Plant-soil distribution of potentially toxic elements in response to elevated atmospheric CO2.

The distribution of contaminant elements within ecosystems is an environmental concern because of these elements' potential toxicity to animals and plants and their ability to hinder microbial ecosystem services. As with nutrients, contaminants are cycled within and through ecosystems. Elevated atmospheric CO2 generally increases plant productivity and alters nutrient element cycling, but whether CO2 causes similar effects on the cycling of contaminant elements is unknown. Here we show that 11 years of experimental CO2 enrichment in a sandy soil with low organic matter content causes plants to accumulate contaminants in plant biomass, with declines in the extractable contaminant element pools in surface soils. These results indicate that CO2 alters the distribution of contaminant elements in ecosystems, with plant element accumulation and declining soil availability both likely explained by the CO2 stimulation of plant biomass. Our results highlight the interdependence of element cycles and the importance of taking a broad view of the periodic table when the effects of global environmental change on ecosystem biogeochemistry are considered.

[1]  H. Lambers,et al.  Plant nutrient-acquisition strategies change with soil age. , 2008, Trends in ecology & evolution.

[2]  B. Hungate,et al.  THE EFFECTS OF ELEVATED CO2 ON NUTRIENT DISTRIBUTION IN A FIRE‐ADAPTED SCRUB OAK FOREST , 2003 .

[3]  K. Giller,et al.  Heavy metals and soil microbes , 2009 .

[4]  Dale W. Johnson,et al.  Elevated CO2, rhizosphere processes, and soil organic matter decomposition , 1998, Plant and Soil.

[5]  Seasonal variability in the effect of elevated CO2 on ecosystem leaf area index in a scrub‐oak ecosystem , 2002 .

[6]  P. Ineson,et al.  Elevated CO2 reduces the nitrogen concentration of plant tissues , 1998 .

[7]  D. Obrist,et al.  Mercury accumulation in grass and forb species as a function of atmospheric carbon dioxide concentrations and mercury exposures in air and soil. , 2006, Chemosphere.

[8]  C. Field,et al.  A unifying framework for dinitrogen fixation in the terrestrial biosphere , 2008, Nature.

[9]  P. Reich,et al.  Quantifying plant response to ozone: a unifying theory. , 1987, Tree physiology.

[10]  J. D. Clark,et al.  Effect of pH of ammonium oxalate extracting solutions on prediction of plant available molybdenum in soil , 1996 .

[11]  M. Lerdau,et al.  Plant and Soil Mediation of Elevated CO2 Impacts on Trace Metals , 2009, Ecosystems.

[12]  Thomas Wichard,et al.  Uptake of molybdenum and vanadium by a nitrogen-fixing soil bacterium using siderophores , 2008 .

[13]  R. Ceulemans,et al.  Forest response to elevated CO2 is conserved across a broad range of productivity. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[14]  B. Hungate,et al.  Priming depletes soil carbon and releases nitrogen in a scrub-oak ecosystem exposed to elevated CO2 , 2009 .

[15]  N. Oh,et al.  Soil acidification induced by elevated atmospheric CO2 , 2004 .

[16]  CO 2 enrichment increases nutrient leaching from model forest ecosystems in subtropical China , 2008 .

[17]  M. Lerdau,et al.  Increased mercury in forest soils under elevated carbon dioxide , 2008, Oecologia.

[18]  B. Hungate,et al.  Decreased leaf-miner abundance in elevated CO2: reduced leaf quality and increased parasitoid attack. , 1999, Ecological applications : a publication of the Ecological Society of America.

[19]  B. Hungate,et al.  Disturbance, rainfall and contrasting species responses mediated aboveground biomass response to 11 years of CO2 enrichment in a Florida scrub‐oak ecosystem , 2009 .

[20]  Bruce A. Hungate,et al.  Altered soil microbial community at elevated CO2 leads to loss of soil carbon , 2007, Proceedings of the National Academy of Sciences.

[21]  C. Strojan.  Forest leaf litter decomposition in the vicinity of a zinc smelter , 2004, Oecologia.

[22]  F. Day,et al.  EFFECT OF ELEVATED CO 2 ON COARSE-ROOT BIOMASS IN FLORIDA SCRUB DETECTED BY GROUND-PENETRATING RADAR , 2007 .

[23]  P. Ambus,et al.  Plant nutrient mobilization in temperate heathland responds to elevated CO2, temperature and drought , 2010, Plant and Soil.

[24]  Correcting mathematically for soil adhering to root samples , 2002 .

[25]  John D. Storey.  The positive false discovery rate: a Bayesian interpretation and the q-value , 2003 .

[26]  Archana Sharma,et al.  Comparison of mercury, lead and arsenic with respect to genotoxic effects on plant systems and the development of genetic tolerance , 2004 .