Effects of elevated concentrations of atmospheric CO2 and tropospheric O3 on decomposition of fine roots†

Chapman, Jack A.; King, John S.; Pregitzer, Kurt S.; Zak, Donald R.
December 2005
Tree Physiology;2005, Vol. 25 Issue 12, p1501
Academic Journal
Rising atmospheric carbon dioxide (CO2) concentration ([CO2]) could alter terrestrial carbon (C) cycling by affecting plant growth, litter chemistry and decomposition. How the concurrent increase in tropospheric ozone (O3) concentration ([O3]) will interact with rising atmospheric [CO2] to affect C cycling is unknown. A major component of carbon cycling in forests is fine root production, mortality and decomposition. To better understand the effects of elevated [CO2] and [O3] on the dynamics of fine root C, we conducted a combined field and laboratory incubation experiment to monitor decomposition dynamics and changes in fine root litter chemistry. Free-air CO2 enrichment (FACE) technology at the FACTS-II Aspen FACE project in Rhinelander, Wisconsin, elevated [CO2] (535 μl 1−1) and [O3] (53 nl 1−1) in intact stands of pure trembling aspen (Populus tremuloides Michx.) and in mixed stands of trembling aspen plus paper birch (Betula papyrifera Marsh.) and trembling aspen plus sugar maple (Acer saccharum Marsh.). We hypothesized that the trees would react to increased C availability (elevated [CO2]) by increasing allocation to C-based secondary compounds (CBSCs), thereby decreasing rates of decomposition. Because of its lower growth potential, we reasoned this effect would be greatest in the aspen–maple community relative to the aspen and aspen–birch communities. As a result of decreased C availability, we expected elevated [O3] to counteract shifts in C allocation induced by elevated [CO2]. Concentrations of CBSCs were rarely significantly affected by the CO2 and O3 treatments in decomposing fine roots. Rates of microbial respiration and mass loss from fine roots were unaffected by the treatments, although the production of dissolved organic C differed among communities. We conclude that elevated [CO2] and [O3] induce only small changes in fine root chemistry that are insufficient to significantly influence fine root decomposition. If changes in soil C cycling occur in the future, they will most likely be brought about by changes in litter production.


Related Articles

  • Depth-resolved particle associated microbial respiration in the northeast Atlantic. Belcher, A.; Iversen, M.; Giering, S.; Riou, V.; Henson, S.; Sanders, R. // Biogeosciences Discussions;2016, Vol. 13 Issue 3, p1 

    The depth at which sinking particulate organic carbon (POC) is remineralized in the ocean is tightly linked to atmospheric levels of carbon dioxide. Rapid attenuation of downward POC flux typically occurs in the upper mesopelagic (top few hundred meters of the water column), with much slower...

  • Effects of elevated concentrations of atmospheric CO2 and tropospheric O3 on leaf litter production and chemistry in trembling aspen and paper birch communities†. Liu, Lingli; King, John S.; Giardina, Christian P. // Tree Physiology;2005, Vol. 25 Issue 12, p1511 

    Human activities are increasing the concentrations of atmospheric carbon dioxide ([CO2]) and tropospheric ozone ([O3]), potentially leading to changes in the quantity and chemical quality of leaf litter inputs to forest soils. Because the quality and quantity of labile and recalcitrant carbon...

  • Sensitivity analysis of the potential impact of discrepancies in stratosphere--troposphere exchange on inferred sources and sinks of CO2. Deng, F.; Jones, D. B. A.; Walker, T. W.; Keller, M.; Bowman, K. W.; Henze, D. K.; Nassar, R.; Kort, E. A.; Wofsy, S. C.; Walker, K. A.; Bourassa, A. E.; Degenstein, D. A. // Atmospheric Chemistry & Physics Discussions;2015, Vol. 15 Issue 7, p10813 

    The upper troposphere and lower stratosphere (UTLS) represents a transition region between the more dynamically active troposphere and more stably stratified stratosphere. The region is characterized by strong gradients in the distribution of long-lived tracers, which are sensitive to...

  • Climate Change and the Middle Atmosphere. Part III: The Doubled CO[sub2] Climate Revisited. Rind, D.; Shindell, D.; Lonergan, P.; Balachandran, N.K. // Journal of Climate;5/1/98, Vol. 11 Issue 5, p876 

    The response of the troposphere-stratosphere system to doubled atmospheric CO[sub2] is investigated in a series of experiments in which sea surface temperatures are allowed to adjust to radiation imbalances. The Goddard Institute for Space Studies (GISS) Global Climate Middle Atmosphere Model...

  • Assessing the near surface sensitivity of SCIAMACHY atmospheric CO2 retrieved using (FSI) WFM-DOAS. Barkley, M. P.; Monks, P. S.; Hewitt, A. J.; Machida, T.; Desai, A.; Vinnichenko, N.; Nakazawa, T.; Arshinov, M. Yu; Fedoseev, N.; Watai, T. // Atmospheric Chemistry & Physics;2007, Vol. 7 Issue 13, p3597 

    Satellite observations of atmospheric CO2 offer the potential to identify regional carbon surface sources and sinks and to investigate carbon cycle processes. The extent to which satellite measurements are useful however, depends on the near surface sensitivity of the chosen sensor. In this...

  • The imprint of surface fluxes and transport on variations in total column carbon dioxide. Keppel-Aleks, G.; Wennberg, P. O.; Washenfelder, R. A.; Wunch, D.; Schneider, T.; Toon, G. C.; Andres, R. J.; Blavier, J.-F.; Connor, B.; Davis, K. J.; Desai, A. R.; Messerschmidt, J.; Notholt, J.; Roehl, C. M.; Sherlock, V.; Stephens, B. B.; Vay, S. A.; Wofsy, S. C. // Biogeosciences Discussions;2011, Vol. 8 Issue 4, p7475 

    New observations of the vertically integrated CO2 mixing ratio, (CO2), from ground-based remote sensing show that variations in (CO2) are primarily determined by large-scale flux patterns. They therefore provide fundamentally different information than observations made within the boundary...

  • Temperature Sensitivity of Microbial Respiration of Fine Root Litter in a Temperate Broad-Leaved Forest. Makita, Naoki; Kawamura, Ayumi // PLoS ONE;Feb2015, Vol. 10 Issue 2, p1 

    The microbial decomposition respiration of plant litter generates a major CO2 efflux from terrestrial ecosystems that plays a critical role in the regulation of carbon cycling on regional and global scales. However, the respiration from root litter decomposition and its sensitivity to...


    Focuses on the problems that emerge from the lack of an understanding of the ways in which leverage over the terrestrial carbon cycle may be exercised to mitigate the growth of atmospheric carbon dioxide. Ways in which terrestrial biotic productivity may be harnessed to retard the increase in...

  • Restless carbon pools. Ciais, Philippe // Nature;3/11/1999, Vol. 398 Issue 6723, p111 

    Discusses the variation in global atmospheric carbon concentrations from the Holocene up to 1,000 years ago. Analysis of more than 400 ice samples from West Antarctica; Persistent changes in atmospheric carbon dioxide concentration as reveal by the Holocene record; Connection of two principal...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics