|Lat / Long||53.0833333, -111.6000000|
|Max depth||1.7 m|
|Mean depth||1.3 m|
|Dr. Basin Area||256 km2|
|Drainage Basin||Battle River Basin|
|TP x||13,058 µg/L|
|CHLORO x||4.0 µg/L|
|TDS x||84,314 mg/L|
Oliva Lake is an extremely saline lake located in the County of Beaver, 144 km southeast of Edmonton. It is situated 15 km east of the town of Viking, just south of Secondary Road 619 (FIGURE 1). The south side of Oliva Lake can be reached from a gravel road. The lake is surrounded by cleared land and mixed forest and there is one cottage on the south side. The water is clear and the lake is used for boating by local residents. There are no boating restrictions specific to this lake, but general federal regulations apply (Alta. For. Ld. Wild. 1988). There are no fish in Oliva Lake.
The first settlers arrived in the region surrounding the hamlet of Kinsella, to the southeast of Oliva Lake, in 1904. Grain and mixed farming and livestock rearing have since developed in this area, where a good quality native grass grows (Kinsella Hist. Book Commit. 1983).
Oliva Lake represents a distinct lake type found in eastern Alberta. It is 2 to 3 times more saline than sea water. The salinity in the lake is the result of high carbonate, sodium and sulphate content; these minerals come from saline groundwater in the region (Currie and Zacharko 1976). The lakeshore is encrusted with salt, which is replaced by gravel away from the shore. The width of the white crust increases over the summer. Saline lakes with similar ion content are common in eastern Alberta - Oliva Lake is an extreme example of what increased concentrations of certain ions do to lake functions. Characteristics such as temperature, nutrient concentrations, plants and animals differ from those in less saline lakes. The temperature of the water under ice drops below 0°C, and in summer the water is warmest at the bottom because it is saltier at the bottom than at the surface. Few species of plants and animals live in Oliva Lake. Although concentrations of phosphorus and nitrogen are the highest recorded for an Alberta lake, plant growth is very limited. However, a few inhabitants, such as the brine shrimp (Artemia salina), reach enormous densities and can turn the water a reddish colour.
Although the drainage basin of Oliva Lake is large (256 km2, FIGURE 1), most of it does not contribute water to the lake, so the contributing drainage area is small (6.3 km2, TABLE 1). The land surrounding the lake is privately owned and is used for cattle grazing. Cattle graze mostly around the northeast shore of the lake.
Although there are no saline soils in the small contributing drainage basin (Wyatt et al. 1944), there is saline groundwater in the region and a marine shale formation to the west (Currie and Zacharko 1976). Interactions between saline groundwater and Oliva Lake contribute to the lake's salinity.
Oliva Lake is small (TABLE 2); it is 1.3-km long and has a maximum width of 0.6 km. The lake basin is bowl-shaped; the deepest part (1.7 m) is towards the west end (FIGURE 2). There are no long-term records of water level fluctuations; however, relative water levels were measured from May 1983 through August 1984. During this period, the maximum fluctuation in lake level was 0.32 m; the highest water level was in July 1983 and the lowest was in August 1984 (Campbell 1986). There are no permanent inlets to, or outlets from, the lake. Oliva Lake is an evaporation basin, and this may contribute to its high level of total dissolved solids. However, groundwater is the primary variable controlling the concentration of total dissolved solids.
Oliva Lake was sampled from 1982 through 1984 and again in 1986 and 1987 by researchers with the University of Alberta (Prepas et al. n.d.; Bierhuizen and Prepas 1985; Campbell 1986; Campbell and Prepas 1986).
Most shallow freshwater lakes in Alberta are easily mixed by wind. Consequently, key variables such as total dissolved solids, temperature and dissolved oxygen are similar from the lake surface to near the bottom sediments during the ice-free season. However, when Oliva Lake was monitored in 1984, it was chemically stratified most of the time (FIGURE 3). During summer, this unusual concentration of mineral salts just over the sediments resulted in the heat from the sun being trapped in the bottom layer; bottom-water temperatures surpassed 26°C, whereas surface waters reached only 24°C (FIGURE 4). In addition, bottom-water dissolved oxygen concentrations dropped to less than 3 mg/L in contrast to those of the surface, which were between 6 and 7 mg/L (FIGURE 5).
Mineral salts in Oliva Lake precipitate and form a hard white crust over the entire lake bottom and along the entire shoreline. The dominant minerals are sulphate, sodium and carbonate (TABLE 3). The pH of the water is extremely high. Open-water pH values often exceeded 10 and rarely dropped below 9.7.
The high mineral content of Oliva Lake water reduces dissolved oxygen concentrations in summer and water temperatures under ice. During summer, dissolved oxygen concentrations at the surface were well below saturation for fresh water (FIGURE 5). In contrast, dissolved oxygen concentrations in March 1984 were fairly high for such a shallow lake. Although the cause of these relatively high winter dissolved oxygen concentrations is unknown, low summer primary productivity (TABLE 4), low under-ice temperatures (down to -1.5°C, FIGURE 4), and sediments with low bacterial activity, may be contributing factors.
In all four years studied, phosphorus and nitrogen concentrations were extremely high in the surface waters of Oliva Lake (TABLE 4). These high nutrient concentrations were accompanied by very low chlorophyll a concentrations (approximately 4 µg/L) in the surface waters in summer (TABLE 4, FIGURE 6). In contrast, a freshwater lake with similar total nitrogen and phosphorus concentrations would be very green, with chlorophyll a levels in excess of 300 µg/L (Campbell and Prepas 1986). High soluble reactive phosphorus concentrations (greater than 12,000 µg/L) and the complete lack of uptake of available phosphorus indicate that algae in this lake are limited by ions other than phosphorus or inhibited by the extreme concentrations of some ions. In contrast, algal biomass in less saline freshwater lakes in Alberta is controlled by phosphorus (Prepas 1983; Prepas and Trew 1983). The salinity of this lake is so extreme that it would be difficult to determine which ions inhibit algal growth.
The water in Oliva Lake is relatively clear; it is not uncommon to be able to see the bottom of the entire lake (FIGURE 6). Although the extremely high nutrient levels make it difficult to classify, chlorophyll a concentrations and water transparency indicate that this lake is mesotrophic.
In general, saline lakes such as Oliva have limited biological productivity; few species of plants and animals can survive and only some of those appear to do very well. Much is to be learned about factors controlling production in inland saline lakes. The plants and animals in Oliva Lake were studied in 1983 and 1984 (Campbell 1986; Campbell and Prepas 1986), and the phytoplankton was studied again from May to August 1987 (Prepas et al. n.d.).
Identification of algae is very difficult in saline lakes such as Oliva, because the samples tend to have high densities of unidentified detrital and crystalline material. Over the three years that the planktonic algae were studied, only a small number of species were found in Oliva Lake; in 1983 and 1984, these included a cryptomonad (Cryptomonas sp.) and small diatoms (Bacillariophyta) such as Fragilaria spp. and Navicula spp. From May to July 1987, no phytoplankton species could be identified amid the other small particles in the sample. The chlorophyll a concentration was low during this period (mean = 2.7 µg/L). In August 1987, the only identifiable algae were two blue-green (Cyanophyta) species, Aphanizomenon flos-aquae and Aphanothece clathrata. The total biomass of these two species was small (0.87 mg/L). The chlorophyll a concentration in August 1987 was the highest measured that summer (10.4 µg/L), and this may have made algal identification easier. The dominant plant living on the lake sediments (phytobenthos) was a filamentous green algae (Chlorophyta) that was relatively dense. Two species of macrophytes grow in the lake: widgeon grass (Ruppia occidentalis), which usually grows in saline waters, and sedge (Carex sp.). The phytobenthos biomass was greater than the macrophyte biomass.
From April to August 1984, the mean summer bacterial density in the open water of Oliva Lake was 23 x 106 cells/mL. A subsequent study indicated that this was probably an underestimate of true bacterial densities (Harvey 1987). The concentration of bacteria in Oliva Lake was 5 to 10 times higher than in freshwater lakes (Bird and Kalff 1984). Bacterial numbers in Oliva Lake are similar to those in other saline lakes. The reason for these high bacterial densities in saline lakes is unknown.
Two species of rotifer were found in Oliva Lake: Branchionus plicatilis, a member of a genus often found in hard waters, and Hexarthra sp., which is common in saline lakes (Pennak 1978). Summer visitors cannot miss the dense red clouds of brine shrimp (Artemia salina). No other zooplankton species were found there. The mean dry weight of zooplankton during the growing season (8.2 mg/L) in Oliva Lake was more than 10 times higher than that predicted from measured chlorophyll a concentrations and from data collected on freshwater lakes (Campbell and Prepas 1986). Bacteria and detritus are likely major sources of food for small invertebrates in this saline lake. Of the benthic invertebrates, shore-fly larvae (Ephydridae) were abundant during summer. These larvae are typically found in saline and alkaline waters (Pennak 1978).
There are no fish in Oliva Lake. There is little potential for fish production due to the lake's extremely high salinity and pH and the dominance of the sulphate anion, rather than chloride, as in the ocean.
There are no data on the wildlife near Oliva Lake.
Alberta Environment. n.d. Tech. Serv. Div., Hydrol. Br. Unpubl. data, Edmonton.
Alberta Forestry, Lands and Wildlife. 1988. Boating in Alberta. Fish Wild. Div., Edmonton.
Bierhuizen, J.F.H. and E.E. Prepas. 1985. Relationship between nutrients, dominant ions, and phytoplankton standing crop in prairie saline lakes. Can. J. Fish. Aquat. Sci. 42:1588-1594.
Bird, D.F. and J. Kalff. 1984. Empirical relationships between bacterial abundance and chlorophyll concentrations in fresh and marine waters. Can. J. Fish. Aquat. Sci. 41:1015-1023.
Campbell, C.E. 1986. A study of low chlorophyll levels relative to high phosphorus and nitrogen levels in prairie saline lakes. MSc thesis. Univ. Alta., Edmonton.
----- and E.E. Prepas. 1986. Evaluation of factors related to the unusually low chlorophyll levels in prairie saline lakes. Can. J. Fish. Aquat. Sci. 43:846-854.
Currie, D.V. and N. Zacharko. 1976. Hydrogeology of the Vermilion area. Alta. Res. Counc. Rep. 75-5, Edmonton.
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Kinsella History Book Committee. 1983. Hoofprints and homesteading: A history of Kinsella and area. Kinsella Hist. Book Commit., Kinsella.
Pennak, R.W. 1978. Fresh-water invertebrates of the United States. 2nd ed. John Wiley & Sons, Toronto.
Prepas, E.E. 1983. Orthophosphate turnover time in shallow productive lakes. Can. J. Fish. Aquat. Sci. 40:1412-1418.
-----, J.F.H. Bierhuizen, C.E. Campbell, J. Shamess, R.W. Howarth and R. Marino. n.d. Unpubl. data, Univ. Alta., Edmonton and Cornell Univ., Ithaca, New York.
Prepas, E.E. and D.O. Trew. 1983. Evaluation of the phosphorus-chlorophyll relationship for lakes off the Precambrian Shield in western Canada. Can. J. Fish. Aquat. Sci. 40:27-35.
Strong, W.L. and K.R. Leggat. 1981. Ecoregions of Alberta. Alta. En. Nat. Resour., Resour. Eval. Plan. Div., Edmonton.
Wyatt, F.A., J.D. Newton, W.E. Bowser and W. Odynsky. 1944. Soil Survey of Wainwrigh-Vermilion sheet. Alta. Soil Surv. Rep. No. 13, Univ. Alta. Bull. No. 42. Univ. Alta., Edmonton.