. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 22 ARMSTRONG, CHIPPENDALE, KNIGHT AND COLT 98 90 § 50 30 10 A • o A pH 8 34 76,68 CONCENTRATION 100 mg/ I 100 mg/l 100 mg/ I 32 mg/l 32 mg/l. 8 10 20 TIME (MRS) 30 40 60 80 120 160 FIGURE 2. Cumulative percentage of mortality of M. roscnbcrgii larvae exposed to several combinations of ammonia and pH. Depicted are data for a single brood. Survival was adjusted to that of controls which averaged 95% at the end of an experiment. and were 9 hr and >144 hr. respectively, while the corresponding NHV con- cen
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 22 ARMSTRONG, CHIPPENDALE, KNIGHT AND COLT 98 90 § 50 30 10 A • o A pH 8 34 76,68 CONCENTRATION 100 mg/ I 100 mg/l 100 mg/ I 32 mg/l 32 mg/l. 8 10 20 TIME (MRS) 30 40 60 80 120 160 FIGURE 2. Cumulative percentage of mortality of M. roscnbcrgii larvae exposed to several combinations of ammonia and pH. Depicted are data for a single brood. Survival was adjusted to that of controls which averaged 95% at the end of an experiment. and were 9 hr and >144 hr. respectively, while the corresponding NHV con- centrations were 319 and 9 mg/liter (Fig. 4). Animals exposed to mg NHa/ liter survived twice as long as those exposed to mg/liter, but the NH4+ con- centration was times higher in the latter case (Fig. 4). Growth of Macrobrachium larvae was reduced in sublethal concentrations of ammonia and also seemed to be influenced by levels of NH4+ rather than NH8. There was no significant effect of treatments in the first growth experiment. The initial mean weight was 52 ± 5 /xg/larva and the final mean weight for all treat- ments was 77 ± 6 /tg/larva, a 48^0 increase. In the second test, with smaller larvae exposed for a longer period, there was reduced gowth (P < ) in solutions of 32 mg ammonia/liter at pH and (Table II). The initial weight of three- day old animals was 35 ± 6 /xg each. At the test's conclusion, larvae of control groups weighed about 77 each (a 120% increase), while those in 32 mg/liter averaged 55 and 61 /xg/larva (57% and 74% increases) in pH and , re- spectively. These weights were significantly less than those of controls (P < , TABLE I Concentrations of ammonia toxic to M. rosenbergii larvae expressed as both the NH3 and molecules.* 24 hr LCso (mg/liter) 144 hr LCto (mg/liter) oH NH8 NH4+ NH3 NH< + * Total ammonia = [NH:j] + [N
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
