|Dijkstra, Paul -|
|Megonigal, Patrick -|
|Ketterer, Michael -|
|Drake, Bert -|
|Johnson, Dale -|
|Hungate, Bruce -|
Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 12, 2013
Publication Date: May 23, 2013
Citation: Duval, B.D., Dijkstra, P., Megonigal, P.J., Ketterer, M.E., Drake, B.G., Johnson, D.W., Hungate, B.A. 2013. Element pool changes within a scrub-oak ecosystem after 11 years of elevated CO2 exposure. PLoS One. DOI:10.1371. Interpretive Summary: Elevated levels of carbon dioxide in the atmosphere are a cause of concern for climate change. However, many plants grow larger under high levels of carbon dioxide, potentially offsetting emissions to the atmosphere. In an effort to determine if elevated levels of carbon dioxide affect a plant’s update of essential nutrients, we took advantage of a long-term experiment in Florida to measure nutrient differences in plant tissues and soils and how they were impacted by high carbon dioxide exposure. We found that elevated carbon dioxide caused certain nutrients to be transferred from soil to plants, suggesting that ecosystems with a large plant growth response under high carbon dioxide will likely experience element movement from soil pools to plant tissue.
Technical Abstract: Elevated CO2 effects on soil element pool size and fluxes are equivocal. We measured above and belowground pools of non-nitrogen macro and micronutrients in a Florida scrub-oak ecosystem exposed to twice-ambient CO2 concentrations for 11 years. We quantified element pools in above ground biomass of the dominant oak (Quercus myrtifolia), as well as in the litter layer, roots, and soil to a depth of 200 cm. Parallel with large biomass stimulation, elevated CO2 increased oak stem Na, Mg, P, K, V, Zn and Mo, and the overall aboveground pool of K and S. However, we observed a negative effect of CO2 on the pool size of elements in roots for most elements. Our calculations of nutrient redistribution from soluble soil pools to plant biomass suggest that the increase in plant Ca is greater than the decline of the plant available pool of elements in soils. We conclude that elevated CO2 caused a net transfer of a subset of nutrients from soil to plants, suggesting that ecosystems with a large positive plant growth response under high CO2 will likely experience mobilization of elements from soil pools to plant biomass.