The potential for climatic factors as well as soil–plant–climate interactions to change as a result of rising levels of atmospheric CO2 concentration is an issue of increasing international environmental concern. Agricultural and forest practices and managements may be important contributors to mitigating elevated atmospheric CO2 concentrations. A computer model was developed using the Structur...

The effect of resource pulses, such as rainfall events, on soil respiration plays an important role in controlling grassland carbon balance, but how shifts in long-term precipitation regime regulate rain pulse effect on soil respiration is still unclear. We first quantified the influence of rainfall event on soil respiration based on a two-year (2006 and 2009) continuously measured soil respira...

Soil respiration of terrestrial ecosystems, a major component in the global carbon cycle is affected by elevated atmospheric CO2 concentrations. However, seasonal differences of feedback effects of elevated CO2 have rarely been studied. At the Gießen Free-Air CO2 Enrichment (GiFACE) site, the effects of +20 % above ambient CO2 concentration have been investigated since 1998 in a temperate grass...

Soil respiration is responsible for recycling considerable quantities of carbon from terrestrial ecosystems to the atmosphere. There is a growing body of evidence that suggests that the richness of plants in a community can have significant impacts on ecosystem functioning, but the specific influences of plant species richness (SR), plant functional-type richness and plant community composition...

The contribution of the organic (O) horizon to total soil respiration is poorly understood even though it can represent a large source of uncertainty due to seasonal changes in microclimate and O horizon properties due to plant phenology. Our objectives were to partition the CO(2) effluxes of litter layer and mineral soil from total soil respiration (SR) and determine the relative importance of...

We estimated total ecosystem respiration from a ponderosa pine (Pinus ponderosa Dougl. ex Laws.) plantation in the Sierra Nevada Mountains near Georgetown, California, from June to October, 1998. We apportioned ecosystem respiration among heterotrophic, root, stem and foliage based on relationships for each component that considered microclimate and vegetation characteristics. We measured each ...

Radiocarbon signatures (DC) of carbon dioxide (CO2) provide a measure of the age of C being decomposed by microbes or respired by living plants. Over a 2-year period, we measured DC of soil respiration and soil CO2 in boreal forest sites in Canada, which varied primarily in the amount of time since the last stand-replacing fire. Comparing bulk respiration DC with DC of CO2 evolved in incubation...

Ecosystem carbon losses from soil microbial respiration are a key component of global carbon cycling, resulting in the transfer of 40-70 Pg carbon from soil to the atmosphere each year. Because these microbial processes can feed back to climate change, understanding respiration responses to environmental factors is necessary for improved projections. We focus on respiration responses to soil mo...

Stable carbon isotopes are used extensively to partition total soil CO2 efflux into root-derived rhizosphere respiration or autotrophic respiration and soil-derived heterotrophic respiration. However, it remains unclear whether CO2 from rhizosphere respiration has the same δC value as root biomass. Here we investigated the magnitude of C isotope fractionation during rhizosphere respiration rela...