Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 4 5 2007 10.5194/bg-4-905-2007 http://www.biogeosciences.net/4/905/2007/ http://www.biogeosciences.net/4/905/2007/bg-4-905-2007.html http://www.biogeosciences.net/4/905/2007/bg-4-905-2007.pdf 905 911 2007-10-25 Climate-driven enrichment of pollutants in peatlands A. Martínez Cortizas edantxon@usc.es H. Biester T. Mighall R. Bindler Dept. Edafología y Química Agrícola, Universidad de Santiago de Compostela, Campus Universitario s/n, 15782 Santiago de Compostela, Spain Institute of Environmental Geochemistry, University of Heidelberg, INF 236 69120 Heidelberg, Germany Department of Geography and Environment, School of Geosciences, University of Aberdeen, Elphinstone Road, Aberdeen, AB24 3UF, UK Dept. of Ecology and Environmental Science, Umeå University, S901 87 Umeå, Sweden Peatlands play an important role for global carbon dynamics, acting as a sink or source depending on climate. Such changes imply a series of additional effects because peatlands are also an important reservoir of atmospherically derived pollutants. Using a multiproxy approach (non-pollen-palynomorphs, δ¹⁵N, C/N, Se, Br, I, Hg, Ti), we show a relationship between climate (wetter–drier) and peat decomposition, which affected element concentrations in a Spanish bog during the last 5500 years. Changes in superficial wetness played a critical role in the cycling of elements coupled to carbon dynamics. Dry phases caused increased peat mineralisation, resulting in a 2–3 times increase in concentrations of the analysed elements independent from atmospheric fluxes. Under the present trend of climate change large areas of northern peatlands are expected to be severely affected; in this context our findings indicate that the increase in carbon release, which leads to an enrichment of elements, may enhance the export of stored contaminants (Hg, organohalogens) to the aquatic systems or to the atmosphere. Aaby, B.: Cyclic variations in climate over the past 5,500 years reflected in raised bogs, Nature, 263, 281–284, 1976. Arnaud, F., Revel, M., Chapron, E., Desmet, M., and Tribovillard, N.: 7200 years of Rhône river flooding activity in lake Le Bourget, France: a high-resolution sediment record of NW Alps hydrology, The Holocene, 15, 420–428, 2005. Barber, K. E.: Peat Stratigraphy and Climate Change, Balkema, Rotterdam, 1981. Biester, H., Keppler, F., Putschew, A., Martínez-Cortizas, A., and Petri, M.: Halogen retention, organohalogens, and the role of organic matter decomposition and halogen enrichment in two Chilean peat bogs, Environ. Sci. Technol. 38, 1984–1991, 2004. Biester, H., Martínez-Cortizas, A., Birkenstock, S., and Kilian, R.: Effect of peat decomposition and mass loss on historic mercury records in peat bogs from Patagonia, Eviron. Sci. Technol., 37, 32–39, 2003. Biester, H., Selimovic, D., Hemmerich, S., and Petri, M.: Release of halogens from peat bogs – The role of peat decomposition and dissolved oprganic matter (DOM), Biogeosciences, 3, 53–64, 2006. Biester, H., Bindler, R., Martínez Cortizas, A., and Engstrom, D. E.: Modeling the past atmospheric deposition of mercury using natural archives, Environ. Sci. Technol. 41, 8451–4860, 2007. Blackford, J. J. and Chambers, F. M.: Determining the degree of peat decomposition in peat-based palaeoclimatic studies, Intern. Peat J., 5, 7–24, 1993. Caseldine, C. J., Baker, A., Charman, D. J., and Hendon, D. A.: Comparative study of optical properties of NaOH peat extracts: implications for humification studies, The Holocene, 10, 649–658, 2000. Chambers, F. M. and Charman, D. J.: Holocene environmental change: contributions from the peatland archive, The Holocene, 14, 1–6, 2004. Cheburkin, A. K. and Shotyk, W.: An Energy-dispersive Miniprobe Multielement Analyzer (EMMA) for direct analysis of Pb and other trace elements in peats, Fress, J. Anal. Chem., 354, 688–691, 1996. Fraga Vila, I.: Vegetación característica de las turberas de Galicia, in: Turberas de Montaña de Galicia, Xunta de Galicia, santiago de Compsotela, edited by: Martínez Cortizas, A. and García-Rodeja Gayoso, E., Colección Ténica Medio Ambiente, Chapter 6, 79–98, 2001. Fraga Vila, I., Romero, D., and Sahuquillo, E.: Patterns of vegetation in relation to environmental conditions in Northwestern Spanish mires, IMCG Mires and Peatlands Field Symposium, Tierra del Fuego 2005, Argentina, 35–36, 2005. 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. Freeman, C., Ostle, N., and Kang, H.: An enzymatic latch on a global carbon storage, Nature, 409, 149, 2001. Gorham, E.: Northern peatlands: Role in the carbon cycle and probable responses to climatic warming, Ecological Applications, 1, 182–195, 1991. Görres, M. and Frenzel, B.: The Pb, Br, and Ti content in peat bogs as indicator for recent and past depositions. Naturwissenschaften, 20, 333–335, 1993. Gribble, G. W.: The diversity of naturally produced organohalogens, Chemosphere, 52, 289–297, 2003. Gutiérrez-Elorza, M. and Peña-Monné, J. L.: Geomorphology and late Holocene climatic change in Northeastern Spain, Geomorphology, 23, 205–217, 1998. Herczeg, A. L.: Early diagenesis of organic matter in lake sediments: a stable carbon isotope study of pore waters, Chem. Geol., 72, 199–209, 1988. Holzhauser, H., Magny, M., and Zumbühl, H. J.: Glacier and lake-level variations in west-central Europe over the last 3500 years, The Holocene, 15, 789–801, 2005. Hughes, P. D. M., Mauquoy, D., Barber, K. E., and Langdom, P. G.: Mire-development pathways and palaeoclimatic records from a full Holocene peat archive at Walton Moss, Cumbria, England, The Holocene, 10, 465–479, 2000. IPCC (Irish Peatland Conservation Council): Peatlands around the world (available at http://www.ipcc.ie/wptourhome1.html), 2000. Kabata-Pendias, A. and Pendias, H.: Trace Elements in Soils and Plants, CRC Press, Boca Raton, 1992. Kalviäinen, E. and Karunen, P.: On the growth, senescence, and decay-resistance of Spahgnum mosses, Proc. 7th Intern. Peat Congress. Dublin, 4, 263–275, 1984. Keppler, F. and Biester, H.: Peatlands: a major sink of naturally formed organic chlorine, Chemosphere, 52, 451–453, 2003. Khury, P. and De Vitt, D. H.: Fossil Carbon/Nitrogen ratios as a measure of peat decomposition, Ecology, 77, 271–275, 1996. Lee, J. A. and Tallis, J. H.: Regional and historical aspects of lead pollution in Britain, Nature, 245, 216–218, 1973. Létolle, R.: Nitrogen-15 in the natural environment, in: Handbook of Environmental Isotope Geochemistry, edited by: Fritz, P. and Fontes, J. Ch., 1 The Terrestrial Environment, Chapter 10, 407–429, Elsevier, Amsterdam, 1980. Macko, S., Entzeroth, L., and Parker, P.: Early diagenesis of organic matter in sediments. Assessment of mechanisms and preservation by the use of isotopic molecular approaches, in: Organic Geochemistry: Principles and Applications, edited by: Engel, J. M. H. and Macko, S. A., Plenum Press, New York, Chapter 9, 211–224, 1993. Magny, M.: Lake-level fluctuations in the Jura and French subalpine ranges associated with ice-rafting debris events in the North Atlantic and variations in the polar atmospheric circulation, Quaternaire, 10, 61–64, 1999. Magny, M.: Holocene climate variability as reflected by mid-European lake-level fluctuations and its probable impact on prehistoric human settlements, Quatern. Int., 113, 65–79, 2004. Magny, M., Bégeot, C., Guiot, J., and Peyron, O.: Contrasting patterns of hydrological changes in Europe in response to Holocene climate cooling phases, Quat. Sci. Rew., 22, 1589–1596, 2003. Mart\'inez Cortizas, A., García-Rodeja, E., Pontevedra Pombal, X., Nóvoa Muñoz, J. C., Weiss, D., and Cheburkin, A.: Atmospheric Pb deposition in Spain during the last 4600 years recorded by two ombrotrophic peat bogs and implications for the use of peat as archive, Sci. Tot. Environ., 292, 33–44, 2002. Mart\'inez Cortizas, A., Garc\'ia-Rodeja, E., and Weiss, D.: Peat bog archives of atmospheric metal deposition, Sci. Tot. Environ., 292, 1–5, 2002. Mart\'inez Cortizas, A., Mighall, T., Pontevedra Pombal, X., Nóvoa Muñoz, J.C., Peiteaddo Varela, E., and Piñeiro Rebolo, R.: Linking changes in atmospheric dust deposition, vegetation change and human activities in northwest Spain during the last 5300 years, The Holocene, 15: 698–706, 2005. Mart\'inez-Cortizas, A., Pontevedra-Pombal, X., Garc\'ia-Rodeja, E., Nóvoa-Muñoz, J. C., and Shotyk, W.: Mercury in a Spanish peat bog: archive of climate change and atmospheric metal deposition, Science, 284, 939–942, 1999. Mason, R. P., Fitzgerald, W. F., and Morel, F. M. M.: The biogeochemical cycling of elemental mercury: Anthropogenic influences, Geoch. Cosmoch. Acta, 58, 3191–3198, 1994. Mauquoy D., Engelkes, T., Groot, M. H. M., Markesteijn, F., Oudejans, M. G., van der Plicht, J., and van Geel, B.: High-resolution records of late-Holocene climate change and carbon accumulation in two north-west European ombrotrophic peat bogs, Palaeogeog. Palaeoclim. Palaeoecol., 186, 275–310, 2002. Meili. M.: The coupling of mercury and organic matter in the biogeochemical cycle – towards a mechanistic model for the boreal forest zone, Water Air Soil Pollut., 56, 333–347, 1991. Mierle, G. and Ingram, R.: The role of humic substances in the mobilization of mercury from watersheds, Water Air Soil Pollut., 56, 349–357, 1991. Mighall, T. M., Mart\'inez Cortizas, A., Biester, H., and Turner, S. E.: Proxy climate and vegetation changes during the last five millennia in NW Iberia: pollen and non-pollen palynomorph data from two ombrotrophic peat bogs in the north western Iberian Peninsula, Rev. Paleobot. Palynol., 141, 203–223, 2006. Mouline, C., Lambert, C. E., Dulac, F., and Dayan, U.: Control of atmospheric export of dust from North Africa by the North Atlantic Oscillation, Nature, 387, 691–694, 1997. Myneni, S. C. B.: Formation of stable chlorinated hydrocarbons in weathering plant material, Science, 295, 1039–1041, 2002. Norton, S. A., Evans, G. C., and Kahl, J. S.: Comparison of Hg and Pb fluxes to hummocks and hollows of ombrotrophic Big Heath bog and to nearby Sargent Mt. Pond, Maine, USA, Water, Air and Soil Poll., 100, 271–286, 1997. Nriagu, J. and Pacyna, J. M.: Quantitative assessment of world contamination of air, water and soils by trace elements, Nature, 333, 134–139, 1988. Ohlson, M. and Okland, R. H.: Spatial variation in rates of carbon and nitrogen accumulation in a boreal bog, Ecology, 79, 2745–2758, 1998. Ohlson, M.: Spatial variation in decomposition rate of \textitCarex rostrata leaves on a Swedish mire, J. Ecol., 75, 1191–1197, 1987. Oldfield, F., Brown, A., and Thompson, R.: The effect of microtopography and vegetation on the catchtment of airborne particles measured by remanent magnetism, Quat. Res., 12, 326–332, 1979. Pontevedra Pombal, X., Nóvoa Muñoz, J.C., Garc\'ia-Rodeja, E., Mart\'inez Cortizas, A.: Mountain mires from Galicia (NW Spain), in: Peatlands: Evolution and Records of Environmental and Climate Changes, edited by: Martini, I. P., Martínez Cortizas, A., and Chesworth, W., Elsevier, Amsterdam, Developments in Earth Surface Processes 9, 85–110, 2006. Pontevedra Pombal, X., Martínez Cortizas, A., and Buurman, P.: Las turberas de montaña de Galicia como sumideros de carbono, Edafolog\'ia, 10(2), 1–10, 2004. Prospero, J. M. and Lamb, P. J.: African droughts and dust transport to the Caribbean: climate change implications, Science, 302, 1024–1027, 2003. Reimann, C. and de Caritat, P.: Distinguishing between natural and anthropogenic sources for elements in the environment: regional geochemical surveys versus enrichment factors, Sci. Tot. Environ., 337, 91–107, 2005. Reynolds, B. and Fenner, N.: Export of organic carbon from peat soils, Nature, 412, 785–786, 2001. Romero, D., Fraga Vila, I., and Sahuquillo, E.: Plant diversity in the Galician mire ecosystems (NW Iberian Penisula), IMCG Mires and Peatlands Field Symposium, Tierra del Fuego 2005, Argentina, 1–2, 2005. Roos-Barraclough, F., van der Knaap, W. O., van Leeuwen, J. F. N., and Shotyk, W.: A Late-glacial and Holocene record of climatic change from a Swiss peat humification profile, The Holocene, 14, 7–19, 2004. Scholtz, M. T., van Heyst, B. J., and Schroeder, W. H.: Modelling of mercury emissions from background soils, Sci. Tot. Environ., 304, 185–207, 2003. Schroeder, W. H. and Munthe, J.: Atmospheric mercury- An overview, Atmosph. Environ., 32, 809–822, 1998. Shotyk, W.: Atmospheric deposition and geochemical mass balance of major elements and trace elements in two oceanic blanket bogs, northern Scotland and the Shetland Islands, Chem. Geol., 138, 55–72, 1997. Shotyk, W., Weiss, D., Appleby, P. G., Cheburkin, A., Frei, R., Gloor, J., Kramers, D., Reese, S., Van der Knaap, W. O.: History of atmospheric lead deposition since 12,370 14C yr BP from a peat bog, Jura Mountains, Switzerland, Science, 281, 1635–1640, 1998. Tarnocai, C. and Stolbovoy, V.: Northern peatlands: their characteristics, development and sensitivity to climate change, in: Peatlands: Evolution and Records of Environmental and Climate Changes, edited by: Martini, I. P., Martínez Cortizas, A., and Chesworth, W., Developments in Earth Surface Processes, 9, Chapter 1 17-51, Elsevier, Amsterdam, 2006. Thorndycraft, V. R. and Benito, G.: Late Holocene fluvial chronology of Spain: the role of climatic variability and human impact, Catena, 66, 34–41, 2006. Updegraff, K., Pastor, J., Bridgham, S. D., and Johnston, C. A.: Environmental and substrate controls over carbon and nitrogen mineralization in northern wetlands, Ecol. Appl., 5, 151–163, 1995. van Pée, K. H. and Unversucht, S.: Biological dehalogenation and halogenation reactions, Chemosphere, 52, 299–312, 2003. Worrall, F., Burt, T., and Adamson, J.: Can climate change explain increases in DOC flux from upland peat catchments?, Sci. Tot. Environ., 326, 95–112, 2001. Xia, K., et al.: X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances, Environ. Sci. Technol., 33, 257–261, 1999. Yin, Y., Allen, H. E., Huang, C. P., Li, Y., and Sanders, P. F.: Adsorption of Mercury(II) by soil: Effect of pH, chloride, and organic matter, J. Environ. Qual., 25, 837–844, 1996. Yu, Z., Campbell, I. D., Campbell, C., Vitt, D. H., Bond, G. C., and Apps, M. J.: Carbon sequestration in western Canadian peat highly sensitive to Holocene wet-dry climate cycles at millenial timescales, The Holocene, 13, 801–808, 2003. Zhang, Y. and Moore, J. Selenium fractionation and speciation in a wetland system, Environ. Sci. Technol., 30, 2613–2619, 1996.