THE EFFECTS OF OXYGEN CONCENTRATION AND ANOXIA ON RESPIRATION OF ABARENICOLA PACIFICA AND LUMBRINERIS ZONATA(POLYCHAETA)

¹ Department of Oceanography, University of Washington, Seattle, Washington 98195

1. The mean values of oxygen concentrations observed in burrows of Abarenicola pacifica in False Bay were 0.9 ml O₂/l at low tide and 2.3 ml O₂/ at high tide.

2. Oxygen concentrations in burrows of Lumbrineris zonata were not measured, but burrow walls were often gray (reduced) although sometimes tan (oxidized).

3. For A. pacifica with nearly empty guts, dry weight is 14.1% of wet weight, ash-free dry weight is 11.0% of wet weight, and ash-free dry weight is 77.7% of dry weight.

4. The following respiratory relationships were found for A. pacifica: (a) Oxygen uptake rate can be expressed as a linear function of oxygen concentration at all oxygen concentrations up to 7.0 ml O₂/l. (b) The relationship between wet weight in grams after defecation and oxygen uptake in µl O₂ worm^-1hr^-1 is log R' = 1.49 + 0.78 log W. (c) The relationship between oxygen concentration in ml O₂/1, wet weight, and oxygen uptake µl O₂g-¹hr^-1 is log R = 0.93 + 0.86 log [O₂]- 0.51 log W. (d) The regression of oxygen uptake on oxygen concentration, wet weight, and temperature in °C is log R= -0.36 + 0.86 log [O₂] - 0.38 log W + 1.33 log T.

5. During January through March, a 2-gram A. pacifica consumes 21.6 µl O₂/hr on the average during high tide and 3.9 µl O₂/hr during low tide or an average of 0.4 ml O₂/day.

6. L. zonata appears to regulate above about 2 ml O₂/1, below which it is a nonregulator.

7. A. pacifica is healthy after 3 days in anoxia; I was not able to determine if it incurred an oxygen debt during anoxia. L. zonata is healthy after 2 days in anoxia and probably incurs an oxygen debt, which it repays upon return to aerated water.

8. Calculations indicate that A. pacifica removes only 1.3% of the organic carbon from sediment it ingests.