Gas exchange (photosynthesis) equipment

  • Tuneable diode laser (TDL) for measuring the stable isotopes of CO2. The TDL is used for measuring the exchange of isotopes during photosynthesis and respiration by plants and soil. Measuring isotope exchange with the TDL is an extremely powerful technique for probing the limitations and determinants of photosynthesis and respiration (e.g. diffusion of CO2 within leaves, determining the respiratory substrate of soil, partitioning C3 versus C4 photosynthesis). The TDL is integrated with gas exchange systems such as the LI 6400 described below.
Tuneable diode laser system
  • Li-Cor LI 6400 gas exchange and fluorescence system. This is used for measuring photosynthesis and transpiration of plants. More recently we have been using its capability of simultaneous gas exchange and fluorescence measurements to estimate the internal conductance to CO2 transfer. It is field portable, but also spends a lot of time inside the lab and glasshouse.
gas exchange system
  • Li-Cor LI 8100 soil respiration system with a 20-cm roving chamber. Recent modifications mean that we can also measure respiration of soil covered by snow.
measuring respiration of soil covered by snow
  • Portable gas exchange system for short-term measurements on grass/shrub ecosystems. It is being used to measure gas exchange of grass and shrub ecosystems, in particular their response to pulses of rainfall. Initial tests show that the system can measure incredibly small fluxes of CO2 and H2O.

portable gas exchange chamber for measuring ecosystem respiration