Lake Acidification as a Limiting Factor in the Distribution of the Freshwater Amphipod Hyalella azteca

1986 ◽  
Vol 43 (2) ◽  
pp. 288-292 ◽  
Author(s):  
M. Stephenson ◽  
G. L. Mackie
Keyword(s):  
Surface Water ◽  
Hyalella Azteca ◽  
Lake Acidification ◽  
Limiting Factor ◽  
Short Term ◽  
Natural Surface ◽  
Bioassay Data ◽  
Plastic Lake

The distribution of the freshwater amphipod Hyalella azteca in 79 Ontario lakes suggests that its absence may be a good indicator of lake acidification. Hyalella azteca was present in 69 of 71 nonacidified lakes, and absent in 8 of 8 lakes which either are now ar recently were considered acidified. Bioassay data indicate a 96-h LC50 of pH 4.4 and a 10-d threshold LC50 of pH 4.5 for H. azteca in a natural surface water. Hyalella azteca is extremely rare in Plastic Lake, which undergoes severe short-term acidification in spring, and recruitment is delayed 2 wk in Heeney Lake which undergoes similar short-term acidification, in Dickie, Harp, Red Chalk, and Blue Chalk lakes, where springtime pH depressions below pH 4.7 were not recorded, H. azteca is abundant.

Empirical Hypothesis to Explain the Restricted Distribution of Hyalella azteca (Amphipoda) in Anthropogenically Acidified Lakes

1987 ◽  
Vol 44 (6) ◽  
pp. 1112-1121 ◽  
Author(s):  
Robert L. France ◽  
Bruce D. LaZerte
Keyword(s):  
Littoral Zone ◽  
Time Trend ◽  
Population Decline ◽  
Hyalella Azteca ◽  
Ecological Data ◽  
Short Term ◽  
Restricted Distribution ◽  
Empirical Hypothesis ◽  
Acidified Lakes ◽  
Plastic Lake

A simple and speculative model is proposed to explain the restricted distribution of Hyalella azteca (Amphipoda) within acidified Ontario lakes. The model integrates field chemical and ecological data with results from laboratory toxicological experiments. Frequent spring depressions of pH to below 5.0, measured in the littoral zone of Plastic Lake during 1982, were predicted to cause a mortality of 35.2% to a theoretically constructed amphipod population. A time trend simulation suggested that population decline of H. azteca in similar anthropogenically acidified lakes could be caused by such direct mortality due to short-term pH fluctuations. Assumptions and factors not considered by the model which could exacerbate or mitigate the effects of acidic snowmelt to H. azteca are discussed.

Toxicity analysis of surface water in the Lower Don basin in Rostov-on-Don City by long-term bioassay data

2015 ◽  
Vol 42 (1) ◽  
pp. 70-77
Author(s):  
E. N. Bakaeva ◽  
A. M. Nikanorov ◽  
N. A. Ignatova
Keyword(s):  
Surface Water ◽  
Toxicity Analysis ◽  
Bioassay Data

Multi-day diurnal measurements of Ti-containing nanoparticle and organic sunscreen chemical release during recreational use of a natural surface water

2017 ◽  
Vol 4 (1) ◽  
pp. 69-77 ◽  
Author(s):  
R. B. Reed ◽  
D. P. Martin ◽  
A. J. Bednar ◽  
M. D. Montaño ◽  
P. Westerhoff ◽  
...  
Keyword(s):  
Surface Water ◽  
Water System ◽  
Recreational Water ◽  
Chemical Release ◽  
Natural Surface ◽  
First Time ◽  
Recreational Use

A recreational water system was monitored for release of both mineral and organic sunscreen constituents for the first time.

scholarly journals Intestinal absorption of different types of folate in healthy subjects with an ileostomy

2002 ◽  
Vol 88 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Erik J. M. Konings ◽  
Freddy J. Troost ◽  
Jacqueline J. M. Castenmiller ◽  
Harry H. S. Roomans ◽  
Piet A. van den Brandt ◽  
...  
Keyword(s):  
Folic Acid ◽  
Folate Intake ◽  
Limiting Factor ◽  
Short Term ◽  
Relative Absorption ◽  
Different Types ◽  
The Difference ◽  
Folate Bioavailability ◽  
Serum Response ◽  
Food Folate

Our knowledge on the absorption of folate is incomplete. The deconjugation process as a possible limiting factor in the absorption of folates was investigated. The study also attempted to validate the use of the area under the serum response curve (AUC) from food compared with folic acid as a proxy variable for food folate bioavailability. Folate absorption was determined in healthy ileostomy volunteers (n11) using a single-dose short-term protocol. In a randomised crossover design, volunteers received spinach meals and a supplement. Based on analysis of test meals and ileostomy effluents, there was no difference in folate absorption between spinach with a mono-:polyglutamate ratio 40:60 and the same spinach with a 100:0 ratio. The absolute absorption of spinach folate (79 %) calculated from the difference between folate intake and folate content of ileostomy effluents was approximately equal to the relative absorption (81 %) calculated from the AUC after consumption of spinach meals in relation to the AUC after consumption of the folic acid supplement. We conclude that the deconjugation process is not a limiting factor in the absorption of spinach folates. Comparison of AUC of food folatev.folic acid in a short-term protocol may be suitable for assessing food folate bioavailability.

Common loon reproduction and chick feeding on acidified lakes in the Adirondack Park, New York

1988 ◽  
Vol 66 (4) ◽  
pp. 804-810 ◽  
Author(s):  
Karl E. Parker
Keyword(s):  
New York ◽  
Food Resource ◽  
Resource Depletion ◽  
Low Ph ◽  
Lake Acidification ◽  
Common Loon ◽  
Feeding Problems ◽  
Short Term ◽  
Lake Acidity ◽  
Adirondack Lakes

The effects of lake acidification on common loon reproduction were studied on a total of 24 Adirondack lakes from May through August in 1983 and 1984. The lakes ranged in size from 10.5 to 179 ha; pH ranged from 4.65 to 6.77 and alkalinity from −66 to 111 μequiv./L. Although loons nesting on small, low-pH lakes had a high fledging rate, possibly because of reduced disturbance or predation, no significant relationship (P > 0.10) was found between lake acidity status and loon reproductive success. No chick mortality could be attributed to lake acidification, but chicks on low-pH lakes were generally fed prey much smaller or much larger than those normally preferred. A pair nesting on a fishless lake fed aquatic insects to their constantly begging chick, spending two to four times longer feeding the chick compared with loons on lakes with fish. This pair, alternating absences, flew to another lake to feed, and on three occasions returned to the nesting lake carrying a fish. Loons on the low-pH study lakes apparently adapted, at least in the short term, to food resource depletion associated with acidification. Despite this, acidification creates potentially severe feeding problems for chicks by reducing prey diversity and quantity.

Gas-chromatographic determination of aliphatic amines in natural surface water and wastewater

2008 ◽  
Vol 63 (7) ◽  
pp. 664-667 ◽  
Author(s):  
N. V. Kuz’mina ◽  
F. F. Khizbullin ◽  
T. Ya. Gadomskii ◽  
V. N. Maistrenko
Keyword(s):  
Surface Water ◽  
Chromatographic Determination ◽  
Aliphatic Amines ◽  
Natural Surface ◽  
Water And Wastewater
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