Changes in Sedimentary Phosphorus Burial Following Artificial Eutrophication of Lake 227, Experimental Lakes Area, Ontario, Canada

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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Dynamics of Cadmium-Stressed Plankton Communities

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-054 ◽

1980 ◽

Vol 37 (3) ◽

pp. 403-414 ◽

Cited By ~ 52

Author(s):

J. S. Marshall ◽

D. L. Mellinger

Keyword(s):

Dissolved Oxygen ◽

Lake Michigan ◽

Zooplankton Community ◽

Cadmium Stress ◽

Crustacean Zooplankton ◽

Functional Responses ◽

Experimental Lakes Area ◽

Individual Values ◽

Zooplankton Density ◽

Plankton Communities

Structural and functional responses of plankton communities to cadmium stress were studied during 1977 in Lake Michigan using small-volume (8 L) completely sealed enclosures, and in Canada's Experimental Lakes Area (ELA) Lake 223 using large-volume (1.5 × 105 L) open-surface enclosures. In Lake Michigan, reductions of the average abundance of micro-crustaceans by cadmium were significantly greater in "light" or shallow epilimnetic incubations than they were in "dark" or deep epilimnetic incubations. Measurements of dissolved oxygen indicated that this interaction with light (depth) was an indirect effect due to a reduction of photosynthesis and primary production. Zooplankton density and species diversity were not significantly affected within 21 d by cadmium concentrations [Formula: see text] and [Formula: see text] Cd/L, respectively, whereas final dissolved oxygen concentration and percentage similarity (PS) of the crustacean zooplankton community were significantly reduced by [Formula: see text] Cd/L. In the ELA Lake 223 experiment, the reducing effect of cadmium on zooplankton density increased up to 31 d after Cd enrichment and then decreased, probably due to decreasing Cd concentrations in the water. Values of PS on day 24 for the ELA enclosures enriched with 1 and 3 μg Cd/L were within the 95% confidence limits for individual values predicted from a regression of PS on cadmium for the 21-d Lake Michigan experiments.Key words: plankton communities, zooplankton, phytoplankton, cadmium stress, Lake Michigan, Canadian Shield lakes

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Phosphorus Budgets and Stoichiometry during the Open-Water Season in Two Unmanipulated Lakes in the Experimental Lakes Area, Northwestern Ontario

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f94-275 ◽

1994 ◽

Vol 51 (12) ◽

pp. 2739-2755 ◽

Cited By ~ 10

Author(s):

P. Campbell

Keyword(s):

Water Column ◽

Bottom Sediments ◽

Open Water ◽

Short Term ◽

Experimental Lakes Area ◽

Northwestern Ontario ◽

Phosphorus Budgets ◽

Mass Balance Approach ◽

Primary And Secondary Producers ◽

Column Total

A comparative mass-balance approach is used to describe and quantify phosphorus (P) cycles during the open-water season in two unmanipulated Experimental Lakes Area (ELA) lakes. A bimodal cycle generally prevailed, in which water-column total phosphorus (TP = total dissolved P plus sestonic particulate P) peaked just after ice-out and again late in the summer. Changes in mass of water-column TP were often much larger than corresponding net external inputs. Shifts of P to and from either zooplankton or fish in the water column do not explain the P residuals. Rather, the bottom sediments must have been adding P to the water column. Short-term regeneration of P from the bottom sediments also probably occurs in artificially eutrophied ELA lakes. The mechanism of regeneration is probably biological. Other aspects of P cycling and P stoichiometry are discussed, particularly in relation to nutrient control of population structure and the function of primary and secondary producers.

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Introduction to the Northwest Ontario Lake Size Series (NOLSS)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f92-269 ◽

1992 ◽

Vol 49 (12) ◽

pp. 2434-2444 ◽

Cited By ~ 32

Author(s):

E. J. Fee ◽

R. E. Hecky

Keyword(s):

Turbulent Energy ◽

Morphological Similarity ◽

Experimental Lakes Area ◽

Mixing Depth ◽

Biological Communities ◽

Renewal Time ◽

Northwest Ontario ◽

Per Se ◽

Lake Size ◽

Size Series

The rationale, design, and limitations of the Northwest Ontario Lake Size Series (NOLSS) research program are described. The primary purpose of NOLSS is to discover how lake size per se influences limnological and fisheries phenomena, so that conclusions drawn from studies of particular lakes can be rigorously scaled and applied to lakes of other sizes. NOLSS consists of six lakes located in a remote wilderness region of Northwest Ontario. These lakes were chosen for their geological, hydrological, and morphological similarity (Canadian Shield geology; water renewal time> 5 yr; fully stratified in summer), but they form an exponential gradient in surface area (from 89 to 34 700 ha.) Associated with this gradient of lake size are gradients of physical properties (turbulent energy, mixing depth, thermal behaviour) to which biological communities must adapt. NOLSS fills the conspicuous gap in size that separates two well-studied groups of lakes in Northwest Ontario: the Experimental Lakes Area (ELA), where whole-lake manipulation experiments are performed, and the Laurentian Great Lakes (Nipigon, Superior), where these experiments find some of their most important applications.

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Decline of Mysis relicta During the Acidification of Lake 223

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-221 ◽

1983 ◽

Vol 40 (11) ◽

pp. 1905-1911 ◽

Cited By ~ 39

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.

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Multiple Dating of a Freeze Core from Lake 227, an Experimentally Fertilized Lake with Varved Sediments

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f94-231 ◽

1994 ◽

Vol 51 (10) ◽

pp. 2274-2285 ◽

Cited By ~ 13

Author(s):

Brent Wolfe ◽

Hedy J. Kling ◽

Gregg J. Brunskill ◽

Paul Wilkinson

Keyword(s):

Algal Blooms ◽

Seasonal Abundance ◽

Sedimentation Rates ◽

Experimental Lakes Area ◽

Varved Sediments ◽

Varve Chronology ◽

Freeze Core ◽

N Loading ◽

Planktonic Community

A freeze core taken from Experimental Lakes Area Lake 227 in 1988 contained 321 rhythmically paired, dark and light laminations in the upper 60.7 cm. Tape peels revealed cyclic, seasonal abundance peaks in organic and inorganic remains, which suggested that the couplets are varves. However, comparison between varve chronology and 22 yr of experimental changes in phosphorus (P) and nitrogen (N) loading and their influence on the planktonic community confirmed that the most recent varve-year estimates were 5 or 6 yr too old; this was caused by irregular sedimentation and multiple algal blooms resulting from experimental fertilization since 1969, and indistinct laminations that hampered precise couplet identification and separation. Dated horizons determined from biostratigraphic markers were used to generate compatible profiles between 1-cm slices of Lake 227 137Cs flux and reference fallout records. Nutrient concentration profiles were less helpful, as increases in carbon, N, and, P were gradual and no distinct horizon was identified as a clear marker of eutrophication. Long-term assessment of the varve chronology using 210Pb was hindered by experimental additions of 226Ra to the lake in 1970, although similar sedimentation rates from varve years 1860–1934 suggested that the varve and the deep part of the 210Pb chronologies were comparable.

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Factors Controlling Oxygen Depletion in Ice-Covered Lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-024 ◽

1980 ◽

Vol 37 (2) ◽

pp. 185-194 ◽

Cited By ~ 79

Author(s):

Jack A. Mathias ◽

Jan Barica

Keyword(s):

Volume Ratio ◽

Lake Management ◽

Eddy Diffusion ◽

Oxygen Depletion ◽

Eutrophic Lakes ◽

Experimental Lakes Area ◽

Lake Volume ◽

Basin Morphometry ◽

Depletion Rate ◽

Prairie Lakes

Winter oxygen depletion rates from four sets of Canadian lakes (prairie, southeastern Ontario, Arctic, and Experimental Lakes Area) differing in morphometry and trophic state, were analyzed. An inverse relationship was found between oxygen depletion rate and mean depth. The effect of lake trophic status on oxygen depletion rate was demonstrable after the influence of basin morphometry was removed by regression of oxygen depletion rate against the sediment area: lake volume ratio. The sediments of eutrophic lakes consumed oxygen about 3 times faster (0.23 g∙m−2∙d−1) than those of oligotrophic lakes (0.08 g∙m−2∙d−1), but water column respiration was about the same (0.01 g∙m−3∙d−1) for both groups of lakes. Data from prairie lakes showed that the winter oxygen consumption was limited by oxygen supply below an average whole-lake oxygen concentration of 3.8 mg∙L−1. The rate of eddy diffusion near the sediments in ice-covered prairie lakes was 3.72 ± 1.41 × 10−3 cm2∙s−1. Implications for lake management during the winter are discussed.Key words: oxygen, depletion, respiration, lakes, ice-covered, winter, sediments, model, consumption

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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

Journal of the Fisheries Research Board of Canada ◽

10.1139/f71-031 ◽

1971 ◽

Vol 28 (2) ◽

pp. 189-201 ◽

Cited By ~ 120

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.

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Population Dynamics of Lake Whitefish (Coregonus clupeaformis) During and After the Fertilization of Lake 226, the Experimental Lakes Area

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-280 ◽

1987 ◽

Vol 44 (S1) ◽

pp. s55-s63 ◽

Cited By ~ 24

Author(s):

K. H. Mills ◽

S. M. Chalanchuk

Keyword(s):

Population Dynamics ◽

The Other ◽

Coregonus Clupeaformis ◽

Lake Whitefish ◽

Experimental Lakes Area ◽

Northwestern Ontario

Responses of an unexploited population of lake whitefish (Coregonus clupeaformis) to the fertilization of Lake 226 in the Experimental Lakes Area, northwestern Ontario, are described for the fifth through eighth years of fertilization (1977–80) and for three years after fertilization was terminated (1981–83). A vinyl curtain separated Lake 226 into two basins. One basin (L226NE) received additions of phosphorus, nitrogen, and carbon; the other (L226SW) received nitrogen and carbon. Lake whitefish in L226NE were faster growing, had higher condition (k), were more numerous, had higher survival from age 0 to age 1, had greater biomass, and had greater production than L226SW whitefish from 1977 to 1980. Some of these effects continued in 1981 and 1982 after fertilization was terminated, but only biomass differences remained by 1983.

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