Soil geochemistry in relation to water chemistry and sensitivity to acid deposition in Finnish Lapland

Ecosystems in Finnish Lapland are threatened by heavy metal pollution and acid deposition derived from emissions of Cu-Ni smelters in Kola Peninsula and to varying extent to pollution from southern Fennoscandian and Central European sources. Extensive chemical analyses of small lake waters collected in Finnish Lapland have demonstrated that a significant number of lakes are acidified (ANC < 0μcq/l) or their buffering capacity is critical (ANC = 0–50μe/l). The relative abundance of mafic, ultramafic and carbonate rock components in the catchment were the chief factors controlling ANC and the main base cation (Ca²⁺, Mg²⁺) concentrations of lake waters. Both humic and clearwater lakes with low buffering capacity (ANC < 50μeq/l) were mainly located in the catchment areas identified as sensitive to acidification on the basis of low content of base cations (Ca²⁺ +Mg²⁺ +K⁺ < 500 meq/kg) in till. The ratio of the catchment area to the lake area was distinctly smaller for acidic lakes than for the well-buffered lakes, indicating the importance of catchment processes in determining the ANC and main base cations. The high sulphur concentrations (median 60μeq/1) of acidic lakes in northeastern Lapland, near the Finnish-Norwegian border, were strongly correlated with the highest deposition of sulphur derived from smelters of Kola Peninsula. The anomalously high concentrations of sulphur of well-buffered lakes in the western part of Lapland were due to sulphide minerals of soil and bedrock. The acidity of humic lakes in southern Lapland was in large part due to the organic acidity derived from peatlands.     

Planktonic and Littoral Microcrustaceans as Indices of Recovery in Limed Lakes in SE Norway

A two year study of planktonic and littoral microcrustaceans (Cladocera and Copepoda) from 15 lakes in the southeastern part of Norway, Østfold county, document the recovery of acidified lakes due to liming. Six lakes that where limed about 10 years ago, seven acid and two neutral reference lakes, were sampled twice a year (1998 and 1999). One acid lake was limed in autumn 1998. Qualitative nethaul samples from the deepest part of the lake and from the most frequent habitat in the littoral zone were used. The limed lakes had a species composition which indicates that these lakes are about to recover. Species associated with neutral lakes dominates while acid-tolerant species were rare. The acid-sensitive species, Daphnia longispina and D. cristata, were found in the limed lakes. This study shows the usefulness of a low-cost sampling program where microcrustaceans are used as bioindicators of recovery.     

The influence of organic acidity on the acid-base chemistry of surface waters in Maine,USA

Results from surveys of low-ANC lakes (high elevation, and seepage lakes), and of surface waters in dystrophic, acidic bogs, indicate that acidic precipitation and organic acidity are each generally necessary, but not solely sufficient, for chronically acidic status in Maine lakes. Acidic, low DOC (ANC < 0; DOC < 5 mg L^-1) lakes of all hydrologic types are acidic due largely to acidic deposition; high DOC (DOC > 30 mg L^-1) acidic seepage lakes are acidic due largely to organic acidity, and high DOC drainage lakes are acidic due to a combination of both factors. No low DOC drainage lakes are known with pH less than about 5.0, suggesting that organic acidity is necessary to depress lake pH values to below 5 in Maine at current deposition loadings,The dominant anion of low DOC, acidic waters is sulfate. Acidic waters with intermediate concentrations of DOC (5 to 30 mg L^-1), may be dominated by S04 and/or organic acidity. Seepage-input lakes were the only group to include both organically-dominated (37% of the acidic lakes) and S0₄-dominated members (63% of the acidic lakes). High DOC systems are typically low pH bogs, and are all organic acid-dominated.     

Trace element accumulation in the tissues of fish from lakes with different pH values

Two species of fish, omnivorous Catostomus commersoni (white suckers) and carnivorous Perca flavescens (yellow perch) were collected from three natural lakes with different pH ranges (circumneutral, pH 6.5 to 6.8; variable, pH 5.8 to 6.7; and acidic, pH 4.9 to 5.4). The lakes are located in the North Branch of the Big Moose River drainage system in the New York State Adirondack Park Preserve. Concentrations of potentially toxic elements (Al, Cd, Cu, Ph, and Se) were measured by electrothermal atomic absorption spectrophotometry in water, sediment and fish (bone, gill, kidney, liver and muscle) from each lake. The results showed that concentrations of Pb and Cd were significantly higher (P < 0.05) in some of the tissues of the fish collected from the acidic lake. Also, the yellow perch from the acidic take had significantly higher (P<0.05) Se concentrations in their muscle and livers than fish from the other lakes. The concentrations of Al were elevated in the gill tissues of both fish species from the acidic lake relative to fish from the other lakes. Possible mechanisms contributing to these differences in tissue concentration are discussed.     

Gradual reduction and extinction of fish populations in acid lakes

Fish communities in four lakes sampled over several years were compared against a reference data set of forty-nine lakes in south-central Ontario. Two of the temporal-comparison lakes (Crosson and Grindstone) exhibit significant changes in their fish communities relative to the reference set. This was due to the extirpation of various fish species (white sucker Catostomus commersoni, lake trout Salvelinus namaycush, and blacknose shiner Notropis heterolepis) during the intervening years. A control lake in the temporal comparison (Poorhouse) showed little change in species composition over time and no loss of species. The fourth temporal lake, Plastic Lake, also showed little change likely as a consequence of the previously documented extinctions in this lake. White suckers within Crosson Lake have demonstrated intermittent recruitment and a 89% reduction in population abundance due to acid-induced reproductive constraints in their spawning stream. Similar conditions contributed to the loss of sucker populations and additional species in Grindstone and Plastic Lakes also. Various species in many of the lakes represent metapopulations. Given the barriers imposed by outflow drainage conditions, these accelerated rates of local extinctions have not been balanced by colonizations from other lakes within the watershed. As a consequence the underlying fish communities have been changed and will remain so without active rehabilitation.     

Reappearance of Highly Acid-Sensitive Invertebrates After Liming of an Alpine Lake Ecosystem

The amphipod Gammarus lacustris was earlier a main food item of brown trout in Lake Svartavatnet at the Hardangervidda mountain plateau in South Norway. In the middle of the 1980's, G. lacustris disappeared from the trout diet due to increased acidification. In order to preserve a unique genetic variant of brown trout living in the area, a liming programme was initiated in 1994. During the first years after liming, G. lacustris was absent both in fish stomachs and in lake littoral samples. In 1999, it reappeared in brown trout stomach samples together with two other strongly sensitive species, the tadpole shrimp Lepidurus arcticus and the freshwater gastropod Lymnaea peregra. Data from monitoring indicate that the water chemical conditions of L. Svartavatnet are still close to the critical limits of these animals. They have probably survived in small refuges of acceptable water quality, either in areas of inflowing groundwater or in the littoral, below the more acidic surface layer. The fact that these sensitive animals have not yet been found in benthic samples emphasise fish diet as an important tool in early registration of the presence/absence of invertebrates with low abundance or patchy distribution.     

Trace element concentrations in fish from three Adirondack lakes with different pH values

Concentrations of 29 elements were detected in the axial muscle, and 44 elements were detected in the gut contents of white suckers (Catostomus commersoni) and yellow perch (Perca favescens) from three lakes located in the New York State Adirondack Preserve. The study lakes were acidic Darts Lake, variable pH Lake Rondaxe, and circumneutral Moss Lake. For the majority of the elements, there were no clear differences in the muscle concentrations among fish inhabiting the three types of lakes. Two notable exceptions were Hg and Pb. With some exceptions, the highest muscle tissue Pb concentrations were found in fish from the acidic lake. For both species, the Hg was higher in the muscle than in the gut regardless of lake acidity. Other elements potentially toxic to humans (As, Cd, Ga, Pb, Se, and TI) were not accumulated in the muscle relative to the gut.     

The benthic fauna of 41 acid sensitive headwater lakes in North Central Ontario

The benthic fauna of 41 nonhumic, soft water lakes situated north of lakes Superior and Huron were sampled during 1980. The pH range of the lakes sampled was 4.6 to 7.7. The benthic infauna displayed regional differences in abundance and composition, with large variation within each district. Total abundance, biomass, and number of taxa were not correlated with lake pH or alkalinity. The Chironomidae displayed a slight change in percent composition of the major species (p < 0.2) with lower pH. The Tanytarsini andChironomus salinarius group decreased, whileC. anthracinus group increased in relative abundance in those lakes with lower pH. Other factors appear to control the distribution of the various invertebrate orders, with depth and sediment nature being important variables.     

Water chemistry and phytoplankton communities in acidic clear and brown-water lakes in Eastern Finland

Water quality, phytoplankton biomass and species composition were surveyed in 9 acidic clear-water and 16 acidic humic lakes in eastern Finland. The lakes were sampled during summer stratification and autumn turnover periods. The lakes showed reasonably low variation within the two lake groups but the differences between the two groups were significant. Nutrient and base cation concentrations and color values declined with decreasing pH, but Secchi disc values increased. Phytoplankton species numbers and chlorophyll a concentrations tended to be lower at low pH, but biomass and cell numbers were more or less independent of pH. The functioning of the phytoplankton communities in both types of environment is discussed.     

Québec Lake Survey: I. Statistical assessment of surface water quality

The Québec Lake Survey (QLS) was conducted as part of the Québec Spatial Lake Acidity monitoring network (RESSALQ). A total of 1253 lakes were visited at winter-time between 1986 and 1990, to quantify and to extrapolate the water quality status of a statistically representative set of lakes to the target lake population of five subregions. Water quality is strongly influenced by terrain characteristics. The airborne anthropogenic pollution also influences greatly the water chemistry of lakes in areas receiving high SO₄ depositions. Within the QLS study area, the Côte-Nord subregion is the most sensitive and the most affected by acidity. Yet, these acidic conditions can be mostly explained by the combination of an important organic acid contribution and the extreme sensitivity of the area. The Outaouais and Abitibi areas also present great proportions of acidic lakes. The acidity of these lakes originates mostly from anthropogenic sources.     

Antioxidant Defences in Planktonic Crustaceans Exposed to Different Underwater Light Irradiances in Andean Lakes

In freshwater environments direct biological effect of ultraviolet radiation (UVR) result from absorption of specific wavelengths by macromolecules and alteration of biochemical processes. Indirect effects are related to UVR interaction with water and dissolved organic carbon to form chemically reactive species (ROS: reactive oxygen species). Zooplankton photoprotection includes mycosporine-like amino acids, pigments, production of quenching agents and antioxidant enzymes. The relative importance of each mechanism would depend on the organisms. In this study, we determined the antioxidant enzyme activities Catalase (CAT) and Glutathione-S-transferase (GST) in the copepod Boeckella gracilipes and the cladoceran Ceriodaphnia dubia in three Andean lakes of the North-Patagonia region. There were differences in antioxidant enzymes expression between copepods and cladocerans. CAT was significantly higher in C. dubia than in B. gracilipes whereas GST was similar in both species. The comparison of B. gracilipes enzyme activity in the three lakes showed also differences in GST but not in CAT. DOC decreases the exposure by absorption of UVR but simultaneously acts as photosensitizer producing ROS and their successive toxic products in the surface waters. We discuss that comparisons among lakes of different DOC should be considered carefully because lake physico-chemicals parameters, as well as food web structure, will difficult any predictions on the net effect of DOC.     

Chrysophyte scales in lake sediments provide evidence of recent acidification in two Quebec (Canada) lakes

Several lake surveys have indicated that many lakes in Quebec are sensitive to acidification, but no historical data are available to provide conclusive evidence of lake acidification. Paleolimnological studies can provide such evidence. Chrysophycean algal microfossils were analyzed from the sediments of Lake Bonneville and Lake Truite Rouge in Quebec. The chrysophyte flora in the study lakes was stable until 40 yr ago, but since then the taxa characteristic of acidic or slightly acidic waters increased in abundance. The study provides evidence of recent lake acidification in Quebec.     

Adirondack headwater lake chemistry relationships with watershed characteristics

The Adirondack Region of New York State has been identified as having surface waters sensitive to acidic deposition and as receiving large annual inputs of acidic deposition. The large amount of data available for this region makes a quantitative study of the region possible. Compiled from a variety of sources, the Adirondack Watershed Data Base (AWDB) contains information on lake chemistry; lake elevation, area, and volume; and associated watershed data, such as size, slope, aspect, elevation, vegetation and wetland types, beaver activity, fire and logging history, and soils data. Bivariate and multivariate procedures were used to examine relationships between watershed attributes and lake chemistry. Because the variables in the data base are being refined and modified, the current relationships should be considered preliminary. Preliminary results indicate that wet deposition, lake elevation, and forest cover are the principal variables that are associated with variance in the data for lake pH and acid neutralizing capacity (ANC) in the Adirondacks. For headwater lakes in the Adirondacks, we estimate approximately 50% have a total ANC ≤ 40 μeq L^?1 and 40% have a pH ≤ 5.5.     

Natural acidification of lakes and rivers in Japan: The ecosystem of Lake Usoriko (ph 3.4–3.8)

Most of the acid lakes and rivers in Japan have been influenced by acid waters of volcanic origin. Acidophilic and acidotolerant organisms are observed in these natural acid lakes and rivers, each of which has its own ecosystem and history. Lake Usoriko (pH 3.4–3.8) is a lake which.has been acidified by strongly acid water containing sulfuric acid and hydrochloric acid. The ecosystem of Lake Usoriko consists of aquatic vascular plants, aquatic bryophytes (Drepanocladus fluitans, etc.), algae, fish (Tribolodon hakonensis), insects, Zooplankton, fungi and bacteria. The paleosediment distributed along Lake Usoriko's northern shore is partly silicified and it contains fossils of a moss (Drepanocladus fluitans) and diatoms such as Pinnularia braunii var. amphicephala which are also distributed in the present lake. ¹⁴C dating of the specimens in the paleosediment, shoots of D. fluitans and the wood and cones of Picea glehnii gave values in the range 11500–34000y B.P. This record shows how long Lake Usoriko has been an acid lake.     

Base neutralizing capacity of sediments from an acidic lake

The base neutralizing capacity (BNC), or alkalinity consumption, of acidic lake sediments may influence the amount of neutralizing agent required to neutralize a lake if the sediment BNC is large relative to the BNC of overlying waters. The extent ofin situ sediment BNC in acidic Bowland Lake (pH 5.0) was inferred by (1) measuring the loss of Ca-45 to acidic sediments from labeled lake water neutralized with CaCO₃, and (2) measuring exchangeable Ca in sediments collected prior to and following neutralization of Bowland Lake with calcite (CaCO₃). The sediment BNC derived from the Ca-45 radiolabeling experiment was 0.01 mg CaCO₃ g^?1 w wt. The mean losses of Ca-45 from the aqueous phase of neutralized and untreated sediment/water mixtures were not significantly different. The mean pH of both neutralized and untreated mixtures decreased to 4.0 during the incubation, possibly because of oxidation of reduced sediments. Sediment BNC estimates derived from literature data for several lakes may be overestimated because of the inclusion of anoxic sediments containing significant amounts of reduced Fe. There was no significant difference in exchangeable Ca between sediments from untreated Bowland Lake and sediments collected 10 m after whole-lake neutralization indicating that little of the supplied alkalinity had been lost to the sediments. Hence,in situ sediment BNC was probably small in Bowland Lake.     

Low Success Rate in Re-Establishing European Perch in Some Highly Acidified Lakes in Southernmost Norway

In order to test whether major reductions in acid inputs had improved water quality sufficiently for fish populations to recover, we stocked wild European perch (Perca fluviatilis) in three highly acidified lakes that had previously supported this species, and in one limed lake. The fish, which were introduced from a local lake (donor lake), generally ranged from 12 to 16 cm in total length, and were stocked at densities of 117–177 fish ha^?1. The untreated lakes were highly acid, with minimum pH values and maximum inorganic aluminium concentrations (Al_i) during the spring of 4.6–4.7 and 118–151 µg L^?1 respectively. In the limed lake, the corresponding values for pH and Al_i ranged between 5.8 and 6.6 and 5 and 19 µg L^?1 respectively. Gill-netting in two subsequent years after the introduction yielded only a few recruits (0+) and one adult in one of the three acidified lakes in one year only. However, stocked perch reproduced successfully in both years in the limed lake. There was a significant linear relationship between the catches (CPUE) of juvenile perch (age 0+) in the different lakes in the autumn and the water quality in May (time of hatching), both in terms of Al_i (r ²=0.934, P<0.05) and pH (r ²=0.939, P<0.05). Our data suggest unsuccessful recruitment in waters of pH <5.1 and Al_i>60 µg L^?1.     

Recovery of previously acidified lakes near Coniston,Canada following reductions in atmospheric sulphur and metal emissions

The purpose of the present study was to assess the rate of recovery of acidified lakes located near the town of Coniston following an abrupt reduction in atmospheric SO₂ and metal emissions at the Coniston smelter which closed in 1972. The water chemistry of several lakes was studied over a period of 16 yr (1968–1984). In one extremely acidic lake close to the smelter, the pH increased from 4.05 in 1972 to 5.8 in 1984. Conductivity, as well as concentrations of SO₄, Cu, Ni, Co, Mn, and Zn decreased by 60% to 90% in the lake water during the same period. In another initially less acidic lake nearby, the increase in pH was less dramatic, while the decrease in conductivity, SO₄, and some metals was similar to that of the more acidic lake. Local SO₄ deposition decreased approximately 75 % while Cu and Ni deposition decreased by 90% following closure of the Coniston smelter. These results indicate that even severely acidified lakes can improve within a few years following a substantial reduction in atmospheric S emissions; and that in some regions recovery can occur due to reductions in SO₂ emissions even in the absence of concurrent NO_x control.     

Mercury concentrations in northern pike,Esox lucius L., in small lakes of Evo area,southern Finland

We measured Hg concentrations in northern pike (Esox lucius) from 17 small lakes in Evo forest area, Lammi, southern Finland. The mean Hg concentration in muscle tissue of a 1 kg pike ranged from 0.15 to 1.36 μg g⁻¹ (ww) in the lakes. There was a trend towards higher concentrations in acidic and humic lakes than in circumneutral and clear-water lakes. The Hg content of pike from successive lakes of a lake chain was similar, whereas there were clear differences in the Hg concentrations among seepage lakes and the uppermost lakes of other lake chains. The latter was probably due to special characteristics of the lakes: in one lake pike was the only fish species, two of the lakes were regulated by beaver, and one lake was a groundwater or spring lake. Our observations indicate that Hg concentrations in pike can vary considerably from lake to lake in a small geographical area and that the variation among lakes in the accumulation of Hg in fish largely depends on lake characteristics and on the diet of pike.     

Effects of Acidification Due to Emissions from the Kola Peninsula on Fish Populations in Lakes Near the Russian Border in Northern Norway

In this paper we document the effects of acidification on fish populations in lakes in Sør-Varanger near the Russian border in northern Norway. We used questionnaires in order to assess the current status and distribution of different fish species, and conducted test-fishing to determine relative abundance (CPUE-T) and age structure. Acidification of surface waters in this area is due to emissions of SO₂ from smelters on the Kola Peninsula in Russia (Nikel and Zapoljarnij) between 10 and 30 km from the Norwegian border. Sulphur deposition in Sør-Varanger ranges from 0.6 to 2.0 g S m-² yr-¹, which is similar to levels in the most acidified areas in southern Norway. However, a dominant fraction of the acidic deposition reaches the ground in particulate form during summer and autumn. Coastal areas in Sør-Varanger receive small amounts of precipitation; the annual mean is 580 mm. We obtained fish status from 401 lakes, about 40% of all lakes larger than 3 ha, which were inhabited by 236 and 293 populations of Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta), respectively. The extent of fish damage was small as only three populations of Arctic charr were lost, while three populations of Arctic charr and eight populations of brown trout were at various stages of reduction. Damaged and lost fish populations were identified in smaller lakes at relatively high elevations (172–349 m) in six areas in the Jarfjord Mountains, covering a land area of 30.0 km². Most of the damage probably occurred during the 1970s and 1980s. In lakes that supported or had supported Arctic charr and brown trout, we found a significant relationship between CPUE-T, and acid neutralizing capacity (ANC) and pH, and also between alkalinity and the concentration of inorganic Al for brown trout. In both species, the catch of fish in age groups 1+ and 2+ (CPUE-R) increased significantly with CPUE-T. Affected populations typically exhibited irregular age composition, and age-classes were missing, indicating that reductions in fish populations were due to recruitment failure. The limited fish damage is related to relatively good catchment resistance to acidic inputs, small amounts of wet deposition as well as precipitation. These conditions result in low accumulation of acidic compounds, producing less acidic run-off waters and few episodes of unfavourable water quality.     

Plankton associations and related factors in a hypereutrophic lake

Cluster analysis was used to group samples collected from ten stations in Moses Lake, Washington, according to the similarity of their contained algal species. During the period 1968 to 1970, nine recurring distinct sample groups, or algal populations, were identified. Of the nine, three were most distinct; they consistently recurred at the same stations, and were dominated by diatom, green, and blue-green algae, respectively. Of the six species of blue-greens that characterized that population, the recreationally nuisance forms,Aphanizomenon flos-aquae andMicrocystis aeruginosa, were dominant. The blue-green population was the most widespread in the lake and occurred in waters that were warmest and contained the lowest concentrations of inorganic nutrients: N, P, and C. Green algae dominated in waters that received treated sewage effluent and contained relatively high concentrations of nutrients. As the nutrient content declined when proceeding away from that area, blue-green algae became dominant. Temporal variation in biomass (chlorophyll content) of the blue-green population was inversely related to phosphate content, but not to the other nutrients. These results support the hypothesis that nuisance blue-green algae dominate in shallow eutrophic lakes during warm summer months when ambient nutrient content is low because, under these conditions, they apparently out-compete other forms for nutrients. In shallow unstable eutrophic lakes like Moses Lake, the nutrient supply rate from sediments may be considered great although ambient concentrations are low which allow the dominating blue-green population to reach a large biomass, e. g., maximums as high as 300 µg l^?1 chlorophyll were observed. Because correlation analysis andin situ bioassays showed that biomass of blue-green algae was most closely related to inorganic phosphate even at times when nitrate was very low and invariable, we suggest that phosphorus availability is most critical to biomass formation. Control of ambient phosphorus content, therefore, would be most apt to result in a reduction in maximum biomass of the blue-greens. Phosphorus control would be unlikely to alter algal dominance in this shallow lake, however, since blue-greens seem to be generally favored over other populations by reduction in nutrient concentration during warm weather.