A study of aquatic vegetation of 31 small, dilute, and unproductive lakes in the Adirondack Mount... more A study of aquatic vegetation of 31 small, dilute, and unproductive lakes in the Adirondack Mountains of New York shows that macrophyte species composition is primarily related to variation in pH and associated factors. Among the lakes, surface water pH ranged from 4.5 to 7.8; conductivity ranged from 11.9 to 58.7 μS/cm. Relationships between aquatic vegetation and environmental factors were studied using detrended correspondence analysis (DCA). Submersed and floating-leaved taxa were analyzed separately from emergent taxa. Correlations between DCA axis 1 and pH-related factors (pH, alkalinity, Ca, Mg, Na, Al, conductivity, elevation) were strong for both submersed plus floating-leaved and emergent taxa. No significant correlations were found with water color, transparency, or trophic status indicators (total P and chlorophyll a). Between-lake variation in composition of aquatic vegetation in Adirondack lakes follows a pH "complex-gradient." Influences of elevation, morphometry, and substrate are secondary. Our results indicate that acidification of softwater lakes could be accompanied by significant changes in aquatic macrophyte assemblages.
Nutrient enrichment is one of the most important causes of ecological impairment in surface water... more Nutrient enrichment is one of the most important causes of ecological impairment in surface waters. More effective management of this problem is constrained by a lack of nutrient criteria that link phosphorus and nitrogen concentrations to levels of biological impairment as defined in management agency regulations. We used a new approach for identifying potential nutrient criteria using diatom assemblages and the Biological Condition Gradient (BCG). We first used diatom count data to assign study sites to BCG impairment categories (levels), then determined P and N concentrations corresponding with the boundaries between those levels. We studied diatom counts and environmental data from 95 river and stream sites throughout the state of New Jersey (NJ), USA. The sites represent five ecoregions, primarily forested uplands and coastal plains, and a wide range of nutrient concentrations (total P range of 15 to > 200 µg L −1 and total N 0.5 to > 4 mg L −1). Advantages of NJ as a study region are the ready availability of streams with a large gradient in nutrient concentrations and similarity to nutrient-stressed systems in many other geographic regions. BCG levels represent a range of ecological conditions from natural to highly impaired. A panel of experts on use of diatoms as ecological indicators assigned 57 study sites to BCG levels based on diatom assemblage composition. Potential nutrient criteria were subsequently derived by determining the measured TP and TN concentrations associated with the boundary between impaired sites and non-impaired sites (BCG levels greater than 4). Based on this approach, statewide criteria of no greater than 50 µg L −1 TP and 1.0 mg L −1 TN are indicated for maintaining or restoring sites to unimpaired condition. In some least-disturbed ecoregions, lower concentrations (e.g., 25 µg L −1 of TP) would be more appropriate to maintain current ecological conditions. Existing diatom TP and TN metric values for the study sites correlate well with BCG level assignments and can be used to determine if nutrient criteria are met. Overall, results demonstrate the usefulness of data derived from diatom assemblages in management of nutrient issues, and the potential widespread applicability of the BCG approach to develop nutrient criteria and to monitor compliance.
... 5. Charles, DF, DR Whitehead, DR Engstrom, BD Fry, RA Hires, SA Norton, JS Owen, LA Roll, SC ... more ... 5. Charles, DF, DR Whitehead, DR Engstrom, BD Fry, RA Hires, SA Norton, JS Owen, LA Roll, SC Schindler, JP Smol, AJ Uutala, JR White & RJ Wise, 1987. Paleolimnological evidence for recent acidification of Big Moose Lake, Adirondack Mountains, NY (USA). ...
Nature is the international weekly journal of science: a magazine style journal that publishes fu... more Nature is the international weekly journal of science: a magazine style journal that publishes full-length research papers in all disciplines of science, as well as News and Views, reviews, news, features, commentaries, web focuses and more, covering all branches of science and ...
Proceedings of the Water Environment Federation, 2005
In 2004 a four year study performed for NJDEP by the Patrick Center for Environmental Research sh... more In 2004 a four year study performed for NJDEP by the Patrick Center for Environmental Research showed that trophic diatom inference models could be used effectively to assess late-summer nutrient concentrations and benthic algal responses specific to different physiographic provinces in the state. Diatoms are widely recognized and used as indicators of river and stream water quality because benthic diatom species composition responds directly to nutrients and can be a more stable indicator of tropic state than measurements of nutrient concentrations or algal biomass (e.g., chlorophyll a). Objectives of the study were to: 1) develop New Jersey specific field and lab protocols for characterizing eutrophication (nutrient concentrations) in streams using attached periphyton algae, 2) assess the relationships between stressors (i.e., total phosphorus/nitrogen) and overt signs of eutrophication (e.g., algae), and 3) develop biological metrics as potential biocriteria (e.g., diatom community structure and trophic diatom indices -TDI). We chose weighted average inference modeling as our approach because it incorporated the most accurate method for quantifying species response to nutrients. We used nutrient concentrations inferred from the models in two ways: 1) directly, by using the inferred diatom values as estimates of the nutrient concentrations prevailing at the site during the time the algal assemblages were developing, and 2) indirectly, by rescaling the inferred concentrations from 0-100 to create trophic diatom indices (TDI) more easily interpretable by non-specialists. In the current study in 2004 we performed a pilot study to test the TDIs above and below two Sewage Treatment Plant (STP) facilities in New Jersey to evaluate their usefulness as a stressor-response model necessary to generate site-specific biocriteria for nutrients. We conclude that the TP and TN diatom inference models and indices are promising tools to monitor and infer nutrient conditions but that further study is necessary to adequately evaluate their effectiveness for routine use as part of a regulatory program. Diatom community composition differed among sites, and the differences can be explained by variation in nutrient concentrations. Diatom indices indicated relatively high nutrient conditions at all sampling sites, and between-site differences were consistent with measured values. Both the diatom indicators of enrichment and the measured nutrient concentrations showed a marked increase below one STP, but not below the other. This may be because the discharge from one plant was much greater than the other, one-time sampling did not represent longer-term nutrient conditions, or there are other important, unaccounted-for factors influencing nutrient concentrations.
ABSTRACT We used sediment diatoms to infer historical changes in total phosphorus (TP) concentrat... more ABSTRACT We used sediment diatoms to infer historical changes in total phosphorus (TP) concentration in 26 New York and New Jersey (USA) lakes using a top–bottom approach (i.e., the top of the core represents present conditions and the bottom represents past conditions). Detailed stratigraphic analyses were performed on cores from Greenwood (New Jersey and New York) and Cossayuna lakes (New York). TP reconstructions were performed using 2 weighted-averaging partial-least-squares (WA-PLS) transfer functions: (1) an interregional 278-lake calibration set from northeastern United States (NE-US model: r2boot = 0.69, root mean square error of prediction RMSEP) = 1.8 μg/L); and (2) a regional 33-lake (callibration set from New Jersey and New York (NJ-NY model: r2boot = 0.54, RMSEP = 1.5 μg/L). The NJ-NY model provided better estimates for modern TP but failed to provide reliable estimates for low TP values and reliable modern analogs for half of the bottom samples. Low TP concentrations were better inferred by the NE-US model, which included a higher number of oligotrophic lakes. Average change for all lakes was an increase of 2 to 7 μg/L TP. Greenwood and Cossayuna lakes inferred TP concentrations have increased up to 21 μg/L, presumably as a result of post-settlement anthropogenic activities. The inferred TP temporal changes provide important insight on the magnitude of cultural eutrophication. The use of 2 different inference models demonstrates the advantage of using a regional versus a larger-scale inference model in estimating the degree of change in historical lake TP. Careful interpretation of TP reconstructions can be used to provide reliable estimates of cost-effective targets for lake restoration programs.
The impacts of atmospheric deposition of sulfur and nitrogen on aquatic ecosystems have been well... more The impacts of atmospheric deposition of sulfur and nitrogen on aquatic ecosystems have been well recognized. However, the interactions between acidic deposition and concurrent changes in landscape cover have received relatively little attention. A review of recent literature suggests that changes in landscape, or land use, and hydrology can influence the delivery, of sulfur, nitrogen and base cations to drainage waters and consequently modify acid-base chemistry and catchment responses to acidic deposition. Research has focussed heavily on the importance of acidic deposition as an agent of surface water acidification, with less emphasis on other important acidifying or alkalizing processes associated with deforestation, forest regrowth and other agents of catchment disturbance. This omission can have important effects on model estimates of future acidification or recovery of surface waters in response to various atmospheric deposition scenarios. A case study was conducted, using available paleolimnological data, for the Adirondack Mountain region of New York, USA, the most intensively studied region in the world regarding the aquatic effects of acidic deposition. The onset of acidification for most paleolimnological study lakes in the Adirondacks corresponded temporally with both the onset or increase in acidic deposition and also the occurrence of major landscape disturbances associated with logging and windthrow. Although such landscape changes are unlikely on their own to cause lakes to become acidic, model scenarios have suggested that they can cause decreases in the base saturation of soils, thereby predisposing sensitive watersheds to subsequent acidification from acidic deposition. Failure to include landscape processes in modeling efforts may cause biased forecasts, with the extent of the bias depending on the nature and magnitude of landscape changes that were not taken into account.
ABSTRACT We analyzed nutrient data from the National Lakes Assessment (NLA), a probability survey... more ABSTRACT We analyzed nutrient data from the National Lakes Assessment (NLA), a probability survey of 1028 lakes >4 ha in lake area across the conterminous USA to quantify and contrast different methods of setting nutrient criteria. We calculated potential nutrient criteria for total P (TP), total N (TN), and chlorophyll a (Chl a) by 4 methods (25th percentile of population, 75th percentile of least-disturbed reference sites, diatom-based paleolimnological reconstruction, and stressor modeling) and compared them to existing draft US Environmental Protection Agency (EPA) criteria within national nutrient ecoregions. At the national scale, the ecoregional criteria derived from the different approaches were highly correlated. However, absolute values differed widely among approaches within ecoregions. Population 25th percentiles were lower (often by a factor of 2–6) than values obtained with other approaches in almost all ecoregions, results indicating that population 25th percentiles cannot be used as a surrogate for reference-site or paleolimnological approaches. Stressor regression models often did not explain much of the variance in nutrient concentration, especially in the less-disturbed ecoregions. For TP, diatom-inferred paleolimnological criteria were higher than reference-site-based criteria, which were higher than stressor-model criteria. For TN, these 3 approaches were very comparable. For Chl a, the reference-site and stressor-model approaches gave similar criterion values in low-nutrient ecoregions, but the reference-site 75th-percentile approach had much higher criterion values than the stressor-modeling approach in the high-nutrient ecoregions. Use of NLA reference-site 75th percentiles as nutrient criteria showed that 42% of the assessed lakes exceeded TP criteria, 47% exceeded TN criteria, and 32% exceeded Chl a criteria. Survey results also suggest that most lakes are P limited. Ninety-three percent of the lakes in the population had molar TN∶TP ratios > 16, and 52% had TN∶TP > 50.
... In the Sierras they are Robert Holmes and Mark Whiting (funded by the Califor-nia Air Resourc... more ... In the Sierras they are Robert Holmes and Mark Whiting (funded by the Califor-nia Air Resources Board), and Mark Whiting, Donald Whitehead, and Donald Charles (funded by Southern California Edison). ... PROJECT COORDINATORS Donald Whitehead Donald Charles ...
We utilized paleoecological techniques to reconstruct long-term changes in lake-water chemistry, ... more We utilized paleoecological techniques to reconstruct long-term changes in lake-water chemistry, lake trophic state, and watershed vegetation and soils for three lakes located on an elevational gradient (661-1150 m) in the High Peaks region of the Adirondack Mountains of New York State (U.S.A.). Diatoms were used to reconstruct pH and trophic state. Sedimentary chrysophytes, chlorophylls and carotenoids supplied corroborating evidence. Pollen, plant macrofossils, and metals provided information on watershed vegetation, soils, and biogeochemical processes. All three lakes were slightly alkaline pH 7-8) and more productive in the late-glacial. They acidified and became less productive at the end of the late-glacial and in the early Holocene. pH stabilized 8000-9000 yr B.P. at the two higher sites and by 6000 yr B.P. at the lowest. An elevational gradient in pH existed throughout the Holocene. The highest site had a mean Holocene pH close to or below 5; the lowest site fluctuated around a mean of 6. The higher pH and trophic state of the late-glacial was controlled by leaching of base cations from fresh unweathered till, a process accelerated by the development of histosols in the watersheds as sprucedominated woodlands replaced tundra. An apparent pulse of lake productivity at the late-glacial-Holocene boundary is correlated with a transient, but significant, expansion of alder (Alnus crispa) populations. The alder phase had a significant impact on watershed (and hence lake) biogeochemistry. The limnological changes of the Holocene and the differences between lakes were a function of an elevational gradient in temperature, hydrology (higher precipitation and lower evapotranspiration at higher elevation), soil thickness (thinner tills at higher elevation), soil type (histosols at higher elevation), vegetation (northern hardwoods at lower elevation, spruce-fir at higher), and different Holocene vegetational sequences in the three watersheds.
Philosophical transactions of the Royal Society of London, Mar 12, 1990
A model of long term acidification (magic) is applied to a range of catchments in Scotland that a... more A model of long term acidification (magic) is applied to a range of catchments in Scotland that are subject to different pollution inputs and land uses. The simulated historical trends in pH are compared with data from palaeolimnological reconstructions undertaken at the same sites. Both techniques produce similar historical acidification trends and, with some exceptions, closely match observed present day pH. The magic model results indicate that pollution inputs and land-use, particularly afforestation, have significant effects on surface water acidification. Moreover, the model indicates that reversibility may be occurring at several sites. Reversibility of acidification is further explored by using the model in predictive mode under several scenarios for reduction deposition.
1 Univariate explanations of biodiversity have often failed to account for broad-scale patterns i... more 1 Univariate explanations of biodiversity have often failed to account for broad-scale patterns in species richness. As a result, increased attention has been paid to the development and testing of more synthetic multivariate hypotheses. One class of multivariate hypotheses, founded in successional diversity theory, predict that species richness is jointly influenced by periodic disturbances that create new niche opportunities in space or time, and the production of community biomass that speeds displacement of inferior by superior competitors. 2 While the joint response of diversity to disturbance and productivity has gained support from theoretical and small-scale experimental studies, evidence that corresponding patterns of biodiversity occur broadly across natural systems is scarce. 3 Using a data set that employed standardized methods to sample 85 streams throughout the mid-Atlantic United States of America, we show that biogeographical patterns of primary producer diversity in stream ecosystems are consistent with the predictions of a multivariate model that incorporates disturbance frequency and community biomass production as independent variables. Periphyton species richness is a concave-down function of disturbance frequency (mean no. floods year -1 ) and of biomass production ( µ g of biomass accrual cm -2 day -1 ), and an increasing function of their interaction. 4 Changes in richness across the disturbance × productivity response surface can be related to several predicted life-history traits of the dominant species. 5 Our findings complement prior studies by showing that multivariate models which consider interactive effects of community production and ecosystem disturbance are, in fact, candidate explanations of much broader patterns of richness in natural systems. Because multivariate models predict synergistic effects of ecological variables on species diversity, human activities -which are simultaneously altering both the disturbance regime and productivity of streams -could be influencing biodiversity more than previously anticipated.
The siliceous scales of 30 mallomonadacean taxa were identified and counted from the surficial se... more The siliceous scales of 30 mallomonadacean taxa were identified and counted from the surficial sediments of 38 Adirondack lakes. The scales were usually abundant and were always well preserved. The Adirondack flora is typical of acidic to circumneutral oligotrophic lakes. Common taxa include Mallomonas acaroides, M. caudata, M. crassisquama, M. hamata, M. pseudocoronata, M. punctifera, Synura echinulata, S. petersenii, S. sphagnicola, S. spinosa, and Chrysosphaerella longispina. The abundance of certain species (e.g., Mallomonas hindonii, M. hamata) appears to be a reliable indication of acidic waters. Reciprocal averaging (RA) ordination was used to determine if distribution of the mallomonadacean assemblages corresponded with major environmental gradients. Correlations between the first RA axis scores and lakewater pH (r2 = 0.63) and related factors (log10 alkalinity, r2 = 0.66; pCa, r2 = 0.39; pMg, r2 = 0.43) were strongest. Relationships were weaker with average depth, summer epilimnion temperature, elevation, NO3, and total Al, and were not statistically significant with conductivity, color, Secchi disc transparency, total P, chlorophyll a, SO4, and Si. Cluster analysis grouped both lakes and taxa into categories best explained by their pH-related characteristics. Analysis of surficial sediment from lakes with known limnological characteristics is a useful approach for the study of the ecology and taxonomy of the Mallomonadaceae. Our data demonstrate that mallomonadacean distributions reflect lake conditions and, therefore, are potentially useful indicators in limnological and paleolimnological studies.
ABSTRACT Paleoecological analysis of the sediment record of 12 Adirondack lakes reveals that the ... more ABSTRACT Paleoecological analysis of the sediment record of 12 Adirondack lakes reveals that the 8 clearwater lakes with current pH -1 have acidified recently. The onset of this acidification occurred between 1920 and 1970. Loss of alkalinity, based on quanitative analysis of diatom assemblages, ranged from 2 to 35 µeq l-1. The acidification trends are substantiated by several lines of evidence including stratigraphies of diatom, chrysophyte, chironomid, and cladoceran remains, Ca:Ti and Mn:Ti ratios, sequentially extracted forms of Al, and historical fish data. Acidification trends appear to be continuing in some lakes, despite reductions in atmospheric sulfur loading that began in the early 1970s. The primary cause of the acidification trend is clearly increased atmospheric deposition of strong acids derived from the combustion of fossil fuels. Natural processes and watershed disturbances cannot account for the changes in water chemistry that have occurred, but they may play a role. Sediment core profiles of Pb, Cu, V, Zn, S, polycyclic aromatic hydrocarbons, magnetic particles, and coal and oil soot provide a clear record of increased atmospheric input of materials associated with the combustion of fossil fuels beginning in the late 1800s and early 1900s. The primary evidence for acidification occurs after that period, and the pattern of water chemistry response to increased acid inputs is consistent with current understanding of lake-watershed acidification processes.
Distributions of both diatoms and chrysophytes (Mallomonadaceae) are clearly correlated with pH i... more 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,). 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 < 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 (<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. Rapidly growing evidence has demonstrated that atmospheric deposition has acidified many low-alkalinity lakes in the U. S., Canada, and Europe (e.g. Natl. Res. Count. 1986). Limnological research has focused on changes in pH and related water chemistry characteristics and how these changes have affected aquatic biota (e.g. Schindler 1985). Because historical limnological data are usually lacking, there has been a surge of interest in applying paleolimnological approaches to the study of patterns of lake
Philosophical transactions of the Royal Society of London, Mar 12, 1990
Analysis of sediment diatom and chrysophyte assemblages is the best technique currently available... more 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 < 5.5) before the onset of anthropogenic acidification. These lakes are typically small (less than 10 haj) are located at moderately high elevations, have thin or peaty soils, or are located in outwash deposits. Many of these have acidified further recently.
Paleoecological analyses of sediments from nine northern Great Lakes states (NGLS) lakes reveal s... more Paleoecological analyses of sediments from nine northern Great Lakes states (NGLS) lakes reveal small pH changes in seven of these lakes since 1860, four of these being declines. The largest diatom-inferred (DI) pH declines of 0.5 pH units were found in Brown L. and Denton L., Wisconsin. Two other lakes with suspected total alkalinity declines (based on an acidification model
A study of aquatic vegetation of 31 small, dilute, and unproductive lakes in the Adirondack Mount... more A study of aquatic vegetation of 31 small, dilute, and unproductive lakes in the Adirondack Mountains of New York shows that macrophyte species composition is primarily related to variation in pH and associated factors. Among the lakes, surface water pH ranged from 4.5 to 7.8; conductivity ranged from 11.9 to 58.7 μS/cm. Relationships between aquatic vegetation and environmental factors were studied using detrended correspondence analysis (DCA). Submersed and floating-leaved taxa were analyzed separately from emergent taxa. Correlations between DCA axis 1 and pH-related factors (pH, alkalinity, Ca, Mg, Na, Al, conductivity, elevation) were strong for both submersed plus floating-leaved and emergent taxa. No significant correlations were found with water color, transparency, or trophic status indicators (total P and chlorophyll a). Between-lake variation in composition of aquatic vegetation in Adirondack lakes follows a pH "complex-gradient." Influences of elevation, morphometry, and substrate are secondary. Our results indicate that acidification of softwater lakes could be accompanied by significant changes in aquatic macrophyte assemblages.
Nutrient enrichment is one of the most important causes of ecological impairment in surface water... more Nutrient enrichment is one of the most important causes of ecological impairment in surface waters. More effective management of this problem is constrained by a lack of nutrient criteria that link phosphorus and nitrogen concentrations to levels of biological impairment as defined in management agency regulations. We used a new approach for identifying potential nutrient criteria using diatom assemblages and the Biological Condition Gradient (BCG). We first used diatom count data to assign study sites to BCG impairment categories (levels), then determined P and N concentrations corresponding with the boundaries between those levels. We studied diatom counts and environmental data from 95 river and stream sites throughout the state of New Jersey (NJ), USA. The sites represent five ecoregions, primarily forested uplands and coastal plains, and a wide range of nutrient concentrations (total P range of 15 to > 200 µg L −1 and total N 0.5 to > 4 mg L −1). Advantages of NJ as a study region are the ready availability of streams with a large gradient in nutrient concentrations and similarity to nutrient-stressed systems in many other geographic regions. BCG levels represent a range of ecological conditions from natural to highly impaired. A panel of experts on use of diatoms as ecological indicators assigned 57 study sites to BCG levels based on diatom assemblage composition. Potential nutrient criteria were subsequently derived by determining the measured TP and TN concentrations associated with the boundary between impaired sites and non-impaired sites (BCG levels greater than 4). Based on this approach, statewide criteria of no greater than 50 µg L −1 TP and 1.0 mg L −1 TN are indicated for maintaining or restoring sites to unimpaired condition. In some least-disturbed ecoregions, lower concentrations (e.g., 25 µg L −1 of TP) would be more appropriate to maintain current ecological conditions. Existing diatom TP and TN metric values for the study sites correlate well with BCG level assignments and can be used to determine if nutrient criteria are met. Overall, results demonstrate the usefulness of data derived from diatom assemblages in management of nutrient issues, and the potential widespread applicability of the BCG approach to develop nutrient criteria and to monitor compliance.
... 5. Charles, DF, DR Whitehead, DR Engstrom, BD Fry, RA Hires, SA Norton, JS Owen, LA Roll, SC ... more ... 5. Charles, DF, DR Whitehead, DR Engstrom, BD Fry, RA Hires, SA Norton, JS Owen, LA Roll, SC Schindler, JP Smol, AJ Uutala, JR White & RJ Wise, 1987. Paleolimnological evidence for recent acidification of Big Moose Lake, Adirondack Mountains, NY (USA). ...
Nature is the international weekly journal of science: a magazine style journal that publishes fu... more Nature is the international weekly journal of science: a magazine style journal that publishes full-length research papers in all disciplines of science, as well as News and Views, reviews, news, features, commentaries, web focuses and more, covering all branches of science and ...
Proceedings of the Water Environment Federation, 2005
In 2004 a four year study performed for NJDEP by the Patrick Center for Environmental Research sh... more In 2004 a four year study performed for NJDEP by the Patrick Center for Environmental Research showed that trophic diatom inference models could be used effectively to assess late-summer nutrient concentrations and benthic algal responses specific to different physiographic provinces in the state. Diatoms are widely recognized and used as indicators of river and stream water quality because benthic diatom species composition responds directly to nutrients and can be a more stable indicator of tropic state than measurements of nutrient concentrations or algal biomass (e.g., chlorophyll a). Objectives of the study were to: 1) develop New Jersey specific field and lab protocols for characterizing eutrophication (nutrient concentrations) in streams using attached periphyton algae, 2) assess the relationships between stressors (i.e., total phosphorus/nitrogen) and overt signs of eutrophication (e.g., algae), and 3) develop biological metrics as potential biocriteria (e.g., diatom community structure and trophic diatom indices -TDI). We chose weighted average inference modeling as our approach because it incorporated the most accurate method for quantifying species response to nutrients. We used nutrient concentrations inferred from the models in two ways: 1) directly, by using the inferred diatom values as estimates of the nutrient concentrations prevailing at the site during the time the algal assemblages were developing, and 2) indirectly, by rescaling the inferred concentrations from 0-100 to create trophic diatom indices (TDI) more easily interpretable by non-specialists. In the current study in 2004 we performed a pilot study to test the TDIs above and below two Sewage Treatment Plant (STP) facilities in New Jersey to evaluate their usefulness as a stressor-response model necessary to generate site-specific biocriteria for nutrients. We conclude that the TP and TN diatom inference models and indices are promising tools to monitor and infer nutrient conditions but that further study is necessary to adequately evaluate their effectiveness for routine use as part of a regulatory program. Diatom community composition differed among sites, and the differences can be explained by variation in nutrient concentrations. Diatom indices indicated relatively high nutrient conditions at all sampling sites, and between-site differences were consistent with measured values. Both the diatom indicators of enrichment and the measured nutrient concentrations showed a marked increase below one STP, but not below the other. This may be because the discharge from one plant was much greater than the other, one-time sampling did not represent longer-term nutrient conditions, or there are other important, unaccounted-for factors influencing nutrient concentrations.
ABSTRACT We used sediment diatoms to infer historical changes in total phosphorus (TP) concentrat... more ABSTRACT We used sediment diatoms to infer historical changes in total phosphorus (TP) concentration in 26 New York and New Jersey (USA) lakes using a top–bottom approach (i.e., the top of the core represents present conditions and the bottom represents past conditions). Detailed stratigraphic analyses were performed on cores from Greenwood (New Jersey and New York) and Cossayuna lakes (New York). TP reconstructions were performed using 2 weighted-averaging partial-least-squares (WA-PLS) transfer functions: (1) an interregional 278-lake calibration set from northeastern United States (NE-US model: r2boot = 0.69, root mean square error of prediction RMSEP) = 1.8 μg/L); and (2) a regional 33-lake (callibration set from New Jersey and New York (NJ-NY model: r2boot = 0.54, RMSEP = 1.5 μg/L). The NJ-NY model provided better estimates for modern TP but failed to provide reliable estimates for low TP values and reliable modern analogs for half of the bottom samples. Low TP concentrations were better inferred by the NE-US model, which included a higher number of oligotrophic lakes. Average change for all lakes was an increase of 2 to 7 μg/L TP. Greenwood and Cossayuna lakes inferred TP concentrations have increased up to 21 μg/L, presumably as a result of post-settlement anthropogenic activities. The inferred TP temporal changes provide important insight on the magnitude of cultural eutrophication. The use of 2 different inference models demonstrates the advantage of using a regional versus a larger-scale inference model in estimating the degree of change in historical lake TP. Careful interpretation of TP reconstructions can be used to provide reliable estimates of cost-effective targets for lake restoration programs.
The impacts of atmospheric deposition of sulfur and nitrogen on aquatic ecosystems have been well... more The impacts of atmospheric deposition of sulfur and nitrogen on aquatic ecosystems have been well recognized. However, the interactions between acidic deposition and concurrent changes in landscape cover have received relatively little attention. A review of recent literature suggests that changes in landscape, or land use, and hydrology can influence the delivery, of sulfur, nitrogen and base cations to drainage waters and consequently modify acid-base chemistry and catchment responses to acidic deposition. Research has focussed heavily on the importance of acidic deposition as an agent of surface water acidification, with less emphasis on other important acidifying or alkalizing processes associated with deforestation, forest regrowth and other agents of catchment disturbance. This omission can have important effects on model estimates of future acidification or recovery of surface waters in response to various atmospheric deposition scenarios. A case study was conducted, using available paleolimnological data, for the Adirondack Mountain region of New York, USA, the most intensively studied region in the world regarding the aquatic effects of acidic deposition. The onset of acidification for most paleolimnological study lakes in the Adirondacks corresponded temporally with both the onset or increase in acidic deposition and also the occurrence of major landscape disturbances associated with logging and windthrow. Although such landscape changes are unlikely on their own to cause lakes to become acidic, model scenarios have suggested that they can cause decreases in the base saturation of soils, thereby predisposing sensitive watersheds to subsequent acidification from acidic deposition. Failure to include landscape processes in modeling efforts may cause biased forecasts, with the extent of the bias depending on the nature and magnitude of landscape changes that were not taken into account.
ABSTRACT We analyzed nutrient data from the National Lakes Assessment (NLA), a probability survey... more ABSTRACT We analyzed nutrient data from the National Lakes Assessment (NLA), a probability survey of 1028 lakes &gt;4 ha in lake area across the conterminous USA to quantify and contrast different methods of setting nutrient criteria. We calculated potential nutrient criteria for total P (TP), total N (TN), and chlorophyll a (Chl a) by 4 methods (25th percentile of population, 75th percentile of least-disturbed reference sites, diatom-based paleolimnological reconstruction, and stressor modeling) and compared them to existing draft US Environmental Protection Agency (EPA) criteria within national nutrient ecoregions. At the national scale, the ecoregional criteria derived from the different approaches were highly correlated. However, absolute values differed widely among approaches within ecoregions. Population 25th percentiles were lower (often by a factor of 2–6) than values obtained with other approaches in almost all ecoregions, results indicating that population 25th percentiles cannot be used as a surrogate for reference-site or paleolimnological approaches. Stressor regression models often did not explain much of the variance in nutrient concentration, especially in the less-disturbed ecoregions. For TP, diatom-inferred paleolimnological criteria were higher than reference-site-based criteria, which were higher than stressor-model criteria. For TN, these 3 approaches were very comparable. For Chl a, the reference-site and stressor-model approaches gave similar criterion values in low-nutrient ecoregions, but the reference-site 75th-percentile approach had much higher criterion values than the stressor-modeling approach in the high-nutrient ecoregions. Use of NLA reference-site 75th percentiles as nutrient criteria showed that 42% of the assessed lakes exceeded TP criteria, 47% exceeded TN criteria, and 32% exceeded Chl a criteria. Survey results also suggest that most lakes are P limited. Ninety-three percent of the lakes in the population had molar TN∶TP ratios &gt; 16, and 52% had TN∶TP &gt; 50.
... In the Sierras they are Robert Holmes and Mark Whiting (funded by the Califor-nia Air Resourc... more ... In the Sierras they are Robert Holmes and Mark Whiting (funded by the Califor-nia Air Resources Board), and Mark Whiting, Donald Whitehead, and Donald Charles (funded by Southern California Edison). ... PROJECT COORDINATORS Donald Whitehead Donald Charles ...
We utilized paleoecological techniques to reconstruct long-term changes in lake-water chemistry, ... more We utilized paleoecological techniques to reconstruct long-term changes in lake-water chemistry, lake trophic state, and watershed vegetation and soils for three lakes located on an elevational gradient (661-1150 m) in the High Peaks region of the Adirondack Mountains of New York State (U.S.A.). Diatoms were used to reconstruct pH and trophic state. Sedimentary chrysophytes, chlorophylls and carotenoids supplied corroborating evidence. Pollen, plant macrofossils, and metals provided information on watershed vegetation, soils, and biogeochemical processes. All three lakes were slightly alkaline pH 7-8) and more productive in the late-glacial. They acidified and became less productive at the end of the late-glacial and in the early Holocene. pH stabilized 8000-9000 yr B.P. at the two higher sites and by 6000 yr B.P. at the lowest. An elevational gradient in pH existed throughout the Holocene. The highest site had a mean Holocene pH close to or below 5; the lowest site fluctuated around a mean of 6. The higher pH and trophic state of the late-glacial was controlled by leaching of base cations from fresh unweathered till, a process accelerated by the development of histosols in the watersheds as sprucedominated woodlands replaced tundra. An apparent pulse of lake productivity at the late-glacial-Holocene boundary is correlated with a transient, but significant, expansion of alder (Alnus crispa) populations. The alder phase had a significant impact on watershed (and hence lake) biogeochemistry. The limnological changes of the Holocene and the differences between lakes were a function of an elevational gradient in temperature, hydrology (higher precipitation and lower evapotranspiration at higher elevation), soil thickness (thinner tills at higher elevation), soil type (histosols at higher elevation), vegetation (northern hardwoods at lower elevation, spruce-fir at higher), and different Holocene vegetational sequences in the three watersheds.
Philosophical transactions of the Royal Society of London, Mar 12, 1990
A model of long term acidification (magic) is applied to a range of catchments in Scotland that a... more A model of long term acidification (magic) is applied to a range of catchments in Scotland that are subject to different pollution inputs and land uses. The simulated historical trends in pH are compared with data from palaeolimnological reconstructions undertaken at the same sites. Both techniques produce similar historical acidification trends and, with some exceptions, closely match observed present day pH. The magic model results indicate that pollution inputs and land-use, particularly afforestation, have significant effects on surface water acidification. Moreover, the model indicates that reversibility may be occurring at several sites. Reversibility of acidification is further explored by using the model in predictive mode under several scenarios for reduction deposition.
1 Univariate explanations of biodiversity have often failed to account for broad-scale patterns i... more 1 Univariate explanations of biodiversity have often failed to account for broad-scale patterns in species richness. As a result, increased attention has been paid to the development and testing of more synthetic multivariate hypotheses. One class of multivariate hypotheses, founded in successional diversity theory, predict that species richness is jointly influenced by periodic disturbances that create new niche opportunities in space or time, and the production of community biomass that speeds displacement of inferior by superior competitors. 2 While the joint response of diversity to disturbance and productivity has gained support from theoretical and small-scale experimental studies, evidence that corresponding patterns of biodiversity occur broadly across natural systems is scarce. 3 Using a data set that employed standardized methods to sample 85 streams throughout the mid-Atlantic United States of America, we show that biogeographical patterns of primary producer diversity in stream ecosystems are consistent with the predictions of a multivariate model that incorporates disturbance frequency and community biomass production as independent variables. Periphyton species richness is a concave-down function of disturbance frequency (mean no. floods year -1 ) and of biomass production ( µ g of biomass accrual cm -2 day -1 ), and an increasing function of their interaction. 4 Changes in richness across the disturbance × productivity response surface can be related to several predicted life-history traits of the dominant species. 5 Our findings complement prior studies by showing that multivariate models which consider interactive effects of community production and ecosystem disturbance are, in fact, candidate explanations of much broader patterns of richness in natural systems. Because multivariate models predict synergistic effects of ecological variables on species diversity, human activities -which are simultaneously altering both the disturbance regime and productivity of streams -could be influencing biodiversity more than previously anticipated.
The siliceous scales of 30 mallomonadacean taxa were identified and counted from the surficial se... more The siliceous scales of 30 mallomonadacean taxa were identified and counted from the surficial sediments of 38 Adirondack lakes. The scales were usually abundant and were always well preserved. The Adirondack flora is typical of acidic to circumneutral oligotrophic lakes. Common taxa include Mallomonas acaroides, M. caudata, M. crassisquama, M. hamata, M. pseudocoronata, M. punctifera, Synura echinulata, S. petersenii, S. sphagnicola, S. spinosa, and Chrysosphaerella longispina. The abundance of certain species (e.g., Mallomonas hindonii, M. hamata) appears to be a reliable indication of acidic waters. Reciprocal averaging (RA) ordination was used to determine if distribution of the mallomonadacean assemblages corresponded with major environmental gradients. Correlations between the first RA axis scores and lakewater pH (r2 = 0.63) and related factors (log10 alkalinity, r2 = 0.66; pCa, r2 = 0.39; pMg, r2 = 0.43) were strongest. Relationships were weaker with average depth, summer epilimnion temperature, elevation, NO3, and total Al, and were not statistically significant with conductivity, color, Secchi disc transparency, total P, chlorophyll a, SO4, and Si. Cluster analysis grouped both lakes and taxa into categories best explained by their pH-related characteristics. Analysis of surficial sediment from lakes with known limnological characteristics is a useful approach for the study of the ecology and taxonomy of the Mallomonadaceae. Our data demonstrate that mallomonadacean distributions reflect lake conditions and, therefore, are potentially useful indicators in limnological and paleolimnological studies.
ABSTRACT Paleoecological analysis of the sediment record of 12 Adirondack lakes reveals that the ... more ABSTRACT Paleoecological analysis of the sediment record of 12 Adirondack lakes reveals that the 8 clearwater lakes with current pH -1 have acidified recently. The onset of this acidification occurred between 1920 and 1970. Loss of alkalinity, based on quanitative analysis of diatom assemblages, ranged from 2 to 35 µeq l-1. The acidification trends are substantiated by several lines of evidence including stratigraphies of diatom, chrysophyte, chironomid, and cladoceran remains, Ca:Ti and Mn:Ti ratios, sequentially extracted forms of Al, and historical fish data. Acidification trends appear to be continuing in some lakes, despite reductions in atmospheric sulfur loading that began in the early 1970s. The primary cause of the acidification trend is clearly increased atmospheric deposition of strong acids derived from the combustion of fossil fuels. Natural processes and watershed disturbances cannot account for the changes in water chemistry that have occurred, but they may play a role. Sediment core profiles of Pb, Cu, V, Zn, S, polycyclic aromatic hydrocarbons, magnetic particles, and coal and oil soot provide a clear record of increased atmospheric input of materials associated with the combustion of fossil fuels beginning in the late 1800s and early 1900s. The primary evidence for acidification occurs after that period, and the pattern of water chemistry response to increased acid inputs is consistent with current understanding of lake-watershed acidification processes.
Distributions of both diatoms and chrysophytes (Mallomonadaceae) are clearly correlated with pH i... more 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,). 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 < 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 (<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. Rapidly growing evidence has demonstrated that atmospheric deposition has acidified many low-alkalinity lakes in the U. S., Canada, and Europe (e.g. Natl. Res. Count. 1986). Limnological research has focused on changes in pH and related water chemistry characteristics and how these changes have affected aquatic biota (e.g. Schindler 1985). Because historical limnological data are usually lacking, there has been a surge of interest in applying paleolimnological approaches to the study of patterns of lake
Philosophical transactions of the Royal Society of London, Mar 12, 1990
Analysis of sediment diatom and chrysophyte assemblages is the best technique currently available... more 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 < 5.5) before the onset of anthropogenic acidification. These lakes are typically small (less than 10 haj) are located at moderately high elevations, have thin or peaty soils, or are located in outwash deposits. Many of these have acidified further recently.
Paleoecological analyses of sediments from nine northern Great Lakes states (NGLS) lakes reveal s... more Paleoecological analyses of sediments from nine northern Great Lakes states (NGLS) lakes reveal small pH changes in seven of these lakes since 1860, four of these being declines. The largest diatom-inferred (DI) pH declines of 0.5 pH units were found in Brown L. and Denton L., Wisconsin. Two other lakes with suspected total alkalinity declines (based on an acidification model
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