. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 6 8 10 12 14 16 18 20 Days Figure 3. Percentage of the zebra mussel (Dreisscna polymorpha) sample dropping from the byssal holdfast and relocating on the plastic plate, prior to death or the end of the 21-day experimental period (whichever came first), when exposed to Po? levels of , , , , and torr. E z TJ «J 0) TO w 55 >, CD 0) V 100 80 60 40 20. 10 12 14 Days 16 18 20 Figure 4. Cumulative daily mean number of byssal threads pro- duced by specimens of the zebra mussel (Dreissena polynwrpha) over a 21
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 6 8 10 12 14 16 18 20 Days Figure 3. Percentage of the zebra mussel (Dreisscna polymorpha) sample dropping from the byssal holdfast and relocating on the plastic plate, prior to death or the end of the 21-day experimental period (whichever came first), when exposed to Po? levels of , , , , and torr. E z TJ «J 0) TO w 55 >, CD 0) V 100 80 60 40 20. 10 12 14 Days 16 18 20 Figure 4. Cumulative daily mean number of byssal threads pro- duced by specimens of the zebra mussel (Dreissena polynwrpha) over a 21-day period, when exposed to agitation rates of 0, 10, 15, 30, and 40 cycles per minute (CPM). exposed to and torr led to increasingly large dis- parities in sample sizes between treatment groups as time progressed. There was very little new byssal thread formation by zebra mussels exposed to or torr over the maxi- mum survival times of 15 and 16 days. However, typical byssal thread production curves, showing a steady in- crease in the number of threads produced with time, were recorded at a Po2 of , , and torr (Fig. la). For mussels exposed to or torr, mean sur- vival times were and days, and maximum sur- vival times were 15 and 16 days, respectively. At torr, sample mortality was observed by the end of the 21 -day experimental period. Mortality declined to at a Po2 of torr. No mortality was observed in the sample of mussels exposed at torr (Fig. 2). At torr, of the sample released from the bys- sus, relocated, and byssally reattached within the experi- mental chamber prior to death or the end of the experi- mental period (whichever came first). This figure was at a Po2 of torr, at torr, at torr, and at torr (Fig. 3). Response to agitation Byssal thread production was inhibited by increasing agitation rates. Maximal byssal thread production over
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
