Testing a method for measuring dissolved oxygen concentrations in microhabitats in fresh water

It was previously known that polyethylene film is permeable to oxygen, and that water-filled polyethylene bags can be used for determination of dissolved oxygen in fresh-water habitats: analysis of oxygen concentrations in the bag water indicates the concentrations in the habitat where the bag has been resting for some time. Field experiments show that the bag method (with minor modifications) is reasonably accurate for ecological studies (a deviation of 0–0.20 ml O₂/l as compared with samples collected with a Ruttner water sampler).The bag method is simple in use. Its main advantage is its usefulness in many microhabitats in fresh-water where other methods may fail. Oxygen deficit in a dense helophyte stand is demonstrated using the bag method.