Published online by Cambridge University Press: 11 May 2010
INTRODUCTION
Soil CO2 efflux, more commonly termed soil respiration, is considered to be the second largest flux of carbon between terrestrial ecosystems and the atmosphere. Current estimates of global soil respiration are in the range of 68–80 Pg C a−1 (Raich and Potter, 1995; Raich et al., 2002), which exceeds estimated annual rates from fossil fuel combustion by an order of magnitude (Schlesinger and Andrews, 2000; IPCC, 2007). It must be noted that these estimates of global soil CO2 efflux are based on a very limited dataset: (1) the distribution of data for biomes is biased towards forests in the Northern hemisphere; (2) a considerable proportion of the data is based on static chamber measurements, which tend to underestimate soil respiration at high flux rates (Norman et al., 1997; Chapter 2, Pumpanen et al.); (3) annual estimates are often based on simplistic relationships (generally only temperature and sometimes also soil moisture) that capture only a limited fraction of the diurnal, seasonal, annual and inter-annual variation of soil respiration and (4) the spatial variation of soil respiration is generally not well captured, both within ecosystems and across similar ecosystems at a regional scale.
A further major problem for obtaining sensible estimates of global soil CO2 efflux is related to the fact that even though an increasing amount of data is becoming available, these more recent datasets are often not easily comparable due to different methodologies and to the limited availability of ancillary parameters.
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.