Reproduction of selected Mollusca in some low alkalinity lakes in south-central Ontario

1985 ◽  
Vol 63 (3) ◽  
pp. 511-515 ◽  
Author(s):  
M. R. Servos ◽  
J. B. Rooke ◽  
G. L. Mackie
Keyword(s):  
Low Ph ◽  
Acidic Lakes ◽  
Recruitment Failure ◽  
South Central ◽  
Summer Growth ◽  
Growth And Reproduction

Growth and reproduction of several species of molluscs were examined in six low alkalinity lakes in south-central Ontario. Amnicola limosa (Gastropoda: Amnicolidae) held through the summer of 1982 in cages in acidic lakes (pH 5.78–5.89) grew slower (p < 0.01) than those held in less acidic lakes (pH 6.03–6.84). The development of eggs of A. limosa in the laboratory was impaired at and below pH 5.0 and delayed at pH 5.5 relative to pH 6.0. Hence the recruitment failure and elimination of A. limosa that has been reported in acidifying lakes may be caused by reduced summer growth and (or) impaired development of the eggs. In contrast, Pisidium spp. (Bivalvia: Pisidiidae) do not appear to be adversely affected by low pH in the lakes in this study (pH 5.78–6.84). Caged Pisidium equilaterale did not have reduced growth in the acidic lakes during the summer of 1982. Pisidium casertanum and Pisidium ferrugineum had only slightly reduced (p < 0.05) fecundity (number of extramarsupial larvae per adult) in acidic lakes relative to less acidic lakes sampled in 1980.

scholarly journals Common Loon, Gavia immer, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

2009 ◽  
Vol 123 (2) ◽  
pp. 146 ◽  
Author(s):  
Robert Alvo
Keyword(s):  
Breeding Success ◽  
Low Ph ◽  
Single Pair ◽  
Gavia Immer ◽  
Common Loon ◽  
Sulphur Deposition ◽  
Acidic Lakes ◽  
Ph Range ◽  
Lake Size ◽  
Critical Ph

I monitored Common Loon (Gavia immer) breeding success in relation to lake pH (range 4.0–8.5) between 1982 and 2007 on 38 single-pair lakes (5–88 ha) in the Sudbury, Ontario, area. No chicks fledged on lakes with pH < 4.4. Chicks fledged on lakes with slightly higher pH only if the lakes were relatively large. Acidic lakes became less acidic as sulphur dioxide emissions from the Sudbury smelters and sulphur deposition from other long-range sources decreased. Two lakes initially too acidic to support successful loon reproduction eventually had successful reproduction. One loon pair used two large acidic lakes (combined area 140 ha) connected by shallow rapids, and one of the adults made extremely long dives (average = 99 s) while foraging for the chicks. One chick died on that lake after apparently ingesting a very large food item; the lack of smaller items was attributed to the lake’s acidity. My results suggest that a shortage of food for chicks is the main reason why low pH reduces breeding success. I suggest that, for lakes without high levels of dissolved organic carbon (DOC), the critical pH for loon breeding success is approximately 4.3, and the suboptimal pH is approximately 4.4–6.0.

Reproductive Success of Amnicola limosa (Gastropoda) in Low Alkalinity Lakes in South-Central Ontario

1989 ◽  
Vol 46 (5) ◽  
pp. 863-869 ◽  
Author(s):  
Margo A. Shaw ◽  
Gerald L. Mackie
Keyword(s):  
Life Cycle ◽  
Reproductive Success ◽  
Hatching Success ◽  
Low Ph ◽  
Critical Stage ◽  
Percent Survival ◽  
South Central ◽  
Order Of Magnitude ◽  
Magnitude Difference

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.

Effects of low pH and low calcium concentration on the pulmonate snail Planorbella trivolvis: a laboratory study

1990 ◽  
Vol 68 (7) ◽  
pp. 1578-1583 ◽  
Author(s):  
R. Douglas Hunter
Keyword(s):  
Calcium Concentration ◽  
Negative Impact ◽  
Stream Water ◽  
Low Ph ◽  
Juvenile Survival ◽  
Developmental Arrest ◽  
Recruitment Failure ◽  
Adult Growth ◽  
Planorbella Trivolvis ◽  
Circumneutral Ph

Freshwater pulmonate snails (Planorbella trivolvis) were maintained in the laboratory in stream water with manipulated pH and Ca2+. Low pH treatments (4.6 and 4.7) resulted in significantly lower adult growth rates and reduced gross fecundity compared with circumneutral pH treatments (7.2 and 7.4) regardless of the Ca2+ level. None of the eggs laid in low pH treatments hatched, mostly because of developmental arrest (gastrula or earlier). Eggs in low Ca2+ treatments took longer to complete development and had a higher incidence of abnormality compared with eggs in the high pH, high Ca2+ treatment. Juveniles that successfully hatched from the low Ca2+ treatments grew very little and all died within 100 days whereas over 7.2% of those in the high Ca2+, circumneutral pH treatment were alive at day 100, some of which had become adults and were laying eggs. This study suggests that both low pH (4.6) and low Ca2+ (1–2 mg/L) are lethal to Planorbella trivolvis, with embryos and juveniles showing much greater sensitivity than adults. Given the ranges of the two variables used in this study (1000-fold for H+ and ca. 30-fold for Ca2+), pH has the greater negative impact and, when below 5.0, led to recruitment failure in P. trivolvis; a similar effect on other pulmonate species would be expected. Furthermore, a Ca2+ concentration as low as 2 mg/L alone, regardless of pH, would be sufficient to cause recruitment failure by reducing juvenile survival. These data suggest that increasing Ca2+ levels does not protect P. trivolvis from the effects of low pH.

The effect of short-term acidification during spring snovvmelt on selected Mollusca in south-central Ontario

1986 ◽  
Vol 64 (8) ◽  
pp. 1690-1695 ◽  
Author(s):  
Mark R. Servos ◽  
Gerry L. Mackie
Keyword(s):  
Sulfuric Acid ◽  
Direct Result ◽  
Confounding Factors ◽  
Life Stages ◽  
Short Term ◽  
Recruitment Failure ◽  
South Central ◽  
Survival And Reproduction ◽  
Plastic Lake ◽  
Spring Snowmelt

Limestone and sulfuric acid were used to manipulate the pH of water in three artificial channels in the outflow of Plastic Lake, south-central Ontario, during the spring of 1982. Using artificial channels allowed the manipulation of pH during a natural pH depression (i.e., spring snowmelt) while minimizing confounding factors such as mobilization of metals from aquatic sediments. Addition of sulfuric acid extended and exaggerated the natural pH depression (from pH 5.8 to 4.8) to as low as pH 3.5 over 5 days, while addition of limestone prevented depression of pH below 6.4. Survival and reproduction of the pisidiid clams Pisidium equilaterale Prime and Pisidium casertanum (Poli) and the hydrobiid snail Amnicola limosa Say held in artificial channels were not significantly different (p > 0.05) among treatments. The survival and reproduction of A. limosa was also not affected by exposure to short-term pH depressions (e.g., 5.8 to 4.8; 4.8 to 4.3) in three south-central Ontario streams during spring snowmelt. For various life stages of both P. equilaterale and A. limosa, 96-h LC50 values were below pH 4.0, which was well below the pH observed in any stream in this study. These results suggest that recruitment failure and elimination of A. limosa from acidifying lakes noted in other studies was not a direct result of short-term pH depression during snowmelt.

Relationship between golgi apparatus and axonal reticulum in sympathetic ganglion cells

1978 ◽  
Vol 36 (2) ◽  
pp. 598-599
Author(s):  
J. Quatacker ◽  
W. De Potter
Keyword(s):  
Golgi Apparatus ◽  
Sympathetic Ganglion ◽  
Phosphotungstic Acid ◽  
Ganglion Cells ◽  
Low Ph ◽  
Dense Core ◽  
Dense Core Vesicles ◽  
Large Dense Core Vesicles ◽  
Cervical Ganglia ◽  
Axoplasmic Reticulum

Mucopolysaccharides have been demonstrated biochemically in catecholamine-containing subcellular particles in different rat, cat and ox tissues. As catecholamine-containing granules seem to arise from the Golgi apparatus and some also from the axoplasmic reticulum we examined wether carbohydrate macromolecules could be detected in the small and large dense core vesicles and in structures related to them. To this purpose superior cervical ganglia and irises from rabbit and cat and coeliac ganglia and their axons from dog were subjected to the chromaffin reaction to show the distribution of catecholamine-containing granules. Some material was also embedded in glycolmethacrylate (GMA) and stained with phosphotungstic acid (PTA) at low pH for the detection of carbohydrate macromolecules.The chromaffin reaction in the perikarya reveals mainly large dense core vesicles, but in the axon hillock, the axons and the terminals, the small dense core vesicles are more prominent. In the axons the small granules are sometimes seen inside a reticular network (fig. 1).

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