The Saguenay Fjord: A Third Factor in the Toxic Chemical Contamination of the St. Lawrence River Estuary

1990 ◽  
Vol 25 (1) ◽  
pp. 1-14
Author(s):  
R.J. Allan
Keyword(s):  
Toxic Metals ◽  
River Estuary ◽  
Organic Chemical ◽  
Organic Chemicals ◽  
Chemical Contamination ◽  
Lawrence Estuary ◽  
The Past ◽  
Saguenay Fjord ◽  
St Lawrence Estuary ◽  
St Lawrence River

Abstract The Saguenay Fjord enters the north shore of the St. Lawrence River estuary. The St. Lawrence River is one source of a variety of toxic metals and organic chemicals to its estuary. Some of these chemicals are transported by the river from its source in Lake Ontario and others are added along its course. However, the second major source of water inflow to the St. Lawrence Estuary is the Saguenay Fjord, which is by no means free of contamination. This paper overviews the types of toxic metals and organic chemical contamination and sources in the fjord proper and upstream in its drainage basin. The principal contaminants recorded in bottom sediments are polyaromatic hydrocarbons and mercury. An extensive forest products industry may also be a source of toxic chlorinated organic chemicals. The combined (peak) inputs of these chemicals to the Saguenay Fjord system was in the past and may have continued for many years, even decades. The relationship between the type of contaminants introduced in the past to the St. Lawrence estuary by the St. Lawrence River and the Saguenay Fjord may have implications concerning contamination of the beluga whale population which is located most frequently in the estuary near the fjord inflow.

Le Panache du Saguenay

1983 ◽  
Vol 40 (1) ◽  
pp. 52-60 ◽  
Author(s):  
J. Lebel ◽  
E. Pelletier ◽  
M. Bergeron ◽  
N. Belzile ◽  
G. Marquis
Keyword(s):  
Surface Layer ◽  
Deep Water ◽  
High Tide ◽  
Lawrence Estuary ◽  
Fresh Waters ◽  
Saguenay Fjord ◽  
Region Data ◽  
Saguenay River ◽  
St Lawrence Estuary ◽  
St Lawrence River

The large difference between the alkalinity of the fresh waters of the St. Lawrence River (1.475 mmol∙kg−1) and the Saguenay River (0.134 mmol∙kg−1) was used to locate the region on the St. Lawrence estuary which is under the influence of the Saguenay River. This method has the advantage over classical measurements such as salinity and temperature that it is independent of the upwelling of deep water in this region. Data was obtained in the St. Lawrence estuary near the mouth of the Saguenay fjord using a network of 33 stations at slack low tide and 23 stations at slack high tide. The results show that, at low tide, Saguenay water forms a plume which extends more than 10 km from the mouth of the fjord into the estuary. At high tide the plume is restricted to the surface layer as the Saguenay waters are pushed back into the fjord.

Hunting for Quaternary Faults in Eastern Canada: A Critical Appraisal of Two Potential Candidates

2020 ◽  
Author(s):  
Nicolas Pinet ◽  
Maurice Lamontagne ◽  
Mathieu J. Duchesne ◽  
Virginia I. Brake
Keyword(s):  
River Estuary ◽  
Seismic Profile ◽  
Fault Scarp ◽  
Seismic Zone ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
Surface Ruptures ◽  
St Lawrence Estuary ◽  
Fault Scarps ◽  
St Lawrence River

Abstract This study documents two potential neotectonic features in the seismically active St. Lawrence estuary and western part of the Gulf of St. Lawrence of Quebec, Canada. Historically, the region is the locus of series of damaging earthquakes, including the 1663 M 7 earthquake, which suggests the occurrence of coseismic surface ruptures beneath the St. Lawrence River. In the western Gulf of St. Lawrence (Lower St. Lawrence seismic zone), a potential fault scarp identified on a vintage seismic profile has been investigated through high-resolution seismic and multibeam bathymetry data. On the seafloor, the scarp corresponds to an ∼1.8  m high (maximum) feature that is located above a buried escarpment of the Paleozoic bedrock. Holocene units are draping over the escarpment on one profile, but are possibly cut on two others. The scarp meets several of the criteria generally associated with neotectonic features. However, a close look at the data indicates that the staircase geometry of the top of the bedrock and its expression at the surface is linked, at least partially, with the presence of an erosion-resistant unit. This makes a neotectonic reactivation possible but not proven. In the Tadoussac area, ∼40  km north of the Charlevoix seismic zone, the offshore extension of the St. Laurent fault corresponds to an ∼110  m high bathymetric escarpment with well-preserved triangular facets. Such “fresh” morphology is unique in the St. Lawrence River Estuary and may attest to Quaternary displacements, yet other interpretations may also explain the unusual preservation of the escarpment. These two case studies illustrate the difficulty to unambiguously document Holocene fault scarps, even in the marine domain in which the sedimentary succession is generally continuous.

L'alcalinité totale comme indicateur de mélange dans un milieu estuarien

1980 ◽  
Vol 17 (8) ◽  
pp. 978-984 ◽  
Author(s):  
E. Pelletier ◽  
J. Lebel
Keyword(s):  
Dissolved Oxygen ◽  
Total Alkalinity ◽  
Dilution Factor ◽  
Mixing Index ◽  
Lawrence Estuary ◽  
Estuarine Mixing ◽  
Saguenay Fjord ◽  
Saguenay River ◽  
St Lawrence Estuary ◽  
St Lawrence River

This paper proposes the use of total alkalinity as a mixing index at the mouth of Saguenay fjord on the St. Lawrence estuary. The large difference in the total alkalinity between the fresh waters from the St. Lawrence River (1.475 meq/kg) and those from the Saguenay River (0.134 meq/kg) allows us to define and calculate a dilution factor relative to total alkalinity (δAt), which is very sensitive to the presence of the fjord marine water in the estuarine mixing area both at the surface and at depth. The authors show the advantage of use of the dilution factor (δAT) in comparison to some other classical oceanographic parameters such as temperature, salinity, density, and dissolved oxygen.

New records of the mysids Boreomysis nobilis G. O. Sars and Mysis litoralis (Banner) in the Saguenay fjord (St. Lawrence estuary)

1974 ◽  
Vol 52 (8) ◽  
pp. 1087-1090 ◽  
Author(s):  
David C. Judkins ◽  
Robert Wright
Keyword(s):  
New Records ◽  
The Arctic ◽  
Glacial Period ◽  
Isolated Populations ◽  
Lawrence Estuary ◽  
Midwater Trawl ◽  
Boreal Region ◽  
Saguenay Fjord ◽  
St Lawrence Estuary

The arctic–subarctic mysids Boreomysis nobilis and Mysis litoralis were abundant in midwater trawl collections from the Saguenay fjord but were almost absent in collections from the confluent St. Lawrence estuary and Gulf of St. Lawrence. Collections from the estuary and Gulf contained boreal mysids more typical of the latitude. The presence of apparently isolated populations of B. nobilis and M. litoralis in the fjord is further evidence that it is an arctic enclave within a boreal region. The hypothesis that populations of arctic and subarctic species in the Saguenay fjord are relicts from a previous glacial period is questioned in view of the possibility of more recent faunal exchange between the Arctic and the fjord via intermediate arctic enclaves on the eastern Canadian coast.

scholarly journals Diet of St. Lawrence Estuary Beluga (Delphinapterus leucas) in a changing ecosystem

2020 ◽  
Vol 134 (1) ◽  
pp. 21-35
Author(s):  
Véronique Lesage ◽  
Stéphane Lair ◽  
Samuel Turgeon ◽  
Pierre Béland
Keyword(s):  
Prey Availability ◽  
Population Decline ◽  
Delphinapterus Leucas ◽  
Anthropogenic Factors ◽  
Adult Males ◽  
Current Time ◽  
Lawrence Estuary ◽  
The Past ◽  
Important Prey ◽  
St Lawrence Estuary

Ecosystems and community structure fluctuate over time as a result of natural and anthropogenic factors that may affect prey availability and population dynamics. Most of what we know about St. Lawrence Estuary (SLE) Beluga (Delphinapterus leucas) diet comes from stomach contents collected 80 years ago mainly from a hunting site that Beluga no longer use. How reflective these data are of Beluga diet at other sites and at the current time is unknown. In the context of the recent population decline, general information of prey species alone may help identify useful conservation actions for potentially important prey or habitats. Here, we examined the diet of SLE Beluga using digestive tracts collected from carcasses recovered over the past 30 years, in the context of historical diet data and recent changes in the St. Lawrence ecosystem. We showed they have a varied diet composed of fish and invertebrates generally <30 cm in length, and that adult males and females differ in their summer diet in a way that is consistent with the sex segregation observed in this population. Our results also indicate that polychaete worms, squid, and cod are still among the most prevalent prey, and that species such as redfish (Sebastes spp.) might be important prey items. This study shows that Beluga diet has changed since the 1930s, and that prey from digestive tracts identified to species are valuable for making comparisons to the past, and for improving applications of molecular analyses, such as stable isotopes and fatty acids.

scholarly journals Spatial variations in CO<sub>2</sub> fluxes in the Saguenay Fjord (Quebec, Canada) and results of a water mixing model

2020 ◽  
Vol 17 (2) ◽  
pp. 547-566 ◽  
Author(s):  
Louise Delaigue ◽  
Helmuth Thomas ◽  
Alfonso Mucci
Keyword(s):  
Surface Waters ◽  
Brackish Water ◽  
Field Measurements ◽  
Mixing Model ◽  
Isotopic Tracers ◽  
Lawrence Estuary ◽  
Relative Contribution ◽  
Saguenay Fjord ◽  
Spring Freshet ◽  
St Lawrence Estuary

Abstract. The Saguenay Fjord is a major tributary of the St. Lawrence Estuary and is strongly stratified. A 6–8 m wedge of brackish water typically overlies up to 270 m of seawater. Relative to the St. Lawrence River, the surface waters of the Saguenay Fjord are less alkaline and host higher dissolved organic carbon (DOC) concentrations. In view of the latter, surface waters of the fjord are expected to be a net source of CO2 to the atmosphere, as they partly originate from the flushing of organic-rich soil porewaters. Nonetheless, the CO2 dynamics in the fjord are modulated with the rising tide by the intrusion, at the surface, of brackish water from the Upper St. Lawrence Estuary, as well as an overflow of mixed seawater over the shallow sill from the Lower St. Lawrence Estuary. Using geochemical and isotopic tracers, in combination with an optimization multiparameter algorithm (OMP), we determined the relative contribution of known source waters to the water column in the Saguenay Fjord, including waters that originate from the Lower St. Lawrence Estuary and replenish the fjord's deep basins. These results, when included in a conservative mixing model and compared to field measurements, serve to identify the dominant factors, other than physical mixing, such as biological activity (photosynthesis, respiration) and gas exchange at the air–water interface, that impact the water properties (e.g., pH, pCO2) of the fjord. Results indicate that the fjord's surface waters are a net source of CO2 to the atmosphere during periods of high freshwater discharge (e.g., spring freshet), whereas they serve as a net sink of atmospheric CO2 when their practical salinity exceeds ∼5–10.

Distribution des spectres de taille des particules en suspension dans le fjord du Saguenay

1979 ◽  
Vol 16 (2) ◽  
pp. 240-249 ◽  
Author(s):  
J. P. Chanut ◽  
S. A. Poulet
Keyword(s):  
Particle Size ◽  
Water Mass ◽  
Layer Structure ◽  
Principal Component ◽  
Water Masses ◽  
Size Spectra ◽  
Lawrence Estuary ◽  
Saguenay Fjord ◽  
Bottom Waters ◽  
St Lawrence Estuary

The spatial distribution of particle size spectra shows a two-layer stratification in May but reveals three-layer structure in September, both in the Saguenay fjord and in the adjacent waters of the St. Lawrence estuary, near the sill. In May, the particle size spectra in the surface layer show considerable variability whereas, in the bottom waters, they appear to be relatively homogeneous. In September, the deeper, more homogeneous water mass is less extensive. It is apparently eroded by diffusion and advection during summer months and becomes restricted to intermediate depths towards the head of the fjord. During the same period, a water mass with physical and particulate properties different from the upper layers occupies the bottom of the fjord. Principal component analysis shows that variations in particle size spectra are independent from one layer to another. Water masses with identical physical and particulate properties located in both sides of the sill illustrate the influence of the St. Lawrence estuary on the Saguenay fjord. These water masses, generally located below the sill depth, indicate the existence of powerful advective mechanisms in this region.

Étude de la remontée relative des niveaux d'eau de l'estuaire du Saint-Laurent

1992 ◽  
Vol 19 (2) ◽  
pp. 252-259 ◽  
Author(s):  
François Anctil ◽  
Jean-Pierre Troude
Keyword(s):  
High Water ◽  
Water Levels ◽  
Freshwater Input ◽  
Relative Variation ◽  
Lawrence Estuary ◽  
High Discharge ◽  
Mean Water Level ◽  
Stability Of Water ◽  
St Lawrence Estuary ◽  
St Lawrence River

Data available on water levels in the St. Lawrence Estuary were used to evaluate the relative variation of mean water levels in this area. Only measurements taken at Pointe-au-Père could be used to evaluate this parameter with the required precision; a relative stability of water levels (−0.3 ± 0.5 mm/year) was observed. Upstream stations, especially the ones in the estuary, are highly influenced by the freshwater input of the St. Lawrence River. The high discharge of the river has been identified as the main cause of high water levels observed between 1970 and 1988 and, consequently, of bank erosion at the limit of the St. Lawrence estuary. Key words: discharge, erosion, estuary, mean water level, relative variation.

Distribution, Transport, and Composition of Suspended Matter in the St. Lawrence Estuary

1973 ◽  
Vol 10 (9) ◽  
pp. 1380-1396 ◽  
Author(s):  
Bruno F. d'Anglejan ◽  
Eric C. Smith
Keyword(s):  
Suspended Matter ◽  
Large Time ◽  
Total Suspended Matter ◽  
Quebec City ◽  
Lawrence Estuary ◽  
Tidal Circulation ◽  
Saguenay River ◽  
St Lawrence Estuary ◽  
Vertical Gradients ◽  
St Lawrence River

The distribution of total suspended matter in the estuary of the St. Lawrence River was studied by quantitative filtration through membrane filters. Tidal fluctuations in the vertical gradients of suspensoids were followed at fixed stations along the estuary. The concentrations varied from nearly 40 mg/1 below near Ile d'Orléans, to values less than 1 mg/1 at the downstream end of the upper estuary near the Saguenay River entrance. The tidal mean concentrations for the fixed stations ranged from 20 mg/1 to 2 mg/1. A turbidity maximum, which develops because of entrapments of particles by the tidal circulation, extends for 100 km below Quebec City. In this zone large vertical gradients changing in intensity with the tide by resuspension of settled material exist above the bottom. The total suspended matter is 60% to more than 90% inorganic by weight, and has a mean particle size between 5 and 7 μ. The annual rate of transport of suspended material out of the upper estuary at a section near the Saguenay River is estimated at less than 1 × 106 metric tons.Chemical and mineralogical analyses were performed on 23 suspensoid samples collected by centrifuging large volumes of water. The clay mineral composition of the less than 2 μ fraction is on the average 1.5% montmorillonite, 8% kaolinite, 31% chlorite, and 60% illite. However, large time and space variations are found both in the chemistry and mineralogy of the suspended matter.

Geochemistry of suspended particulate matter in the Saguenay Fjord

1978 ◽  
Vol 15 (6) ◽  
pp. 1002-1011 ◽  
Author(s):  
Bjørn Sundby ◽  
Douglas H. Loring
Keyword(s):  
Particulate Matter ◽  
Suspended Particulate Matter ◽  
Major Elements ◽  
Time And Space ◽  
Lawrence Estuary ◽  
Saguenay Fjord ◽  
Suspended Particulate ◽  
Bottom Waters ◽  
St Lawrence Estuary

Analysis of major elements in suspended particulate matter from the Saguenay Fjord in May and September 1974 shows that the content of Si, Al, Ca, Mg, and K remain relatively constant in time and space, reflecting the constancy of the silicate mineralogy of the particulate matter. Large variations in time and space occur, however, in the content of Fe and Mn. High levels of Fe occur in particulate matter from near-bottom waters of the fjord during both time periods. Variations in the Fe/Al ratios indicate that Fe is enriched in the non-silicate fraction of the particulate matter (oxides, hydroxides, etc.) in the near-bottom waters, but not elsewhere. In contrast, Mn is enriched relative to both Al and Fe in particulate matter from intermediate depths, and varies in time and space. This is attributed to the in situ uptake of Mn from seawater and (or) the input of particles, already containing high levels of Mn, from the St. Lawrence Estuary.

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