Changes In Carbon Dioxide Content Research Articles

An update on bridge carbon dioxide footprint data

Transport infrastructure accounts for a significant proportion of the world's carbon dioxide emissions. Bridges and viaducts use a significant amount of steel and cement; these two industries alone amount to about 16% of the world's total carbon dioxide emissions. The carbon dioxide footprint of bridges and viaducts has been studied, and this paper adds some additional data from various sources. The data analysis is extended, and the key issues of substructure carbon dioxide and bridge size noted in the original research are explored in more detail. New datasets of bridge carbon dioxide with time, with span and carbon dioxide in substructures are introduced to note progress towards net zero. The paper indicates that there has been little change in carbon dioxide content over the past 60 years. The paper summarises the key conclusions from the new data and gives five recommendations towards net zero, along with key performance indicators of good bridge designs considering carbon dioxide footprint.

Effect of Different Growth Media on Algae’s Ability for Carbon Dioxide Biofixation

Carbon dioxide makes up 72% of all greenhouse gases produced, which makes it the leading source of air pollution. Certain green algal species such as Chlorella vulgaris fix the carbon dioxide into fatty acids present in cells in a process known as “carbon dioxide biofixation”. This project tests the effect of different algal growth media on the efficiency of Chlorella vulgaris’s carbon dioxide biofixation. In the testing process, we added Chlorella vulgaris to four bottles, each containing four different substances (distilled water, Blue Green 11 medium, Bold’s Basal Medium, and Guillard’s f/2 medium), and cultured for eight days. Each algae and medium mixture was then divided equally into three smaller bottles and rotated for three days. To compare data, we measured the change in carbon dioxide content by subtracting the carbon dioxide content of the bottles with algae to a similar bottle without algae. The results for the average change in carbon dioxide content were 59.3 ppm for Blue Green 11 medium and algae, 50.6 ppm for Guillard’s medium and algae, 22.6 ppm for Bold’s Basal Medium and algae, and 10 ppm for distilled water and algae. The Blue Green 11 medium most effectively decreased carbon dioxide content of the bottles. This supported our hypothesis that algae's capacity for biofixation can be greatly enhanced through the effective use of media, a finding that has extensive real-world benefits in reducing pollution.

Reconstruction of the Wolf Numbers Based on Radiocarbon Data from the Early 11th Century until the Middle of the 19th Century with Respect to Climate Changes

The results of the reconstruction of Wolf numbers from the 11th century until the middle of the 19th century A.D. based on radiocarbon data are presented. This time span includes the Oort, Wolf, Sporer, Maunder, and Dalton minima of solar activity, as well as the Medieval Solar Maximum (the 12th century and the first half of the 13th century A.D.) and the Late Medieval Maximum (the second half of the 14th century). It is known that the climate changed appreciably over the studied period: there were changes in the global temperature and in the concentration of carbon dioxide in the Earth’s atmosphere; more precisely, there was the Little Ice Age. This work differs from previous reconstructions of other authors in taking into account the influence of climate changes on the radiocarbon content in examined samples at that time span. During the reconstruction, changes in carbon dioxide content and changes in the regimen of carbon dioxide exchange between the ocean and the atmosphere are considered. It is especially important to consider changes in these parameters for the Little Ice Age, which was accompanied by significant changes in global temperature and the carbon dioxide content in the Earth’s atmosphere.

Carbon dioxide and climate: The effects of water transport in radiative‐convective models

Considerable attention is being focused on the possible climatic effects resulting from increases in the concentration of atmospheric carbon dioxide. In calculating CO2 influence on the thermal structure of the atmosphere, the role of clouds is critically important. Not only are the cloud properties, such as amount, numbers of clouds, altitudes, and optical properties important but also whether or not these properties are fixed or coupled to model temperatures. The transport of water vapor determines whether or not a region has clouds, the cloud properites, and the water vapor profiles appropriate for clear and cloudy skies. Results are presented of the change in surface temperature with changes in carbon dioxide content for two radiative‐convective models with three different cloud coverages. We used (1) the Manabe‐Wetherald radiative‐convective model in which three clouds with fixed pressures, thicknesses, and optical properties and a single water vapor profile are inputed and (2) the Hummel‐Kuhn model, which couples radiative heating, convection, and water vapor transport in order to calculate locations and thicknesses. The Hummel‐Kuhn model yields temperature increases for doubled CO2 larger than the Manabe‐Wetherald model for various assumed total cloud cover amounts. For assumed standard cloud cover amounts the Hummel‐Kuhn estimate is 20% larger than the Manabe‐Wetherald estimate. For reduced and enhanced cloud cover amounts the Hummel‐Kuhn estimates are 37% and 17% larger, respectively. The calculated cloud locations and thicknesses did not change in the calculations; therefore the increased sensitivity in the Hummel‐Kuhn model is due to the larger water vapor amounts in the Hummel‐Kuhn model and the added infrared absorption by the water vapor dimer.

Transpiration and Stomatal Opening with Changes in Carbon Dioxide Content of the Air

Increasing the carbon dioxide content of air reduces the transpiration rate of corn and sorghum plants and, to a lesser extent, of cotton, soybean, and tomato plants by causing the stomata to close. Closure of corn and sorghum stomata occurred when the concentrations of carbon dioxide were 2000 and 3000 parts per million, respectively. Cotton, soybean, and tomato stomata did not close completely at concentrations of carbon dioxide up to 4000 parts per million.

Effect of Photosynthesis and Respiration on the Electrical Conductance of Sea-water

RECENTLY one of us (K. P.) and his colleagues examined the effect of carbon dioxide on the electrical conductance of sea-water1. They stated that one of the major causes of changes in the conductance due to the changes in carbon dioxide content in the sea is by biological activities (photosynthesis and respiration). A recent experiment in the laboratory shows that there is a measurable change in conductance as a result of the photosynthesis and respiration of a marine alga.

EFFECT OF CERTAIN NUTRIENT DEFICIENCIES ON STOMATAL BEHAVIOR

Although a great deal of research has been done on stomata, nevertheless, the facts regarding these important plant structures are still fragmentary and there are differences of opinion as to their fundamental characteristics. In 1895 Blackman (3) demonstrated the importance of stomata in gaseous exchange, although the possible relations of stomata to transpiration had long been recognized. Regarding the regulatory role of stomata in respect to transpiration, differences of opinion exist. That the stomata open and close periodically during twenty-four hours has been established. Various theories have been advanced concerning the mechanism of opening and closure and the cellular changes associated with these. According to some, the changes of starch to sugar and vice versa with consequent changes in osmotic relations are responsible for the opening and closure. Scarth (31), in recent years, has emphasized the importance of changes in the pH of the guard-cell vacuome due to changes in carbon dioxide content of the leaf, the opening and closure of the stomata being dependent directly or otherwise upon the effects of pH on starch-sugar changes or protein hydration, or both. Whatever eventually may be found to be the actual mechanism involved in the opening and closure of stomata, it is clear that the metabolism of the guard cells and the adjacent tissues must also be involved. While much attention has been given to the direct influence of light, of leaf water content, and of chemical reagents and reactions on stomatal behavior, no attention, except for the work of Pleasants (27), has been given to the part played by nutrients on stomatal behavior. There has been some work reported on the effect of nutrient deficiency on the rate of photosynthesis and respiration by Gruzit and Hibbard (11), Briggs (4), Lyon (20, 21), Gregory and Richards (8), and others. Since stomatal behavior through its effects on the loss of water and gaseous exchange may markedly influence plant behavior, a fuller knowledge of the effect of various factors on stomatal behavior is desirable. Of the factors that are of importance, theoretically and practically, that of mineral nutrient supply may be of considerable significance.

A STUDY OF THE NITROGEN METABOLISM AND OF ACIDOSIS AFTER THE TRANSPLANTATION OF A URETER INTO THE DUODENUM IN DOGS

1. The present work was undertaken to study the metabolism in the dog after a ureter-intestinal transplantation. Four dogs, Nos. I, 2, 5, and 7, were originally operated upon. Two, Nos. 2 and 7, showed kidney infection; the other two were not infected, and in these the metabolism was studied; one of the latter (No. 1) showed marked hydronephrosis and hydroureter. 2. Both after the transplantation of the right ureter into the intestine and the ligation of the right ureter, there is generally a moderately increased output of nitrogen in the urine and, in the former instance especially, a retention of nitrogen in the blood, but no change in carbon dioxide content in the blood. The significance of this is probably an increased tissue catabolism, the cause of which is doubtful without further work. 3. After removal of the left kidney subsequent to transplantation of the right ureter into the duodenum, renal insufficiency and resulting retention developed. The non-protein and urea nitrogen in the blood steadily increased and the carbon dioxide content of the blood diminished to the level characteristic of a moderate acidosis. No ketones were found in the blood The dogs died 5 to 10 days after the nephrectomy under conditions characteristic of suspended renal activity-deep respiration, unconsciousness, and sopor.