Responses of an Amazonian Teleost, the Tambaqui (Colossoma                         macropomum), to Low pH in Extremely Soft Water

Smolting Atlantic salmon, Salmo salar, were kept from 11 April to 24 May in soft water of pH 5 or in soft water of pH 5 and 50 μg aluminum (Al)∙L−1. Control fish were kept in soft water of pH 6.3–6.5. Water temperature was 8–14 °C. In mid-May, some of the control smolts were transferred to the test conditions for 8 d. Exposure to acid water resulted in osmoregulatory failure and high mortality rate. Al strongly enhanced toxicity. Sensitivity to low pH or low pH/Al exposure greatly increased when fish had developed to seawater tolerant smolts. In control and acid-exposed fish, gill carbonic anhydrase activity remained unchanged throughout the experiment whereas in Al-exposed fish, carbonic anhydrase activity decreased. Gill Na+K+-ATPase activity in control fish peaked in mid-May simulanteously with development of seawater tolerance. Fish from both acid-exposed groups had low seawater tolerance. Na+,K+-ATPase activity declined to 60% of start value in acid-exposed fish and to parr level in Al-exposed fish. Hypoosmoregulatory ability was linearly correlated with gill Na+K+-ATPase activity. Reduction in plasma Na+ concentration in acid-exposed fish was linearly correlated with the reduction in gill Na+,K+-ATPase activity.

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The Influence of Calcium on the Physiological Responses of the Rainbow Trout, Salmo Gairdneri, to Low Environmental pH

Journal of Experimental Biology ◽

10.1242/jeb.88.1.109 ◽

1980 ◽

Vol 88 (1) ◽

pp. 109-132

Author(s):

D. G. McDONALD ◽

H. HŌBE ◽

C. M. WOOD

Keyword(s):

Rainbow Trout ◽

Calcium Concentration ◽

Physiological Responses ◽

Hard Water ◽

Low Ph ◽

Soft Water ◽

Salmo Gairdneri ◽

Minor Depression ◽

Regulatory Failure ◽

A Minor

The physiological responses of 1- to 2-year-old rainbow trout to low pH are dependent on the environmental calcium concentration. Trout, maintained for 5 days in moderately hard water ([Ca2+] = 1·6–2·7 m-equiv/1) at a mean pH of 4·3, developed a major blood acidosis but exhibited only a minor depression in plasma ion levels. In acidified soft water ([Ca2+] = 0·3 m-equiv/1), only a minor acidosis occurred, but plasma ion levels fell and there were substantially greater mortalities. Lethal bioassays performed on fingerling trout over a range of pH levels (3·0–4·8) revealed an important influence of external [Ca2+] on resistance to acid exposure. Terminal physiological measurements on adult fish succumbing to low pH in soft water indicate the singular importance of iono-regulatory failure as the toxic mechanism of action under these circumstances.

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Hatching Success of Mayfly Eggs at Low pH

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f88-195 ◽

1988 ◽

Vol 45 (9) ◽

pp. 1649-1652 ◽

Cited By ~ 11

Author(s):

Locke Rowe ◽

Jeffrey Hudson ◽

Michael Berrill

Keyword(s):

Hatching Success ◽

Low Ph ◽

Soft Water ◽

The Other ◽

Hatching Rate ◽

Field Surveys ◽

Acid Sensitivity ◽

Significant Mortality

Eggs of the mayflies Leptophlebia cupida, Habrophlebia vibrans, Stenonema femoratum, and Baetis flavistriga were reared in soft water at several pH levels (4.0, 4.5, 5.0, and 6.5) in the laboratory. The proportion of eggs undergoing eclosion did not vary with pH. However, in B. flavistriga, significant mortality of nymphs occurred before the hatch was complete at pH 4.0 (91%) and 4.5 (12%). Hatching rate of H. vibrans was significantly retarded at pH 4.0, 4.5, and especially at pH 5.0, but was unaffected in the other three species. The effects of elevated [H+] on these species are in agreement with their relative acid sensitivity inferred from field surveys.

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Effect of low pH on sodium regulation in two species of Daphnia

Canadian Journal of Zoology ◽

10.1139/z84-288 ◽

1984 ◽

Vol 62 (10) ◽

pp. 1965-1970 ◽

Cited By ~ 32

Author(s):

Magda Havas ◽

Thomas C. Hutchinson ◽

Gene E. Likens

Keyword(s):

Daphnia Magna ◽

Hard Water ◽

Low Ph ◽

Soft Water ◽

Sodium Influx ◽

Daphnia Middendorffiana ◽

Sodium Loss ◽

Sodium Regulation

The effect of low pH on sodium-22 influx and outflux of Daphnia magna and Daphnia middendorffiana was assessed. Experiments were conducted in both hard and soft water with experimental pHs ranging from 3.5 to 8.0. In hard water, at and below pH 4.0, there was a net loss of sodium from both species. The rate of sodium loss (outflux) increased significantly, while the rate of uptake (influx) remained constant at pH 4.0 compared with the reference pH 8.0. Only at extremely low pH (pH 3.5) was sodium influx inhibited in hard water. In soft water, D. magna responded quite differently. Sodium influx was inhibited by 23% at pH 5.0 and by 69% at pH 4.5 compared with the control (pH 6.5). Sodium outflux was stimulated to 125% of the control at pH 4.5. The net loss of sodium in soft water was due to both an increase in sodium outflux and a decrease in sodium influx, while in hard water the effect was primarily on sodium outflux. Daphnia magna and D. middendorffiana have problems with sodium regulation below pH 5.5 in soft water and below pH 4.5 in hard water, which indicates that they are considerably more sensitive to low pH in soft water than in hard water.

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An investigation of the erosive effect on concrete of soft water of low pH value

Magazine of Concrete Research ◽

10.1680/macr.1954.6.17.93 ◽

1954 ◽

Vol 6 (17) ◽

pp. 93-98 ◽

Cited By ~ 3

Author(s):

P. E. Halstead

Keyword(s):

Ph Value ◽

Low Ph ◽

Soft Water ◽

Erosive Effect

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The effect of aluminum in soft water at low pH on oxygen consumption by the dragonfly Libellula julia Uhler

Hydrobiologia ◽

10.1007/bf00020687 ◽

1990 ◽

Vol 190 (1) ◽

pp. 55-59 ◽

Cited By ~ 9

Author(s):

John P. Rockwood ◽

Daniel S. Jones ◽

Robert A. Coler

Keyword(s):

Oxygen Consumption ◽

Low Ph ◽

Soft Water

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Variation in tolerance to low environmental pH by the crayfish Orconectes rusticus, O. propinquus, and Cambarus robustus

Canadian Journal of Zoology ◽

10.1139/z85-386 ◽

1985 ◽

Vol 63 (11) ◽

pp. 2586-2589 ◽

Cited By ~ 41

Author(s):

Michael Berrill ◽

Lois Hollett ◽

Arlene Margosian ◽

Jeff Hudson

Keyword(s):

Life Cycle ◽

Laboratory Experiments ◽

Low Ph ◽

Soft Water ◽

Stage Iii ◽

Aluminum Concentration ◽

Orconectes Rusticus ◽

Juvenile Stages ◽

Ph Range ◽

Crayfish Species

We compared the tolerance of three common Ontario crayfish species to low pH under natural and laboratory conditions in water varying in aluminum concentration and hardness. Both transplant and laboratory experiments indicated that exposure to a pH range of 5.4–6.1 in soft water was toxic to attached juvenile stages of Orconectes rusticus and O. propinquus but not to females carrying the broods. In contrast, stage III juveniles of Cambarus robustus molted and survived in soft water at pH 4. Cambarus robustus is clearly far less sensitive to low pH stress than the two Orconectes species. No increased mortality due to the presence of elevated aluminum occurred among stage III juveniles of the three species exposed to pH 4.5–5.0 in soft water. Physiological differences, augmented by differences in life cycle, may account for the continued presence of C. robustus in acid-stressed lakes and streams.

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