scholarly journals Effects of lake size, water clarity, and climatic variability on mixing depths in Canadian Shield lakes

1996 ◽  
Vol 41 (5) ◽  
pp. 912-920 ◽  
Author(s):  
E. J. Fee ◽  
R. E. Hecky ◽  
S. E. M. Kasian ◽  
D. R. Cruikshank
Keyword(s):  
Climatic Variability ◽  
Water Clarity ◽  
Canadian Shield ◽  
Shield Lakes ◽  
Lake Size

Effects of Lake Size on Phytoplankton Nutrient Status

1994 ◽  
Vol 51 (12) ◽  
pp. 2769-2783 ◽  
Author(s):  
S. J. Guildford ◽  
L. L. Hendzel ◽  
H. J. Kling ◽  
E. J. Fee ◽  
G. G. C. Robinson ◽  
...  
Keyword(s):  
Nutrient Status ◽  
Canadian Shield ◽  
Small Lakes ◽  
Large Lakes ◽  
P Deficiency ◽  
Water Renewal ◽  
Mixed Layers ◽  
Shield Lakes ◽  
Lake Size ◽  
Total P

Phytoplankton nutrient status measurements (C/P, C/N, C/chlorophyll, N/P, alkaline phosphatase activity, and N debt) were measured for 6 yr in seven remote Canadian Shield lakes. Lakes Nipigon and Superior were also studied for 2 yr. These lakes varied in surface area from 29 to 8.223 × 10 ha, they all stratified fully during the summer and had water renewal times > 5 yr. All lakes were severely P deficient; however, the large lakes (> 2000 ha) were consistently less P deficient than small lakes. A growth-rate indicator (photosynthesis normalized to particulate C) agreed with nutrient status indicators, in that small lakes had lower rates than large lakes. Total P was a good predictor of chlorophyll, but factors related to lake size (temperature and mixed depth) were equally good or better predictors of nutrient status. Decreasing mean water column light intensity could not explain the lower P deficiency of large lakes. The deeper, more energetic mixed layers in large lakes apparently cause P to be recycled more efficiently. Extrapolation of observations or experimental results from small to large lakes requires recognition that phytoplankton in large lakes are less nutrient deficient and may have higher growth rates.

Cadmium concentrations of crustacean zooplankton of acidified and nonacidified Canadian Shield lakes

1990 ◽  
Vol 24 (9) ◽  
pp. 1367-1372 ◽  
Author(s):  
Norman D. Yan ◽  
Gerald L. Mackie ◽  
Peter J. Dillon
Keyword(s):  
Canadian Shield ◽  
Crustacean Zooplankton ◽  
Shield Lakes

Calibration of the zooplankton community size spectrum as an indicator of change in Canadian Shield lakes

2019 ◽  
Vol 76 (12) ◽  
pp. 2268-2287
Author(s):  
Lauren Emily Barth ◽  
Brian John Shuter ◽  
William Gary Sprules ◽  
Charles Kenneth Minns ◽  
James Anthony Rusak
Keyword(s):  
Zooplankton Community ◽  
Canadian Shield ◽  
Rate Of Change ◽  
Crustacean Zooplankton ◽  
Size Spectrum ◽  
Community Size ◽  
Mean Values ◽  
Sampling Protocols ◽  
Stable Characteristic ◽  
Shield Lakes

Developing the crustacean zooplankton community size spectrum into an indicator of change in lakes requires quantification of the natural variability in the size spectrum related to broad-scale seasonal, annual, and spatial factors. Characterizing seasonal patterns of variation in the size spectrum is necessary so that monitoring programs can be designed to minimize the masking effects that seasonal processes can have on detecting longer-term temporal change. We used a random effects model to measure monthly, annual, and interlake variability in the slope (i.e., relative abundance of small and large organisms) and centered height (i.e., total abundance) of the crustacean zooplankton normalized abundance size spectrum from 1981 to 2011 among eight Canadian Shield lakes. Consistent with theoretical predictions, the slope was a relatively stable characteristic of the zooplankton community compared with the height, which varied significantly among lakes. We identified a seasonal signal in height and slope and used a mixed effects model to characterize the linear rate of change from May to October; there was an overall decline in height and an overall increase in slope. Seasonal variance was greater than annual variance for both the height and the slope, suggesting that long-term monitoring of lakes and interlake comparisons using zooplankton size spectra should be based on temporally standardized sampling protocols that minimize the effects of seasonal processes. We recommend sampling the zooplankton community in midsummer because this results in size spectrum estimates close to seasonal mean values.

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