Respiration rates of Chiloplacus sp. and other arctic nematodes at low and high temperatures

Abstract

Respiration of an undescribed species of soil nematode of the genus Chiloplacus from the Canadian High Arctic was measured at 2°, 5°, 10°, 15°, 20° and 25°C. The corresponding metabolic rates were 0.2697×10-3 μl, 0.3406×10-3 μl, 0.8408×10-3 μl, 0.8539×10-3 μl, 1.8420×10-3 μl and 2.9360×10-3 μl O2 ind-1 h-1, respectively, for a nematode of 1.0 μg dry weight. The relationship between respiration and dry weight for Chiloplacus sp. at 10°C is described by the function log R=-3.0693+0.8844 log W. Q10 values for the 2°–5°, 5°–10°, 10°–15°, 15°–20° and 20°–25°C temperature intervals were 2.18, 6.09, 1.03, 4.65 and 2.54, respectively. Chiloplacus sp. showed raised metabolic rates at low tempetatures compared with species from warmer environments. Metabolic rates of representative samples of the soil, nematode fauna (dominated by individuals of the genus Plectus) from the same location were 0.1593×10-3 μl, 0.3603×10-3 μl and 0.5332×10-3 μl O2 ind-1 h-1 at 5°, 10° and 15°C for an average nematode of 0.4297 μg dry weight.