Application of CO2-porometer methods to assessment of components of photosynthetic production in estuarine ecosystems

A portable system for CO₂ gas exchange measurements is described that allows determination of net photosynthesis and transpiration rates as well as leaf conductance of salt marsh vascular plants, and photosynthesis rates of macrophytic algae and epibenthic algae of sediment cores during low tide periods of exposure. Carbon fixation processes of these several different types of organisms can be studied on the same day. Measurements may be carried out at an estuarine field site using controlled conditions of light, temperature, and air CO₂ partial pressure. Algal samples are enclosed in the cuvette for only a matter of minutes and do not dry significantly during measurement. The rapidity with which gas exchange rates of samples may be assessed will allow routine processing of many sediment cores. Thus, the distribution of producer populations can be studied with greater resolution than previously possible.