Morphological variation of Elliptio complanata (Bivalvia: Unionidae) in differing sediments of soft-water lakes exposed to acidic deposition

1989 ◽  
Vol 67 (8) ◽  
pp. 1895-1899 ◽  
Author(s):  
Scott G. Hinch ◽  
Laura J. Kelly ◽  
Roger H. Green
Keyword(s):  
Water Chemistry ◽  
Acidic Deposition ◽  
Principal Component ◽  
Environmental Water ◽  
Shell Morphology ◽  
Environmental Data ◽  
Sediment Type ◽  
Elliptio Complanata ◽  
Lake Water Chemistry ◽  
South Central

Clam shell morphology was related to lake water chemistry and sediment properties for Elliptio complanata from 40 south central Ontario lakes. Principal component analyses described the major trends in the environmental data. Relationships between shell morphology and the environmental trends were ascertained through a canonical correlation analysis. Thicker shells were related to increasing alkalinity, conductivity, and pH, suggesting that shell formation is favoured in well-buffered habitats that are not affected by acidic deposition. We also determined that narrow shells were related to coarse sediment in deeper water. This pattern of variation in shell morphology may be adaptive because streamlined shells would better enable clams to maintain their position in turbulent habitats. The water chemistry and sediment property correlates with shell morphology were independent of each other. Any attempt to use unionid shells as long-term indicators of changes in environmental water chemistry must be preceded by a consideration of other habitat variables such as water turbulence, sediment type, and depth.

scholarly journals Acidification and recovery of aquatic ecosystems in south central Ontario, Canada: regional application of the MAGIC model

2003 ◽  
Vol 7 (4) ◽  
pp. 561-573 ◽  
Author(s):  
J. Aherne ◽  
P. J. Dillon ◽  
B. J. Cosby
Keyword(s):  
Water Chemistry ◽  
Dynamic Model ◽  
Lake Water ◽  
Base Cation ◽  
Regional Modelling ◽  
Lake Chemistry ◽  
Emission Reductions ◽  
Lake Water Chemistry ◽  
South Central ◽  
Magic Model

Abstract. The dynamic model MAGIC was applied to 25 lakes in south-central Ontario, Canada using a regional modelling methodology. Soil and lake water chemistry for each lake catchment was simulated for the period 1850–2050. Sulphate (SO42–) deposition forecasts were derived from recently proposed emission reductions, which correspond roughly to a 50% reduction in SO42– deposition by 2010 from the 2000 baseline. Changes in SO42– deposition had a significant impact on lake chemistry. Simulated lake water chemistry showed a recovery potential under the current deposition scenario; by 2050 concentration levels recovered to values predicted for the early 1900s. Moreover, simulated future lake water chemistry showed significant recovery compared to 1975 levels. However, although regional simulations predict that base cation losses have decreased in recent years, soils in the region will continue to acidify with Ca2+ losses dominating depletion of the exchangeable pool. Base cation losses from the exchangeable pool are currently buffering lakes against the impacts of acid deposition; ultimately base cation inputs into the lakes will decrease as exchangeable base cation pools become depleted. Further emission reductions are necessary to ensure continued recovery from acidification. Keywords: regional dynamic model, sulphate, acid neutralising capacity, critical loads, lake chemistry, soil base saturation

Physico-chemical structure of the benthic environment of a Galician ría (Ría de Ares-Betanzos, north-west Spain)

1999 ◽  
Vol 79 (1) ◽  
pp. 1-21 ◽  
Author(s):  
A. Sánchez-Mata ◽  
M. Glémarec ◽  
J. Mora
Keyword(s):  
Organic Carbon ◽  
Principal Component ◽  
Clay Content ◽  
Size Composition ◽  
Total Carbon ◽  
Sediment Type ◽  
Overlying Water ◽  
Sediment Distribution ◽  
North West ◽  
Inorganic Content

In a preliminary study of the marine benthos of Ría de Ares-Betanzos, 50 stations covering the quadrant delineated by the coordinates 43°26′42″N–43°20′42″N and 08°18′54″W–08°10′12″W were sampled and sediment samples analysed for particle-size composition, sand, silt and clay content, degree of sorting, median diameter and grain-size diversity of sediments. Organic and inorganic content, total carbon and nitrogen, carbonates, organic carbon/total nitrogen ratio and bathymetric data were also collected. On a smaller scale a few stations were sampled for sediment redox potential and pH measurement. The salinity, temperature and oxygen content of the overlying water was also assessed.Cluster analysis and Principal Component Analysis methods were used to describe seabed heterogeneity and the pattern of sediment distribution within the ría, and to relate the environmental variables to each sediment type. Sediments were predominantly fine to very fine sands, and exhibited a direct depth-related gradient, i.e. with the finer grades, higher organic carbon and silt and clay occurring at the shallower areas of Pontedeume, Ares and Redes inlets and Ría de Betanzos sector where terrigenous input was important. Carbonate, organic carbon and organic matter maxima occurred in the central sector of the ría where most mollusc recruitment takes place: revealing the chiefly bioclastic origin of sediments. Taking into account the geological and hydrographic processes, explanations for the formation of the sedimentary bottoms in Ría de Ares-Betanzos are provided.

Mountain lake research (MOLAR): atmospheric deposition and lake water chemistry

2000 ◽  
Vol 27 (2) ◽  
pp. 1008-1012
Author(s):  
R. Psenner ◽  
R. Mosello ◽  
A. Boggero ◽  
A. Marchetto ◽  
B. Wathne ◽  
...  
Keyword(s):  
Atmospheric Deposition ◽  
Water Chemistry ◽  
Lake Water ◽  
Mountain Lake ◽  
Lake Water Chemistry

Acidic deposition and surface water chemistry

Eos ◽  
1988 ◽  
Vol 69 (22) ◽  
pp. 626
Author(s):  
M. R. Church
Keyword(s):  
Surface Water ◽  
Water Chemistry ◽  
Acidic Deposition ◽  
Surface Water Chemistry
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