Infrared CO2 Gas Analyzer Research Articles

Phosphorus mineralization in response to organic and inorganic amendment in a semi-arid pasture soil

Phosphorus deficient soil was amended with compost (C) (organic source of phosphorus) and inorganic P (KH2PO4 as inorganic phosphorus) at different rates and incubated for 28 days. Six treatments were used including i) Control ii) Inorganic P (0.79 mg per 30 g of soil sample) iii) 100 % C (0.13 g) iv) 75% C (0.1 g) + 25% P (0.2 mg) v) 50% C (0.065 g) + 50% P (0.4 mg) vi) 25% C (0.03 g) + 75% P (0.6 mg). Soil respiration was recorded using Infra-red CO2 gas analyzer. MBC was determined by using fumigation extraction method. Resin P and MBP extraction was carried out by anion exchange membranes and was determined colorimetrically. P pools were determined by using DeLuca method. Cumulative respiration microbial biomass significantly increased in organic amended soil with higher increase in soil emended with 75% C +25% P rate followed by 50% C and 50% P rate. It was concluded that compost amended with high inorganic P stimulated the formation of P labile pools which supply long term slow release of P for plants and microbes.

Practice for <i>In Situ</i> Measurement of CO<sub>2</sub> Flux at Soils Profiles in Arid Areas

An approach is described for thein situmeasurement of CO2flux at various depths in arid soil. In this method, a sampling tube is inserted to the desired soil depth in a pre-drilled hole, and an infrared CO2gas analyzer connected to the sampling tube is used to quantify CO2(based on absorption of CO2by infrared rays). In a preliminary test, the method was used to quantify CO2concentration and flux in an arid grassland soil. The results indicated that it could be used to quantify CO2flux in soil from 0–200 cm depths , and should be useful for estimating CO2flux and storage at different soil depths, for estimating the change in CO2emission from soil caused by change in land-use/land-cover, for assessing the rate of restoration of soil fertility and other soil properties in arid soils, and for monitoring leakage from geological storage of CO2.

Evaluation of a portable chamber system for soil CO2 efflux measurement and the potential errors caused by internal compensation and water vapor dilution

A portable, easy-to-install chamber system for rapid measurement of soil CO2 efflux is needed for the immediate analysis of CO2 flushes after events such as tillage and grassland renovation. We conducted field measurements and simple simulations to validate the effectiveness of a portable chamber system with an infrared CO2 gas analyzer (IRGA) and a temperature/humidity sensor (the SIR system). We confirmed that a measurement period of 60-180 s after the closure of the chamber was sufficient for the calculation of soil CO2 efflux. We compared the SIR system with a closed static chamber system and an automated open/closed chamber system. The efflux data obtained with the SIR system were linearly related to the data obtained with the other systems, and the relationships between the soil temperature and efflux were similar in the three systems. These results show that the SIR system provided soil CO2 efflux values with a reasonable accuracy relative to the other systems. We also examined how the calculated efflux values were affected by the internal compensation of the IRGA for environmental parameters and water vapor dilution in the chamber. The potential error caused by the default internal compensation of the IRGA was within 3.1% under general environmental conditions. The effect of water vapor dilution was large (>20%) for small CO2 effluxes. The combined effects of the default internal compensation and water vapor dilution were larger for small CO2 effluxes than for large CO2 effluxes, and the effects became larger under low air pressure conditions. We recommend that accurate environmental compensation and water vapor correction be applied for analysis of small CO2 effluxes when there is a rapid increase in water vapor, especially under low air pressure conditions.

Development of the IRGA enclosed-chamber system for soil CO2 efflux measurement and its application to a spatial variation measurement

A new system was developed for measuring soil CO2 efflux. The chamber in this system contains a small infrared CO2 gas analyzer. This system does not need air tubes or pumps for circulating air, so it is expected to offer the advantages of mobility and durability. This system was verified by a comparison with measurements made by using a closed-dynamic-chamber (CDC) system. The spatial variation in the soil CO2 efflux in a broadleaved deciduous forest was measured using the new system. The soil CO2 efflux at sampling locations 50–70cm apart varied within a range of 60%–150%. This variation was smaller than the variation due to differences in soil characteristic reflected in different moisture conditions, etc.

Effect of desiccation on the photosynthesis of seaweeds from the intertidal zone in Honshu, Japan

SUMMARY Intertidal seaweeds are periodically exposed during low tide and thus experience extreme levels of desiccation. The physiological activity of seaweeds changes during this water loss process. This study examined how desiccation affects the photosynthesis and respiration of seaweeds from different intertidal levels, and whether the ability to retain photosynthesis and respiration rates during desiccation varies among these species. Photosynthesis and respiration rates of 12 species of seaweeds were measured under various levels of desiccation, using an infrared CO2 gas analyzer. High levels of drought negatively affected photosynthesis, while most species showed initial rises in photosynthetic rates. The ability to retain photosynthesis and respiration activities under desiccation conditions varied among species. These physiological responses were not related to the intertidal level at which these species occur, but to their ability to prevent water loss. The species with lower rates of water loss had slower declines in the rate of photosynthesis and respiration.

Photosynthesis and respiration of exposed salt-marsh fucoids

Photosynthesis and respiration of the salt-marsh fucoids Ascophyllum nodosum ecad scorpioides and Fucus vesiculosus were investigated using an infrared CO2 gas analyzer under a variety of light intensities, temperatures, and levels of desiccation while the algae were exposed to the atmosphere. Results indicated that net photosynthesis (0.5 to 2.0 mg C/g dry weight/h) saturated rapidly at light intensities (0.1 to 0.2 g cal/cm2/min) which were approximately 10 to 50% of the daily summer maximum intensities for algae found under phanerogam (Spartina alterniflora) canopies. Desiccation exhibited the most pronounced effect on photosynthesis, which increases slightly between 0 and 25% water loss, levels off, and decreases sharply at water losses greater than 50%. Dark respiration (0.1 to 0.3 mg C/g dry weight/h) is also inhibited by desiccation. Both species of algae appear to be broadly adapted to all three parameters investigated.

Limitations of an eddy-correlation technique for the determination of the carbon dioxide and sensible heat fluxes

A modified infrared CO2 gas analyzer, a small thermocouple assembly, a heated-thermocouple anemometer for horizontal wind, and a propeller-type vertical wind sensor were used to measure the eddy fluxes of heat and CO2 above a corn crop. Experimental results of these fluxes are discussed. The main sources of errors of the eddy fluxes using these instruments were estimated:

The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.

Photosynthesis and photorespiration rates at the CO2 compensation point

Attached soybean leaves in a closed system were fed high specific activity 14CO2 at four CO2 compensation points (30, 53, 110, 204 μl/l CO2) which were produced by different O2 concentrations (10, 21, 44, 80% O2). Rates of CO2 uptake and evolution were measured simultaneously using an infrared CO2 gas analyzer and a Geiger tube. The CO2 compensation point was proportional to O2 concentration but did not change for the two light intensities used. The rates of CO2 exchange at the compensation point did increase with light intensity. These rates of CO2 exchange also increased with the increasing CO2 concentration of the compensation point (for increasing O2 concentrations) but tended to saturate for compensation points greater than 110 μl/l CO2.

Sensitivity of the infrared CO2 gas analyzer to 14CO2

The infrared CO2 gas analyzer (Beckman model 215) is only 5% as sensitive to 14CO2 as it is to 12CO2.