Epilithic diatoms of the St. Lawrence River and their relationships to water quality

1998 ◽  
Vol 76 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Euan D. Reavie ◽  
John P. Smol
Keyword(s):  
Water Quality ◽  
Epilithic Diatoms ◽  
St Lawrence River

Epilithic diatoms of the St. Lawrence River and their relationships to water quality

1998 ◽  
Vol 76 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Euan D Reavie ◽  
John P Smol
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Suspended Solids ◽  
Fecal Coliforms ◽  
Weighted Averaging ◽  
Quebec City ◽  
Diatom Assemblages ◽  
Epilithic Diatoms ◽  
Epilithic Diatom ◽  
St Lawrence River

Epilithic diatoms were sampled at 48 sites along the St. Lawrence River, from Salaberry de Valleyfield to Québec City, in an attempt to determine how diatom assemblages were related to measured water quality variables. Canonical correspondence analysis was used to explore the relationships between environmental variables and patterns in the epilithic diatom assemblages. "Distance downstream from Cornwall" was determined to be the strongest variable influencing the structure of epilithic diatom assemblages, likely due to the effect of tides (favouring aerophilic species) closer to the river outlet. Variables related to pollution (suspended solids, fecal coliforms, chlorophyll a) also explained significant (P < 0.05) amounts of variance in the diatom assemblages. The optima of common diatom species to suspended solids were explored further. Reconstructive models using weighted-averaging calibration and regression illustrated that "distance from Cornwall" and concentrations of suspended solids, fecal coliforms, and chlorophyll a, the most influential variables, could be inferred from the diatom assemblages. When compared with the inference models developed for pollution variables using epiphytic diatom assemblages (attached to macrophytes or Cladophora), the epilithon model appears to perform better.Key words: diatoms, rocks, epilithic, St. Lawrence River, water quality, calibration.

Organic and Inorganic Contaminants in the St. Lawrence River: Some Preliminary Results on Their Distribution

1986 ◽  
Vol 21 (4) ◽  
pp. 592-603 ◽  
Author(s):  
Ken R. Lum ◽  
Klaus L.E. Kaiser
Keyword(s):  
Water Quality ◽  
Great Lakes ◽  
Toxic Effect ◽  
Mississippi River ◽  
Aquatic Organisms ◽  
Inorganic Contaminants ◽  
Volatile Hydrocarbons ◽  
Quality Guidelines ◽  
Intensive Sampling ◽  
St Lawrence River

Abstract Volatile hydrocarbons (VHC’s) have been measured at many locations in the St. Lawrence River, Several concentrations of VHC’s were higher than those measured at other polluted Great Lakes sites, e.g. the St. Clair River. Tributaries to the St. Lawrence River were found to be significant sources of VHC’s. Cadmium in the St. Lawrence River is mostly found in dissolved (bioavailable) forms as compared to the Mississippi River where dissolved cadmium accounts for about 10% of the total cadmium. The major sources of cadmium appear to be in the Montreal area. Although the analytical results show local impairment in water quality, intensive sampling is required to pinpoint sources and/or quantify loadings, However, none of the VHC or cadmium concentrations exceed water quality guidelines or objectives. In fact there are no guidelines for most VHC’s. Nevertheless, the concentrations of VHC’s and cadmium found should have no toxic effect on aquatic organisms. The results of this study indicate that there are major sources of VHC’s and cadmium in Quebec. For example, inputs on the southwestern portion of Lac St.Louis may be a major source of perchloroethylene, and effluents in the vicinity of the Montreal STP may be a major source of cadmium. U.S. tributaries, e.g. the Grassy River, may also be a significant source of VHC’s.

Use of epilithic diatoms to evaluate water quality of Akgay Stream (Büyuk-Menderes River) in Mugla/Turkey

River Systems ◽  
2007 ◽  
Vol 17 (3-4) ◽  
pp. 327-338
Author(s):  
Cunyed Nadir Solak ◽  
Giszella Fehér ◽  
Murar Barlas ◽  
Koksal Pabugccu
Keyword(s):  
Water Quality ◽  
Epilithic Diatoms ◽  
Büyük Menderes River

Cumulative impacts of hydrology and human activities on water quality in the St. Lawrence River (Lake Saint-Pierre, Quebec, Canada)

2008 ◽  
Vol 65 (6) ◽  
pp. 1165-1180 ◽  
Author(s):  
Christiane Hudon ◽  
Richard Carignan
Keyword(s):  
Water Quality ◽  
Spatial Variability ◽  
Human Activities ◽  
Urban Areas ◽  
Nutrient Retention ◽  
Quality Criterion ◽  
Cumulative Impacts ◽  
Aquatic Life ◽  
Navigation Channel ◽  
St Lawrence River

The cumulative impacts of discharge and human activities on the spatial variations of water quality were assessed from monthly measurements at 80–110 stations in a ~300 km2 widening of the St. Lawrence River (Lake Saint-Pierre, Québec). Water quality was poorest under high discharge conditions and in shallow riparian areas under the influence of small tributaries draining farmlands; spatial variability was amplified by aquatic macrophytes. In 2004, over 40% of the study area exceeded the provincial water quality criterion (total phosphorus = 30 µg P·L–1) to protect aquatic life in rivers. Nutrient retention occurred mostly during summer when macrophytes were abundant and current velocities were low. Erosion of dredged deposits near the navigation channel was observed during summer, when current velocities increased in the deep channel because of flow obstruction by macrophytes growing in shallow areas. Low discharge conditions and high macrophyte abundance sharpened the contrast between the Lake Ontario waters flowing rapidly through the central river channel and the slow-flowing, low-quality tributary waters along the shores. The cumulative effect of high nutrient inflow from urban areas and farmlands, the man-made navigation channel, and seasonal flow obstruction by macrophytes thus induce a marked spatial variability in water quality within Lake Saint-Pierre.

scholarly journals Sampler collection gadget for epilithic diatoms

2007 ◽  
Vol 67 (4) ◽  
pp. 681-683 ◽  
Author(s):  
SE. Salomoni ◽  
LC. Torgan ◽  
O. Rocha
Keyword(s):  
Water Quality ◽  
Water Quality Monitoring ◽  
Density Variation ◽  
Quality Monitoring ◽  
Diatom Community ◽  
Epilithic Diatoms ◽  
Epilithic Diatom

This work present a new gadget for sampling epilithic diatoms from both lentic and lotic enviroments. The sampler consists of a polystyrene cylinder, left to float on the surface of the water, to which stone substrates are attached. This epilithic diatom sampler (EDS) can be used to detect spatial and temporal richness and density variation in the study of the diatom community, as well as in water quality monitoring.

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