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Journal of Experimental Biology 92,109-124 (1981)
Published by Company of Biologists 1981

The Effect of Long-Term Aerial Exposure on Heart Rate, Ventilation, Respiratory Gas Exchange and Acid-Base Status in the Crayfish Austropotamobius Pallipes

E. W. TAYLOR ¹ and MICHÈLE G. WHEATLY ¹

¹ Department of Zoology and Comparative Physiology, University of Birmingham, Birmingham B15 2TT, U.K.

1. When first removed into air, crayfish showed transient increases in heart rate (f_H) and scaphognathite rate (f_R) which rapidly recovered to submerged levels and were unchanged for 24 h. The rate of O₂ consumption(M_oo2) increased from an initially low level and was then maintained for 24 h in air at the same level as in settled submerged animals.

2. There was an initial acidosis in the haemolymph which was both respiratory and metabolic due to the accumulation of CO₂ and lactate. Progressive compensation by elevation of the levels of bicarbonate buffer in the haemolymph and reduction of circulating lactate levels returned pH towards submerged levels after 24 h in air.

3. Exposure to air resulted in a marked internal hypoxia with haemolymph O₂, tensions, both postbranchial P_a, _oo2 and prebranchial P_v, _oo2, remaining low throughout the period of exposure. The oxygen content or the haemolymph was initially reduced, with a – v_OO2 content difference close to zero. Within 24 h both C_a, _oo2 and C_v, _OO2 had returned towards their levels in submerged animals. These changes are explained by the Bohr shift on the haemocyanin consequent upon the measured pH changes.

4. After 48 h in air, M_O2 and f_H were significantly reduced and ventilation became intermittent. There was a slight secondary acidosis, increase in lactic acid levels and reduction in a – v_O2 content difference in the haemolymph.

5. When crayfish were returned to water after 24 h in air, M_OO2, f_H f_R were initially elevated by disturbance and there was a period of hyperventilation. In the haemolymph there was an initial slight alkalosis, and an increase in C_a, _OO2 lactic acid. All variables returned to their settled submerged levels within 8 h.

This article has been cited by other articles:

				D. Jackson, T Wang, P Koldkjaer, and E. Taylor Lactate sequestration in the carapace of the crayfish Austropotamobius pallipes during exposure in air J. Exp. Biol., January 3, 2001; 204(5): 941 - 946. [Abstract] [PDF]