Carbon dioxide as a measure of microbial activity in the unsaturated zone by Brian David Wood Download PDF EPUB FB2
Carbon dioxide concentrations were measured at various depths and times in the unsaturated zones of two hydraulically and geochemically contrasting field sites, In situ measurement of microbial activity and controls on microbial CO 2 production in the unsaturated zone Brian D.
Wood. Search for more papers by this by: Carbon dioxide concentrations were measured at various depths and times in the unsaturated zones of two hydraulically and geochemically contrasting field sites, one in southeastern Washington state, and the other in south central Saskatchewan.
In situ CO 2 production rates were calculated from a mass balance that accounted for diffusive fluxes and Cited by: Carbon dioxide has a dual physiological role in microorganisms since it can both stimulate and inhibit cell development. The inhibitory action has been increasingly exploited to improve the hygiene of both liquid and solid foodstuffs by protecting them from bacterial spoilage (6, 7, 9, 20).Cited by: Carbon dioxide‐free N 2 gas, in addition to CO 2 gas concentrations of 10, 50, andμmol mol −1, were used to calibrate sensors, all of which reported an accuracy of ±% of the range + 2% of the reading.
Time‐domain reflectometry (TDR) probes with 15‐cm‐long rods were horizontally installed at depths of, 12 Cited by: 3. Microbial respiration rates were determined through a m thick, sandy unsaturated zone in a m diameter x m high mesocosm. The mesocosm was maintained under near constant temperature ( The long residence time of SOC and CO 2 in the unsaturated zone (29 years at the study site) suggests that the unsaturated zone of deep aquifers may have a significant storage capacity for carbon.
Arctic temperatures are rising faster than in temperate regions, and are expected to increase °C over the next years, resulting in thawing of permafrost, increasing active layer, AL, thickness, and exposure of labile carbon to microbial activity. Although CO2 and CH4 fluxes have been studied in permafrost environments, the relationship between methanogenic.
Similar to carbon mineralization, nitrogen mineralization is dependent on soil microbial activity, organic matter content, and substrate quality and availability.
Nitrogen mineralization is shown in Fig. for the same three soils described in Fig.which range in carbon content from % to %, and a similar C:N ratio of 20 in all soils. These microbial reactions can occur in either the unsaturated or saturated zone, and in some cases involve a two-step process such as: 1) methane generation in anaerobic zones above and below the water table, and 2) the methane oxidation in the unsaturated zone by naturally occurring bacteria utilizing oxygen diffusing in from the surface.
The use of sealed microcosms allows for the measurement of microbial activity within the sample as determined by the flux of CO 2 and/or O 2 within the headspace atmosphere. Headspace gas samples can be withdrawn using a gastight syringe, and the CO 2 or O 2 concentrations can be determined using gas chromatography.
] and influence the carbon source/sink terms in the global CO2 mass balance [•imtinek and Suarez, ; Wood et al., ]. Carbon dioxide production in the unsaturated zone may be attributed to heterotrophic respiration, the biologically me- diated mineralization of organic C to CO2, and autotrophic (root) respiration.
Direct link to YouTube video. Carbon Dioxide Measurement Using Colorimetric Gas Detection Tubes. Carbon Dioxide Gas Detection Tubes. Colorimetric gas detector tube are used to measure the amount of a target gas present in an environment when a known volume of that environment’s air is pumped through a tube.
Quantitative information on microbial processes in the field is important. Here we propose a new field method, the “gas push−pull test” (GPPT) for the in-situ quantification of microbial activities in the vadose zone.
To evaluate the new method, we studied microbial methane oxidation above an anaerobic, petroleum-contaminated aquifer. A GPPT consists of.
In situ determinations of geochemical reaction rates in mine waste-rock piles remain a challenge. Depth-profiles of field O2 and CO2 pore-gas concentrations, δ13CCO2 values, and moisture contents were used to characterize and quantify geochemical reaction rates in two waste-rock piles at the Key Lake Uranium Mine in northern Saskatchewan, Canada.
CO 2 and oxygen O 2 are crucial components of the rhizosphere, “the narrow zone subject to the influence of living roots, as manifested by the leakage or exudation of substances that affect microbial activity” (Curl and Truelove, ).In field soil, CO 2 and O 2 concentrations vary depending on soil type, soil moisture, organic matter content, temperature, type of crops, and.
Thickness of the Unsaturated Zone Barriers and Conductive Zones Figure C Impermeable Surface Layer Figure D Zone of High Microbial Activity Figure E Source of VOCs in the Vadose Zone Hydrologic and Hydrogeologic Properties Water Table Oscillations wastes to produce ammonia and carbon dioxide in.
Carbon Dioxide. APHA et al. CO 2 C (titrimetric) or CO 2 D (calculation requiring known values for total alkalinity and pH) ISE for field measurement. Carbon dioxide is a by-product of both aerobic and anaerobic degradation. Elevated levels of carbon dioxide indicate microbial activity has been stimulated.
Indicator parameter. The results showed that total PLFA increased with plant growth, indicating an increase of microbial biomass. But the mono-unsaturated PLFAs increased faster than the branched chain fatty acids.
The 13 C was incorporated into PLFAs immediately after the plant 13 CO 2 assimilation, proving the tight coupling of microbial activity to plant. Analyses of soil gas composition and stable and radioactive carbon isotopes in the vadose zone above an alluvial aquifer were conducted at an organic solvent disposal site in southeast Phoenix, Arizona, USA.
The source and movement of carbon dioxide above a plume of organic solvent contamination were investigated. Two soil gas monitor wells, each screened and grouted at. Carbon dioxide is a by-product of both aerobic and anaerobic degradation.
Elevated levels of carbon dioxide indicate microbial activity has been stimulated. Indicator parameter. Carbon dioxide coming in through the root system of a plant denies it of the oxygen needed for nutrient absorption. In these tree kill areas, the carbon dioxide makes up % of the gas content of the soil, resulting in a tree kill area that presently.
Soils play a key role in the global cycling of carbon (C), storing organic C, and releasing CO2 to the atmosphere. Although a large number of studies have focused on the CO2 flux at the soil–air interface, relatively few studies have examined the rates of CO2 production in individual layers of a soil profile.
Deeper soil horizons often have high concentrations of CO2. Once peat is drained, it oxidises due to microbial activity and releases stored carbon to the atmosphere as carbon dioxide. This ongoing rapid peat decomposition leads to the irreversible process of peatland subsidence.
Carbon dioxide from a pressurized cylinder was mixed with air pumped by a vacuum pump. Gases were mixed on a tee and then they were introduced into the culture. The concentration of carbon dioxide in the introduced gas was calibrated using a Sick type analyzer (measurement range of 0–40 vol%).
The flow rate was l/h. This approach is highly versatile since label can be added as either 13 C-bicarbonate or carbon dioxide 9, 13, as 13 C-labelled organisms or their remains (such as plant litter or cultured al 15), or as any other organic substrate (e.g.
13 C-acetate or 13 C-toluene) to link processes to specific microbial populations 5, 10, 16, 17, The principal source of carbon dioxide species that produce alkalinity in surface or ground water is the CO2 gas fraction of the atmosphere, Ior the atmospheric gases present in the soil or in the unsaturated zone lying between the surface of the land and the water table.
The CO2 content of the atmosphere is near percent by volume. An aerobic biodegradation zone (see Figure 1) is typically present along the perimeter of the PHC plumes in groundwater and soil gas.
Within this bioactive zone, natural microbial activity can degrade many PHCs into nontoxic end products like carbon dioxide and water (although some biodegradation pathways. Microbes are critical players in every geochemical cycle relevant to climate including carbon, nitrogen, sulfur, and others.
The sum total of microbial activity is enormous, but the net effect of microbial activities on the concentration of carbon dioxide and other climate-relevant gases is currently not known. In February ofthe American Academy of Microbiology convened a.
While carbon dioxide fluxes from microbial activity The deeper unsaturated zone maintains beneficial levels of water and air and is annually resupplied with organic carbon.
Microbial Community: As shown in a lot of factors above, high microbial activity can lead to carbon being lost as a product of respiration. However, microbes are necessary as degraders of complex organic material, facilitating carbon mineralization, and are a large portion of organic matter itself as dead microbial biomass.
Soil microbial respiration apparatus (20 fluid oz plastic soda bottles) CO 2 gas delivery mechanism (#4 one-hole stopper, attached glass tube and rubber tubing. One per bottle.) Collecting vessels (small jars, flasks, beakers, etc.) ml graduated cylinders (to measure limewater and sugar water) Celsius thermometers (to test ambient.The approach developed for the Galloway Township site is to identify stoichiometric relations among oxygen consumption, carbon dioxide production, and hydrocarbon degradation.
Once these relations are established, fluxes of oxygen and carbon dioxide through the unsaturated zone are used to estimate in situ biodegradation rates.solar radiation absorbed) – this is a measure of ‘greenhouse trapping’.
Infrared spectral absorption by water vapour and carbon dioxide The amount of radiation trapped depends fundamentally on the gaseous composition of the atmosphere and the spectral Figure 1.