Ecosystem, Plant and Soil Respiration & Isotope Labeling Chambers. One approach to estimating ecosystem or plant respiration / gas exchange is to use air-tight chambers, either (i) enclosing the whole ecosystem (e.g. a mesocosm, smaller plant communities such as grasslands) and directly providing the net ecosystem CO2 exchange (NEE), or (ii) chambers enclosing only a part of the ecosystem (e.g. plant, leaves, soil (soil respiration) etc.) and thus requiring some additional up-scaling. Isotope labeling also requires airtight plant labeling chambers.
Gas Flux Chamber Systems. Vienna Scientific Instruments offers customised plant and ecosystem respiratory chambers for field and laboratory use, constructed of transparent polycarbonate (higher PAR transmission) or PMMA in various chamber sizes and geometries. If required, a modular design allows the chamber size to be increased as the plant grows, and potentially more important, the height can be adapted to optimize the chamber volume towards the fluxes to be measured. In specific, in closed chamber settings the volume can be varied by modules to make sure that the rate of increase of a gas (e.g. CO2) is small enough to avoid problems related to gas (CO2) build-up during the measurement of the flux while being well above the limits of accuracy of the CO2 gas analyser. Gaskets around each collar (and the hole in the base plate, when a mesocosm is used) ensure adequate gas tightness. For field use, a metal frame can be installed under the chambers to ensure gas tightness to the soil. Chamber air can be stirred by one or more adjustable (direction and speed) fans to homogenise the air. Fan size, speed and angle can be adjusted to avoid interfering with plants or IRGA measurements. A range of pipe fittings/connection plates are available for common IRGA systems. An environmental monitoring system consisting of temperature (air/leaf), rH and possibly PAR sensors can be added on request or appropriate positions for entering cables or fixing sensors can be foreseen during the respiration chamber designing phase.
Various different chamber designs are available on customer request:
Various shapes and sizes or respiration chambers are available to suit your mesocosm, pot, growth tube or soil / plant measurements in the field. See below for a list of key considerations when planning your custom ecosystem / mesocosm / set-top / soil respiration chamber systems. See example images below for some design ideas.
There are a number of important considerations when designing a customised gas flow measurement chamber (aka "respiration chamber"):
Overall, the construction of a gas flux / respiration chamber requires careful consideration of the materials used and environmental factors relevant in the study. Consultation with Vienna Scientific can be helpful to ensure that the chamber design is appropriate for your specific research objectives.
Custom-made Isotope Labeling Chambers. Two types of labeling chamber set-ups for plants are generally used with 13C stable isotopes. The first type are commercially available, automatic cultivation chambers with a built-in regulation module for environmental parameters such as light, temperature and humidity. The second type, as oftered by Vienna Scientific, makes use of custom-made labeling devices placed in growth chambers or glasshouses which external light, temperature etc. regulation. Both approaches equally enable continuous monitoring and regulation of atmospheric parameters during labeling. Commonly conducted enrichment of other isotopes such as 15N or 34S does not require closed systems but systems allowing to add labeled liquids. Generally, both equipment types are suitable to perform pulse labeling and uniformly, long-term labeling of plants towards different isotope enrichment.
The specific design of the isotope labeling chamber will depend on the type of isotope(s) you wish to use and the specific experimental protocol you wish to follow. However, here are some general guidelines Vienna Scientific will follow to support the development of an isotope labeling chamber suiting your needs - analogue to the recomendation for respiration chambers (see above):
See above concerning further general recommendation for respiration chamber designs. Contact us to discuss possible isotope labeling chamber designs that meet your scientific objectives.
Global 13C isotope labeling is used to produce uniformly 13C-labeled plants (here referred to as 13C plants) and requires either a continuous supply of 13CO2 throughout the cultivation or in pulses. The 13CO2 isotope is applied as a substrate which is further converted into all the assimilates required to maintain plant metabolism. This requires airtight growth chambers (labeling chambers) with a 13CO2 atmosphere. As the production of 13C-enriched plants requires long-term cultivation, the technical equipment must allow the regulation of growth parameters such as temperature, light and humidity, as well as CO2 and O2 levels. For rhizoboxes, the rhizobox top-up respiration chambers of Vienna Scientific allow to reach this goal cost effectvely and in combination with root and rhizosphere studies, proving a sealed top-up chamber for most rhizobox design - proviving an effective solution to label rhizobox-grown plants over a longer period or in pulses. The closed chambers allow for connecting labeled gas sources and/or to connect isotopic analysers via simple in- and outlets. Advanced chamber mixing (advisable for larger top-up chambers with volumes beyond the mixing capacitiy of connected instruments) can be provided by optional internal ventilators.