Relationships Between Dipteran Emergence and Phytoplankton Production in the Experimental Lakes Area, Northwestern Ontario

1980 ◽  
Vol 37 (3) ◽  
pp. 523-533 ◽  
Author(s):  
I. J. Davies
Keyword(s):  
Euphotic Zone ◽  
Dry Weight ◽  
Single Equation ◽  
Phosphorus Loading ◽  
Phytoplankton Production ◽  
Lake Depth ◽  
Lake Productivity ◽  
Experimental Lakes Area ◽  
Surface Distribution ◽  
Northwestern Ontario

Dipteran emergence was monitored at the Experimental Lakes Area (ELA) between 1973 and 1977 in seven lakes of different trophic status. The data were used to develop a number of equations which related the quantity and spatial distribution of average annual emergence to lake productivity. These models explained > 94% of the variation in mean emergent biomass among lakes or > 76% of the variation in numbers of emergent Diptera in terms of phytoplankton production or phosphorus loading. On average, ELA lakes produced 40.8 dipteran adults (9 mg dry weight) per gram carbon fixed by phytoplankton. A single equation for all lakes predicts the surface distribution of emergent biomass, relative to lake depth at any location, from vertical profiles of phytoplankton production. The mean size of dipteran adults was related to lake depth at the point of emergence and average phytoplankton production. An empirical model which used data on the vertical profile, and lake average, of phytoplankton production was developed to predict the number of Diptera emerging from each depth. The maximum depth of emergence was related to depth of the euphotic zone and average phytoplankton production in each lake. Initial tests suggested that the models may provide useful predictions of dipteran emergence for a wider spectrum of lakes.Key words: aquatic insects, Diptera, Chironomidae, eutrophication, primary production

Primary Production and Phytoplankton in the Experimental Lakes Area, Northwestern Ontario, and other Low-Carbonate Waters, and a Liquid Scintillation Method for Determining 14C Activity in Photosynthesis

1971 ◽  
Vol 28 (2) ◽  
pp. 189-201 ◽  
Author(s):  
D. W. Schindler ◽  
S. K. Holmgren
Keyword(s):  
Primary Production ◽  
Liquid Scintillation ◽  
Species Abundance ◽  
Euphotic Zone ◽  
Phytoplankton Production ◽  
Phytoplankton Species ◽  
Experimental Lakes Area ◽  
Phytoplankton Species Composition ◽  
Northwestern Ontario ◽  
Filtration Error

A modified 14C method is described for measuring phytoplankton production in low-carbonate waters. The procedure includes the use of the Arthur and Rigler (Limnol. Oceanogr. 12: 121–124, 1967) technique for determining filtration error, liquid scintillation counting for determining the radioactivity of membrane filters and stock 14C solutions, and gas chromatography for measuring total CO2.Primary production, chlorophyll a, and total CO2 were measured for two dates in midsummer from each of several lakes in the Experimental Lakes Area (ELA), ranging from 1 to 1000 ha in area and from 2 to 117 m in maximum depth. Phytoplankton species abundance and biomass were determined for the same dates. Production ranged from 0.02 to 2.12 gC/m3∙day and from 0.179 to 1.103 g C/m2∙day. Chlorophyll ranged from 0.4 to 44 mg/m3 and from 5 to 98 mg/m2 in the euphotic zone. The corresponding ranges for live phytoplankton biomass were 120–5400 mg/m3 and 2100–13,400 mg/m2. Chrysophyceae dominated the phytoplankton of most of the lakes.A system for classifying the lakes in terms of phytoplankton species composition and production–depth curves is developed.

Phytoplankton, Nutrients, and Primary Production in Fertilized and Natural Lakes at Saqvaqjuac, N.W.T.

1989 ◽  
Vol 46 (1) ◽  
pp. 90-107 ◽  
Author(s):  
Harold E. Welch ◽  
John A. Legauit ◽  
Hedy J. Kling
Keyword(s):  
Primary Production ◽  
Light Flux ◽  
Phytoplankton Production ◽  
Small Lakes ◽  
Experimental Lakes Area ◽  
Natural Lakes ◽  
Northwestern Ontario ◽  
North Temperate Lakes ◽  
P Addition ◽  
Very High

Whole-lake phosphorus (P) and nitrogen (N) addition experiments at Saqvaqjuac, N.W.T. (63°N in the central Canadian arctic), showed that the lakes were P limited but required both P and N for increased production. Photosynthetic response to 0.1 g P and 1.0 g N∙m−2∙yr−1 was immediate (15→30 g C∙m−2∙yr−1), with simultaneous increases in protozoa, while oligotrophic chrysophyte assemblages gave way to volvocalean greens. Cyanophytes were not important during P-only or P and N additions or in oligotrophic lakes, but formed permanent blooms in several naturally mesotrophic lakes near sea level. Retention of P was naturally low, but high during P addition. Silicon (Si) retention was always very high. Chlorophyll: P ratios were similar to those of subarctic and north-temperate lakes. Saturation light intensity (Ik) tracked surface light flux with a 2- to 3-wk delay, averaging 15 E∙m−2∙s−1 in winter and peaking at 140 E∙m−2∙s−1 in July. Comparison of our data with those for lakes in the Experimental Lakes Area (northwestern Ontario, 50°N) and Char Lake (75°N) shows that with increasing latitude, in small lakes, (a) phytoplankton production decreases, (b) phytoplankton production per unit light decreases less sharply, and (c) the proportion of primary production occurring beneath ice cover increases.

Phosphorus Input and Its Consequences for Phytoplankton Standing Crop and Production in the Experimental Lakes Area and in Similar Lakes

1978 ◽  
Vol 35 (2) ◽  
pp. 190-196 ◽  
Author(s):  
D. W. Schindler ◽  
E. J. Fee ◽  
T. Ruszczynski
Keyword(s):  
Lake Management ◽  
Phosphorus Loading ◽  
Phytoplankton Production ◽  
Phosphorus Concentration ◽  
Nutrient Inputs ◽  
Experimental Lakes Area ◽  
Total Phosphorus Concentration ◽  
Water Renewal ◽  
Rapid Changes ◽  
Shield Lakes

Correlation and regression analyses were used to assess several expressions for phosphorus loading, with and without corrections for water renewal and sedimentation, as predictors of total phosphorus concentration, chlorophyll, phytoplankton volume, and phytoplankton production in the Experimental Lakes Area (ELA) lakes. All expressions tested were good predictors, allowing predictions of the above parameters with 95% confidence intervals of 20–30% of the mean for any loading value. In general, correction for water renewal improved the fit of the expression, but correction for sedimentation did not. When the above strategy was applied to lakes outside ELA but with Shield or Shield-like drainage, good results were also obtained when expressions incorporating water renewal were used. If uncorrected for water renewal, loading was a poor predictor. Correction for sedimentation did not improve the expressions significantly. Correction for rapid changes in phosphorus input did not improve the predictability of equations, indicating that the equilibrium between ELA lakes and new loading conditions occurs very rapidly. Key words: Precambrian Shield lakes, eutrophication, lake management, nutrient inputs

Chemical Factors Involved in the Control of Phytoplankton Production in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 203-213 ◽  
Author(s):  
Mitsuru Sakamoto
Keyword(s):  
Inorganic Carbon ◽  
Phytoplankton Production ◽  
Carbon Uptake ◽  
Short Term ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Photosynthetic Carbon ◽  
General Order ◽  
Chemical Factors

In short-term experiments (6 hr–3 days) the general order of decreasing importance of nutrients added individually to samples of lake water and contained phytoplankton was inorganic carbon, Fe, P, and N. The comparable order for long-term experiments (8–20 days) was P, Fe, N; or P, N, Fe. No relation was found between concentrations of chlorophyll and inorganic carbon in the lakes. The addition of iron and trace elements in chelated form and chelators (HEDTA, NTA) alone, increased photosynthetic carbon uptake. The deficiency of iron was mostly due to a lack of iron in a readily assimilable form.

Vertical Distribution and Seasonal Abundance of Zooplankton in Two Shallow Lakes of the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 245-256 ◽  
Author(s):  
D. W. Schindler ◽  
Bengt Novén
Keyword(s):  
Vertical Distribution ◽  
Dry Weight ◽  
Distribution Patterns ◽  
Zooplankton Biomass ◽  
Seasonal Abundance ◽  
Experimental Lakes Area ◽  
Leptodora Kindtii ◽  
Northwestern Ontario ◽  
Vertical Distributions ◽  
Diurnal Movement

Seasonal variations in the abundance of zooplankton were studied in lakes 122 and 132 for a period of 10 months beginning in mid-May 1968. Seasonal dynamics of various species are discussed in relation to their patterns in the Canadian Shield and in other localities.Day and night vertical distributions for each lake were sampled on two dates in summer. Three species of rotifers migrated diurnally in lake 122, but no evidence of diurnal movement was found in lake 132. All crustaceans studied in both lakes migrated vertically to some degree, except for nauplius larvae and Leptodora kindtii. There was little difference in vertical distribution patterns on the two dates studied.Average zooplankton biomass in the two lakes was calculated and compared with that found in other studies. Average zooplankton biomass during the ice-free season was 72 and 156 mg/m3 dry weight for lakes 122 and 132, respectively. Dominant species in both lakes were Diaptomus minutus, Cyclops bicuspidatus thomasi, Holopedium gibberum, and Bosmina longirostris. Ecological tolerances for rotifer species agreed well with those found for Swedish waters.

Changes in methyl mercury concentrations in zooplankton from four experimental reservoirs with differing amounts of carbon in the flooded catchmentsThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1910-1919 ◽  
Author(s):  
Britt D. Hall ◽  
Katharine A. Cherewyk ◽  
Michael J. Paterson ◽  
R. (Drew) A. Bodaly
Keyword(s):  
Food Web ◽  
Methyl Mercury ◽  
Dry Weight ◽  
Experimental Lakes Area ◽  
Organic C ◽  
Dissolved Organic C ◽  
Northwestern Ontario ◽  
Highly Correlated ◽  
Source Waters

Methyl mercury (MeHg) concentrations in zooplankton were compared from four experimental reservoirs at the Experimental Lakes Area in northwestern Ontario, Canada, to test the hypothesis that increases in concentrations of MeHg in zooplankton would be proportional to C availability. The experimental reservoirs included three upland reservoirs flooded between 1999 and 2003 that differed in amounts of flooded organic terrestrial C (high, medium, and low C) and an experimental reservoir created over a wetland–peatland complex in 1993. After flooding, MeHg in zooplankton increased from <100 ng·g dry weight–1 in inflow source waters to >500 ng·g dry weight–1 in all reservoirs. In the first two years of flooding, MeHg in zooplankton was not correlated with amounts of flooded C, but the rates of decline in mean annual concentrations were negatively correlated with the amount of C stored in flooded catchments. Concentrations of MeHg in zooplankton were highly correlated with MeHg concentrations in unfiltered water, with reductions in bioaccumulation associated with increases in dissolved organic C and decreases in pH. Overall, our results suggest that reservoir designs that minimize the amount of flooded terrestrial C should result in shorter periods of elevated MeHg in the food web.

Relationship of Crayfish (Orconectes virilis) Growth to Population Abundance and System Productivity in Small Oligotrophic Lakes in the Experimental Lakes Area, Northwestern Ontario

1985 ◽  
Vol 42 (6) ◽  
pp. 1096-1102 ◽  
Author(s):  
R. L. France
Keyword(s):  
Sexual Maturity ◽  
Egg Production ◽  
Maximum Size ◽  
Reproductive Capacity ◽  
Phytoplankton Production ◽  
Orconectes Virilis ◽  
Experimental Lakes Area ◽  
System Productivity ◽  
Frequency Distributions ◽  
Northwestern Ontario

Crayfish growth in four lakes in the Experimental Lakes Area (ELA) was examined by analysis of size-frequency distributions, molt increment data, and calculation of instantaneous growth and mean size at onset of sexual maturity. Orconectes virilis growth rates at ELA are only 27–38% of those reported for other areas. Growth varied both among study lakes and between years. Higher temperatures and a longer growing season during 1980 increased growth an average of 12% over that of the preceding year. Crayfish growth and maximum size in four to six lakes were significantly correlated with phytoplankton production and chlorophyll a concentration. Growth regulated both the number of age 1 animals attaining sexual maturity and the per capita egg production, and was also directly related to the proportion of mature females that were fertilized. I believe population regulation is mediated through alterations in reproductive capacity that is correlated with system productivity.

Chemistry of Surface Sediments of Sixteen Lakes in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 277-294 ◽  
Author(s):  
G. J. Brunskill ◽  
D. Povoledo ◽  
B. W. Graham ◽  
M. P. Stainton
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Chemical Weathering ◽  
Major Ions ◽  
Fine Fraction ◽  
Dry Weight ◽  
Terrestrial Vegetation ◽  
Experimental Lakes Area ◽  
Sediment Samples ◽  
Northwestern Ontario

This paper contains some descriptive chemical data on bedrock, soils, and profundal lake sediments of the Experimental Lakes Area (ELA). The acid granodiorite bedrock and the plagioclase–K-feldspar–quartz glacial drift of the region exhibit low rates of chemical weathering. Terrestrial vegetation, soil organic matter, and the fine fraction of the glacial drift are concentrated in the lake sediments. The major minerals of the lake sediments are quartz, plagioclase, K-feldspar, illite, chlorite, kaolinite. Loss on ignition for the lake sediment samples varies from 18 to 62% dry weight, organic carbon from 8 to 34% dry weight, total nitrogen from 0.9 to 3.5% dry weight, and total phosphorus from 0.1 to 0.3% dry weight. These surficial lake sediment samples are 88–96% water, and concentrations of major ions in sediment interstitial water are 1.5–5 times the concentration of major ions in lake water.

Eutrophication of Lake 227, Experimental Lakes Area, Northwestern Ontario, by Addition of Phosphate and Nitrate

1971 ◽  
Vol 28 (11) ◽  
pp. 1763-1782 ◽  
Author(s):  
D. W. Schindler ◽  
F. A. J. Armstrong ◽  
S. K. Holmgren ◽  
G. J. Brunskill
Keyword(s):  
Standing Crop ◽  
Dominant Species ◽  
Inorganic Nitrogen ◽  
Late Summer ◽  
Phytoplankton Production ◽  
Experimental Lakes Area ◽  
Algal Production ◽  
Ph Values ◽  
Northwestern Ontario ◽  
Nitrogen Concentrations

Addition of 0.34 g P as Na2HPO4 and 5.04 g N as NaNO3 per square meter to a small unproductive Canadian Shield lake over a period of 17 weeks caused a severalfold increase in phytoplankton standing crop, and a change in dominant species from Chrysophyceae to Chlorophyta. Reactive phosphate concentrations remained at undetectable levels in the epilimnion after fertilization, and inorganic nitrogen concentrations remained low. Most of the added phosphorus and nitrogen was rapidly taken up by phytoplankton and sedimented with the seston.Although concentrations of total CO2 decreased to less than 20 μmoles/liter and pH values increased to greater than 9 in late summer, a high standing crop of phytoplankton was maintained. No marked increase in the rate of phytoplankton production was noticed Experiments in polyethylene containers suspended in the lake during this period of low total CO2 indicated that carbon was not limiting to algal production, except possibly at algal standing crops in excess of 100 μg/liter chlorophyll a, and that phosphorus was the primary limiting nutrient.Sodium added with the nutrients remained in the epilimnion until fall overturn, indicating that very little of it was utilized by phytoplankton.

Land water linkages: influences of riparian deforestation on lake thermocline depth and possible consequences for cold stenotherms

1997 ◽  
Vol 54 (6) ◽  
pp. 1299-1305 ◽  
Author(s):  
Robert France
Keyword(s):  
Thermal Stratification ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Thermocline Depth ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Riparian Trees ◽  
Tree Removal ◽  
Riparian Tree ◽  
Land Water

The purpose of the present study was to determine if riparian deforestation would expose lake surfaces to stronger winds and therefore bring about deepening of thermoclines and resulting habitat losses for cold stenotherms such as lake trout (Salvelinus namaycush). Removal of protective riparian trees through wind blowdown and two wildfires was found to triple the overwater windspeeds and produce thermocline deepening in two lakes at the Experimental Lakes Area. A survey of thermal stratification patterns in 63 northwestern Ontario lakes showed that lakes around which riparian trees had been removed a decade before through either clearcutting or by a wildfire were found to have thermocline depths over 2 m deeper per unit fetch length compared with lakes surrounded by mature forests. Riparian tree removal will therefore exacerbate hypolimnion habitat losses for cold stenotherms that have already been documented to be occurring as a result of lake acidification, eutrophication, and climate warming.

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