The effects of wildfires on the magnetic properties of soils in the Everglades

We present results of a rock‐magnetic study of soils that were affected by wildfires that burned portions of the Everglades in the Spring of 2008. Soils at sites that were extensively burned exhibit a pronounced surface magnetic enhancement effect with magnetizations of surface samples up to 16 times greater than that observed at depth (>7 cm) at these sites. The increase in magnetization results from an increased abundance of a low‐coercivity phase (maghemite) that occurs at the expense of the abundance of a high‐coercivity phase (goethite). These results indicate that fire‐induced heating caused goethite in the surface soils to convert into a more magnetic, low‐coercivity phase, such as maghemite. Goethite is an excellent adsorber of phosphorus, and therefore we hypothesize that the destruction of goethite as a result of burning may have important implications for phosphorus cycling in the Everglades ecosystem. Copyright © 2010 John Wiley & Sons, Ltd.

[1]  J. Crowther,et al.  Establishing fire incidence in temperate soils using magnetic measurements , 2007 .

[2]  S. Grunwald,et al.  Assessment of the spatial distribution of soil properties in a northern Everglades marsh. , 2006, Journal of environmental quality.

[3]  H. Stanjek,et al.  Thermomagnetic measurements of soil iron minerals: the role of organic carbon , 2006 .

[4]  Peter Wallbrink,et al.  Magnetic enhancement in wildfire‐affected soil and its potential for sediment‐source ascription , 2006 .

[5]  Subir K. Banerjee,et al.  Signature of magnetic enhancement in a loessic soil in Nebraska, United States of America , 2004 .

[6]  B. Maher,et al.  High-field remanence properties of synthetic and natural submicrometre haematites and goethites: significance for environmental contexts. , 2004 .

[7]  D. Rancourt,et al.  Nanogoethite is the dominant reactive oxyhydroxide phase in lake and marine sediments , 2003 .

[8]  Fahu Chen,et al.  An integrated study of the grain‐size‐dependent magnetic mineralogy of the Chinese loess/paleosol and its environmental significance , 2003 .

[9]  L. Iverson,et al.  Soil temperature and moisture fluctuations during and after prescribed fire in mixed-oak forests, USA , 2002 .

[10]  S. Newman,et al.  Differential effects of surface and peat fire on soil constituents in a degraded wetland of the northern Florida Everglades. , 2001, Journal of environmental quality.

[11]  Yuncong C. Li,et al.  Phosphorus-Sorption Characteristics of Calcareous Soils and Limestone from the Southern Everglades and Adjacent Farmlands , 2001 .

[12]  D. Heslop,et al.  Quantification of magnetic coercivity components by the analysis of acquisition curves of isothermal remanent magnetisation , 2001 .

[13]  Q. Ketterings,et al.  Changes in Soil Mineralogy and Texture Caused by Slash‐and‐Burn Fires in Sumatra, Indonesia , 2000 .

[14]  F. Oldfield.  Identifying goethite and hematite from rock magnetic measurements of soils and sediments , 2000 .

[15]  Subir K. Banerjee.  Rock Magnetism: Fundamentals and Frontiers , 1998 .

[16]  B. Maher,et al.  Magnetic properties of modern soils and Quaternary loessic paleosols: paleoclimatic implications. , 1998 .

[17]  Michael J. Singer,et al.  A conceptual model for the enhancement of magnetic susceptibility in soils , 1996 .

[18]  G. Kletetschka,et al.  Magnetic stratigraphy of Chinese Loess as a record of natural fires , 1995 .

[19]  F. Heller,et al.  Magnetic enhancement and palaeoclimate: study of a loess/palaeosol couplet across the Loess Plateau of China , 1994 .

[20]  M. Dekkers.  Magnetic properties of natural goethite.III, Magnetic behaviour and properties of minerals originating from goethite dehydration during thermal demagnetization , 1990 .

[21]  U. Schwertmann,et al.  Phosphate adsorption and desorption by goethites differing in crystal morphology. , 1990 .

[22]  W. Odum,et al.  Porewater oxidation, dissolved phosphate and the iron curtain , 1990 .

[23]  W. Lowrie.  Identification of ferromagnetic minerals in a rock by coercivity and unblocking temperature properties , 1990 .

[24]  Michael J. Singer,et al.  Pedogenic Factors Affecting Magnetic Susceptibility of Northern California Soils , 1989 .

[25]  M. Dekkers.  Magnetic properties of natural goethite. I: Grain-size dependence of some low- and high-field related rockmagnetic parameters measured at room temperature , 1989 .

[26]  B. Maher.  Characterisation of soils by mineral magnetic measurements , 1986 .

[27]  R. J. Raison,et al.  Soil temperatures during and following low-intensity prescribed burning in a Eucalyptus pauciflora forest , 1986 .

[28]  U. Schwertmann,et al.  The Influence of Aluminum on Iron Oxides: XI. Aluminum-Substituted Maghemite in Soils and Its Formation1 , 1984 .

[29]  F. Oldfield,et al.  Artificial magnetic enhancement of stream bedload: a hydrological application of superparamagnetism , 1981 .

[30]  U. Schwertmann.  THE INFLUENCE OF ALUMINUM ON IRON OXIDES: 5. CLAY MINERALS AS SOURCES OF ALUMINUM , 1979 .

[31]  C. E. Mullins,et al.  MAGNETIC SUSCEPTIBILITY OF THE SOIL AND ITS SIGNIFICANCE IN SOIL SCIENCE – A REVIEW , 1977 .

[32]  R. Atkinson,et al.  Phosphate adsorption on goethite (α-FeOOOH) , 1976, Nature.

[33]  M. Tite,et al.  Effect of climate on the magnetic susceptibility of soils , 1975, Nature.

[34]  W. H. Patrick,et al.  Phosphate Release and Sorption by Soils and Sediments: Effect of Aerobic and Anaerobic Conditions , 1974, Science.

[35]  U. Schwertmann,et al.  Maghemite in soils and its origin , 1974, Clay Minerals.

[36]  U. Schwertmann,et al.  Maghemite in soils and its origin , 1974, Clay minerals.

[37]  J. L. Butler,et al.  Effects of Burning on Soil Temperature and Yield of Coastal Bermudagrass 1 , 1974 .

[38]  R. E. Munn.  4 – Soil Temperature and Moisture , 1966 .