We measured soil bacteria, fungi, protozoa, nematodes, and biological activity in serpentine and sandstone annual grasslands after 4 years of exposure to elevated atmospheric CO2. Measurements were made during the early part of the season, when plants were in vegetative growth, and later in the season, when plants were approaching […]
The results of a 3-yr study on the effects of elevated CO2 on soil N and P, soil pCO2, and calculated CO2 efflux in a fire-regenerated Florida scrub oak ecosystem are summarized. We hypothesized that elevated CO2 would cause (i) increases in soil pCO2 and soil respiration and (ii) reduced […]
Soil organic carbon (SOC) is the largest reservoir of organic carbon in the terrestrial biosphere. Though the influence of increasing atmospheric CO2 on net primary productivity, on the flow of newly fixed carbon belowground, and on the quality of new plant litter in ecosystems has been examined, indirect effects of […]
The effect of elevated atmospheric CO2 concentration (Ca) on the aboveground biomass of three oak species, Quercus myrtifolia, Q. geminata, and Q. chapmanii, was estimated nondestructively using allometric relationships between stem diameter and aboveground biomass after four years of experimental treatment in a naturally fire-regenerated scrub-oak ecosystem. After burning a […]
Leaf conductance often decreases in response to elevated atmospheric CO2 concentration (Ca) potentially leading to changes in hydrology. We describe the hydrological responses of Florida scrub oak to elevated Ca during an eight-month period two years after Ca manipulation began. Whole-chamber gas exchange measurements revealed a consistent reduction in evapotranspiration […]
To date, most research that has examined the effect of elevated atmospheric carbon dioxide concentration ([CO2]) on litter decomposition has focused on changes in the leaf litter quality of individual species. Results from California grasslands indicate that other CO2 responses may have greater consequences for decomposition rates. For instance, CO2-driven […]
For two species of oak, we determined whether increasing atmospheric CO2 concentration (Ca) would decrease leaf mitochondrial respiration (R) directly, or indirectly owing to their growth in elevated Ca, or both. In particular, we tested whether acclimatory decreases in leaf-Rubisco content in elevated Ca would decrease R associated with its […]
The effects of grassland conversion to forest vegetation and of individual tree species on microbial activity in Siberia are largely unstudied. Here, we examined the effects of the six most commonly dominant tree species in Siberian forests (Scots pine, spruce, Arolla pine, larch, aspen and birch) on soil C and […]
Increased levels of atmospheric carbon dioxide (CO2) are likely to affect the trophic relationships that exist between plants, their herbivores and the herbivores’ natural enemies. This study takes advantage of an open-top CO2 fertilization experiment in a Florida scrub oak community at Kennedy Space Center, Florida, consisting of eight chambers […]
Elevated atmospheric carbon dioxide (Ca) usually reduces stomatal conductance, but the effects on plant transpiration in the field are not well understood. Using constant-power sap flow gauges, we measured transpiration from Quercus myrtifolia Willd., the dominant species of the Florida scrub-oak ecosystem, which had been exposed in situ to elevated […]