Respiration rates of two species of Gnathostomulids.

Respiration rates for two species of Gnathostomulida from poorly oxygenated subtidal sands of Bermuda were measured using Cartesian diver respirometers.ForHaplognathia cf.ruberrima a respiration-body weight regression gaveR=0.790·W 0,649 (in μl·10-3O2/h and μg wet weight). Respiration rates for adult animals ofGnathostomula sp. of a mean weight of 1.3 μg ranged between 0.25 and 0.63 μl·10-3 O2/h. These rates are low when compared with literature data on meiobenthic species from a wider habitat range but similar to respiration rates of marine and limnic nematodes living in sediments with strongly reducing capacity.