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.

Decline of Mysis relicta During the Acidification of Lake 223

1983 ◽  
Vol 40 (11) ◽  
pp. 1905-1911 ◽  
Author(s):  
R. W. Nero ◽  
D. W. Schindler
Keyword(s):  
Confidence Limits ◽  
Experimental Lakes Area ◽  
Mysis Relicta ◽  
Ph Values ◽  
Northwestern Ontario ◽  
Population Comparisons ◽  
Acidification Of Lake ◽  
Ph Range ◽  
Shield Lakes ◽  
Direct Toxicity

The population size of Mysis relicta in Lake 223 of the Experimental Lakes Area, northwestern Ontario, decreased from 6 700 000 ± 1 330 000 (± 95% confidence limits) during August of 1978, to 270 000 ± 75 000 during August of 1979, a 96% decrease. Because Mysis, a cold stenotherm, is restricted to the metalimnion and hypolimnion of lakes during summer, the pH range encountered by the population was 5.51 to 6.32 in 1978 and 5.23 to 6.10 in 1979, even though mean pH values in epilimnion waters for the 2 yr were 5.84 and 5.60. A decrease in pH of its habitat from 6.2 to 5.6 during fall overturn in 1979 caused the elimination of the remaining 4% of the population. Comparisons with four control lakes suggested that the decline and disappearance were not normal occurrences in unstressed lakes. Concentrations of Zn, Al, Mn, Fe, Cd, Cu, Ni, and Hg in Lake 223 water were low, and concentrations in Mysis were less than or equal to those in animals from five control lakes, suggesting that the decline in this species was not due to the toxic effects of metals. All size classes were affected, so that direct toxicity of hydrogen ion may be responsible for this abrupt population collapse. These results suggest that Mysis may be a useful early indicator of acidification damage to Precambrian Shield lakes.

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.

Cladocera Community Response to Experimental Eutrophication in Lake 227 as Recorded in Laminated Sediments

1994 ◽  
Vol 51 (10) ◽  
pp. 2312-2321 ◽  
Author(s):  
Brenda J. Hann ◽  
Peter R. Leavitt ◽  
Philip S. S. Chang
Keyword(s):  
Standing Crop ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Community Response ◽  
Laminated Sediments ◽  
Accumulation Rates ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Annually Laminated Sediments ◽  
Chemical Conditions

The response of pelagic zooplankton to experimental fertilization was compared with the fossil record of Cladocera obtained from the annually laminated sediments of Lake 227, Experimental Lakes Area, northwestern Ontario. Constrained cluster analysis of both total fossil Cladocera and littoral chydorid communities clearly distinguished between pre- and post-eutrophication communities and further differentiated between years of high and low nitrogen:phosphorus fertilization ratios. However, there were few chydorid species extirpations resulting from the manipulation. Total chydorid accumulation rates and indices of species diversity, richness, and equitability were relatively constant over the last century and were not affected by fertilization. Among pelagic Cladocera, Bosmina longirostris abundance declined > 60% after initial fertilization. Although harsh chemical conditions (pH > 10) may have contributed to reduced abundance of pelagic Cladocera, Bosmina populations were also naturally variable prior to manipulation. Changes in Bosmina morphology (mucrone, antennule, and carapace length) and cladoceran size ratios (Daphnia/[Daphnia + Bosmina]) suggested that zooplanktivory by fish and invertebrates exercised important control of herbivore populations. Fossil Bosmina concentration (remains∙[g dry wt]−1 or remains∙[g organic matter]−1) were significantly correlated (r = 0.66, P < 0.01, 1970–1989) to standing crop in the water column (animals∙m−2). Fossil accumulation rate (remains∙cm−2∙yr−1) was not significantly correlated to Bosmina abundance, perhaps because of errors in determining bulk sediment accumulation rates.

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.

Zoobenthos of Fifteen Lakes in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 257-263 ◽  
Author(s):  
Andrew L. Hamilton
Keyword(s):  
Dissolved Oxygen ◽  
Dominant Species ◽  
Bottom Water ◽  
Individual Species ◽  
Lake Morphometry ◽  
Dissolved Oxygen Concentration ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Morphometric Features ◽  
The Individual

The composition of the profundal and sublittoral zoobenthos of 15 lakes in northwestern Ontario was closely related to morphometric features of the individual lakes. The amphipod Pontoporeia affinis Lind., and the sphaeriid Pisidium conventus Clessin, were the dominant species in the larger deeper lakes whereas species of Chironomidae and Chaoborinae were the dominant forms in all lakes with mean depths of less than 10 m. Dissolved oxygen concentration and temperature of the bottom water, two characteristics that are largely a function of lake morphometry, are probably the primary factors limiting the distribution of individual species.

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.

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.

Phytoplankton Community Responses to Nutrient Addition in Lake 226, Experimental Lakes Area, Northwestern Ontario

1987 ◽  
Vol 44 (S1) ◽  
pp. s35-s46 ◽  
Author(s):  
D. L. Findlay ◽  
S. E. M. Kasian
Keyword(s):  
Species Composition ◽  
Water Exchange ◽  
Phytoplankton Community ◽  
Late Summer ◽  
Nitrogen And Phosphorus ◽  
Experimental Lakes Area ◽  
Carbon And Nitrogen ◽  
Northwestern Ontario ◽  
Average Biomass ◽  
Reference Lakes

Inclusion of phosphorus in fertilizer added to one of two basins of a small lake, between which water exchange was greatly reduced by a vinyl sea-curtain, significantly increased epilimnetic phytoplankton biomass, and altered species composition. Over an 8-yr period, the average biomass of phytoplankton in the basin receiving carbon, nitrogen, and phosphorus (in ratios of 10:5:1) increased 4 to 8 times and the biomass in the basin receiving only carbon and nitrogen (in ratios of 10:5) increased 2 to 4 times over non-fertilized years. The basin receiving all three nutrients consistently had blooms in late summer which were dominated by nitrogen fixing species of cyanophytes. In comparison with unfertilized reference lakes, the proportion of phytoplankton in fertilized basins which was available to zooplankton as food was 10 times greater in the basin receiving all three nutrients, and two times greater in the basin receiving only nitrogen and carbon. When fertilization of both basins was stopped, species composition and levels of biomass reverted within a year to the composition and biomass levels of phytoplankton observed in the reference lakes and remained at those levels for 2 further years of study.

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

The Malachite Green Biodegradation in Bioreactors on Various pH Domains

2019 ◽  
Vol 70 (8) ◽  
pp. 2996-2999
Author(s):  
Viorel Gheorghe ◽  
Catalina Gabriela Gheorghe ◽  
Andreea Bondarev ◽  
Vasile Matei ◽  
Mihaela Bombos
Keyword(s):  
Malachite Green ◽  
Contact Time ◽  
Dominant Species ◽  
Wastewater Treatment Plants ◽  
Organic Substances ◽  
Biological Degradation ◽  
Growth Promoters ◽  
Ph Values ◽  
Biological Sludge ◽  
Ph Range

In the experimental study was studied the malachite green colorant biodegradation in biological sludge with biological activity. The biodegradability tests were carried out in laboratory bioreactors, on aqueous solutions of green malachite contacted with microorganisms in which the dominant species is Paramecium caudatum, in a pH range between 8 and 12, temperatures in the ranges 25-350C, using pH neutralizing substances and biomass growth promoters. The colorant initial concentrations and those obtained after biological degradation depending on the contact time, at certain pH values, were established through UV-Vis spectrometry. The studies have shown the measure of possible biological degradation of some organic substances with extended uses, with largely aromatic structure, resistance to biodegradation of microorganisms, commonly used in wastewater treatment plants.

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