. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. COST OF BREATHING IN THE LUGWORM 215 sw 2O°C Pi, AIR — TO B. ov ov Figure 1. Apparatus. The glass tube containing the lugworm was placed in a thermostatted seawater bath. The rear (caudal) part of the tube was connected through very low-resistance glass tubing to a constant level tonometer (TO) equipped with an O2 electrode measuring the O2 partial pressure in the inspired water (Ploj). At the anterior (cephalic) end of the tube were serially fitted (1) a small acrylic chamber containing an O2 electrode measuring the O: part
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. COST OF BREATHING IN THE LUGWORM 215 sw 2O°C Pi, AIR — TO B. ov ov Figure 1. Apparatus. The glass tube containing the lugworm was placed in a thermostatted seawater bath. The rear (caudal) part of the tube was connected through very low-resistance glass tubing to a constant level tonometer (TO) equipped with an O2 electrode measuring the O2 partial pressure in the inspired water (Ploj). At the anterior (cephalic) end of the tube were serially fitted (1) a small acrylic chamber containing an O2 electrode measuring the O: partial pressure in the expired water (PE0,). immediately followed by a T-connection to a pressure transducer (PT); (2) two different tubing lengths corresponding to two different exit resistances, Rl and R2; and (3) a photocell drop meter (DM). A and B: separated water baths; OV: overflow; R: potentiometric recorder; C: microcomputer; Arrows: direction of air or water circulation. Twelve hours after collection, a lugworm (mean wet mass: ± g, N = 10) was placed unrestrained in the artificial gallery; measurements were started about 1 h later. Each experiment was carried out on a different ani- mal and was divided into three periods lasting between 90 and 180 min each and corresponding to a different exit resistance. One day the sequence was R1, R2, R1 and the next day R2, Rl, R2, to cancel the possible influence of fatigue. During each period, PEO,, APHYD and Vw were continuously recorded graphically by a potentio- metric recorder. In parallel, when the lugworm ventilated in a regular and continuous way, PEO, and APHYD were recorded on tape by a Hewlett-Packard HP85B micro- computer for separate runs each lasting 6 min. For each period, 12 to 15 runs were recorded. During each run, the corresponding total volume of ventilated water, Vw, was collected and measured to the nearest ml with a measuring cylinder. This value; the calibration coefficients for the O2 electr
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
