The influence of acclimation and substratum on the metabolism of the Antarctic amphipods Waldeckia obesa (Chevreux 1905) and Bovallia gigantea (Pfeffer 1888)
Respiration rates in the Antarctic amphipods Waldeckia obesa (Chevreux 1905) and Bovallia gigantea (Pfeffer 1888) were measured in relation to the presence or absence of a substratum to attach to, and the amount of time spent in a respirometer. During the first 4 h after placing animals in respirometers oxygen consumption in W. obesa was reduced by factors between 1.2 and 3.6 times by the presence of a nylon mesh net substratum. Oxygen consumption over the first 12 h after being placed in respirometers was reduced by factors of between 1.1 and 3.9 times for B. gigantea by the presence of pieces of corrugated plastic pipe. The effects on oxygen consumption of acclimating animals to respirometers were only assessed for W. obesa. Rates during the first 12 h after placing animals in chambers were 3.6 times higher than rates between 12 and 30 h after the start of trials. Standard metabolic rates were measured in W. obesa in the presence of a mesh substratum and following a 12 h acclimation period after 60 days of starvation. Under these conditions oxygen consumption was 2.5 μl O2 h−1 for a specimen of 0.113 g dry mass. This was 3–5 times lower than routine metabolic rates previously reported for W. obesa and 2.4–18 times lower than routine rates for other Antarctic gammaridean amphipods.