Measurements Of CO2 Evolution Research Articles

Microbiological characterization and nitrate reduction in subsurface soils

Two borings (20 m depth) were performed in a sandy-clayey soil over a limestone bed and in a sandy soil with lumps of clay in some depths. Bacteria were found in the deeper soil layers of both profiles. The methods used to detect bacteria were those normally used for topsoil layers, plate counts of bacteria, ATP content, and direct microscopy. Measurements of CO2 evolution showed that the potential for bacterial activity was present in all depths of the two profiles. However, the activity was strongly dependent on the presence of easily available organic C. An indication of the denitrification potential was obtained by measuring the N2O evolution. Under aerobic incubation without the addition of glucose, N2O was detected only in the topsoil. When glucose was added to the soil samples, N2O was found at a low level in the deeper soil layers. Under anaerobic incubation, N2O was detected in all deeper layers, and increased markedly when glucose was added to the soil samples.

Developmental changes in energy metabolism ofSchistosoma mansoni and physiological role of oxygen in maintaining parasite function

The time course of the conversion from a cyanide-sensitive to a cyanide-insensitive energy metabolism in immatureSchistosoma mansoni was followed by correlating transitions in CO2 and lactate formation with physiological properties of the parasite. Volume conducted electrical potentials and measurement of CO2 evolution indicate that 3-hr posttransformational schistosomula are highly sensitive to 1 mM cyanide. By 24 hr after transformation, evolution of CO2 under control conditions is reduced by 77% from 3-hr levels, while lactate excretion rises by 84%. At the 24-hr stage, neither cyanide nor rotenone affects the frequency or magnitude of endogenous electrical transients, but cyanide does eliminate 83 % of the already reduced levels of CO2 evolved in 24-hr schistosomula. The adult parasite evolves a low level of CO2 which is reduced by 88% in the presence of 1 mM cyanide. No significant Pasteur effect is detected, however, and endogenous electrical activity as well as mechanical responses of the adult musculature are unaffected by cyanide exposure. Furthermore, adult schistosomes were not adversely affected in terms of the physiological parameters measured by 24-hr incubations in oxygen-free medium. Adults were only marginally affected by 24-hr exposure to several respiratory inhibitors, but responded rapidly to some uncouplers of oxidative phosphorylation, including 2,4-DNP, carbonyl cyanide 3-chlorphenylhydrazone, and closantel. Our results indicate that schistosomula continue to rely on cyanide-sensitive respiratory components for at least 3 hr after transformation; by 24 hr, however, the parasites are metabolically similar to the adult stage, i.e, they depend on lactate fermentation for most of their energy requirements.

Decomposition of Potato Processing Wastes in Soil

AbstractSolid filtered or centrifuged potato processing wastes were obtained from three potato processors in Idaho. The waste samples were dried and ground to pass a 2‐mm sieve and added to soils at rates of 0, 2.5, 10, and 25 g/kg. The 100‐g samples of Portneuf silt loam soil containing the waste material was incubated at 26 °C and decomposition of the added wastes was determined by measuring CO2 evolution in a flowing air stream passing over the soil in the incubation flask. Each increment of added organic waste material increased the amount of carbon evolved during the 12‐week incubation. The waste materials contained 6.8, 20.4, or 65.5 g N/kg waste. However, these differences in N did not change the amount of CO2 evolved at the 12‐week incubation, although the evolution curves were shaped somewhat differently during the 12 weeks. Regression analyses of the cumulative carbon resulted in highly significant R2 values being obtained for each potato processing waste material. Decomposition of the solid waste materials ranged from 24 to 92% depending upon the source and application rate. The rapid decomposition of the solid wastes verified field research indicating that potato wastes have not more than 1 yr residual fertilizer value. The organic waste is not likely to accumulate in the field.

Atividade respiratória de solo tratado com vinhaça e herbicida

Um experimento foi instalado a campo num Latossolo Vermelho-Escuro distrófico textura argilosa, da Estação Experimental de Limeira, em Cordeirópolis, SP, do Instituto Agronômico, para avaliar a atividade respiratória desse solo, quando enriquecido com vinhaça e tratado com o herbicida 2,4D. A vinhaça fora aplicada por quatro vezes, de seis em seis meses, em doses de 0, 100 e 1.000 m³/ha, sendo as determinações feitas seis meses após a última aplicação. O herbicida foi aplicado imediatamente antes do início das determinações das atividades respiratórias e, o solo, mantido livre de vegetação. A atividade respiratória foi avaliada, medindo-se o CO2 coletado em solução de KOH, em câmaras cilíndricas de PVC, em turnos de doze horas, durante quatro dias. As maiores taxas de CO2 (77,5 mg CO2/m².h) foram observadas no período diurno, e estiveram relacionadas com as temperaturas mais elevadas. Mesmo aos seis meses da aplicação da vinhaça, observou-se maior atividade respiratória nos tratamentos com o resíduo. O herbicida 2,4D, na dose de 3,0 litros /hectare, não influenciou a atividade respiratória.

Relationships between CO2 evolution from soil, substrate temperature, and substrate moisture in four mature forest types in interior Alaska

A soda lime technique was used to measure CO2 evolution at the soil surface in four mature forest types (aspen (Populustremuloides Michx.), paper birch (Betulapapyrifera Marsh.), black spruce (Piceamariana (Mill.) B.S.P.), and white spruce (Piceaglauca (Moeneh) Voss)) in interior Alaska. Surface temperature, 15-cm depth temperature, and soil moisture were measured concurrently with CO2 evolution. Accumulated CO2 evolution ranged from 1315 to 1654 g CO2•m−2 for the period May 1 – September 30 in 1981 and 1982 in the four stands. Data were used to develop three-dimensional response surfaces and test mathematical models of respiration in relation to substrate temperature and moisture. GRESP, a biologically based model, provided a fairly accurate simulation of the seasonal course of respiration as a function of substrate temperature and moisture. In an attempt to better define the observed response surface trends, a best-fit equation model, BRESP, was formulated. BRESP includes the moisture portion of the GRESP equation, and an altered temperature equation which more adequately defines the upper and lower thresholds of respiration in relation to substrate temperature. GRESP and BRESP each produced similar r2 values; however, higher order polynomial equations gave a better-fit model. The weakest area of all models for simulating seasonal trends was during the periods of peak respiration in June.

CO2 efflux from deciduous forest litter and soil in response to simulated acid rain treatment

Using both field and laboratory measurements of CO2 evolution as an index of decomposer activity, forest microcosms were used to evaluate the impact of simulated acidic precipitation on decomposition. The following pH treatments: 5.7, 4.5, 4.0, and 3.5 annual average were applied for a 30 mo period. No statistically significant effect of treatment on decomposition could be found in the field measurements. When the microcosm was partitioned into 01 and 02 litter, mineral soil (A and B horizons), and roots within the mineral soil horizons for laboratory determination of CO2 efflux, only the 02 litter exhibited a statistically significant decrease as a function of treatment. The data collected do not allow a complete evaluation of the potential impact of this decrease. However, efflux of CO2 from the 02 layer was small compared to the other layers, and this may account for the failure to detect a significant response in the field measurements. Although the field data did not exhibit a significant response, there is sufficient question concerning the 02 response to warrant additional investigation, especially since many plants derive a major portion of their nutritional requirements directly from the 02 litter layer.

Fate of Hydrocarbons During Oily Sludge Disposal in Soil

A 1,280-day laboratory simulation of the "landfarming" process explored the fate in soil of polynuclear aromatics (PNAs) and total extractable hydrocarbon residues originating from the disposal of an oily sludge. In addition to the measurement of CO(2) evolution, periodic analyses of PNAs and hydrocarbons monitored biodegradation activity. The estimation of carbon balance and of soil organic matter assessed the fate of residual hydrocarbons. Seven sludge applications during a 920-day active disposal period were followed by a 360-day inactive "closure" period with no further sludge applications. A burst of CO(2) evolution followed each sludge addition, but substantial amounts of undegraded hydrocarbons remained at the end of the study. Hydrocarbon accumulation did not inhibit biodegradation performance. Conversion of hydrocarbons to CO(2) predominated during active disposal; incorporation into soil organic matter predominated during the closure period. In this sludge, the predominant PNAs were degraded more completely (85%) than total hydrocarbons. Both biodegradation and abiotic losses of three- and four-ring PNAs contributed to this result. Some PNAs with five and six rings were more persistent, but these constituted only a small portion of the PNAs in the sludge. The study confirmed that the microbially mediated processes of mineralization and humification remove sludge hydrocarbons from soils of landfarms with reasonable efficiency.

LABORATORY STUDIES OF FACTORS AFFECTING MICROBIAL DEGRADATION OF WHEAT STRAW RESIDUES IN SOIL

A simple laboratory method for measuring CO2 evolution from soil was developed using 580-mL plastic containers. Rate of CO2 evolution was measured by exposing 0.1 N NaOH in the closed containers for 4 h and determining the altered conductivity of the absorbent. With 400 g of soil per unit plus 0.172% straw, a coefficient of variation < 2% (total CO2 evolved, 6 wk) was typical with three replicates. Tests with two low-fertility Ontario soils showed that rate of straw decomposition was not affected significantly by fertilizer amendment or length of straw cuttings, but it did increase when soil depth was reduced; also the amount of CO2 evolved increased with duration of soil storage. The method was applied to problems relating to the Mediterranean climate, burning of crop residues, and consequent depletion of soil organic matter. Simulation studies directed towards increasing soil organic matter showed that straw decomposition rates would (1) decrease as crop residues added to soil were increased two- to fivefold, (2) recover markedly over the winter from delayed decomposition caused by the late arrival of autumn rains, and (3) be unaffected by depth of straw placement in soil. Key words: Straw decomposition, chemical fertilizer, CO2 evolution, moisture, temperature, straw placement

MEASUREMENT OF CO2 EVOLVED FROM ORGANIC SOIL AT DIFFERENT DEPTHS IN SITU

A new technique for measuring CO2 evolved from organic soil at different depths in situ was used to monitor CO2 evolution in four experimental sites in southwestern Quebec and in an undisturbed soil column in the laboratory. The technique can be used in conjunction with in situ measurements of surface evolution of CO2, which are used as indicators of total subsidence by oxidation. Subsurface measurements of CO2 evolution provide more detailed estimates of where oxidation is occurring within the profile in organic soils. It also provides a simpler, more direct way of measuring CO2 fluxes below the soil surface than modelling from concentration profiles.

An Open Chamber Technique for the Measurement of Carbon Dioxide Evolution from Soils

This paper describes a new open chamber technique for measuring CO2 evolution from soil in situ, which minimizes measurement errors due to soil disturbance and chamber effects. An analysis of the data collected by this new technique, and a reanalysis of data already published, shows that there is clearly a relationship between the metabolic activity of a soil and the velocity of wind passing over that soil. The mechanism and implications of this relationship are discussed.

The Impact of Zinc Smelter Emissions on Forest Litter Arthropods

Tullgren extractions were used to sample the litter arthropod fauna from mid-August through mid-October in three mixed-oak forest stands located about 1, 6 and 40 km from a zinc smelter in Pennsylvania. Mean arthropod density (n mn2) was estimated to be about 35000 at the 1-km site, about 72000 at 6 km, and about 161000 at the 40-km control site. Densities of all major taxonomic groups were lower near the smelter, with oribatid mites showing the greatest absolute decrease. Measurements of CO2 evolution were made on 02 litter samples and indicated that soil respiration rates were highest at the 40-km site and significantly less at both the 6-km and 1-km sites. Mean concentrations of about 26000 ppm Zn, 10000 ppm Fe, 2300 ppm Pb, 900 ppm Cd, 340 ppm Cu and 0.40% S were measured in the 02 litter layer at the 1-km site. Mean concentrations at 6 km were about 15000 ppm Zn, 6500 ppm Fe, 970 ppm Pb, 250 ppm Cd, 170 ppm Cu and 0.26% S. Mean concentrations from the control site (40 km) were 2800 ppm Fe, 650 ppm Zn, 260 ppm Pb, 50 ppm Cu, 9 ppm Cd and 0.13% S.

Biodegradation of petroleum in seawater at low temperatures.

To evaluate the significance of biodegradation in the removal of polluting oil from cold oceans, freshly collected seawater samples were treated with petroleum and were incubated at controlled temperatures between 5 and 20 °C. Biodegradation was monitored by the measurement of CO2 evolution and by quantitative gas chromatographic analysis. Low water temperatures not only resulted in slower degradation rates, but caused increasing lag periods that preceded the onset of measurable biodegradation. A substantial portion of these lag periods was eliminated when, instead of fresh petroleum, a "weathered" sample was used. The results suggest that some volatile components of petroleum that are inhibitory to oil-degrading microorganisms evaporate only very slowly at low temperatures, and thus retard biodegradation.

Cycles of Temperature and Carbon Dioxide Evolution From Litter and Soil

Periodic measurement of CO2 evolution from various biotopes reveals a daily cycle in soil respiration with a predawn minimum and an afternoon maximum that parallels the daily temperature cycle. A second maximum occasionally occurs between midnight and dawn when soil temperatures exceed temperature of the surface air. This predawn flush may result from thermal convection of CO2—rich subsurface air to the surface. The time of measurement must be considered for comparisons of rates of CO2 evolution from different sites, and measurements should be made over a 24—hr period for estimates of daily CO2 evolution.

A Rapid Method for Measurement of CO2 Evolution by Soil Microorganisms

A Rapid Method for Measurement of CO2 Evolution by Soil Microorganisms

Comparative Rates of Decomposition in Soil of Wood and Bark Particles of Several Softwood Species

AbstractThe rates of decomposition of 10 kinds of finely‐ground woods and the corresponding barks at two nitrogen levels were determined in the laboratory by measuring CO2 evolution over periods varying from 53 to 800 days. The following species were studied: California incense cedar, cypress, redwood, western larch, eastern hemlock, red fir, white fir, Douglas‐fir, red cedar, and Engleman spruce. The woods and barks of all of these species were considerably more resistant to biological attack than is shortleaf pine sawdust. California incense cedar, cypress, redwood, eastern hemlock, and red cedar, were decomposed to the extent of < 7% during a 2‐month period. The comparative resistance of woods and barks to decay varied for individual species but the average values for the 10 species were similar. Due to the slow rates of decomposition, the soil was able to furnish adequate available nitrogen for maximum rates of decomposition for all of the wood products, and supplemental nitrogen was not needed.

The Heterotrophic Nutrition of Chlorella vulgaris (Brannon No. 1 Strain): With two Figures In the Text

A range of sugars, sugar alcohols, sugar phosphates, organic acids, and monohydric alcohols have been tested as carbon sources for growth and as respiratory substrates using Chlorella vulgaris, Brannon I, grown in darkness. Much higher rates of growth and respiration were obtained with d-glucose than with any other substance tested. Ethanol (at 0·005 M.) sustained both growth and respiration at c. 50 per cent, of the level with glucose (0·028 M. or higher). Evidence was obtained that the organism can become ‘adapted’ to utilize d-galactose and sucrose as effective carbon sources. Sustained growth was not obtained with any of the other substances tested. The glucose monophosphates, methanol and certain organic acids (oxalacetate, α-ketoglutarate, cis-aconitate, and pyruvate) clearly stimulated oxygen uptake but to a less extent than ethanol. The other substances tested were either inhibitory to respiration or inactive or of very low activity as substrates. The growth in darkness and in liquid culture of Chlorella when supplied with d-glucose was insensitive to pH over the range 4·5 to 7·0 and was markedly enhanced by a high level of aeration. Gains in cellular dry weight ranging from 45 to 90 per cent, of the weight of d-glucose disappearing from the culture medium were recorded in growth experiments; measurements of CO2 evolution in the Warburg indicated retention of up to two-thirds of the glucose-C in cell material.