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

1990 ◽  
Vol 327 (1240) ◽  
pp. 403-412 ◽  
Keyword(s):  
United States ◽  
New England ◽  
Sierra Nevada ◽  
Acidic Deposition ◽  
Land Use Changes ◽  
Acid Neutralizing Capacity ◽  
Calibration Data ◽  
Contributing Factors ◽  
Neutralizing Capacity ◽  
Inferred Ph

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 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.

scholarly journals Freshwater salinization syndrome on a continental scale

2018 ◽  
Vol 115 (4) ◽  
pp. E574-E583 ◽  
Author(s):  
Sujay S. Kaushal ◽  
Gene E. Likens ◽  
Michael L. Pace ◽  
Ryan M. Utz ◽  
Shahan Haq ◽  
...  
Keyword(s):  
United States ◽  
Major Ions ◽  
Base Cations ◽  
Acid Neutralizing Capacity ◽  
United States Geological Survey ◽  
Past Century ◽  
Accelerated Weathering ◽  
Continental Scale ◽  
Neutralizing Capacity ◽  
Freshwater Salinization

Salt pollution and human-accelerated weathering are shifting the chemical composition of major ions in fresh water and increasing salinization and alkalinization across North America. We propose a concept, the freshwater salinization syndrome, which links salinization and alkalinization processes. This syndrome manifests as concurrent trends in specific conductance, pH, alkalinity, and base cations. Although individual trends can vary in strength, changes in salinization and alkalinization have affected 37% and 90%, respectively, of the drainage area of the contiguous United States over the past century. Across 232 United States Geological Survey (USGS) monitoring sites, 66% of stream and river sites showed a statistical increase in pH, which often began decades before acid rain regulations. The syndrome is most prominent in the densely populated eastern and midwestern United States, where salinity and alkalinity have increased most rapidly. The syndrome is caused by salt pollution (e.g., road deicers, irrigation runoff, sewage, potash), accelerated weathering and soil cation exchange, mining and resource extraction, and the presence of easily weathered minerals used in agriculture (lime) and urbanization (concrete). Increasing salts with strong bases and carbonates elevate acid neutralizing capacity and pH, and increasing sodium from salt pollution eventually displaces base cations on soil exchange sites, which further increases pH and alkalinization. Symptoms of the syndrome can include: infrastructure corrosion, contaminant mobilization, and variations in coastal ocean acidification caused by increasingly alkaline river inputs. Unless regulated and managed, the freshwater salinization syndrome can have significant impacts on ecosystem services such as safe drinking water, contaminant retention, and biodiversity.

Diatom-inference models for acid neutralizing capacity and nitrate based on 41 calibration lakes in the Sierra Nevada, California, USA

2013 ◽  
Vol 50 (2) ◽  
pp. 159-174 ◽  
Author(s):  
James O. Sickman ◽  
Danuta M. Bennett ◽  
Delores M. Lucero ◽  
Thomas J. Whitmore ◽  
William F. Kenney
Keyword(s):  
Sierra Nevada ◽  
Acid Neutralizing Capacity ◽  
Inference Models ◽  
Neutralizing Capacity

scholarly journals Rapid Recent Recovery from Acidic Deposition in Central Ontario Lakes

Soil Systems ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 10 ◽  
Author(s):  
Shaun A. Watmough ◽  
M. Catherine Eimers
Keyword(s):  
Acidic Deposition ◽  
Base Cation ◽  
Acid Neutralizing Capacity ◽  
Chemical Recovery ◽  
Charge Balance ◽  
Limited Effect ◽  
Lake Recovery ◽  
Neutralizing Capacity ◽  
Carbon Concentrations ◽  
S Deposition

In many regions, chemical recovery in lakes from acidic deposition has been generally slower than expected due to a variety of factors, including continued soil acidification, climate-induced sulphate (SO4) loading to lakes and increases in organic acidity. In central Ontario, Canada, atmospheric sulphur (S) deposition decreased by approximately two-thirds between 1982 and 2015, with half of this reduction occurring between 2005 and 2015. Chemical recovery in the seven lakes was limited prior to 2005, with only small increases in pH, Gran alkalinity and charge-balance ANC (acid-neutralizing capacity). This was because lake SO4 concentrations closely followed changes in S deposition, and decreases in base cation concentration closely matched declines in SO4. However, decreases in S deposition and lake SO4 were more pronounced post-2005, and much smaller decreases in lake base cation concentrations relative to SO4 resulted in large and rapid increases in pH, alkalinity and ANC. Dissolved organic carbon concentrations in lakes increased over the study period, but had a limited effect on lake recovery. Clear chemical recovery of these lakes only occurred after 2005, coinciding with a period of dramatic declines in S deposition.

Effects of low pH and aluminum on amphibians at high elevation in the Sierra Nevada, California

1994 ◽  
Vol 72 (7) ◽  
pp. 1272-1279 ◽  
Author(s):  
David F. Bradford ◽  
Christina Swanson ◽  
Malcolm S. Gordon
Keyword(s):  
Body Size ◽  
Sierra Nevada ◽  
Sublethal Effects ◽  
High Elevation ◽  
Low Ph ◽  
Soft Water ◽  
Post Treatment ◽  
Acid Neutralizing Capacity ◽  
Pseudacris Regilla ◽  
Neutralizing Capacity

At high elevation in the Sierra Nevada of California, surface waters are extremely low in acid-neutralizing capacity and thus may be vulnerable to changes in water chemistry due to acid deposition. The present study assesses the sensitivity of embryos and hatchling larvae of two Sierran amphibians, Pseudacris regilla (Pacific chorus frog) and Ambystoma macrodactylum (long-toed salamander), to low pH and an elevated level of dissolved aluminum. The populations of these two species are not known to be declining at present. These findings are compared with results for two other Sierran amphibians, Rana muscosa (mountain yellow-legged frog) and Bufo canorus (Yosemite toad), both of which reportedly have declined substantially in numbers in recent years. Embryos and hatchlings of P. regilla and A. macrodactylum were kept for 7 d in reconstituted soft water at pH 4.0–6.0 (inorganic monomeric aluminum effectively 0 or 39–80 μg/L at pH ≥ 4.9), and subsequently for a post-treatment period of up to 16 d in reconstituted soft water at pH 6.0 (no aluminum). LC50 pH values for post-treatment survival averaged 4.3 for embryos and tadpoles of both species. The estimated extreme pH for Sierra Nevada surface water, 5.0, did not cause a significant reduction in survival for either life stage of either species, and sublethal effects on body size and hatching time were not evident at pH ≥ 5.0. Aluminum also did not affect survival of either species, although sublethal effects were evident as reduced body size of A. macrodactylum larvae and earlier hatching in P. regilla. Pseudacris regilla and A. macrodactylum were not consistently more tolerant of low pH than R. muscosa and B. canorus. However, the latter two species show sublethal effects of low pH at pH ≥ 5.0, whereas the former two do not.

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