Whole Body Ions of Brook Trout (Salvelinus fontinalis) Alevins: Responses of Yolk-Sac and Swim-Up Stages to Water Acidity, Calcium, and Aluminum, and Recovery Effects

1990 ◽  
Vol 47 (8) ◽  
pp. 1604-1615 ◽  
Author(s):  
C. M. Wood ◽  
D. G. McDonald ◽  
C. G. Ingersoll ◽  
D. R. Mount ◽  
O. E. Johannsson ◽  
...  

Water pH, rather than Ca or Al, was the most important factor affecting whole body ions in yolk-sac or swim-up fry exposed to a matrix of pH (6.5–4.0), Ca (0.5–8 mg/L), and Al (0–1000 μg/L). Fry were raised from fertilization (day 0) in flowing soft water (pH = 6.5, Ca = 2 mg/L, Al = 0 μg/L), exposed to pH/Ca/Al on day 49 (yolk-sac, 2 d post-hatch) or day 70 (swim-up) for 21 d, and then allowed to recover a further 20 d. Yolk-sac fry were extremely resistant at [Formula: see text]; developmental effects, as indicated by body weight and Mg, were negligible. However whole body Na, Cl, K, and Ca were depressed by low pH, while water Ca was protective. Aluminum (37–111 μg/L) raised most ions above control values, while higher Al lowered them. Swim-up fry were more sensitive, showing pronounced developmental inhibition (lower weight, higher Mg) under adverse conditions; mortality continued during recovery. Low pH was again the dominant influence on body ions, water Ca was protective, while Al (12–111 μg/L) was only protective and not stimulatory. These effects persisted significantly; indeed responses in body Ca were larger after recovery than after the exposure itself, in the field, emergence from the redd into ambient acidic water is probably the critical stage. Water pH will be the principal determinant of whole body ions in alevins surviving this emergence, in contrast to fry exposed continuously from fertilization.

1990 ◽  
Vol 47 (8) ◽  
pp. 1593-1603 ◽  
Author(s):  
C. M. Wood ◽  
D. G. McDonald ◽  
C. G. Ingersoll ◽  
D. R. Mount ◽  
O. E. Johannsson ◽  
...  

Water Ca, rather than pH or Al, was the most important factor affecting whole body electrolyte levels in fry exposed from fertilization to swim-up (91 d) to 84 combinations of pH (6.5, 5.2, 4.8, 4.4, 4.0), Ca (0.5, 1, 2, 8 mg/L), and Al (0, 12, 37, 111, 333, 1000 μg/L) in flowing soft water. Aluminum accumulation occurred only at water Al levels > 111 μg/L; Al accumulation was inhibited both by increasing Ca and decreasing pH. Under control conditions (pH = 6.5, Ca = 2 mg/L, Al = 0 μg/L), whole body Na, Cl, K, and Ca levels all increased greatly during development, while Mg decreased. Body Ca levels were elevated up to 3-fold, and Na, Cl, and K up to 2-fold by increasing water Ca at the same pH and Al. Low pH had a small negative influence, intermediate levels of Al (37, 111) a slight positive influence, and higher levels of Al a negative influence on Na, Cl, K, and Ca levels. Whole body Mg showed opposite trends, reflecting delayed development under adverse conditions. At pH = 6.5, the positive influence of increasing water Ca on most whole body ions showed a clear threshold between 0.5 and 1 mg/L. At lower pH, this threshold was shifted to between 2 and 8 mg/L, indicating that Ca levels sufficient to support healthy development at circumneutral pH may prove inadequate under acidified conditions.


1990 ◽  
Vol 47 (1) ◽  
pp. 210-216 ◽  
Author(s):  
Joseph Freda ◽  
D. Gordon McDonald

In this study, we conducted a series of toxicity tests investigating the response of embryos, prestage 25 tadpoles and 3-wk old tadpoles of the leopard frog (Rana pipiens) to a wide range pf pH (4.2–4.8) and Al (0–1000 μg∙:L−1}, and to pH 6.5 with no Al present. In embryos and prestage 25 tadpoles, Al ameliorated the toxic effects of very low pH's (4.2–4.4), while becoming toxic at higher pH's (4.6–4.8). Although both embryos and prestage 25 tadpoles were killed by low pH (pH 4.2–4.4 and 4.2, respectively) and elevated Al ([Formula: see text] and [Formula: see text] Al, respectively), embryos were relatively more sensitive (i.e. higher percent mortality) to low pH, whereas prestage 25 tadpoles were relatively more sensitive to Al Three week old tadpoles did not die at any test pH (without Al) and mortality (>20%) caused by Al occurred at only pH 4.8 and 750–1000 μg∙L−1 Al. The body sodium concentrations of 3-wk old tadpoles that survived high Al exposure were depressed indicating sublethal stress. Whole body Al uptake in 3-wk old tadpoles was also elevated in water containing high concentrations of Al, but it was positively related to water pH and exposure time. This result suggests that body Al content is not an accurate indicator of Al exposure in tadpoles living in acidic, Al contaminated ponds.


1988 ◽  
Vol 45 (9) ◽  
pp. 1563-1574 ◽  
Author(s):  
C. E. Booth ◽  
D. G. McDonald ◽  
B. P. Simons ◽  
C. M. Wood

Adult brook trout (Salvelinus fontinalis) were exposed for up to 11 d to one of a matrix of 18 Al, low pH, and Ca2+ combinations, chosen as representive of acidified softwater environments in the wild. Reduction in water pH led to pH-dependent net losses of Na+ and Cl− exacerbated by the presence of Al in the water and reduced by elevating Ca2+. Any animal losing more than 4% of its total body Na+ over the first 24 h of Al exposure had a greater than 90% likelihood of eventual mortality. Na+ losses arose from inhibition of influx and stimulation of efflux. The inhibition was persistent and pH dependent. Addition of Al to acidified water had a slight further inhibitory effect on Na+ influx and a large stimulatory effect on efflux. The latter was dependent on Al concentration, was the main cause of initial ion losses and mortality, and declined with time in surviving animals. All Al-exposed fish accumulated Al on their gills, but this was apparently mainly surface or subsurface bound, since no internal Al (plasma or liver) could be detected. Nonsurviving fish had substantially higher gill Al levels than survivors.


1988 ◽  
Vol 45 (9) ◽  
pp. 1587-1596 ◽  
Author(s):  
C. M. Wood ◽  
D. G. McDonald ◽  
C. E. Booth ◽  
B. P. Simons ◽  
C. G. Ingersoll ◽  
...  

Brook trout (Salvelinus fontinalis) adapt to chronic sublethal acid/Al stress. The accompanying acclimation confers greater resistance to short-term increases in Al and acidity. Adult trout were exposed in flowing soft water to eight combinations of pH (6.5, 5.2) × Ca2+ (25, 400 μequiv/L) × Al (0, 75, 150 μg/L = 0, 2.8, 5.6 μmol/L). After 10 wk, blood sampling by caudal puncture revealed no significant variations in osmolality, plasma protein, or hemoglobin and only minor differences [Formula: see text] in plasma Na+ and Cl−. Overall, most electrolytes were higher in fish exposed to higher water Al and/or Ca2+; only plasma Ca2+ was directly depressed by low pH. Hematocrit was raised by both low pH and elevated Al. When trout naive to both acid and Al were challenged with pH = 4.8, Al = 333 μg/L under flow-through conditions, there were large negative whole-body Na+ fluxes and marked depressions of plasma Na+ and Cl−, hemoconcentration, and substantial mortality over 48 h. Prior exposure for 10 wk to pH = 5.2 plus either 75 or 150 μg Al/L prevented mortality and ameliorated or abolished these effects through a more rapid recovery of net Na+ balance. Prior exposure to pH = 5.2 alone ameliorated these effects only slightly.


1986 ◽  
Vol 43 (10) ◽  
pp. 2048-2050 ◽  
Author(s):  
W. H. Tam ◽  
P. D. Payson ◽  
R. J. J. Roy

Brook trout fry (Salvelinus fontinalis) were exposed to pH 4.66 for various durations up to 141 d and then returned to neutral water. Growth of test fish was in general significantly lower than that of control fish for exposures up to days 45–78. In four of six groups of acid-treated fish, growth eventually recovered and the growth rates were not different from that of control fish. The results suggested that growth inhibition was induced early in the exposure to sublethally low pH and that recovery in the latter phase of the experiment occurred whether pH remained acidic or was readjusted to neutral.


1988 ◽  
Vol 136 (1) ◽  
pp. 243-258 ◽  
Author(s):  
J. FREDA ◽  
D. G. MCDONALD

This study investigated ion regulation in relation to water pH in three species of fish of differing tolerance to low pH (common shiners, Notropis cornutus, most sensitive; rainbow trout, Salmo gairdneri, intermediate; yellow perch, Perca flavescens, least sensitive). Increasing sensitivity to exposure to low pH was characterized by shorter survival times, greater losses of whole-body ions, more complete inhibition of Na+ uptake, and greater stimulation of Na+ efflux, the latter being the most important factor in determining survival. Interspecific variations in acid tolerance were also correlated with Na+ transport characteristics at circumneutral pH; Km was directly correlated and Vmax inversely correlated with acid tolerance. In addition, there were large qualitative differences among the species in the Ca2+-dependence of Na+ efflux. Sodium efflux induced by low pH was markedly Ca2+-dependent in both trout and shiners in a manner consistent with a simple competition between Ca2+ and H+ for gill binding sites. The increased sensitivity of shiners relative to trout was related to lowered Ca2+- binding activity. In contrast, Na+ efflux in perch was virtually unaffected by water [Ca2+]. Similarly, La3+ (a Ca2+ antagonist) stimulated higher Na+ losses from shiners than from trout, but had little effect upon perch. Ionic losses produced by saturating La3+ concentrations were generally lower than those produced by H+, suggesting that Ca2+ displacement is not the only mechanism for increased gill permeability at low pH. Nonetheless, the results obtained are consistent with the notion that acid tolerance may be related to Ca2+-binding activity in some species (e.g. trout and shiners) although not in others (e.g. perch).


2005 ◽  
Vol 71 (7) ◽  
pp. 3427-3432 ◽  
Author(s):  
Siouxsie Wiles ◽  
Kathryn Ferguson ◽  
Martha Stefanidou ◽  
Douglas B. Young ◽  
Brian D. Robertson

ABSTRACT The availability of cloned luciferase genes from fireflies (luc) and from bacteria (luxAB) has led to the widespread use of bioluminescence as a reporter to measure cell viability and gene expression. The most commonly occurring bioluminescence system in nature is the deep-sea imidazolopyrazine bioluminescence system. Coelenterazine is an imidazolopyrazine derivative which, when oxidized by an appropriate luciferase enzyme, produces carbon dioxide, coelenteramide, and light. The luciferase from the marine copepod Gaussia princeps (Gluc) has recently been cloned. We expressed the Gluc gene in Mycobacterium smegmatis using a shuttle vector and compared its performance with that of an existing luxAB reporter. In contrast to luxAB, the Gluc luciferase retained its luminescence output in the stationary phase of growth and exhibited enhanced stability during exposure to low pH, hydrogen peroxide, and high temperature. The work presented here demonstrated the utility of the copepod luciferase bioluminescent reporter as an alternative to bacterial luciferase, particularly for monitoring responses to environmental stress stimuli.


1989 ◽  
Vol 46 (5) ◽  
pp. 863-869 ◽  
Author(s):  
Margo A. Shaw ◽  
Gerald L. Mackie

The reproductive success of the gastropod Amnicola limosa was examined in six lakes ranging in pH from 4.62 to 7.42 to determine which stages in the life cycle were most sensitive to acidification. Although fecundity was significantly greater (p < 0.01) for adults reared at pH 7.42 than at pH 5.89–6.64, a failure to oviposit was documented only at pH 4.62. Hatching success was uniformly high (88–97%) at pH 5.59 to 7.42, while embryos incubated at pH 4.62 suffered complete mortality. The most critical stage in the life cycle is the newly hatched stage. Survival during the 20 d post hatch ranged from 23% at pH 5.59 to 69% at pH 7.42. There was an order of magnitude difference in the cumulative percent survival of recruits in lakes ranging in pH from 5.59 (5.1%) to 7.42 (44.0%). Juveniles raised at low pH (5.59–5.70) were on average 0.20 mm (20%) smaller than those in circumneutral lakes (pH 6.64–7.42). The present low densities of Amnicola limosa in Heney Lake (pH 5.59) can be explained by low recruitment since 1980. Evidence presented suggests that the disappearance of this species from clear low pH lakes (pH < 5.8) is due to reductions in fecundity and hatchling survival.


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