Measurements Of Carbon Dioxide Evolution Research Articles

Canary in the coliform mine: Exploring the industrial application limits of a microbial respiration alarm system.

Fundamental ecological principles of ecosystem-level respiration are extensively applied in greenhouse gas and elemental cycle studies. A laboratory system termed CEMS (Carbon Dioxide Evolution Measurement System), developed to explore microbial biofilm growth and metabolic responses, was evaluated as an early-warning system for microbial disturbances in industrial settings: in (a) potable water system contamination, and (b) bioreactor inhibition. Respiration was detected as CO2 production, rather than O2 consumption, including aerobic and anaerobic metabolism. Design, thresholds, and benefits of the remote CO2 monitoring technology were described. Headspace CO2 correlated with contamination levels, as well as chemical (R2 > 0.83-0.96) and microbiological water quality indicators (R2 > 0.78-0.88). Detection thresholds were limiting factors in monitoring drinking water to national and international standards (0 CFU/100 mL fecal coliforms) in both open- (>1500 CFU/mL) and closed-loop CO2 measuring regimes (>100 CFU/100 mL). However, closed-loop detection thresholds allow for the detection of significant contamination events, and monitoring less stringent systems such as irrigation water (<100 CFU/mL). Whole-system respiration was effectively harnessed as an early-warning system in bioreactor performance monitoring. Models were used to deconvolute biological CO2 fluctuations from chemical CO2 dynamics, to optimize this real-time, sustainable, low-waste technology, facilitating timeous responses to biological disturbances in bioreactors.

Biofilm dynamics: linking in situ biofilm biomass and metabolic activity measurements in real-time under continuous flow conditions

The tools used to study biofilms generally involve either destructive, end-point analyses or periodic measurements. The advent of the internet of things (IoT) era allows circumvention of these limitations. Here we introduce and detail the development of the BioSpec; a modular, nondestructive, real-time monitoring system, which accurately and reliably track changes in biofilm biomass over time. The performance of the system was validated using a commercial spectrophotometer and produced comparable results for variations in planktonic and sessile biomass. BioSpec was combined with the previously developed carbon dioxide evolution measurement system (CEMS) to allow simultaneous measurement of biofilm biomass and metabolic activity and revealed a differential response of these interrelated parameters to changing environmental conditions. The application of this system can facilitate a greater understanding of biofilm mass–function relationships and aid in the development of biofilm control strategies.

Biodegradation kinetic modeling of acrylic acid-grafted polypropylene during thermophilic phase of composting

This work aims at modelling and characterizing the kinetics of biodegradation of acrylic acid-grafted polypropylene. Different films of acrylic acid-grafted polypropylene were prepared. These films were degraded aerobically during thermophilic phase of composting process for measurement of carbon dioxide evolution as per ASTM D 5338. The experimental data were analyzed using an eight-parameter Komilis model containing a flat lag phase. The model formulations involved hydrolysis of primary solid carbon and its subsequent mineralization. The first step was rate controlling and it included hydrolysis of primary slowly, moderately, and readily hydrolyzable carbon fractions in parallel. The model parameters were evaluated by means of nonlinear regression technique. The model parameters, undegraded/hydrolyzable/mineralizable carbon evolutions and morphology revealed two typical kinetic regimes. The first five films exhibited slow degradation in the first regime involving slowly and moderately hydrolyzable carbons. They exhibited low degradability value in the range of 1.5–3.7% in 45 days. Their degradability decreased with an increase in the slowly hydrolyzable carbon refractory in nature. The remaining three films exhibited the second regime involving the moderately and readily hydrolyzable carbons. These showed relatively high degradability in the range of 4.7–5.6% in 45 days. The magnitudes of their moderately hydrolyzable carbon fractions were substantially higher than those of the first regime. All the eight films showed the absence of growth phase because of their small initial readily hydrolyzable carbon fractions. The study shows progressive enhancement in the biodegradation of effectively non-biodegradable polypropylene with an increase in degree of acrylic acid grafting. The methods presented here can be used for the design and control of other similar systems.

Зависимость дыхания стволов дуба разных классов роста от условий окружающей среды

Зависимость дыхания стволов дуба разных классов роста от условий окружающей среды

Characterisation and properties of visible light-active bismuth oxide-titania composite photocatalysts

Bismuth oxide – titanium dioxide composite materials were produced by pulsed DC reactive magnetron sputtering onto two types of commercially available titanium dioxide nanoparticles. The use of an oscillating bowl enabled deposition of bismuth oxide uniformly onto loose powders, in contrast to solid substrates typically used for the conventional magnetron sputtering processes. Variation of the deposition time allowed the production of composite materials with different amounts of bismuth oxide. The composite materials, as well as uncoated titania powders, were extensively analysed by a range of analytical techniques, including SEM/EDX, XRD, BET, XPS, TEM and UV–visible diffuse reflectance spectroscopy. Photocatalytic properties of the materials were assessed under simulated visible light irradiation via degradation of acetone and methanol through measurements of carbon dioxide evolution. Additionally, the composite materials were characterised with a newly developed technique of reversed double-beam photoacoustic spectroscopy in order to obtain information on the distribution of electron traps. Bismuth oxide was found in crystalline β-Bi2O3 form on both types of substrates without any additional heat treatment applied. Though the distribution of bismuth oxide on titanium dioxide was found to depend strongly on particle size and deposition time used, the composite materials exhibited significantly enhanced visible light photocatalytic activity compared to either of the commercial titania materials used as a substrate.

Comments on: “Underwater measurements of carbon dioxide evolution in marine plant communities: A new method” by J. Silva and R. Santos [Estuarine, Coastal and Shelf Science 78(2008) 827–830

Silva et al. propose a new method for quantifying benthic net community production (NCP) of tidal flats under submerged condition, based on the monitoring of water pCO 2 in a transparent benthic chamber around high tide. I demonstrate here with theoretical considerations that this method is inappropriate for coastal environments, because it allows only the quantification of the change in the dissolved CO 2 which, at classical seawater pH, is only ∼10% of the change of the dissolved inorganic carbon (DIC). Total Alkalinity and/or DIC must be measured at the beginning and end of incubations in order to compute NCP in coastal environments. However, I also demonstrate that when pH is below 7, more than 95% of the DIC change occurs in the CO 2 pool. The method proposed by Silva et al. is thus valuable for freshwater environments with acidic, low alkalinity waters, where monitoring the water pCO 2 in a vial or chamber provides alone a very close approximation of the planktonic or benthic net community production.

Reply to comments of G. Abril on “Underwater measurements of carbon dioxide evolution in marine plant communities: A new method” by J. Silva and R. Santos [Estuarine, Coastal and Shelf Science 78(2008) 827–830

Reply to comments of G. Abril on “Underwater measurements of carbon dioxide evolution in marine plant communities: A new method” by J. Silva and R. Santos [Estuarine, Coastal and Shelf Science 78(2008) 827–830

Underwater measurements of carbon dioxide evolution in marine plant communities: A new method

We developed a new methodology to determine CO 2 fluxes in intertidal and shallow subtidal plant communities, namely seagrasses, both when the plants are submerged and when they are air-exposed. The apparatus comprises closed incubation chambers and a gas exchange column, designed to remove carbon dioxide from the water. Different types of incubation chambers were designed and built to adapt the system to distinct environments and incubation requirements. The methodology was tested under a comprehensive range of situations and its advantages and limitations are discussed. Overall, the method provides precise measurements of community carbon dioxide fluxes, through a fast and non-intrusive process, allowing repeatable in situ measurements of carbon uptake both in submerged and air-exposed conditions. As the experimental apparatus is identical, directly comparable measurements of air-exposed and submerged community production may be obtained, allowing sound estimates of daily carbon budgets of intertidal and shallow subtidal communities.

The Biodegradation and Disintegration of Paper Products in the Composting Environment

The compostability of several paper products was determined according to the standards and criteria of the European standardization committee (CEN). The lignin content of the materials seems to be the main reason for the low biodegradability level achieved in the controlled composting test, which is a biodegradability test based on microbial degradation and measurement of carbon dioxide evolution. Mechanically pulped paper, which contains more lignin and more closely resembles natural wood than chemically bleached paper, generated smaller amounts of carbon dioxide. All the chemically bleached papers generated more than 70% of their organic carbon content as CO2, while the mechanically pulped unbleached papers in general generated less than 70%. Paper containing mechanical pulp degrades slower because lignin both interferes the biodegradation of cellulose and becomes incorporated in the humus. The test protocol also defines that, even if the biodegradability of paper products is not tested, their disintegration and effect on compost quality have to be determined. In the present study, we also evaluated a number of disintegration test methods in full-scale composting facilities. According to CEN, the disintegration can be studied either in composter bin-scale test equipment or in full-scale composting facilities. In this study, we only present the data from full-scale composting in which several test methods were used to evaluate the degradation of the samples. The disintegration of the paper products in full-scale composting facilities is highly dependent on the method used. The slowest degradation rate was achieved when the samples were composted in nylon bags.

Measurements of carbon dioxide evolution from alkyd paint films: Part I Oxidative scission during film ageing

A recently developed in situ FTIR method of monitoring CO2 evolution during oxidation of paint films has been used to measure CO2 produced by alkyd paints when enclosed in a high humidity oxygen atmosphere. Evolution of CO2 from paint films in the dark was observed and was found to persist over long periods. It is likely that this is the result of β-scission of fatty-acid side-chains which accompanies oxidative cure of alkyd films: it decreases as these processes go to completion. The rate of CO2 evolution from aged films is reduced after the initial rate of cure has been accelerated by oven ageing or by increasing the concentration of catalytic driers. It has also been shown that resistance to photo-degradation increases as ageing of the films proceeds. Our results demonstrate that the sensitivity of CO2 detection by FTIR provides a useful method for following film cure and ageing. The technique has wider potential, e.g. for the study of oxidation in food oils and cosmetic preparations.

On-line control of fed-batch fermentation of dilute-acid hydrolyzates.

Dilute-acid hydrolyzates from lignocellulose are, to a varying degree, inhibitory to yeast. In the present work, dilute-acid hydrolyzates from spruce, birch, and forest residue, as well as synthetic model media, were fermented by Saccharomyces cerevisiae in fed-batch cultures. A control strategy based on on-line measurement of carbon dioxide evolution (CER) was used to control the substrate feed rate in a lab scale bioreactor. The control strategy was based solely on the ratio between the relative increase in CER and the relative increase in feed rate. Severely inhibiting hydrolyzates could be fermented without detoxification and the time required for fermentation of moderately inhibiting hydrolyzates was also reduced. The feed rate approached a limiting value for inhibiting media, with a corresponding pseudo steady-state value for CER. However, a slow decrease of CER with time was found for media containing high amounts of 5-hydroxymethyl furfural (HMF). The success of the control strategy is explained by the conversion of furfural and HMF by the yeast during fed-batch operation. The hydrolyzates contained between 1.4 and 5 g/l of furfural and between 2.4 and 6.5 g/l of HMF. A high conversion of furfural was obtained (between 65-95%) at the end of the feeding phase, but the conversion of HMF was considerably lower (between 12-40%).

Measurement of carbon dioxide evolution from a Japanese cedar ( Cryptomeria japonica D. Don) forest floor using an open-flow chamber method

Little information is available on the fluctuation of soil respiration in Japanese cedar forests ( Cryptomeria japonica D. Don), a principal and highly productive plantation in Japan. We measured the seasonal change in soil respiration for three years in thinned and intact sections of a Japanese cedar forest to establish the relationship between soil respiration and environmental factors and to examine the effects of a common silvicultural practice, namely forest thinning. We measured soil respiration while regulating CO 2 concentration and wind speed in a chamber using a portable open-flow chamber system. Soil respiration rates, ranging from 2570 to 3060 (g CO 2) m −2 year −1 and 1830 to 2170 (g CO 2) m −2 year −1 in the thinned and intact sections, respectively, increased in summer and decreased in winter. Soil respiration rates ( R s) significantly correlated with soil surface temperature ( T s). The relationship was approximately ln ( R s) = a + b( T s), where a and b are constant values, varying from 0.067 to 0.106 and from 3.30 to 4.62, respectively. The Q 10 values were 2.0 and 2.5 in the thinned and intact sections, respectively. Soil surface CO 2 concentrations (0.8–3.9 g m −3), calculated from the soil respiration rates, were higher than ambient atmospheric CO 2 concentrations. They tended to increase in summer and decrease in winter. Soil respiration rates in the thinned section were significantly higher than those of the intact section in the first and second years of the measurement, but not in the third year, namely the fifth year after thinning; an indication that thinning may have increased soil respiration from the forest floor temporarily.

Field measurement of carbon dioxide evolution from soil by a flow-through chamber method using a portable photosynthesis meter

Extract Since a rise in atmospheric carbon dioxide (CO2) concentration is expected to lead to global warming, it is important to quantify the global carbon circulation. The CO2 evolution rate from soil has usually been measured by one of three methods: 1) CO2 absorption (Anderson 1982), where the evolved CO2 is absorbed in an alkali solution and the content subsequently determined, 2) closed chamber (Rolston 1986) in which the CO2 evolution rate is calculated from the increase of the CO2 concentration in a closed chamber covering the soil surface, and 3) flow-through chamber (Rolston 1986) in which a fixed rate of ambient air is pumped through an open chamber and the difference in the. CO2 concentration between the inlet and the outlet is measured. Although the CO2 absorption method is very simple in terms of apparatus and procedure, the determined CO2 evolution rate tends to be underestimated in cases where the evolved CO2 is not fully absorbed in the alkali solution (Ewel et al. 1987; Sakamoto and Yoshida 1988), or overestimated in cases where the CO2 concentration in the chamber is too low to stimulate microbial activity (Koizumi et al. 1991; Nakadai et al. 1993), In the closed chamber method, when the gas concentration in the chamber is higher than that of the ambient air, gas diffusion from the soil to the atmosphere is restricted (Denmead 1978). At this point, the flow-through chamber method seems to be most suitable for measuring the CO2 evolution rate, because the rate is determined under nearly natural conditions. However, this method has a disadvantage in that the apparatus is composed of an infra-red CO2 analyzer, air pumps, mass flow meters, a recorder, and other items, which are too large, heavy, and complex to use in the field (Freijer and Bouten 1991). Hence, in spite of the above limitations, most of the studies on CO2 evolution in situ have been carried out using the CO2 absorption method (Kowalenko et al. 1978; Seto et al. 1978a, b; Ewel et al 1981, 1987; Gupta and Singh 1981; Reinke et al. 1981; Edwards and Ros-Todd 1983; Grahammer et al. 1991) or the closed chamber method (Naganawa et al. 1989; Mariko et al. 1994). The flow-through chamber method has been used only at sites where electric power supply and other types of equipment were available (Mathes and Schriefer 1985; Ewel et al. 1987; Nakadai et al. 1993). In the present report a flow-through chamber method using a portable CO2 analyzer system was examined, for the determination of CO2 evolution from soil without an electric power supply or other special equipment.

Continuous, automated and simultaneous measurement of oxygen uptake and carbon dioxide evolution in biological systems

Commercial respirometers are capable of continuously and automatically measuring oxygen uptake in bioreactors. A method for continuously and automatically measuring carbon dioxide evolution can be retrofitted to commercial respirometers. Continuous and automatic measurements of carbon dioxide evolution are achieved by measuring the change in electrical conductivity of barium hydroxide solution. Continuous stirring of the barium hydroxide solution was necessary to prevent the carbon dioxide absorption from controlling the oxygen uptake rate. Three separate experiments (aqueous biodegradation of phenol, soil slurry biotreatment of soil contaminated with phenol, and aqueous biodegradation of crude oil) were conducted to test the oxygen uptake and carbon dioxide evolution measurement system. The respiratory quotient, defined as the ratio of carbon dioxide evolution to oxygen uptake, is close to one until a plateau of oxygen uptake is reached, after which it is greater than one due to degradation of biomass and metabolite products. Unsteady‐state simulation of CO2 evolution in batch reactors, based on the experimental data, showed that carbon dioxide exists primarily as bicarbonate in the liquid phase. The concentration of carbon dioxide in the gas phase is small mainly due to fast reaction with the stirred barium hydroxide solution.

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.

Influence of Cadmium and Zinc on Carbon Dioxide Evolution from Litter and Soil from a Black Oak Forest

AbstractStudies have shown that heavy metals can reduce decomposition rates. Since litter decomposition is an essential part of forest mineral cycles, understanding the degree of impact that these substances have on such a key process is important. Two similar black oak forests, East Chicago (impacted) and Willow Slough (background), were chosen as study areas. Microcosms containing litter and mineral soil were collected at each site and returned to the laboratory where comparative measurements of carbon dioxide evolution were taken at 0, 12, 36, and 84 hours, and at 23 days. Measurements indicated a higher decomposition rate for the Willow Slough microcosms (138 mg CO2/hour per kg at 23 days) compared to the East Chicago microcosms (94 mg CO2/hour per kg). Additional microcosms from Willow Slough were treated with solutions containing all possible combinations of 0, 0.1, or 10 ppm CdCl2 and 0, 100, or 1,000 ppm ZnCl2. Metal concentrations applied were equivalent to litter and soil levels at East Chicago. Statistically significant differences were detected only 36 hours and 23 days after treatment. Reduced respiration rates were associated with high concentrations of CdCl2/ZnCl2. Suppression of respiration rates due to osmotic effects of metal salts was rejected after microcosms treated with KCl and CaCl2 exhibited no change in respiration. While high levels of cadmium and zinc produced reductions in respiration rates compared to controls, low level treatments may have stimulated decomposition slightly.

Continuous Measurement of Carbon Dioxide Evolution From Partitioned Forest Floor Components

Loss rates of organic detritus in ecosystems can be determined by measuring rates of CO_2 release from decomposing organic substrates. We used an open system employing inverted boxes and an infrared gas analyzer (IRGA) to obtain continuous measurements of CO_2 evolution from the floor or a mixed mesophytic forest. Plexiglass sheets were used to partition respiratory activity of two litter horizons (01 and 02) and soil. Root respiration rates were determined with a differential respirometer. We compared the open system with a closed system in which KOH was used as the CO_2 absorber. Respiration measurements with KOH were 63% of IRGA values at 20 degrees C and 90% at 12 degrees. Flow rates (28 to 340 liters hr—1) had no effect on rates of CO_2 evolution. Nighttime CO_2 evolution rates were generally higher day—1. Preliminary data indicate annual CO_2 evolution of 3.8 kg m—2 (48% from litter, 17% from soil, and 35% from roots). This estimate is equivalent to 2.3 kg m—2 organic mass catabolized, assuming a carbohydrate substrate, which is 11% higher than independent estimates of the organic detritus annually available for catabolism.

A Procedure for the Measurement of Carbon Dioxide Evolution from Individual Fruits over Brief Time Intervals12

Abstract A procedure is given for measurement of carbon dioxide evolution from individual fruits during brief time intervals, by utilizing the change in optical density of a bromthymol blue-sodium bicarbonate solution exposed to varying CO2 atmospheres. The method permits the accurate estimation of CO2 evolution during a five-minute period from a single 100 g fruit respiring at the rate of less than 5 ml CO2/kg/hr. Although the system is “static,” build-up of CO2 concentrations surrounding the respiring fruit held to less than 1%.

A Procedure for the Measurement of Carbon Dioxide Evolution from Individual Fruits over Brief Time Intervals12

Abstract A procedure is given for measurement of carbon dioxide evolution from individual fruits during brief time intervals, by utilizing the change in optical density of a bromthymol blue-sodium bicarbonate solution exposed to varying CO2 atmospheres. The method permits the accurate estimation of CO2 evolution during a five-minute period from a single 100 g fruit respiring at the rate of less than 5 ml CO2/kg/hr. Although the system is “static,” build-up of CO2 concentrations surrounding the respiring fruit held to less than 1%.