Ecosystem CO release driven by wind occurs in drylands at global scale.

Subterranean ventilation is a non-diffusive transport process that provokes the abrupt transfer of CO -rich air (previously stored) through water-free soil pores and cracks from the vadose zone to the atmosphere, under high-turbulence conditions. In dryland ecosystems, whose biological carbon exchanges are poorly characterized, it can strongly determine eddy-covariance CO fluxes that are used to validate remote sensing products and constrain models of gross primary productivity. Although subterranean ventilation episodes (VE) may occur in arid and semi-arid regions, which are unsung players in the global carbon cycle, little research has focused on the role of VE CO emissions in land-atmosphere CO exchange.

Soil water content effects on net ecosystem CO exchange and actual evapotranspiration in a Mediterranean semiarid savanna of Central Chile.

Biosphere-atmosphere water and carbon fluxes depend on ecosystem structure, and their magnitudes and seasonal behavior are driven by environmental and biological factors. We studied the seasonal behavior of net ecosystem CO exchange (NEE), Gross Primary Productivity (GPP), Ecosystem Respiration (RE), and actual evapotranspiration (ETa) obtained by eddy covariance measurements during two years in a Mediterranean Acacia savanna ecosystem (Acacia caven) in Central Chile. The annual carbon balance was -53 g C m in 2011 and -111 g C m in 2012, showing that the ecosystem acts as a net sink of CO, notwithstanding water limitations on photosynthesis observed in this particularly dry period.

The human footprint in the carbon cycle of temperate and boreal forests.

Temperate and boreal forests in the Northern Hemisphere cover an area of about 2 x 10(7) square kilometres and act as a substantial carbon sink (0.6-0.7 petagrams of carbon per year).

Assessing forest soil CO(2) efflux: an in situ comparison of four techniques.

A dynamic, closed-chamber infrared gas analysis (IRGA) system (DC-1: CIRAS-1, PP-Systems, Hitchin, U.K.) was compared with three other systems for measuring soil CO(2) efflux: the soda lime technique (SL), the eddy correlation technique (EC), and another dynamic, closed-chamber IRGA system (DC-2: LI-6250, Li-Cor, Inc.