Microalgal cultures are usually sparged with CO2-enriched air to preclude CO2 limitation during photoautotrophic growth. However, the CO2 vol% specifically required at operating conditions to meet the carbon requirement of algal cells in photobioreactor is never determined and 1-10% v/v CO2-enriched air is arbitrarily used. A scheme is proposed and experimentally validated for Chlorella vulgari...

The O2 and CO2 compensation points (O2 and CO2) of plants in a closed system depend on the ratio of CO2 and O2 concentrations in air and in the chloroplast and the specificities of ribulose bisphosphate carboxylase/oxygenase (Rubisco). The photosynthetic O2 is defined as the atmospheric O2 level, with a given CO2 level and temperature, at which net O2 exchange is zero. In experiments with C3 pl...

We examined the effects of elevated carbon dioxide concentration ([CO2]) on the relationship between light-saturated net photosynthesis (A(sat)) and area-based foliar nitrogen (N) concentration (N(a)) in the canopy of the Duke Forest FACE experiment. Measurements of A(sat) and N(a) were made on two tree species growing in the forest overstory and four tree species growing in the forest understo...

Nidicolous ectoparasites such as fleas and gamasid mites that feed on small and medium-sized mammals spend much of their time in their hosts' burrows, which provide an environment for living, and often feeding, to their pre-imaginal and/or adult stages. Thus, these ectoparasites should be adapted to environmental conditions in burrows, including high fractional concentrations of CO2 (F(CO2)). W...

Ocean uptake of anthropogenic CO2 reduces pH and saturation state of calcium carbonate materials of seawater, which could reduce the calcification rate of some marine organisms, triggering a negative feedback on the growth of atmospheric CO2. We quantify the effect of this CO2-calcification feedback by conducting a series of Earth system model simulations that incorporate different parameteriza...

Ocean storage of CO2 was proposed by Marchetti as one of greenhouse gas control technologies, where CO2 is captured from flue gas of fossil fuels and injected into deep seafloor below the depth of 3500m to be sequestered from the atmosphere as shown in Fig. 1. In the last decade of the twenties century, there was a great progress in study on the ocean storage. Aya and his colleagues and Nishika...

Three approaches for determining the stable isotopic composition (δ13C and δ18O) of soil CO2 efflux were compared. A new technique employed mini-towers, constructed of open-topped piping, that were placed on the soil surface to collect soil-emitted CO2. Samples were collected along a vertical gradient and analyzed for CO2 concentration and isotopic composition. These data were then used to prod...

The CO2 concentration in the atmosphere has increased significantly in recent decades and is projected to rise in the future. The effects of elevated CO2 concentrations on morphological and anatomical characteristics, and nutrient accumulation have been determined in several plant species. Carrot is an important vegetable and the effects of elevated CO2 on carrots remain unclear. To investigate...