. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 40 60 70 80 90 INDIVIDUAL GROWTH RATE CJJM-DAY ) 29°C * 25°C O 20°C Figure 6. Maximum length of larval life as a function of estimated individual growth rate (^rn-day ') in Experiment IV (r = , y = - (ln x) + ). Individual growth rates were estimated from the size and age at which each individual underwent spontaneous metamorphosis in glass bowls that were cleaned daily. Larvae were cultured at three temperatures, as indicated (n = 64, 62. and 63 larvae per treatment at 29°C, 25°C and 20°C, respectively). VI, for
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 40 60 70 80 90 INDIVIDUAL GROWTH RATE CJJM-DAY ) 29°C * 25°C O 20°C Figure 6. Maximum length of larval life as a function of estimated individual growth rate (^rn-day ') in Experiment IV (r = , y = - (ln x) + ). Individual growth rates were estimated from the size and age at which each individual underwent spontaneous metamorphosis in glass bowls that were cleaned daily. Larvae were cultured at three temperatures, as indicated (n = 64, 62. and 63 larvae per treatment at 29°C, 25°C and 20°C, respectively). VI, for example, larvae grew more rapidly at 20 ppt than at 25 ppt, but took longer to become competent at the lower salinity (Table III and Fig. 8). Experiment VI was terminated before all larvae were allowed to metamor- phose, so calculation of age and size at metamorphosis was not possible. There was no significant difference (P > ) in the percentage of larvae induced to metamorphose when KC1 concentrations were elevated by 20 versus 23 mAl at 20 ppt. Thus, the dilution of full strength seawater to make 20 ppt and 25 ppt seawater did not significantly affect the ability of KC1 to induce larval metamorphosis. Discussion The primary goal of these experiments was to deter- mine, for Crepidula planu. whether changes in tempera- ture and salinity alter rates of growth, morphological dif- ferentiation, and the onset of competence equally. We must first consider the effects of temperature and salinity on each of these three components of development in- dividually. Larvae grew significantly faster at progressively higher temperatures (Table I) in only one experiment (Experi- ment III). Lima and Pechenik (1985) also found an in- 1600 1500 1400 1300 1200 i 1100 1000. o * 30 40 50 60 70 80 90 INDIVIDUAL GROWTH RATE (UM DAY ) 29"C * 25°C O 20°C A Figure 7. Size at metamorphosis as a function of individual larval growth rate (^m - day ') (Experiment IV). Faster growing larv
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
