Spatial and temporal variations in aluminum chemistry of a dilute,acidic lake

Elevated concentrations of Al have been observed in acidic surface waters. An assessment of the chemistry of aqueous Al is of interest because of its role as a toxicant to aquatic organisms, a pH buffer, and an adsorbent of orthophosphate and organic carbon. In this investigation we evaluated the spatial and temporal fluctuations of Al forms in an acidic drainage lake.High concentrations of NO ₃ ^– (51.0 ± 11 mol l^–1), H⁺ (14.9 ± 3.5 mol l^–1), and Al (19.6 ± 3.5 mol l^–1) were introduced to Dart's Lake through drainage water during the snowmelt period. During low flow periods microbially mediated depletions of nitrate served to neutralize H⁺ and aluminum base neutralizing capacity. Thus in Dart's Lake, NO ₃ ^– transformations were extremely important in regulating short-term changes in pH and subsequent changes in the inorganic forms of Al. During stratification periods Al appeared to be non-conservative within the lake system. Although we know very little about the character and transformations of alumino-organic solutes, these substances were correlated with dissolved organic carbon (DOC) concentrations. Alumino-organic substances appear to be introduced to the lake from both drainage water and sediments.     

Effect of supersaturated water on fish in the River Nidelva, southern Norway

Fish mortalities in the River Nidelva, South Norway in 1978, were suspected to be caused by Gas Bubble Disease. In June 1980, the hydrological situation occumng in the Nidelva in 1978 was reconstructed, and the effects were analysed by keeping fish in cages. Examination of the dead fish showed that most were killed by Gas Bubble Disease. The results also showed that brown trout, Salmo trutta , was the least tolerant, and eel, Anguilla anguih , was the most tolerant to dissolved gas supersaturation. Only fish kept near the surface were killed while fish kept at 3 m depth were mildly affected due to hydrostatic pressure compensation. In contrast to the situation in 1978, few of the wild fish were killed during the experiment in 1980.     

The effects of vegetation removal by grass carp and herbicides on the water chemistry of four Florida lakes

SUMMARY.

• 1 Four lakes in central Florida each received a different weed control treatment consisting of herbicide and/or different stocking ratios of grass carp (Ctenopharyngodon idella Val.).
• 2 Submersed vegetation was eliminated by grass carp within 6 months In Lake Orienta and within 14 months in Clear Lake. Because Little Lake Fairview, treated with herbicide and a smaller stocking ratio of grass carp, retained abundant vegetation levels over the first two study years, grass carp which had been introduced initially were replaced with a greater number of fish at the beginning of the third year. Submersed vegetation was subsequently eliminated in this lake within LO months. Aquatic vegetation was reduced but not eliminated in Lake Mann which was treated with herbicide only.
• 3 Where macrophytes were removed there tended to be increased bottom dissolved oxygen, higher and more stable total alkalinity values, increased turbidity, lowered transparency, higher specific conductivity and increased chlorophyll levels. Significant increases in pH were probably due to low water levels resulting from a severe drought rather than weed control. Low water also affected specific conductivity. Annual means for nutrients did not differ significantly between years in the four lakes.

     

Incomplete mixing of limed water and acidic runoff restricts recruitment of lake spawning brown trout in Hovvatn, southern Norway

Repeated liming of Hovvatn during the 1981–1995 period assured successful reintroduction of lake spawning brown trout, Salmo trutta. Poor natural recruitment to the population was associated with low survival during early life stages (before hatching) as shown by the 0.5, 3.5, 0.9 and 1.0% of live embryos found in natural redds during the 1992–1995 period, respectively. The low survival was most likely caused by the combination of shallow spawning areas (<2.0 m) and acidic runoff (pH 4.0–4.8) which overlayed the limed part of the water body during the ice covered period. It is therefore concluded that this type of episodic acidification poses a major threat to lake spawning salmonids, and that it can retard or inhibit biotic recovery towards preacidified conditions expected as a result of liming. Addition of limestone gravel (8–32 mm) onto spawning grounds was an efficient alternative liming strategy as 33–36% live embryos were found in this substrate. Conversely, the trout actively avoided additions of shellsand, a behaviour most likely caused by the small particle size of shellsand (3–7 mm) relative to natural spawning gravel.     

Paleolimnological reconstruction of the effects of atmospheric deposition of acids and heavy metals on the chemistry and biology of lakes in New England and Norway

Sediment cores from nine lakes in southern Norway (N) and six in northern New England (NE) were dated by ¹³⁷Cs, ²¹⁰Pb and in NE also by pollen, and were analyzed geochemically and for diatoms. Cores from two N and three NE lakes were analyzed for cladocerans. ¹³⁷Cs dating is unreliable in these lakes, probably due to mobility of Cs in the sediment. In Holmvatn sediment, an up-core increase in Fe, starting ca. 1900, correlates with geochemical indications of decreasing mechanical erosion of soils. Diatoms indicate a lake acidification starting in the 1920's. We propose that soil Fe was mobilized and runoff acidified by acidic precipitation and/or by soil acidification resulting from vegetational succession following reduced grazing. Even minor land use changes or disturbances in lake watersheds introduce ambiguity to the sedimentary evidence relating to atmospheric influences. Diatom counts from surface sediments in 36 N and 31 NE lakes were regressed against contemporary water pH to obtain coefficients for computing past pH from subsurface counts. Computed decreases of 0.3–0.8 pH units start between I890 and I930 in N lakes already acidic (pH 5.0–5.5) before the decrease. These and lesser decreases in other lakes start decades to over a century after the first sedimentary indications of atmospheric heavy metal pollution. It is proposed that the acidification of precipitation accompanied the metal pollution. The delays in lake acidification may be due to buffering by the lakes and watersheds. The magnitude of acidification and heavy metal loading of the lakes parallels air pollution gradients. Shift in cladoceran remains are contemporary with acidification, preceding elimination of fishes.     

Mineralization, pore water chemistry and phosphorus release from peaty sediments in the eutrophic Loosdrecht lakes, The Netherlands

SUMMARY. 1. Pore water chemistry in peaty sediment was monitored for a year at two representative locations of the eutrophic shallow Loosdrecht lakes. The Netherlands. Phosphorus fluxes over the sediment-water interface were calculated using measured concentration gradients in the pore water and compared to fluxes measured under laboratory conditions. Results were analysed with Redundancy Analysis to detect patterns of variation in pore water chemistry and in measured and calculated fluxes, that could be ascribed to environmental variables.
2. It was demonstrated that phosphorus fluxes measured in long-term laboratory incubations were not correlated to any of the pore water characteristics.
3. Initial phosphorus fluxes measured in sediment columns, which varied between −7.7 and 1330 μmol m⁻²: day⁻¹, were correlated significantly to the calculated phosphorus flux over the sediment-water interface.
4. The high correlation between calculated fluxes of ammonia, phosphorus and methane and measured initial flux of phosphorus, conclusively pointed to mineralization of organic matter as the driving force for phosphorus release from the sediment.
5. Redundancy Analysis demonstrated that the rates of mineralization and phosphorus release were only weakly related to temperature. They appeared to be especially stimulated by the autumnal decrease in temperature which was probably related to an extra input of organic matter.     

Interacting effects of wildfire severity and liming on nutrient cycling in a southern Appalachian wilderness area

Aims

Wilderness and other natural areas are threatened by large-scale disturbances (e.g., wildfire), air pollution, climate change, exotic diseases or pests, and a combination of these stress factors (i.e., stress complexes). Linville Gorge Wilderness (LGW) is one example of a high elevation wilderness in the southern Appalachian region that has been subject to stress complexes including chronic acidic deposition and several wildfires, varying in intensity and extent. Soils in LGW are inherently acidic with low base cation concentrations and decades of acidic deposition have contributed to low pH, based saturation, and Ca:Al ratio. We hypothesized that wildfires that occurred in LGW followed by liming burned areas would accelerate the restoration of acidic, nutrient depleted soils. Because soils at LGW had extremely low concentrations of exchangeable Ca²⁺ and Mg²⁺ dolomitic lime was applied to further boost these cations. We evaluated the effectiveness of dolomitic lime application in restoring exchangeable Ca²⁺ and Mg²⁺ and subsequently increasing pH and Ca:Al ratio of soils and making Ca and Mg available to recovering vegetation.

Methods

Five treatment areas were established: severely burned twice (2000 & 2007) with dolomitic lime application (2xSBL); moderately burned twice with lime application (2xMBL); severely burned twice, unlimed (2xSB); moderately burned once (2000), unlimed (1xMB); and a reference area (REF; unburned, unlimed). In 2008 and 2009, we measured overstory, understory, and ground-layer vegetation; forest floor mass and nutrients; and soil and soil solution chemistry within each treatment area.

Results

All wildfire burned sites experienced substantial overstory mortality. However, understory biomass doubled between sample years on the most recently burned sites due to the rapid regrowth of ericaceous shrubs and prolific sprouting of deciduous trees. Burning followed by lime application (2xSBL and 2xMBL) significantly increased shallow soil solution NO₃-N, but we found no soil solution NO₃-N response to burning alone (2xSB and 1xMB). Surface soil base saturation and exchangeable Ca²⁺ were significantly affected by liming; Ca²⁺ concentrations were greater on 2xMBL and 2xSBL than 2xSB, 1xMB and REF. There was a smaller difference due to moderate burning along with greater soil Ca²⁺ on 1xMB compared to REF, but no difference between 2xSB and REF. Surface and subsurface soil exchangeable Al³⁺ were lower on 2xSBL than 2xSB, 2xMBL, 1xMB, and REF. Liming decreased soil acidity somewhat as surface soil pH was higher on the two burned sites with lime (pH?=?3.8) compared to 2xSB without lime (pH?=?3.6).

Conclusions

Liming resulted in decreased soil Al³⁺ on 2xSBL coupled with increased soil Ca²⁺ on both 2xSBL and 2xMBL, which improved soil Ca/Al ratios. However, the soil Ca/Al ratio response was transitory, as exchangeable Al³⁺ increased and Ca/Al ratio decreased over time. Higher lime application rates may be necessary to obtain a substantial and longer-term improvement of cation-depleted soils at LGW.     

Multivariate analysis of diatoms and water chemistry in Bolivian saline lakes

Diatom assemblages are described from surface sediments in thirteen salt lakes located in the southern Bolivian Altiplano. Factor analysis of correspondences and cluster analysis are used to classify the diatom assemblages. New methods are proposed to establish the qualitative and quantitative relationships between diatom floras and ecological parameters. Diatom assemblages are linked more to the ionic elements than to the salinity, pH, depth, temperature or elevation. Environmental variables are divided into three modalities which allow considerations of many different variables not under the same units.     

Short-term effects of nutrient compensation following whole-tree harvesting on soil and soil water chemistry in a young Norway spruce stand

A growing demand for bioenergy from conventional forestry in Sweden will increase the need of nutrient compensation, that preferably should be made relatively shortly after harvesting and have no undesired side-effects. This study compared the effects of granulated wood ash (Ash), N-free, dolomite-based fertiliser (Vitality) and the green fraction of harvest residues (Residues) on the podsolic soil and soil solution of a young Norway spruce (Picea abies (L.) Karst) stand in SW Sweden. The treatments were applied three years after clear-felling and whole-tree harvesting. The soil solution was repeatedly sampled in the rooting zone 2–5 years after treatment. The soil study was performed 4 years after the Ash treatment and 3 years after Residues treatment and the last Vitality treatment (the Vitality treatment was applied on two occasions over 2 years). The Vitality treatment increased base saturation and effective CEC in the humus layer in relation to the other treatments, and also increased Ca and K concentrations in the soil solution. The Ash treatment resulted in higher exchangeable K concentration than Vitality in the litter layer, and Residues increased K concentrations in the soil water. No treatment influenced the KCl-exchangeable nitrate concentrations in the soil or the nitrate levels in the soil water. The results indicate that granulated wood ash could be used for long-term nutrient compensation without undesired short-term side-effects.     

Effects of wildfire ash on water chemistry and biota in South-Western U.S.A. streams

1. We monitored streams within the Gila River drainage in south‐western New Mexico, U.S.A., over a 5‐year period, to investigate the influence of ash input on water quality and stream biota following forest wildfires. 2. Nutrients [ammonium, nitrate, soluble reactive phosphate (SRP)], potassium and alkalinity were most affected by fires; all were increased in stream water following ash input. Concentrations of each returned to prefire conditions within 4 months. Ammonium and nitrate also increased in stream water as a result of atmospheric fallout (e.g. smoke) from fires outside the catchment. 3. Periphyton biomass was not affected significantly by wildfires, although there was a shift in diatom assemblage to smaller more adnate taxa. Cocconeis placentula was frequently the dominant postfire species. 4. The influence of wildfires on macroinvertebrates ranged from minimal to dramatic reductions in density depending upon the duration of ash flows and the characteristics of the ash material that entered each system. Macroinvertebrate densities returned to prefire conditions within 1 year. 5. An in‐situ ashing experiment was conducted on a first‐order stream in the Gila River drainage to monitor on‐site physiochemical and biotic responses during and after fire ash addition, for comparison with ash delivery from real wildfires on monitored streams. Physical–chemical parameters and algae and macroinvertebrates were monitored in an ashed and upstream reference reach for 13 months. Results generally substantiated findings from monitored streams. 6. Concentrations of major ions and nutrients, as well as turbidity, conductivity and pH, increased immediately in stream water below the point of ashing, while dissolved oxygen decreased. Changes in water chemistry were short‐lived (=24 h) except for SRP. The concentration of SRP in stream water was significantly higher in the ashed reach than the control reach for at least 1 month after ash input. 7. Periphyton biomass and diatom assemblages were not significantly altered in the ashing study, whereas macroinvertebrate density was measurably lower in the ashed reach for nearly a year. Macroinvertebrate drift was over 10‐fold greater in the ashed reach compared with the reference reach during ashing. Dissimilarity between macroinvertebrate communities in the reference and ashed reaches was significantly greater than variation within reaches for nearly a year.     

Lime treatment and its effects on the chemistry and biota of hardwater eutrophic lakes

1. The main focus of this study was to investigate the effects of single and multiple moderate doses of lime (slaked lime, Ca(OH)₂, and/or calcite, CaCO₃) on eutrophic hardwater lakes. This information would contribute to strategies to manage phytoplankton and macrophyte biomass in eutrophic lakes.
2. Water chemistry and biota were monitored for up to 7 years after initial lime treatment and results were compared with reference systems.
3. Complementary studies investigated the effect of lime on macrophytes in ponds, irrigation canals and microcosm experiments.
4. When water pH was kept within its natural range (≤ 10), single and multiple lime applications to lakes and ponds controlled macrophyte biomass, without negatively affecting invertebrate communities.
5. Single lime treatments at moderate dosages of lakes and ponds resulted in variable and mostly temporary changes in chlorophyll a (chl a ) and phosphorus (P) concentration. Although sediment P release was reduced in single-dose lakes during the first winter following treatment, reductions appeared temporary.
6. Multiple treatments of lakes and ponds were effective at reducing both chl a and P concentrations over longer periods. Mean winter P release rate was also reduced after initial treatment.
7. In laboratory studies, sediment cores were incubated with eight different treatments to assess P release. Redox-sensitive treatments were no more effective at lowering total P concentration in overlying water than some redox-insensitive treatments. Lime reduced total P concentrations, but was not as effective as treatments with alum.
8. The use of lime in managing macrophyte and phytoplankton biomass in shallow, hardwater lakes and ponds may be preferable over other treatments, because lime is economical and non-toxic as long as pH is kept within a natural range.     

A survey on water chemistry and plankton in high mountain lakes in northern Swedish Lapland

A helicopter survey was carried out on 56 water bodies in the Abisko mountains, Swedish Lapland, in August 1981. Water chemistry was found to be highly correlated with bedrock quality in the drainage area of the lakes. Low pH values (down to 5.1) appeared in the neighbourhood of sulphuric iron-ores. Natrium and chloride concentrations showed large scale patterns which can be explained by orographic rainfall. Biologically, northern high mountain conditions are reflected in species composition rather than in biomass or possibly in diversity. Small chrysomonades and dinoflagellates, as well as Keratella hiemalis and Cyclops scutifer characterize the most ‘arctic’ waters. A comparison with data from earlier investigations did not confirm expected signs of acidification.     

Linking nutrient limitation and water chemistry in upland lakes to catchment characteristics

Overbank sedimentation on river floodplains can result in significant reduction of the suspended sediment load transported by a river and can thus represent an important component of the catchment sediment budget. Such conveyance losses will also exert an important influence on sediment-associated contaminant fluxes and budgets. This contribution reports the results of a study of sediment-associated contaminants (i.e. total-P, Cr, Cu, Pb and Zn) fluxes in the River Swale (1346 km²) and River Aire (1002 km²) in Yorkshire, U.K., aimed at quantifying the role of overbank floodplain sedimentation in the sediment-associated contaminant budgets. The catchment of the River Aire is dominated by urban and industrial land use in its middle and lower reaches, whereas the River Swale drains a largely rural catchment, although there is a legacy of metal mining in its headwaters which impacts on heavy metal transport by the river. The results for the River Swale indicate that the conveyance losses associated with the deposition of sediment-associated contaminants on the floodplains bordering the main river can be as high as 47% of the total flux through the main channel system. Equivalent values for the River Aire range up to 26%. Contrasts between the two rivers reflect both the location of the contaminant sources within the catchments and the relative magnitude of the fine sediment deposition fluxes associated with their floodplains.     

Molecular identification of filterable bacteria and archaea in the water of acidic lakes of northern Russia

Wetland ecosystems are the natural centers of freshwater formation in northern Russia lowland landscapes. The humic acidic waters formed in bogs feed the numerous lakes of the northern regions. One milliliter of the water in these lakes contains up to 10⁴ ultrasmall microbial cells that pass through “bacterial” filters with a pore size of 0.22 μm. The vast majority of these cells do not grow on nutrient media and cannot be identified by routine cultivation-based approaches. Their identification was performed by analysis of clone libraries obtained by PCR amplification of archaeal and bacterial 16S rRNA genes from the fraction of cells collected from water filtrates of acidic lakes. Most of the obtained bacterial 16S rRNA gene sequences represented the class Betaproteobacteria and exhibited the highest homology of (94–99%) with 16S rRNA genes of representatives of the genera Herbaspirillum, Herminiimonas, Curvibacter, and Burkholderia. The archaeal 16S rRNA gene clone library comprised genes of Euryarchaeota representatives. One-third of these genes exhibited 97–99% homology to the 16S rRNA genes of taxonomically described organisms of the orders Methanobacteriales and Methanosarcinales. The rest of the cloned archaeal 16S rRNA genes were only distantly related (71–74% homology) to those in all earlier characterized archaea.     

Fossil diatom inferred reconstruction of the pH history of two acidic,clear water lakes from insular Newfoundland,Canada

Palaeoecological research has been used to evaluate the impact of acidic deposition on lakes in insular Newfoundland. Terrestrial organic deposits in the region have considerable influence on freshwaters and have placed constrains on interpretation of the degree of anthropogenic acidification. In this paper, a region-specific calibration equation unique to clear water lakes (colour values 15) is developed from diatom assemblages in surface sediments from 22 lakes. The inferred pH history of two acidic, clear water lakes is then developed with a view to eliminating the influence of organic acidity from the interpretation of historical acid-base chemistry. The pH histories of the two lakes suggest modest declines (0.3 to 0.4 unit) in the most recent strata (i.e. since the 1930's). Both lakes demonstrate an increase in inferred pH in the surface horizon, which is consistent with declines in acidic deposition in the region since the mid 1970's. The magnitude and timing of the pH trends in these two lakes is common to those previously developed from more highly coloured lakes. The similar magnitude and onset of pH declines in lakes with varying amounts of organic influence provides no palaeolimnological evidence to suggest a contribution to, or modification of, lake acidification by organic acids.     

The effects of liming an Adirondack lake watershed on downstream water chemistry

Calcite treatment of chronically acidic lakes has improved fish habitat, but the effects on downstream water quality have not previously been examined. In this study, the spatial and temporal effects of watershed CaCO₃ treatment on the chemistry of a lake outlet stream in the Adirondack Mountains of New York were examined. Before CaCO₃ treatment, the stream was chronically acidic. During spring snowmelt before treatment, pH and acid-neutralizing capacity (ANC) in the outlet stream declined, and NO ₃ ^– and inorganic monomeric aluminum (Al_IM) concentrations increased sharply. During that summer, SO ₄ ^– and NO ₃ ^– concentrations decreased downstream, and dissolved organic carbon (DOC) concentrations and ANC increased, in association with the seasonal increase in decomposition of organic matter and the attendant SO ₄ ^– -reduction process. A charge-balance ANC calculation closely matched measured downstream changes in ANC in the summer and indicated that SO ₄ ^– reduction was the major process contributing to summer increases in ANC. Increases in Ca²⁺ concentration and ANC began immediately after CaCO₃ application, and within 3 months, exceeded their pretreatment values by more than 130 eq/L. Within 2 months after treatment, downstream decreases in Ca²⁺ concentration, ANC, and pH, were noted. Stream mass balances between the lake and the sampling site 1.5 km downstream revealed that the transport of all chemical constituents was dominated by conservative mixing with tributaries and ground water; however, non-conservative processes resulted in significant Ca²⁺ losses during the 13-month period after CaCO₃ treatment. Comparison of substrate samples from the buffered outlet stream with those from its untreated tributaries showed that the percentage of cation-exchange sites occupied by Ca²⁺ as well as non-exchangeable Ca, were higher in the outlet-stream substrate than in tributary-stream substrate. Mass-balance data for Ca²⁺ H⁺, Al_IM, and DOC revealed net downstream losses of these constituents and indicated that a reasonable set of hypothesized reactions involving Al_IM, HCO ₃ ^– , Ca²⁺, SO ₄ ^– NO ₃ ^– , and DOC could have caused the measured changes in stream acid/base chemistry. In the summer, the sharp decrease in ANC continued despite significant downstream decreases in SO₄ ^2– concentrations. After CaCO₃ treatment, reduction of SO ₄ ^– was only a minor contributor to ANC changes relative to those caused by Ca²⁺ dilution from acidic tributaries and acidic ground water, and Ca²⁺ interactions with stream substrate.     

The effect of water movement on the distribution of Oligochaeta in lakes

The Oligochaeta are more exposed to disturbance under conditions of intense water movement than other invertebrates, particularly when the substrate is unstable. Furthermore, low mobility of bottom water, which can lead to excessive accumulation of organic matter in sediments, and to the formation of sapropel, can also be limiting to the distribution of oligochaetes. Organic contamination in conditions of low water dynamics can result in the absence of Oligochaeta through oxygen depletion. Dynamic water movement can stimulate the mass development of Oligochaeta in organically polluted areas.     

Whole-lake lead burdens in sediments of lakes in southern Ontario,Canada

The anthropogenic stable lead content of the sediments of eight softwater Precambrian lakes in southern Ontario was measured at 34–92 sites per lake. Whole-lake anthropogenic lead burdens varied between only 610 and 770 mg m^–2. There was no relationship between lead burden and either water replenishment time of the lake (T_W) or the ratio of watershed area to lake area (Ad/A₀), which varied by factors of 4 and 12 respectively. These results can be explained if a) the lead deposition in this region is uniform, and b) the only significant input of lead to the lakes is via deposition from the atmosphere directly on the lakes' surfaces. Therefore spatial differences in anthropogenic lead within a lake represent the redistribution or focusing pattern of the sediments.     

Acidification affects the perch,Perca fluviatilis,populations in small lakes,of southern Finland

Synopsis Characteristics of perch were studied in 4 recently acidified lakes in southern Finland. The densities of the populations were 0–250 ha^–1 compared with 1400–3300 ha^–1 in two circumneutral reference lakes. The perch were close to extinction in one acidic lake and dominated by 7 year old fish in two other acidic lakes, suggesting decreased reproduction. Individual fecundity was not reduced by the acidity, but high mortality (close to 100%) of eggs in two acidic lakes indicated recruitment failure. In one of the acidified lakes reproduction had continued resulting in a population dominated by younger fish. However, increased egg mortality, low density, and the resulting high growth rate of perch in this lake were considered to be consequences of the acidity. These findings are the first documentation on the possible decrease of fish populations in Finland due to acid precipitation.