Limnological Features of Cedar Lake, Manitoba

1965 ◽  
Vol 22 (5) ◽  
pp. 1123-1136
Author(s):  
D. W. Webb
Keyword(s):  
Thermal Stratification ◽  
River System ◽  
Dry Weight ◽  
Total Dissolved Solids ◽  
Mean Value ◽  
Total Alkalinity ◽  
Bottom Fauna ◽  
Chemical Factors ◽  
Main Basin ◽  
Physical And Chemical

Cedar Lake, largest lake in the Saskatchewan River system, was studied from June 14 until August 31, 1962. Twenty stations, located in the main basin of the lake, were examined during six sampling periods. These stations were located along five transects, at depths of 1.5, 3, 6, and 9 m. No thermal stratification occurred and the oxygen concentration never fell below 78% of air saturation. Total alkalinity and total dissolved solids averaged above 65 and 270 ppm, respectively.The average number of bottom organisms increased with depth, with the bulk of these being made up of spheariid clams, mayflies, chironomids, and gastropods. The number of genera also increased with depth. The standing crops determined for the six sampling periods ranged from 17.7 to 33.2 lb/acre (dry weight), with a mean value of 23.4 lb/acre. Correlations between the physical and chemical factors and the distribution of bottom fauna are examined and it is felt that the bottom type is the major factor affecting the distribution and abundance of bottom organisms in Cedar Lake. On the basis of the physical and chemical criteria, Cedar Lake may be classified as eutrophic.

Indices of Productivity in British Columbia Lakes

1956 ◽  
Vol 13 (4) ◽  
pp. 515-540 ◽  
Author(s):  
T. G. Northcote ◽  
P. A. Larkin
Keyword(s):  
British Columbia ◽  
Total Dissolved Solids ◽  
Solid Content ◽  
General Level ◽  
Bottom Fauna ◽  
Significant Relation ◽  
Dissolved Solids ◽  
Hyperbolic Curve ◽  
Total Dissolved Solid ◽  
Physical And Chemical

The relation between physical and chemical indices of production and standard crops of plankton, bottom fauna and fish was examined in 100 British Columbia lakes. A significant increase in plankton and fish quantities with increase in total dissolved solid content of lake waters was demonstrated and a similar relationship suggested for bottom fauna. Although the general form of the relationship between mean depth and plankton, and between bottom fauna and fish quantity, suggested a hyperbolic curve with larger quantities in lakes of low mean depth, the only generalization which seemed justified was that quantities of fauna from lakes of great mean depth were never as high as those found in some lakes of low mean depth. No significant relation was found between intensity and length of growing season and quantities of plankton, bottom fauna or fish, although a significant relationship was demonstrated between summer epilimnion temperature and plankton.In a multiple regression analysis using all lakes the predominance of total dissolved solids over mean depth in affecting summed indices of lake fauna was shown. However for lakes in the southern interior plateau, one of the 9 regions distinguished in British Columbia, no significant relation could be demonstrated between mean depth or total dissolved solids and summed indices of fauna or plankton alone. Thus total dissolved solid content of the water appeared to be the most important factor in determining the general level of productivity in lakes studied throughout the province, although within a region neither total dissolved solids nor mean depth could be used either singly or together to predict plankton, bottom fauna or fish quantities.

Further Studies upon Chemical Factors Affecting the Breeding of Anopheles in Trinidad

1934 ◽  
Vol 25 (4) ◽  
pp. 491-494 ◽  
Author(s):  
P. A. Buxton
Keyword(s):  
Analytical Study ◽  
Chemical Constituents ◽  
Physical Factors ◽  
Factors Affecting ◽  
Early Stages ◽  
Freshwater Biology ◽  
Chemical Technique ◽  
Chemical Factors ◽  
Physical And Chemical

During the last decade, entomologists have made progress in understanding the environment in which certain insects live; in particular, we begin to understand the effect of certain physical and chemical factors, which make up a part of the environment. With this gain in knowledge, it is sometimes possible to forecast outbreaks of insects and of diseases conveyed by them, and one can sometimes say that a particular alteration of the environment will result in loss or gain. But so far as mosquitos are concerned, one must admit that though much work has been devoted to the analytical study of the water in which the early stages are passed, the results are disappointing. A consideration of the published work suggests several reasons for this. Investigation into the ecology of the mosquito has had a vogue, and much of it has been done by workers who were isolated and whose knowledge of chemical technique and freshwater biology was limited. Apart from that, the inherent difficulties are great, for the worker must hunt for the limiting chemical and physical factors among a host of others which are doubtless unimportant, and there are few clues to indicate which of the chemical constituents of the water affects the mosquito. The data are therefore voluminous and it is difficult to reduce them to order and present them so that they can be readily understood.

scholarly journals STUDY AND ESTIMATION OF THE RATIO OF 137CS AND 40K SPECIFIC ACTIVITIES IN SANDY AND LOAM SOILS / 137CS IR 40K SAVITŲJŲ AKTYVUMŲ SANTYKIŲ TYRIMAS IR VERTINIMAS PRIESMĖLIO IR PRIEMOLIO DIRVOŽEMYJE

2011 ◽  
Vol 3 (5) ◽  
pp. 37-42
Author(s):  
Renata Mikalauskienė ◽  
Donatas Butkus ◽  
Ingrida Pliopaitė Bataitienė
Keyword(s):  
Chemical Properties ◽  
Dry Weight ◽  
Soil Samples ◽  
Physical And Chemical Properties ◽  
Nuclear Testing ◽  
Specific Activities ◽  
Physical And Chemical ◽  
Chernobyl Nuclear Plant ◽  
Properties Of Soil ◽  
And Chemical Properties

The present article describes changes in specific activities and fluctuations in the ratio of natural 40K and artificial 137Cs radionuclides in soil samples taken from different places of Lithuanian territory. The samples of soil have been selected from the districts polluted after the accident in Chernobyl nuclear plant performing nuclear testing operations. The study has established the main physical and chemical properties of soil samples and their impact on the concentration of 40K activities. 137Cs/40K specific activities in soil have been observed under the dry weight of the sample that varied from 0.0034 to 0.0240. The results of the study could be used for establishing and estimating 137Csand 40K transfer in the system “soil-plant”. Santrauka Straipsnyje nagrinėjama gamtinės (40K) ir dirbtinės (137Cs) kilmės radionuklidų savitųjų aktyvumų ir jų santykio kaita skirtinguose Lietuvos teritorijos dirvožemiuose. Dirvožemio mėginiai parinkti iš vietovių, kurios buvo labiau užterštos po Černobylio atominės elektrinės avarijos ir buvusių branduolinių bandymų. Tyrimo metu nustatytos pagrindinės fizinės cheminės dirvožemio savybės ir jų poveikis 40K aktyvumų koncentracijai. 137Csir 40K savitieji aktyvumai dirvožemyje tirti esant sausam mėginio svoriui. 137Cs savitieji aktyvumai sausame dirvožemyje svyravo nuo 1,1±1,0 iki 14,3±0,9 Bq/kg, o 40K savitieji aktyvumai – nuo 326±29 iki 740±15 Bq/kg. 137Csir 40K savitųjų aktyvumų santykis skirtingų vietovių dirvožemiuose kito nuo 0,0034 iki 0,0240 Bq/kg. Tyrimo rezultatai gali būti panaudoti, nustatant ir įvertinant 137Csir 40K pernašą sistemoje dirvožemis–augalai.

Menadione nicotinamide bisulphite as a source of vitamin K and niacin activities for the growing pig

2000 ◽  
Vol 71 (1) ◽  
pp. 111-117 ◽  
Author(s):  
M. Marchetti ◽  
M. Tassinari ◽  
S. Marchetti
Keyword(s):  
Vitamin K ◽  
Control Diet ◽  
Live Weight ◽  
Organic Salt ◽  
Free Form ◽  
Food Supplementation ◽  
Sodium Bisulphite ◽  
Chemical Factors ◽  
And Control ◽  
Physical And Chemical

AbstractWhen compared with other menadione derivatives such as menadione sodium bisulphite (MSB), menadione nicotinamide bisulphite (MNB), an organic salt combining menadione and nicotinamide, shows better stability towards physical and chemical factors once it is added to pre-mixes or foods. The present work evaluates the bioavailability of the two vitamins present in this compound and toxicity in the pig. To assess vitamin bioavailability, pigs were given small amounts of food containing MNB or equivalent amounts of MSB and nicotinamide in the free form. Menadione and nicotinamide concentrations in blood samples drawn at set times after the diets were given did not reveal any significant differences between the two modes of administration. Haematic levels of both vitamins in animals receiving MNB, or MSB and nicotinamide, were after 2, 4, 8 and 12 h higher (P < 0·001) than those of untreated animals. The tolerance level to MNB was evaluated in pigs given diets containing graded amounts of MNB (100, 500, 2500 mg/kg) for 28 days. No significant (P > 0·05) differences were recorded in live weight, food intake and gain/food ratio in pigs given these diets when compared with those given an unsupplemented diet. Haemoglobin and bilirubin levels did not differ between animals given various amounts of MNB and control animals. Plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in pigs given 100 mg/kg of MNB did not show significant differences when compared with those observed in pigs given an unsupplemented control diet. In pigs on the diets supplemented with 500 and 2500 mg/kg of MNB there was a significant increase in the two enzymatic activities as compared with controls (P < 0·001 and P < 0·01). In the case of ALT this had disappeared by 28 weeks. MNB is a good source of vitamin K for the pig and does not appear to have any adverse effects, even when administered at levels higher than those normally used in pig food supplementation.

The Qualitative and Quantitative Distribution of Plankton in the Strait of Georgia in Relation to Certain Oceanographic Factors

1957 ◽  
Vol 14 (4) ◽  
pp. 521-552 ◽  
Author(s):  
Joseph Eugène Henri Légaré
Keyword(s):  
Salinity Gradient ◽  
General Distribution ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Quantitative Distribution ◽  
Qualitative And Quantitative ◽  
Chemical Factors ◽  
Physical And Chemical ◽  
Plankton Communities ◽  
Made In

In order to gain some picture of the seasonal variations in the plankton communities two cruises were made in the Strait of Georgia, one in June 1955, and the other in November 1955; 165 plankton collections were taken, also surface temperatures.The correlation of these data have resulted in a number of conclusions concerning the distribution of plankton in the Strait of Georgia. The chief factor affecting the general distribution of plankton is the salinity gradient. The inflow of fresh water from the Fraser River forms zones of varying properties, and leads to the development of different plankton communities. The extent to which physical and chemical factors may determine the presence or absence of certain organisms from the zones described is discussed.

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