[1] Biological and geochemical CO2 proxies provide critical constraints on understanding the role of atmospheric CO2 in driving climate change during Earth history. As no single existing CO2 proxy is without its limitations, there is a clear need for new approaches to reconstructing past CO2 concentrations. Here we develop a new preQuaternary CO2 proxy based on the stable carbon isotope composi...

Homeostasis of internal carbon dioxide (CO2) and oxygen (O2) levels is fundamental to all animals. Here we examine the CO2 response of the nematode Caenorhabditis elegans. This species inhabits rotting material, which typically has a broad CO2 concentration range. We show that well fed C. elegans avoid CO2 levels above 0.5%. Animals can respond to both absolute CO2 concentrations and changes in...

Experimental research investigating the responses of forest trees to rising concentrations of atmospheric CO2 has for the past two decades been justified on the basis of the prominent role of forests in the global carbon cycle. The C cycle regulates the airborne fraction of CO2 from fossil fuel combustion, and, therefore, the rate of increase of CO2 in the atmosphere and the associated effects ...

BACKGROUND Carbon dioxide (CO2) dose-dependently decreases minimum alveolar concentration (MAC) of anaesthetics in rats. CO2 also dose-dependently decreases cerebrospinal fluid pH. N-methyl-D-aspartate (NMDA) channels exhibit pH sensitivity and are putative targets for inhaled anaesthetics. We hypothesized that CO2 dose-dependently decreases rat NMDA channel current via an acidifying effect at ...

The injection of supercritical carbon dioxide (CO2) in deep saline aquifers leads to the formation of a CO2 rich phase plume that tends to float over the resident brine. As pressure builds up, CO2 density will increase because of its high compressibility. Current analytical solutions do not account for CO2 compressibility and consider a volumetric injection rate that is uniformly distributed al...

Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive man...

Reducing the CO2 levels in the atmosphere is one of the emerging challenges for human society. It is commonly accepted that CO2, as a greenhouse gas, is partly responsible for climate changes. It is thus important to reduce those CO2 levels in every possible way. This can be achieved in different manners, for example by decreasing CO2 emission by developing energy efficient processes with a red...

The authors investigate the influence of El Niño on midtropospheric CO2 from the Atmospheric Infrared Sounder (AIRS) and the Model for Ozone and Related Chemical Tracers, version 2 (MOZART-2). AIRS midtropospheric CO2 data are used to study the temporal and spatial variability of CO2 in response to El Niño. CO2 differences between the central and western Pacific Ocean correlate well with the So...

This paper is the first of a series that attempts to assess the possible health and safety risks associated with large scale CO2 sequestration in deep brine reservoirs. The approach is based on analysis of available data on the operational track record from CO2 transportation and injection associated with enhanced oil recovery (CO2-EOR) in the US. This paper is particularly concerned with ident...

[1] Using in situ measurements, we find a semiannual oscillation (SAO) in the midtropospheric and surface CO2. Chemistry transport models (2-D Caltech/JPL model, 3-D GEOS-Chem, and 3-D MOZART-2) are used to investigate possible sources for the SAO signal in the midtropospheric and surface CO2. From model sensitivity studies, it is revealed that the SAO signal in the midtropospheric CO2 originat...