Temporal dynamics of fine roots under long-term exposure to elevated CO2 in the Mojave Desert.
Deserts are considered 'below-ground dominated', yet little is known about the impact of rising CO(2) in combination with natural weather cycles on long-term dynamics of root biomass. This study quantifies the temporal dynamics of fine-root production, loss and standing crop in an intact desert ecosystem exposed to 10 yr of elevated CO(2). We used monthly minirhizotron observations from 4 yr (2003-2007) for two dominant shrub species and along community transects at the Nevada Desert free-air CO(2) enrichment Facility. Data were synthesized within a Bayesian framework that included effects of CO(2) concentration, cover type, phenological period, antecedent soil water and biological inertia (i.e. the influence of prior root production and loss). Elevated CO(2) treatment interacted with antecedent soil moisture and had significantly greater effects on fine-root dynamics during certain phenological periods. With respect to biological inertia, plants under elevated CO(2) tended to initiate fine-root growth sooner and sustain growth longer, with the net effect of increasing the magnitude of production and mortality cycles. Elevated CO(2) interacts with past environmental (e.g. antecedent soil water) and biological (e.g. biological inertia) factors to affect fine-root dynamics, and such interactions are expected to be important for predicting future soil carbon pools.
Department of Mathematics and Statistics, Northern Arizona University, Flagstaff, AZ, 86011, USA.|School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.
Derek L
DL
Sonderegger
School of Life Science, Arizona State University, Tempe, AZ, 85287, USA.
Kiona
K
Ogle
School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA.
R Dave
RD
Evans
Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, 89557, USA.
Scot
S
Ferguson
Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, 89557, USA.
Robert S
RS
Nowak
D002245:Carbon Dioxide / Q000494:pharmacology*; D018556:Crops, Agricultural / Q000502:physiology; D003889:Desert Climate; D006813:Humidity; D008954:Models, Biological; D009505:Nevada; D018517:Plant Roots / Q000187:drug effects* / Q000502:physiology*; D011891:Rain; D012987:Soil / Q000737:chemistry; D013997:Time Factors; D014867:Water
D012987:Soil; D014867:Water; D002245:Carbon Dioxide