. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 400 MORRIS H. ROBERTS, JR. introduced at the bottom from the separatory funnel so as to obtain a sharp gradient between the two layers. A preliminary test with dyes indicated that mixing occurred over a distance of about 2-3 mm with little increase in the thickness of the mixed layer through time. The second column (unstratified) served as a control. All tests were conducted in a dark room. Light from a 25 watt incandescent bulb was passed through a 3 cm diameter hole in an illuminator located cm above the top of each w
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 400 MORRIS H. ROBERTS, JR. introduced at the bottom from the separatory funnel so as to obtain a sharp gradient between the two layers. A preliminary test with dyes indicated that mixing occurred over a distance of about 2-3 mm with little increase in the thickness of the mixed layer through time. The second column (unstratified) served as a control. All tests were conducted in a dark room. Light from a 25 watt incandescent bulb was passed through a 3 cm diameter hole in an illuminator located cm above the top of each water column, with no lens to concentrate the light FIGURE 1. Discontinuity column apparatus, consisting of a plastic cylinder marked off into ten 4 cm segments. A glass tube cemented into the bottom connects to a separatory funnel from which water is introduced. A canula inserted 2 cm above the bottom and con- nected to a syringe permits injection of the larvae into the bottom stratum. The cylinders were placed in a compartmented wooden box so that each was iso- lated from extraneous light and from its twin. No difference in light intensity was detected with a Yentsch photometer between the light sources for each column. Once the desired salinity discontinuity was established, 50 light-adapted zoeae of the desired stage were drawn into a syringe, the syringe was attached to the canula (previously flushed of air) and the larvae were carefully introduced into the test column. Only on rare occasions were any larvae damaged by this pro- cedure, even the large Zoea IV. The control column was always filled first. During the first 15 minute period, the larvae were observed and notes taken concerning their movements and behavior. After 15, 30, and 60 minutes, the number of larvae visible in each 4 cm segment was counted and recorded. Some. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and a
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
