Lake Water pH Research Articles

Interrelationships between mercury levels in yearling yellow perch, fish condition and water quality

Yearling yellow perch were collected from sixteen Muskoka-Haliburton lakes to determine interrelationships between water quality, Hg residues in fish and fish condition. The lakes studied were Precambrian shield lakes with a pH range of 5.6 to 7.3 and total inflection point alkalinities of 0.4 to 16.0 mg L−1. Mercury residues in yellow perch ranged from 31 to 233 ng g−1 and were inversely correlated (p < 0.001; r = 0.84) with lakewater pH. Stepwise linear regression analyses selected lakewater pH as the only significant parameter associated with Hg accumulations. Alkalinities, sulphate, Ca and dissolved organic carbon (DOC) were not selected as significant. Likewise, lakewater pH and Hg residues in yellow perch were inversely (p < 0.001) correlated with fish condition. Lakewater pH, accounted for 74% and Hg in fish a further 11% of the variability in fish condition. Terrestrial drainage size/lake volume ratios were also correlated (p < 0.05; r = 0.78) with Hg accumulations in perch from a subset of nine headwater lakes. No temporal trends in Hg residues were evident in yellow perch over a 9 yr interval (1978–1987).

Phosphatase activity in relation to phytoplankton composition and pH in Swedish lakes

SUMMARY. 1. Potential phosphatase activity and phytoplankton from several lakes of different character were compared in order to evaluate the importance of lake water pH and phytoplankton composition for the activity and pH optimum of lake water phosphatases.2. In oligotrophic lakes, in which phytoplankton biomass was most often dominated by Ochromonadaceae spp., optimum phosphate activity was found at pH values &lt;6. In eutrophic lakes, where species of Cyanophyceae and Bacillariophyceae dominated the phytoplankton biomass, optimum phosphatase activity was found at pH 7.5 or 8.5.3. The pH optimum of phosphatase activity often differed from the corresponding lake water pH.4. Experimental variation in phosphorus availability resulted in predictable changes in phosphatase activity. However, specific phosphatase activity, calculated per biomass of phytoplankton, was dependent on plankton species composition.

Effects of acidic deposition on North American lakes: palaeolimnological evidence from diatoms and chrysophytes

Analysis of sediment diatom and chrysophyte assemblages is the best technique currently available for inferring past lake water pH trends. Use of this approach for assessing the ecological effects of acidic deposition is increasing rapidly. As of August 1989, sediment core inferred pH data existed for at least 150 lakes in North America and cores from about 100 more lakes are being analysed. Equations for inferring past pH are based on at least 15-20 calibration data-sets involving about 700 lakes. Palaeolimnological studies indicate that recent acidification has been caused by acidic deposition in the Adirondack Mountains (New York), northern New England, Ontario, Quebec and the Canadian Atlantic provinces. Inferred pH decreases are commonly as much as 0.5-1.0 pH units. With the exception of one lake, no acidification trends were observed in regions currently receiving low deposition of strong acids (e.g. Rocky Mountains and Sierra Nevada in the western United States). Slight or no trends towards decreasing pH were observed in study lakes receiving moderately acidic deposition (upper Mid-west and northern Florida). The amount of inferred acidification (increase in H+concentration) correlates with the amount of S and N loading and the ability of watersheds and lakes to neutralize acid inputs, and is generally consistent with current lake-acidification theory. In most cases, the primary cause of recent acidification (post-1850) is acidic deposition, as opposed to land-use changes or natural processes, though these may be contributing factors. Acid loading has decreased in some regions since 1970 (e.g., northeastern United States). Some lakes have become less acidic in response, but others continue to lose acid neutralizing capacity. Many currently acidic lakes were naturally acidic (pH &lt; 5.5) before the onset of anthropogenic acidification. These lakes are typically small (less than 10 ha) are located at moderately high elevations, have thin or peaty soils, or are located in outwash deposits. Many of these have acidified further recently.

Diatoms and pH reconstruction

Palaeolimnological diatom data comprise counts of many species expressed as percentages for each sample. Reconstruction of past lake-water pH from such data involves two steps; (i) regression, where responses of modern diatom abundances to pH are modelled and (ii) calibration where the modelled responses are used to infer pH from diatom assemblages preserved in lake sediments. In view of the highly multivariate nature of diatom data, the strongly nonlinear response of diatoms to pH, and the abundance of zero values in the data, a compromise between ecological realism and computational feasability is essential. The two numerical approaches used are (i) the computationally demanding but formal statistical approach of maximum likelihood (m l) Gaussian logit regression and calibration and (ii) the computationally straightforward but heuristic approach of weighted averaging (w a ) regression and calibration. When the Surface Water Acidification Project (SWAP) modern training set of 178 lakes is reduced by data-screening to 167 lakes, w a gives superior results in terms of lowest root mean squared errors of prediction in cross-validation. Bootstrapping is also used to derive prediction errors, not only for the training set as a whole but also for individual pH reconstructions by WA for stratigraphic samples from Round Loch of Glenhead, southwest Scotland covering the last 10000 years. These reconstructions are evaluated in terms of lack-of-fit to pH and analogue measures and are interpreted in terms of rate of change by using bootstrapping of the reconstructed pH time-series.

Mercury in fish in Swedish lakes ? Linkages to domestic and European sources of emission

The work deals primarily with data from 894 Swedish lakes. The following parameters are discussed: Hg- and Se-concentrations and Hg-quantity in the mor layer reflecting the atmospheric deposition of Hg and Se-, Hg- and S-emissions deposition from Swedish and continental sources, precipitation, Hg in pike, lake area, lake mean depth, pH, color, alkalinity, hardness, S and chloride in lake water. The results are focused on geographical variations and statistical correlations for the Hg-content in 1-kg pike (=FHg), and on computer simulations to get insights and data on the linkages between various historical Hg-emissions and FHg. Selected results: Increased FHg-values may be attributed to atmospheric emissions of Hg and to acid rain. Southern Sweden is significantly influenced by continental Hg-emissions. East Germany, Great Britain, West Germany and Poland seem to have contributed with the largest foreign Hg-amounts in the Swedish mor layer and, at the end, to increased Hg-concentrations in Swedish fish. We have calculated that there are about 10 300 Swedish lakes with FHg > 1 mg Hg kg−1 (= the Swedish blacklisting limit). What would happen with FHg if atmospheric depositions of Hg and S were significantly reduced? Reductions of S would be beneficial primarily for lakes in S. Sweden. About 50% of the elevated levels of Hg in Swedish pike in the 1980s may be linked to Swedish Hg-emissions during the last 100 yr, about 10 to 15% could be attributed to foreign Hg-emissions and 35 to 40% to acid rain. There is a long lag phase between emission reduction and reduction of FHg. The known, major Swedish emissions of Hg have already been significantly reduced, but new point sources of Hg have appeared. There has been a significant change in the character of the Hg-emissions during the last decades. High FHg-values in fish in Swedish lakes will be a major environmental problem for decades to come.

Pore water dynamics in the sediment of a shallow and hypertrophic lake

Seasonal variations in pore water with main stress on pH and phosphate were investigated in the sediment of the shallow and hypertrophic Lake Sobygaard, Denmark. The purpose was to evaluate factors affecting the internal phosphorus loading. Pore water was obtained by in situ incubation of ceramic cups, sampled anaerobicaly from a fixed position in the sediment. The method is evaluated. During summer, pH and phosphate concentrations increased in the upper 8–10 cm of the sediment. Increased pH was most pronounced in the upper 5 cm, where pH increased to between 9 and 10. This is believed to be caused by the photosynthetically elevated pH in the above lake water. Phosphate concentrations increased with depth, from 0–2 mg P 1−1 in the upper 5 cm to 3–6 mg P 1−1 in 6–10 cm depth. Average phosphate gradient in the upper 6–8 cm was 1.0 mg P 1−1 cm −1 in the summer decreasing to 0.2 mg P 1−1 cm t‐1 in the autumn/winter. In spite of low redox potential, Fe(II) was not present in the upper 20 cm. The seasonal variation in pore water phosphate is believed mainly to be due to the variations in pore water pH inducing a substitution of phosphate ions with hydroxyl ions on ironhydroxides during summer. A considerable sedimentation of organic bound phosphorus and decomposition in the sediment is also considered important. Phosphorus release from the sediment is facilitated by bio- and gas turbation and by the frequent occurrence of resuspension caused by windaction. Net release rate is highly variable during the season. The summer average is 40 mg P m−2 d−1.

Maximum likelihood prediction of lake acidity based on sedimented diatoms

Abstract. As an example of ecological gradient analysis, Gaussian response functions, with Poisson or quasi‐Poisson error distribution, were fitted for diatom taxa on a pH gradient. It is possible to predict or infer the pH of lake water from the fitted curves using the method of maximum likelihood, which is easily implemented in standard non‐linear regressionprograms. Due to overdis‐persion with respect to the Poisson distribution, moment estimates forthe negative binomial distribution were also applied, both in estimating the species response curves and in prediction. Simulations indicated that the theoretical maximum precision (measuredby standard deviation of prediction errors) in our data set was 0.17 pH units. The observed errors were much greater (SD 0.35 to 0.43). It seems that roughly equal proportions of the excess error were caused (1) by systematic differences between the training (estimation) data and the validation (prediction) data, and (2) from a misspecified model. It is suggested that the error due to model misspecification consists of inadequacy of the presumed error distribution and of inadequacy of the simple Gaussian response function.

Utility of scaled chrysophytes for inferring lakewater pH in northern New England lakes

Scaled chrysophytes in the surface sediments of 58 soft-water northern New England lakes were analyzed to assess their usefulness for inferring pH. The distributions of many taxa are correlated with lakewater pH and associated variables. Canonical correspondence analysis (CCA) and clustering grouped chrysophyte taxa according to their distributions along the pH gradient. For example, Chrysodidymus synuroideus, Mallomonas hindonii, and M. hamata commonly occur in acidic waters (pH<5.5), whereas M. caudata and M. pseudocoronata are common in circumneutral to alkaline waters. Of the five predictive models developed to infer pH, CCA based calibration had the lowest standard error (0.35 pH units). A CCA based predictive model was also developed to infer total alkalinity. The study provides strong evidence that, in the absence of past measured pH data, stratigraphic studies of sedimentary chrysophyte scales will provide accurate reconstructions of pH in northern New England lakes.

Relationship between Chrysophyte Assemblages and Environmental Variables in Seventy-Two Sudbury Lakes as Examined by Canonical Correspondence Analysis (CCA)

Relationship between surface sediment chrysophyte scales and limnological variables in 72 Sudbury lakes was examined using canonical correspondence analysis (CCA). CCA is a recently developed multivariate direct gradient analysis that has many advantages over indirect gradient analyses. Lakewater pH was identified as the most important variable influencing the distribution of scaled chrysophytes in Sudbury lakes. Almost all common chrysophyte taxa can be assigned a pH indicator value. In addition to pH, many chrysophyte taxa are sensitive to metal concentrations. A calibration model was developed to predict chrysophyte inferred pH using CCA. The model proved to be far superior to traditionally used models derived from multiple regression of pH indicator chyrsophyte assemblages. Applicability of the predictive pH equation was examined by reconstructing the recent pH history of Lohi Lake. The study provides compelling evidence that canonical correspondence analysis offers great promise in surface sediment calibration and pH reconstruction studies.

Lake Acidification Recovery can be Monitored using Chrysophycean Microfossils

Chrysophyte scales in a sediment core from Swan Lake, Sudbury, Ontario were studied to examine their sensitivity for inference of recent lakewater pH change. The study indicates that, corresponding to an increase in metal mining and smelting activity in the Sudbury basin, lake acidification commenced in 1940. However, as a result of reductions in SO2 emissions in the early 1970's, the lake's pH has recovered from its chronic low pH of 4.0 in 1977 to its high of 5.6 in 1987. The chrysophyte-inferred pH recovery mirrors the increase in measured lakewater pH. The study identifies the potential of chrysophytes to document recent pH recovery in soft-water lakes containing undisturbed sediments. The approach offers promise for understanding the response in lakes of poorly buffered regions to decreased atmospheric loadings of SO2 and in establishing and implementing SO2 mitigation standards.

Surface-sediment chrysophytes from 35 Quebec lakes and their usefulness in reconstructing lake-water pH

Chrysophyte scales from surface sediment samples of 35 Quebec lakes were analyzed to examine their relationship with lake-water pH. The percent composition of common chrysophyte taxa were plotted against the measured lake-water pH. The distribution of many taxa was found to be closely associated with pH. The pH indicator status and abundance-weighted mean pH values of the majority of taxa of the studied region agreed with the published work. Chrysophyte counts were quantified to establish a predictive pH model using multiple regressions of pH indicator chrysophyte assemblages with lake-water pH. A strong relationship (r2 = 0.72) was observed between measured and inferred pH values. The pH predictive ability of chrysophytes was further corroborated by reconstructing the recent pH history of Lake Bonneville. Over the last 30 years, the inferred pH of this lake has declined ≈ 1 pH unit. The present study accentuates that stratigraphic analysis of chrysophytes will provide useful measurements of the extent of lake-water acidity in Quebec.

Bone Characteristics and Metal Concentrations in White Suckers (Catostomus commersoni) from One Neutral and Three Acidified Lakes in Maine

The bone characteristics of white suckers, Catostomus commersoni, from four lakes in Maine were studied in relation to lake water quality and metal concentrations in fish. Green Lake had a neutral pH, high buffering capacity, and low aluminum concentrations, whereas the other three lakes had low pH, low buffering capacity, and elevated aluminum concentrations. The concentrations of aluminum in white suckers did not differ among the four lakes, but concentrations of cadmium, lead, and mercury were greater in fish from the three low-pH lakes. The vertebrae were weaker and more flexible in fish from the low-pH lakes than in those from neutral-pH Green Lake. The inferior mechanical properties of bone in fish from the low-pH lakes were probably a result of the significantly lower proline concentrations in collagen. Low pH of lake water or elevated whole-body concentrations of cadmium, lead, and mercury, either individually or combined, could have caused the inferior mechanical properties of bone of white suckers from the low-pH lakes.

Paleolimnological evidence for the recent acidification of Llyn Hir, Dyfed, Wales

A variety of paleolimnological techniques, coupled with historical data on land-use and fisheries, are used to evaluate the magnitude, timing, and causes of acidification of Llyn Hir, a moorland lake in central Wales. pH reconstruction based on diatom analysis suggests a gradual decline in lakewater pH beginning ca. 1870 and intensifying in the mid-1930's, with a total decline of 1.1 pH units between 1870 and 1984. This pH decline correlates with increased sedimentary concentrations of carbonaceous particles, trace metals, and magnetic minerals, which indicate the local deposition of atmospherically transported products of fossil-fuel combustion. Pollen data and the historical record show no significant alterations in land-use or catchment vegetation, indicating that acidification of Llyn Hir is a result of the increased deposition of atmospheric pollutants, not of land-use and vegetation change.

Sediment pH in Profundal Core Samples from the Turkey Lakes (Algoma, Ontario)

Vertical pH profiles were recorded in sediment cores from four of the Turkey Lakes in the Algoma region of northern Ontario. In the three upper lakes of the chain, median down-core pH, which should be correlated with historic lake water pH, was below the median down-core pH for other lakes in northeastern Ontario. The Turkey lakes had probably been relatively acidic, therefore, since pre-industrial times. Down-core pH tended to be lower in upstream lakes. While a pH minimum was typically observed at the sediment–water interface, the surficial sediments were not acidified relative to down-core sediments.

New methods for using diatoms and chrysophytes to infer past pH of low‐alkalinity lakes

Distributions of both diatoms and chrysophytes (Mallomonadaceae) are clearly correlated with pH in low‐alkalinity lakes. Their siliceous remains are well preserved in lake sediments and have been used to infer long‐ and short‐term acidification trends. Until now, however, only diatoms have been used quantitatively.We describe new methods for inferring past pH in lake water using diatoms alone, chrysophytes alone, and the two together. We developed the equations with multiple regression analysis of diatom and chrysophyte assemblage data and pH measurements for 47 Adirondack lakes (pH range, 4.7–7.8). Correlations of measured vs. calculated values of pH yield r2 values of 0.70–0.94 and standard errors of 0.13–0.35 pH unit. The best predictive equations, especially for acidic lakes (pH &lt; 5.5) incorporate both diatoms and chrysophytes. Major advantages of using chrysophytes in addition to diatoms in paleoecological studies are that chrysophytes are more sensitive at lower pH values (&lt;5.0) than diatoms, are nearly all planktonic, represent a different phycological group, can be counted on the same slides as diatoms, and can be counted faster because there are fewer taxa. Stratigraphic diatom and chrysophyte data for two lake sediment cores are used to evaluate the equations. These methods are widely applicable in studies of cultural and natural acidification of low‐alkalinity lakes in many regions of the world.

Sedimentary diatom assemblages and their utility in computing diatom-inferred pH in Sudbury Ontario lakes

Surface sediment diatoms from 30 Sudbury lakes were analyzed to establish a relationship between diatoms and limnological characteristics of these lakes. Factor analysis of various chemical and physical variables suggested that most of the variance was associated with the pH, pH-metal, and conductivity factors. Factor analysis of common diatom taxa indicated that the distribution of most of these diatoms is closely related to lake water pH and/or pH related factors. Regression analysis of various pH indicator assemblages with measured lake water pH also demonstrated significant relationships. Among the transfer functions employed to compute diatom-inferred pH, multiple regressions using pH indicator assemblages proved to be the best. Using this method an accuracy of about 0.3 pH unit can be achieved, even for lakes which have received large trace metal inputs concurrent with increase in acidity. The presence of planktonic diatoms in acidic lakes suggests that the widely accepted hypothesis that planktonic diatoms are greatly reduced in waters at pH below 5.6 is not always true.

Scaled Chrysophytes (Chrysophyceae) as Indicators of pH in Sudbury, Ontario, Lakes

Surface sediment chrysophytes (Chrysophyceae) of 30 Sudbury, Ontario, lakes were analyzed to investigate the relationship of these algal microfossils with the limnological characteristics of the study lakes. The distribution of the majority of common chrysophyte taxa is correlated closely with lake water pH, pH-related factors, or both. Chrysodidymus synuroideus, Synura echinulata, Mallomonas hamata, M. acaroides var. muskokana, and Chrysosphaerella longispina appear to be indicators of strongly to moderately acidic waters whereas M. pseudocoronata and M. caudata are indicators of circumneutral to alkaline waters. Using multiple regression of pH indicator chrysophyte assemblages against the measured lake pH, a calibration equation was developed to compute chrysophyte-inferred pH. Chrysophyte-inferred pH values were closely related with measured lake water pH (r2 = 0.74). The study indicates that in the absence of historical pH data, stratigraphic analysis of scaled chrysophytes would provide useful information about the history of lake acidification in the Sudbury area. There is some indication that high metal concentrations, in addition to pH, may influence chrysophycean species distribution in acidic lakes.

Attempts to reconstruct lake water pH and colour from sedimentary diatoms and Cladocera

(1988). Attempts to reconstruct lake water pH and colour from sedimentary diatoms and Cladocera. SIL Proceedings, 1922-2010: Vol. 23, No. 2, pp. 870-873.

The relationship between sedimentary diatom assemblages and lakewater pH in 35 Quebec lakes, Canada

Surface sediment diatoms from 35 soft-water lakes in southern Quebec were studied to examine the relationship with lakewater pH. The lakes ranged in pH from 5.25 to 7.66. The species composition and the relative abundance of diatoms in the study lakes was found to be closely related to pH and/or factors closely associated with pH. Predictive models were developed to infer lakewater pH using simple linear regression equations of index alpha, index B, and multiple regressions using pH preference categories. Among the predictive models examined here, the multiple regression technique provided the highest correlation coefficient (r2=0.88) and the lowest standard error (±0.26 of a pH unit) in computing diatom-inferred pH. This model appears to be the most appropriate to reconstruct lake pH histories in Quebec region.

Low chemical concentration and pH as factors limiting the success of inoculation to enhance biodegradation

AbstractA strain of Pseudomonas that mineralized 1 microgram of p‐nitrophenol (PNP) per milliliter in culture failed to mineralize the compound in nonsterile or sterile lake water. The bacterium did not act on PNP at the pH of the lake water (pH 8.0) or in culture medium at the same pH, although it did mineralize PNP when added to sterile lake water samples adjusted to pH 7.0. A second strain of Pseudomonas that grew and mineralized 1 μg PNP/ml in culture at pH 8.0 and in sterile lake water at pH 7.0 neither mineralized nor grew on PNP in sterile lake water at pH 8.0. A third strain of Pseudomonas grew on and mineralized 1 μg PNP/ml in sterile lake water at pH 8.0 but failed to enhance mineralization when added to nonsterile lake water at that pH. Corynebacterium sp. grew on and mineralized 1 μg PNP/ml in culture medium and in sterile lake water, and its inoculation into nonsterile lake water greatly reduced the time for the mineralization of 1.0 and 0.1 μg PNP/ml. The inoculation of nonsterile lake water with Corynebacterium sp., which mineralized 26 and 17 ng PNP/ml in culture, resulted in a biphasic transformation of 26 and 16 ng PNP/ml. Only the initial phase was more rapid than in uninoculated lake water. Inoculation of Corynebacterium sp. into sewage markedly shortened the time for extensive mineralization of 100 ng but not of 26 and 16 ng PNP/ml. We suggest that microorganisms that are able to degrade chemicals in culture may not do so when introduced into natural environments because of unfavorable pH or the organisms' inability to readily use compounds that are present at low concentrations.