A NEW RECORDER FOR SIMULTANEOUSLY RECORDING THE ACTIVITY AND OXYGEN-CONSUMPTION OF SMALL BENTHIC INVERTEBRATES

Respiration studies of small benthic invertebrates are generally compl eted without regard to the inclusion of a substrate or the quantificat ion of activity in the experimental chamber. We describe a new activit y monitoring system for continuously recording the activity and oxygen consumption of small benthic invertebrates in water with the presence of a substrate. We used the freshwater amphipod Diporeia hoyi to test the new system. Activity rates were significantly higher without sedi ment than with sediment, and oxygen consumption was directly related t o activity. Future invertebrate respiration studies, especially those with infaunal organisms, will benefit from such a system by allowing r esearchers to determine possible test condition - treatment interactio ns.