Aspects of respiratory function in the blood of the intertidal lugworm abarenicola affinis (Polychaeta)

Abstract

The oxygen transport characteristics of lugworm blood were studied over a range of temperature and pH values encompassing tidal and seasonally dependent measurements from worm burrows. The blood showed a small carbon dioxide Bohr effect (Δlog P50/ΔpH = -0.14 to -0.06), contrasting with the known pH sensitivity of blood in the European lugworm, Arenicola marina. The exothermic nature of oxygen binding was greater for the New Zealand species (ΔH ≈ -36 kJ mol-1) but less than that shown for most other invertebrates. The CO2-Bohr effect was indistinguishable from the fixed acid Bohr effect, suggesting a lack of specific CO2 binding by the blood. Worms acclimated at 15 and 25°C did not show thermal compensation of in vitro blood oxygenation; these data are discussed in relation to the temperature induced Bohr effect in A. marina. © 1984 Taylor & Francis Group, LLC.