Turkey Lakes Watershed Research Articles

Ion leaching from a sugar maple forest in response to acidic deposition and nitrification

Year-to-year variation in acidic deposition within a mature sugar maple-dominated forest and in leaching of ions from the associated podzolic soil were examined at the Turkey Lakes Watershed between 1981 and 1986. Below-canopy inputs to the soil of SO42− and NO3− in throughfall averaged 640 and 295 eq. ha−1 yr−1; the corresponding ranges were 493–917 and 261–443 eq. ha−1 yr−1. The contribution of atmospheric deposition to SO42− NO3− and Ca2+ leaching decreased over the six years. During the study period, the mean annual volume-weighted NO3− concentration decreased in throughfall and forest-floor percolate and increased in the mineral-soil solution collected below the effective rooting zone. A substantial shift in the balance between SO42− and NO3−leaching from the mineral soil was observed; leaching of SO42−decreased and NO3− leaching increased with time. Leaching of Ca2+ and Mg2+ from the soil was increased as a result of excess NO3− production in the soil. The calculated output of NO3− from the soil, which averaged 1505 eq. ha−1 yr−1, considerably exceeded the atmospheric deposition of NO3−, whereas SO42− outputs were only moderately greater than inputs.

Temporal Variation in Nitrate and Nutrient Cations in Drainage Waters from a Deciduous Forest

AbstractTemporal variations in soil solution and stream chemistry were examined in 1984 in an undisturbed sugar maple‐yellow birch (Acer saccharum Marsh.‐Betula alleghaniensis Britton) forest in the Turkey Lakes Watershed, Ontario. Nitrate was the dominant anion associated with cation depletion from soil. Nitrogen in precipitation was less important than soil N in the determination of solution chemistry. Growing‐season increases in NH+4 and NO−3 in soil solution were greatest in the Oe horizon and decreased with depth. Nitrate concentrations in mineral soil solution and streamwater were highest during the dormant period and peaked at the start of spring snowmelt. Although NO−3 concentrations in streamwater were positively correlated (r = 0.7–0.9) with NO−3 and Ca2+ concentrations in mineral soil solution during the dormant period, NO−3 contributed far less to cation fluxes in streamwater than HCO−3 or SO2−4.

Sources of acidity in forest-floor percolate from a maple-birch ecosystem

Ion concentrations in water collected within a forest of sugar maple and yellow birch at the Turkey Lakes Watershed near Sault Ste. Marie, Ontario were examined from 1982 to 1984 to determine sources of acidity and the extent of cation leaching from forest floor horizons. Volume-weighted concentrations and ion fluxes in throughfall and forest-floor percolate during the growing and dormant seasons were calculated. Hydrogen ion content of the forest-floor percolate decreased in relation to that of throughfall in the dormant season and increased in the growing season. Hydrogen ion deposition in throughfall could account for 100% of the flux of H+ through the forest floor in the dormant period, and 40% of the flux during the growing season. In forest-floor percolate, Ca2+ concentrations were positively correlated with those of SO42-, NO3- and organic anions during both dormant and growing seasons. Sources of NO3- and organic anions within the ecosystem and major external inputs of NO3- and SO42- were critical factors that influenced cation mobility in the forest floor.

Physical, Chemical, and Biological Characteristics of the Turkey Lakes Watershed, Central Ontario, Canada

The Turkey Lakes Watershed (TLW) in central Ontario was selected for intensive research into the effects of the long-range transport of air pollutants (primarily acidic deposition) at a site on the Canadian Shield having both vulnerable terrain and an undisturbed Great Lakes forest type. The terrestrial and aquatic resources within the basin are representative of the surrounding region of Algoma, although for Ontario, it does have high relief (290 m) and high annual precipitation (>1200 mm). The TLW contains a chain of four lakes (five distinct lake basins) that range from 5.8 to 52.0 ha in area and 2.2 to 12.2 m in mean depth. The lakes are dimictic and, except for the deepest lake, experience dissolved oxygen depletion in undisturbed bottom waters. There is a gradient in the major ion composition of lakes within the TLW, the most dilute waters occurring at high elevations. Calcium levels increase from 55 to 138 μmol∙L−1 down the chain. Sulphate is the dominant lake water anion in the headwater lake, while alkalinity dominates in the lowest lake. Phosphorus is the limiting nutrient in these lakes; NO3-N levels are relatively high (7.9–16.4 μmol∙L−1) because the terrestrial basin exhibits low utilization of this nitrogen species. Seasonal and episodic variations in surface water composition can be large. The headwater lake contains no fish; however, fish communities in the lower three lakes (composed of 8-11 species) are typical of the Algoma region. The distribution of benthic organisms is primarily a function of lake depth and presence/absence of fish rather than variations in water chemistry. Zooplankton species composition is similar across all lakes, and cyanophytes are the dominant algae throughout. The forest is an uneven-aged, mature-to-overmature, old-growth tolerant hardwood stand. The principal tree species is sugar maple (90%) with lesser amounts of other hardwoods (9%, usually yellow birch) and various conifers (1%). Production is typical of forest at this northerly latitude (47°N). Foliar bioelement concentrations are generally similar to those observed at Hubbard Brook, New Hampshire.

Acid Deposition and Nutrient Leaching from Deciduous Vegetation and Podzolic Soils at the Turkey Lakes Watershed

Mean annual ion concentrations and ion fluxes in precipitation induced by contact with a maple–birch forest and soil were determined for 1981–85 at the Turkey Lakes Watershed (47°03′N, 84°15′W). Neutralization of atmospherically deposited H+ was effected by the canopy and mineral soil. Sulphate was an important counter-ion for K+ leached from the vegetation. Acid deposition had a minor impact on the quality of stemflow and forest floor percolate, which were enriched in K+ and Ca2+ mobilized in association with organic anions. Calcium and Mg2+ were leached from the mineral soil in association with SO42− and NO3−. Sulphate was derived largely from acid deposition, and NO3− from both precipitation and nitrification of native soil N.

Comparison of Bulk, Wet-Only, and Wet-plus-Dry Deposition Measurements at the Turkey Lakes Watershed

Four different types of atmospheric deposition measurements were made at the Turkey Lakes Watershed from 1981 to 1984. They included weekly and variable period bulk deposition measurements. The resulting annual and seasonal deposition estimates from the four methods were compared for numerical and statistical differences. Several results unexpected from the theory of the measurement methods appeared in the comparison: (1) one of the bulk deposition measurements produced lower deposition of acid-related ions than the two wet-only measurements and (2) the monthly wet-only measurements produced higher deposition of sulphate than the two bulk deposition data sets (by 6 and 19%). Several results were consistent with the theory of the measurements: (1) the daily wet-only measurements produced deposition values lower than the weekly bulk deposition measurements and (2) the wet-plus-dry deposition measurements produced higher estimates of sulphate and nitrate deposition than the two bulk data sets (15 – 35% higher). Laboratory biases appeared to be partially responsible for some of the differences found in the comparison.

Chemistry of Atmospheric Deposition, the Snowpack, and Snowmelt in the Turkey Lakes Watershed

Bulk and wet-only deposition and the snowpack were monitored at the Turkey Lakes Watershed in northern Ontario over the winter and spring of 1986. Based on a comparison with snowpack and cumulative snowmelt, the bulk sampler overcollected major ions by factors ranging from 6 to 22%. Nitrate appeared to be preferentially collected by the bulk sampler relative to SO42− during snow events. Dry deposition was estimated to be 12 and 5% of total deposition forSO42− and NO3−, respectively. Ion budgets for cumulative bulk deposition and snowmelt supported the hypothesis that ion losses from the snowpack are insignificant during a winter having no melt episodes. Snowmelt was characterized by chemical fractionation of major ions; SO42− and H+ in initial meltwaters were 10 times more concentrated than the premelt snowpack. Preferential elution of ions in the snowmelt followed the sequence: SO42− > NO3− > H+ > Cl−. Snowmelt chemistry was used to predict changes in lake chemistry: H+, NO3−, and NH4+ levels should increase in lake waters; Ca2+ decreases through dilution by snowmelt; SO42− concentrations remain fairly constant.

Acid Precipitation and Groundwater Chemistry at the Turkey Lakes Watershed

To determine correctly the response of a basin to various acid loading events, the groundwater hydrology must be considered as a function of the basin stratigraphy and mineralogy. Groundwaters in the Turkey Lakes Watershed are well buffered and in general provide a reservoir of alkalinity for surface waters in the basin. The groundwater chemistry is dominated by the weathering of carbonates present in the tills. Groundwater can follow a variety of pathways through the subsurface. These pathways can have very different flow rates and groundwater chemistry. As a result of this the influence of groundwater on surface water is highly site specific.

Ion Mass Budgets for Lakes in the Turkey Lakes Watershed, June 1981 – May 1983

Ion mass budgets were determined for two water years (June – May 1981–83) for Batchawana L. South, Wishart L., Little Turkey L., and Turkey L. Water budgets balance within measurement error except for Little Turkey L. (output surplus for both water years) and Batchawana L. South (output surplus for 1982–83). Groundwater seepage is hypothesized to explain these water budget imbalances. The chemical budgets show that H+, NH4+, and NO3− are retained by the lakes to varying degrees. The major input pathway for H+ and NH4+ is via direct atmospheric deposition, while relatively weaker terrestrial retention of NO3− causes basin runoff to be the major input pathway for this parameter. All three species are playing an acidifying role on the Turkey Lakes Watershed. Chemical budgets for Mg2+, Na+, K+, SO42−, and Cl− are generally balanced for all lakes relative to the water budgets. In contrast, Ca2+ and acid-neutralizing capacity (ANC) exhibit excess output over measured plus estimated inputs. Probable unmeasured inputs of these two parameters include groundwater seepage and Ca2+ exchange with the sediments. In-lake generation of ANC by SO42− reduction is of minor importance.

Risk to Salmonids of Water Quality in the Turkey Lakes Watershed as Determined by Bioassay

Batchawana Lake, the headwater lake in the Turkey Lakes Watershed, was devoid offish. Although a number of factors could cause this fishless state, we conducted in situ studies to partially address conditions related to lake acidification. The spring pH depression did not induce significant, consistent mortality to rainbow trout (Salmo gairdneri) or lake trout (Salvelinus namaycush) caged in situ. In 1981, however, considerable mortality occurred to fish caged in Batchawana Lake during or immediately following the maximum spring pH depression. In the remaining lakes, mortality occurred later in the exposure period. Whole-body concentrations of Na+, Ca2+, and Mg2+ in rainbow trout caged (1980) in three lakes of the watershed were similar; however, K+ appeared slightly higher (but not statistically different) in fish held in the headwater lake. Static bioassays indicated that the 96-h pH-LC50 for brook trout (Salvelinus fontinalis) was 3.80–4.09, considerably lower than the lowest pH, 4.66, observed during spring. Brook trout corralled in Batchawana Lake grew slightly faster and accumulated more Pb and Hg than fish held in a downstream lake. Although pH and trace metal levels in Batchawana Lake may at times be inhospitable to fish, other factors likely contributed to the fishless condition of this lake.

Distribution of Trace Metals within the Aboveground Phytomass of Acer saccharum Marsh, and Betula alleghaniensis Britt. at the Turkey Lakes Watershed

A study of Mn, Fe, Zn, Cu, Pb, Ni, and Cd distribution in Acer saccharum Marsh, (sugar maple) and Betula alleghaniensis Britt. (yellow birch) was carried out at the Turkey Lakes Watershed (TLW) in the District of Algoma, Ontario. Aboveground phytomass was dominated by stemwood (134 200 kg∙ha−1), stembark (19 300 kg∙ha−1), and branches > 2 cm (38 800 kg∙ha−1). Acer saccharum was the dominant species, accounting for 88% of the aboveground phytomass. The generalized phytomass trace metal concentration series for A. saccharum was Mn > Fe > Zn > Cu > Pb > Ni > Cd and for B. alleghaniensis was Mn > Zn > Fe > Cu > Pb > Ni > Cd. Concentrations of metals were highest in the foliage or stembark and lowest in stemwood but, because of its large mass, stemwood generally contained the greatest amount of metal per tree and per hectare. Components of B. alleghaniensis contained higher Zn and Cd concentrations than did those of A. saccharum by a factor of between 4 and 10, an indication that B. alleghaniensis is an accumulator of these metals. Lead levels in all components were one-third to one-half those reported elsewhere, a reflection of lower deposition at TLW. Historical data from other sites in North America gave no indication that concentrations of essential trace metals in aboveground components were higher than normal for these species.

Water and Chemical Budgets for Terrestrial Basins at the Turkey Lakes Watershed

Twenty terrestrial basins ranging in area from 2.3 to 62.7 ha were monitored in the 1050-ha Turkey Lakes Watershed (TLW) to measure discharge and ion loss from the terrestrial ecosystem and to estimate terrestrial contributions to the main aquatic system. These basins span 400 m of elevation, beginning at 60 m above Lake Superior (183 m a.s.l.). Annual streamflow represented 28–63% of precipitation; 30–60% of the total occurred during springmelt. Water, H+, and NH4+ output of the small basins increased with basin elevation; conductivity, alkalinity, Ca2+, and NO3− decreased. Losses of Mg2+, K+, Na+, SO42−, and Cl− were not related to basin elevation. Input–output values indicate a net loss of Ca2+, Mg2+, K+, and Na+; Cl− slowly accumulated, N was strongly retained, and SO42− was generally in balance. Alkalinity values indicate that HCO3− was important in balancing cation losses in low-elevation basins but that SO42− dominated in high-elevation basins. Output of H+ was substantially lower than its input through precipitation at ail elevations; however, H+ removal by the terrestrial system was greater in low-elevation than in high-elevation basins within the main watershed. Precipitation quantity and SO42− and NO3− input were measured at the Atmospheric Environment Service APN station southeast of the TLW; other chemical parameters were measured on samples collected near the main outlet on the west side of the TLW.

Fish Community Structure, Biomass, and Production in the Turkey Lakes Watershed, Ontario

The Turkey Lakes Watershed contains four lakes, and the headwater lake (Batchawana Lake) consists of two distinct basins, neither of which supports a native, reproducing fish stock. Fish biomass varied by a factor of 3.3 among the other three lakes in the watershed. Fish flesh production varied by a factor of only 1.5 in the system. Salmonid and small cyprinid contribution to biomass and production increased with progression downstream. Both fish biomass and production per unit surface area decreased with increasing lake depth. The fish biomass and production in the watershed was strongly influenced by depth, but alkalinity and phytoplankton carbon assimilation also were related to stock and production. Wishart Lake, immediately below Batchawana Lake, has a fish stock with restricted recruitment, and cyprinids make only a limited contribution to the observed production. Although both these conditions may be symptomatic of lake acidification, it is unclear whether the situation in this watershed results from lake acidification or biogeographic factors.

Effect of Acid Precipitation on Microbial Decomposition Processes in Sediment From Streams in the Turkey Lakes Watershed

The effect of simulated acid precipitation (pHs between 3.5 and 5.9) on the breakdown of organic matter in streams was examined under laboratory conditions using two different sediment types from streams. Decomposition processes were measured using 14C-labelled glucose, leaf leachate, and leached leaf material. The data indicated that penetration of acid into settled sediment is small. Therefore, little effect of pH on organic matter breakdown could be perceived. During suspended conditions, however, a marked decrease in breakdown rates was noted. It appeared that under these conditions a slight stimulation in decomposition rates caused by the sulphate and nitrate present in the acid precipitation occurred. The effect of pH on the rate of organic matter breakdown depended on the type of substrate used in the experiment. Glucose decomposition was least inhibited by pH, followed by leaf leachate, and leached leaf material breakdown was the most inhibited. Sediment with higher organic matter was more sensitive under conditions of suspension, but less sensitive than the sediment with less organic matter under settled conditions. This appeared to be a result of the lower penetration of acid in the settled organic sediment.

Modelling Stream Chemistry for the Turkey Lakes Watershed: Comparison with 1981–84 Data

Simulation results obtained from interfacing a hydrological model with a hydrogeochemical model are used to explain the increase of Ca2+ + Mg2+, alkalinity, and pH in a progressively buffered stream system in the Turkey Lakes Watershed, Ontario. Results from the model, which were calibrated with observed data for 1981, were confirmed with those from 1982, 1983, and 1984. The results further supported the hypothesis that the increases of the groundwater input of Ca into the lower streams contributed to the increase of alkalinity and pH in the downstream lakes which appeared to have caused a corresponding increase in the biological primary productivity in these lakes.

Detailed Analysis of Sulphate and Nitrate Atmospheric Deposition Estimates at the Turkey Lakes Watershed

Daily concentrations of sulphates and nitrates in air and precipitation were measured atthe Turkey Lakes Watershed from September 1980 until December 1984. The measurement data were used to estimate wet, dry, and total deposition of sulphates and nitrates to the watershed. Over the 4 yr, the annual values of total (wet plus dry) deposition ranged from 34 to 38 (± 15%) mmol∙m−2∙yr−1 for SO42− and from 38 to 47 (± 30%) mmol∙m−2∙yr−1 for NO3−. On a molar basis, the deposition of total NO3− exceeded the deposition of total SO42− by 19%. However, when converted to equivalents, total SO42− exceeded total NO3− by 68%. Dry deposition represented approximately 15 and 25% of the total deposition of SO42− and NO3−, respectively, to the watershed. Wet and dry deposition of sulphate and nitrate was found to be highly episodic, with the top 20% of daily events delivering 60–70% of the total sulphur and nitrogen deposition to the watershed. Statistically significant seasonal cycles were found in the concentration and deposition values of most of the sulphur and nitrogen species measured at the watershed.

Application of a Hydrological Model to the Acidified Turkey Lakes Watershed

A hydrological model applied to the Turkey Lakes Watershed at different locations produced results which agreed closely with observed stream flow, groundwater flow, snowpack, and snowpack chemistry. The model results are consistent with many of the episodic events that have occurred in the watershed. The snowpack sulphate concentration is simulated with a simple sulphate model linked to the hydrological model. The different calibrated hydrological coefficients were found to vary with the geology and geomorphology at several locations in he watershed. The general applicability of these coefficients was confirmed by comparing model results with a new set of data from subsequent years.

Zoobenthic Distribution and Biomass in the Turkey Lakes

The composition of the benthic fauna in the four oligotrophic lakes of the Turkey Lakes Watershed was dependent on the absence offish, depth, and hypolimnetic oxygen concentrations, rather than the chemical gradient in the watershed. Biomass in the littoral zone was greatest in the fishless upper lake of the watershed (0.35 g∙m−2), dominated by amphipods and predatory insects, which replaced fish as top predators in the lake. The shallowest lake (Wishart) had the lowest lakewide biomass (199 g∙ha−1) and estimated production of the four lakes, in spite of having the greatest algal and fish production in the watershed. The biomass present below 2 m was greater in the lower two lakes, dominated by the Chironomidae. Little Turkey Lake had the greatest area weighted lakewide biomass (843 g∙ha−1) and estimated production, as a result of a large population of Chironomus spp. in the hypolimnion. Batchawana Lake, the upper lake in the watershed, had the lowest benthic populations due to severe oxygen depletion in the hypolimnion.

Bulk Deposition of Ions in the Turkey Lakes Watershed

Abstract Bulk deposition has been collected at the Turkey Lakes Watershed (near Sault Ste. Marie, Ontario) on a weekly basis since September 1981. Average precipitation quantity was 1212 mm over four years with rain fall accounting for approximately 70% of the total. The chemistry of bulk deposition is dominated by hydrogen and sulphate ions. Seasonal variations in chemistry were observed with summer concentrations of SO4, NH4, and Ca exceeding winter values by about 40%. The hydrogen ion content of hulk deposition is lower in the summer months while the SO4:NO3 equivalent ratio is at a maximum. Sulphate, NO3, NH4 and H ion concentrations are significantly correlated (p<.001). A greater proportion of NO3, appears to be associated with HNO3, than SO4 with its strong acid counterpart, e.g. sulphate is better correlated with NH4 and Ca than H. Annual deposition to the watershed is comparable to other areas experiencing more acidic precipitation due to the relatively high precipitation rate in this location.

Influence of atmospheric deposition on lake mass balances in the Turkey Lakes Watershed, Central Ontario

Influence of atmospheric deposition on lake mass balances in the Turkey Lakes Watershed, Central Ontario