J. Ormerod. 2005. Population data and in situ toxicity tests reveal consistent effects of spring acid episodes on macroinvertebrates. Freshwater Biology 50: 1568–1577.CrossRefGoogle Scholar
- Lepori, F., A. Barbieri, and S.J. Ormerod. 2003a. Causes of episodic acidification in Alpine streams. Freshwater Biology 48: 175–198.CrossRefGoogle Scholar
- Lepori, F., A. Barbieri, and S.J. Ormerod. 2003b. Effects of episodic acidification on macroinvertebrate assemblages in Swiss Alpine streams. Freshwater Biology 48: 1873–1885.CrossRefGoogle Scholar
- Lewis Jr., W.M., and W.A. Wurtsbaugh. 2008. Control of lacustrine phytoplankton by nutrients: Erosion of the phosphorus paradigm. International Review of Hydrobiology 93: 446–465.CrossRefGoogle Scholar
- Liess, A., S. Drakare, and M. Kahlert. 2009. Atmospheric nitrogen-deposition may intensify phosphorus limitation of shallow epilithic periphyton in unproductive lakes. Freshwater Biology 54: 1759–1773.CrossRefGoogle Scholar
- Marchetto, A., A. Barbieri, R. Mosello, and G.A. Tartari. 1994. Acidification and weathering processes in high mountain lakes in Southern Alps. Hydrobiologia 274: 75–81.CrossRefGoogle Scholar
- Matson, P.A., K. Lohse, and S. Hall. 2002. The globalization of nitrogen deposition: Consequences for terrestrial ecosystems. Ambio 31: 113–119.Google Scholar
- McCrackin, M.L., and J.J. Elser. 2010. Atmospheric nitrogen deposition influences denitrification and nitrous oxide production in lakes. Ecology 91: 528–539.CrossRefGoogle Scholar
- McCrackin, M.L., and J.J. Elser. 2011. Denitrification kinetics and denitrifier abundances in sediments of lakes receiving atmospheric nitrogen deposition (Colorado, USA). Biogeochemistry. doi: 10.1007/s10533-011-9571-5.Google Scholar
- Meybeck, M. 1982. Carbon, nitrogen, and phosphorous transport by world rivers. American Journal of Science 282: 401–450.CrossRefGoogle Scholar
- Mitchell, M.J., G. Iwatsubo, K. Ohrui, and Y. Nakagawa. 1997. Nitrogen saturation in Japanese forests: An evaluation. Forest Ecology and Management 97: 39–51.CrossRefGoogle Scholar
- Nanus, L., M.W. Williams, D.H. Campbell, K.A. Tonnessen, T. Blett, and D.W. Clow. 2009. Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains. Ecological Applications 19: 961–973.CrossRefGoogle Scholar
- Newbold, J. 1992. Cycles and spirals of nutrients. In Rivers Handbook, Vol. 1: Hydrological and Ecological Principles, ed. P. Calow and G.E. Petts, 379–408. Oxford: Blackwell Science.Google Scholar
- Ohte, N., M.J. Mitchell, H. Shibata, N. Tokuchi, H. Toda, and G. Iwatsubo. 2001. Comparative evaluation on nitrogen saturation of forest catchments in Japan and northeastern United States. Water, Air, and Soil pollution 130: 649–654.CrossRefGoogle Scholar
- Ollinger, S.V., J.D. Aber, G.M. Lovett, S.E. Millham, R.G. Lathrop, and J.M. Ellis. 1993. A spatial model of atmospheric deposition for the northeastern U.S. Ecological Applications 3: 459–472.CrossRefGoogle Scholar
- Ormerod, S.J. 1992. Effects on aquatic ecosystems. In Atmospheric acidity sources, consequences and abatement, ed. M. Radojević, and R.M. Harrison, 363–404. London: Elsevier.Google Scholar
- Passy, S.I. 2006. Diatom community dynamics in streams of chronic and episodic acidification: The roles of environment and time. Journal of Phycology 42: 312–323.CrossRefGoogle Scholar
- Phoenix, G.K., W.K. Hicks, S. Cinderby, J.C.I. Kuylenstierna, W.D. Stock, F.J. Dentener, K.E. Giller, A.T. Austin, et al. 2006. Atmospheric nitrogen deposition in world biodiversity hotspots: The need for a greater global perspective in assessing N deposition impacts. Global Change Biology 12: 470–476.CrossRefGoogle Scholar
- Rhee, G.Y., and I.J. Gotham. 1980. Optimum N:P ratios and coexistence in phytoplankton. Journal of Phycology 16: 486–489.CrossRefGoogle Scholar
- Robinson, C.T., U. Uehlinger, and M.O. Gessner. 2003. Nutrient limitation. In Ecology of a glacial floodplain, ed. J.V. Ward, and U. Uehlinger, 231–241. Dordrecht: Kluwer Academic Publishers.Google Scholar
- Rogora, M., A. Marchetto, and R. Mosello. 2001. Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment. Hydrology and Earth System Sciences 5: 379–390.CrossRefGoogle Scholar
- Saunders, P.A., W.H. Shaw, and P.A. Bukaveckas. 2000. Differences in nutrient limitation and grazer suppression of phytoplankton in seepage and drainage lakes of the Adirondack region, NY, U.S.A. Freshwater Biology 43: 391–407.CrossRefGoogle Scholar
- Schindler, D.W. 1977. Evolution of phosphorous limitation in lakes. Science 195: 260–262.CrossRefGoogle Scholar
- Schlesinger, W.H. 2009. On the fate of anthropogenic nitrogen. Proceedings of the National Academy of Sciences 106: 203–208.CrossRefGoogle Scholar
- Seitzinger, S.P., E. Mayorga, A.F. Bouwman, C. Kroeze, A.H.W. Beusen, G. Billen, G. Van Drecht, E. Dumont, et al. 2010. Global river nutrient export: A scenario analysis of past and future trends. Global Biogeochemical Cycles 24:GB0A08. doi: 10.1029/2009GB003587.
- Seitzinger, S., J.A. Harrison, J.K. Böhlke, A.F. Bouwman, R. Lowrance, B. Peterson, C. Tobias, and G. Van Drecht. 2006. Denitrification across landscapes and waterscapes: A synthesis. Ecological Applications 16: 2064–2090.CrossRefGoogle Scholar
- Simpson, K.W., R.W. Bode, and J.R. Colquhoun. 1985. The macroinvertebrate fauna of an acid-stressed headwater stream system in the Adirondack Mountains, New York. Freshwater Biology 15: 671–681.CrossRefGoogle Scholar
- Smith, V.H. 1983. Low nitrogen to phosphorus ratios favor dominance by blue-green algae in lake phytoplankton. Science 221: 669–671.CrossRefGoogle Scholar
- Stelzer, R.S., and G.A. Lamberti. 2001. Effects of N:P ratio and total nutrient concentration on stream periphyton community structure, biomass, and elemental composition. Limnology and Oceanography 46: 356–367.CrossRefGoogle Scholar
- Sterner, R.W., and D.O. Hessen. 1994. Algal nutrient limitation and the nutrition of aquatic herbivores. Annual Review of Ecology and Systematics 25: 1–29.CrossRefGoogle Scholar
- Sterner, R.W., D.D. Hagemeier, W.L. Smith, and R.F. Smith. 1993. Phytoplankton nutrient limitation and food quality for Daphnia. Limnology and Oceanography 38: 857–871.CrossRefGoogle Scholar
- Stoddard, J.L. 1994. Long-term changes in watershed retention of nitrogen, its causes and aquatic consequences. In Environmental chemistry of lakes and reservoirs, ed. L.A. Baker, 223–284, Washington, DC: American Chemical Society.Google Scholar
- Stoddard, J.L. 1995. Episodic acidification during snowmelt of high elevation lakes in the Sierra Nevada mountains of California. Water, Air, and Soil pollution 85: 353–358.CrossRefGoogle Scholar
- Stoddard, J.L., D.S. Jeffries, A. Lükewille, T.A. Clair, P.J. Dillon, C.T. Driscoll, M. Forsius, M. Johannessen, et al. 1999. Regional trends in aquatic recovery from acidification in North America and Europe. Nature 401: 575–578.CrossRefGoogle Scholar
- Stoddard, J.L., T.S. Traaen, and B.L. Skjelkvåle. 2001. Assessment of nitrogen leaching at ICP-waters sites (Europe and North America). Water, Air, and Soil pollution 130: 781–786.CrossRefGoogle Scholar
- Sullivan, T.J., J.M. Eilers, B.J. Cosby, and K.B. Vaché. 1997. Increasing role of nitrogen in the acidification of surface waters in the Adirondack Mountains, New York. Water, Air, and Soil pollution 95: 313–336.Google Scholar
- Throop, H.L., and M.T. Lerdau. 2004. Effects of nitrogen deposition on insect herbivory: implications for community and ecosystem processes. Ecosystems 7: 109–133.CrossRefGoogle Scholar
- Tilman, D. 1980. A graphical-mechanistic approach to competition and predation. American Naturalist 116: 362–393.CrossRefGoogle Scholar
- Tilman, D., R.L. Kiesling, R. Sterner, S.S. Kilham, and F.A. Johnson. 1986. Green, bluegreen and diatom algae: Taxonomic differences in competitive ability for phosphorus, silicon, and nitrogen. Archiv für Hydrobiologie 106: 473–485.Google Scholar
- Van Migroet, H. 1994. The relative importance of sulfur and nitrogen compounds in the acidification of fresh water. In Acidification of freshwater ecosystems: Implications for the future, ed. C.E.W. Steinberg and R.F. Wright, 33–49, Chichester: Wiley.Google Scholar
- Vertucci, F.A., and P.S. Corn. 1996. Evaluation of episodic acidification and amphibian declines in the Rocky Mountains. Ecological Application 6: 449–457.CrossRefGoogle Scholar
- Vitousek, P.M., J.D. Aber, R.W. Howarth, G.E. Likens, P.A. Matson, D.W. Schindler, W.H. Schlesinger, and D.G. Tilman. 1997. Human alteration of the global nitrogen cycle: Sources and consequences. Ecological Applications 7: 737–750.Google Scholar
- Waldrop, M.P., D.R. Zak, and R.L. Sinsabaugh. 2004. Microbial community response to N deposition in northern forest ecosystems. Soil Biology and Biochemistry 36: 1443–1451.CrossRefGoogle Scholar
- Wellburn, A. 1994. Air pollution and climate change: The biological impact, 2nd ed. Harlow: Longman Scientific & Technical.Google Scholar
- Wigington Jr, P.J., D.R. DeWalle, P.S. Murdoch, W.A. Kretser, H.A. Simonin, J. Van Sickle, and J.P. Barker. 1996. Episodic acidification of small streams in the northeastern United States: Ionic controls of episodes. Ecological Applications 6: 389–407.CrossRefGoogle Scholar
- Williams, M.W., J. Baron, N. Caine, R. Sommerfeld, and R. Sanford. 1996. Nitrogen saturation in the Colorado Front Range. Environmental Science and Technology 30: 640–646.CrossRefGoogle Scholar
- Wolfe, A.P., J.S. Baron, and R.J. Cornett. 2001. Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of the Colorado Front Range (USA). Journal of Paleolimnology 25: 1–7.CrossRefGoogle Scholar
- Wolfe, A.P., C.A. Cooke, and W.O. Hobbs. 2006. Are current rates of atmospheric nitrogen deposition influencing lakes in the Eastern Canadian Arctic? Arctic, Antarctic, and Alpine Research 38: 465–476.CrossRefGoogle Scholar
- Wright, R.F. 1998. Effect of increased CO2 and temperature on run-off chemistry at a forested catchment in southern Norway (CLIMEX project). Ecosystems 1: 216–225.CrossRefGoogle Scholar
- Wright, R.F., C. Alewell, J.M. Cullen, C.D. Evans, A. Marchetto, F. Moldan, A. Prechtel, and M. Rogora. 2001. Trends in nitrogen deposition and leaching in acid-sensitive streams in Europe. Hydrology and Earth System Sciences 5: 299–310.CrossRefGoogle Scholar