. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. IN AIR AND WATER 257 200 160 120 O 80 40. —i— —i— —i— —i— ~n— —i— ~n 0123456 Emersion Period (days) Figure 4. Rates of oxygen consumption (M0,) of Corhiciilu Ili/nii- iicn on reimmersion after periods of aerial exposure. Circles represent initial values, within 5-15 min of the initiation of siphoning activity upon reimmersion. Squares are values measured one hour after siphon- ing activity commenced. The unconnected points represent corre- sponding initial and 1 h control M0, measurements in tapwater accli- mated
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. IN AIR AND WATER 257 200 160 120 O 80 40. —i— —i— —i— —i— ~n— —i— ~n 0123456 Emersion Period (days) Figure 4. Rates of oxygen consumption (M0,) of Corhiciilu Ili/nii- iicn on reimmersion after periods of aerial exposure. Circles represent initial values, within 5-15 min of the initiation of siphoning activity upon reimmersion. Squares are values measured one hour after siphon- ing activity commenced. The unconnected points represent corre- sponding initial and 1 h control M0, measurements in tapwater accli- mated clams. Bars are standard errors of the means and n = 5 animals (breach point. movements in emersed clams occupied 70% and 49% of the exposure period at 15 and 25°C, respectively. A sim- ilar pattern of valve movement behaviors while emersed has been reported for the high estuarine mangrove cor- biculid, Polymesoda erosa. In P. erosa, ventilation of the mantle cavity air space occurred at irregular intervals, interspersed with periods of mantle edge exposure and valve closure (McMahon, 1988). These behaviors in C. jluminea seem to be associated with aerial oxygen uptake (this study; McMahon and Williams, 1984). However, the highest rates of aerial oxy- gen consumption took place during the first few minutes of valve opening in what was referred to as ventilatory behavior, with lower rates during mantle edge exposure. This is consistent with the hypothesis of a periodically renewed, mantle cavity oxygen store (McMahon and Williams, 1984; Pamatmat, 1984). When the valves first open, the oxygen depleted mantle cavity gas mixes with the air, causing a sudden decline in atmospheric P0l in the respiration chamber. Aerial oxygen uptake has been reported for several freshwater bivalves. The unionid clam, Ligumia subro- slrata was reported to have aerial oxygen uptake rates of between 21-23%- of the aquatic rate (Dietz, 1974), and the sphaeriid, Sphaerium occidenta
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
