It was previously revealed that the total CO2 concentration in seawater decreased during the Late Archean. In this paper, to assess the secular change of total CO2 concentration in seawater, we focused on the Paleoproterozoic era when the Earth experienced its first recorded global glaciation. The 2.4 Ga Ongeluk Formation outcrops in the Kaapvaal Craton, South Africa. The formation consists mai...

Carbon dioxide is the fourth most common gas present in the earth’s atmosphere, with an average ambient concentration (in fresh air) of about 350 ppm. Carbon dioxide is one of the most common byproducts of living organisms. With every exhaled breath we produce and release CO2 into the atmosphere (with an average concentration in exhaled breath of about 3.8%). According to one USDA study, an ave...

Significant differenoes in CO2 compensation concentration measured in the field among varieties of the species Zea mays L. are reported for the first time. CO2 compensation concentrations were signifioantly (P< 0.01) and negatively oorrelated with apparent photosynthesis at 300 pl C02/liter air. The Michaelis constant (as defined) for a leaf was significantly (P< 0.01) and positively correlated...

Environment Canada methods for acute toxicity tests with rainbow trout require continuous aeration of test solutions during exposure. Depending on the sample, this procedure can result in an increase in pH as dissolved carbon dioxide (CO2) is stripped from solution as a result of aeration. In samples that contain ammonia, the pH may increase to the point where the unionized fraction results in ...

Rising atmospheric CO2 is increasing the availability of dissolved CO2 in the ocean relative to HCO3 (-). Currently, many marine primary producers use HCO3 (-) for photosynthesis, but this is energetically costly. Increasing passive CO2 uptake relative to HCO3 (-) pathways could provide energy savings, leading to increased productivity and growth of marine plants. Inorganic carbon-uptake mechan...

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...

The general assumption, in the first phase of elevated carbon dioxide (CO2) research, was that increasing atmospheric CO2 concentration would act as a fertilizer for plant systems. Under this “large-plant-scenario” (Fig. 9.1), increased photosynthesis at elevated CO2 would lead to higher plant biomass which would induce a negative atmospheric feedback loop that would offset anthropogenic carbon...

A method for the direct assessment of the dissolved CO2 concentration in supersaturated water is presented that is based on changes to the physical chemistry of soda lime due to uptake of CO2. The approach is an adaptation of a standard method used for the quantifi cation of soil respiration, and was found to agree with pCO2 measurements made using infrared gas analysis. In this method, the sod...