Observations in the turbidity maximum of the St. Lawrence Estuary

1979 ◽  
Vol 16 (4) ◽  
pp. 939-950 ◽  
Author(s):  
Norman Silverberg ◽  
Bjørn Sundby
Keyword(s):  
Bottom Sediments ◽  
Suspended Matter ◽  
Detailed Examination ◽  
Lawrence Estuary ◽  
The North ◽  
Suspended Particulate ◽  
High Turbidity ◽  
St Lawrence Estuary ◽  
Maximum Turbidity Zone ◽  
Maximum Turbidity

A series of 13 and 25 h anchor stations and individual stations were occupied along the axis of the North Channel of the St. Lawrence Estuary during periods of both high and low river runoff. The data collected have permitted a detailed examination of the variations in salinity, suspended matter concentrations, and the size distributions of the suspended matter and the bottom sediments of the maximum turbidity zone. The high turbidity appears to be maintained by a complex density-driven circulation in combination with the resuspension of bottom sediments near the head of the estuary. The phenomenon may be aided by the breaking of internal waves. A longitudinal structure, which is only slightly influenced by changes in river discharge, is discernible for the zone. The highest concentrations of suspended matter occur in a well mixed region at the head of the estuary and suspended particulate matter levels decrease seaward as a two-layer estuarine circulation becomes better developed.

scholarly journals Do Barrow's Goldeneyes, Bucephala islandica, Breed South of the St. Lawrence Estuary in the Gaspé Peninsula, Eastern Canada?

2010 ◽  
Vol 124 (2) ◽  
pp. 179
Author(s):  
Jean-François Ouellet ◽  
Pierre Fradette ◽  
Isabel Blouin
Keyword(s):  
North America ◽  
Breeding Season ◽  
Breeding Habitat ◽  
Eastern North America ◽  
Eastern Canada ◽  
Lawrence Estuary ◽  
North Shore ◽  
The North ◽  
Bucephala Islandica ◽  
St Lawrence Estuary

We report the first observations of Barrow's Goldeneyes south of the St. Lawrence estuary in typical breeding habitat during the breeding season. Until recently, the confirmed breeding locations for the species in Eastern North America were all located on the north shore of the Estuary and Gulf of St. Lawrence.

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.

The structure of psoluthurin A, the major triterpene glycoside of the sea cucumber Psolusfabricii

1983 ◽  
Vol 61 (7) ◽  
pp. 1465-1471 ◽  
Author(s):  
François-Xavier Garneau ◽  
Jean-Luc Simard ◽  
Odette Harvey ◽  
John W. Apsimon ◽  
Michel Girard
Keyword(s):  
Triterpene Glycoside ◽  
Sea Cucumber ◽  
Chemical Data ◽  
Lawrence Estuary ◽  
North Shore ◽  
The North ◽  
Extraction And Purification ◽  
Physico Chemical ◽  
St Lawrence Estuary

The isolation of the major triterpene glycoside from the sea cucumber Psolusfabricii obtained from the north shore of the St. Lawrence estuary is described. Versatile extraction and purification procedures were used and physico-chemical data is presented in support of structure 1 for psoluthurin A.

scholarly journals La mer de Goldthwait au Québec

2010 ◽  
Vol 31 (1-2) ◽  
pp. 61-80 ◽  
Author(s):  
Jean-Claude Dionne
Keyword(s):  
Quebec City ◽  
The South ◽  
Lawrence Estuary ◽  
Marine Invasion ◽  
North Shore ◽  
The North ◽  
Upper Limit ◽  
South Shore ◽  
Anticosti Island ◽  
St Lawrence Estuary

The Goldthwait Sea is defined as the late- and post-Glacial marine invasion in the St. Lawrence Estuary and Gulf east of Québec City. In Québec, this sea has submerged an area of about 25 000 km2. The largest areas submerged are the north shore of the St. Lawrence between Les Escoumins and Blanc-Sablon, the south shore between Levis and Tourelles, and the Anticosti Island. The upper limit of the Goldthwait Sea varies from place to place. The Goldthwait Sea began 14 000 years ago and land emergence is still in progress, since the pre-Wisconsin marine level has not been recovered yet. For a better chronology, this long interval needs to be subdivided. Three main periods have been recognized: Goldthwaitian I, II and III. However, a geographical subdivision is also needed. Numerous shorelines were observed at various elevations throughout the area formely submerged by the Goldthwait Sea. However, only a few shorelines are well developed and extensive, and correlations between former shorelines are difficult to establish. Only three levels are widespead and common to the Estuary and parts of the Gulf. The isostatic recovery has been rapid during the first three thousand years after déglaciation of the area: about 75%.

Autumnal patterns of nocturnal passerine migration in the St. Lawrence estuary region, Quebec, Canada: a weather radar study

2011 ◽  
Vol 89 (1) ◽  
pp. 31-46 ◽  
Author(s):  
François Gagnon ◽  
Jacques Ibarzabal ◽  
Jean-Pierre L. Savard ◽  
Marc Bélisle ◽  
Pierre Vaillancourt
Keyword(s):  
The United States ◽  
North Coast ◽  
Lawrence Estuary ◽  
Migratory Activity ◽  
Late Night ◽  
The North ◽  
Flight Direction ◽  
The Mean ◽  
St Lawrence Estuary ◽  
Passerine Migration

We documented the pattern of nocturnal passerine migration on each side of the St. Lawrence estuary (Côte-Nord north and Gaspésie south), using the Doppler Canadian weather surveillance radar of Val d’Irène (XAM). We examined whether autumnal migrants flew across the St. Lawrence, resulting in a uniform broad-front migration, or avoided crossing it, resulting in a bird concentration along the north coast. We found that a proportion of migrants crossed the estuary but that most followed the north coast. Ranges at which birds were detected were, on average, greater on Côte-Nord, thereby rejecting the uniform broad-front migration hypothesis, inasmuch as reflectivity measurements suggested that bird concentrated along Côte-Nord. The mean flight direction on Côte-Nord was southwest but shifted westward as the night progressed, avoiding crossing the estuary by late night. In Gaspésie, the mean flight direction over land was south and no directional shift was observed throughout the night. Flight altitude reach up to 1000 m above sea level (a.s.l.), but migratory activity was highest in the first 500 m a.s.l. It appears that the St. Lawrence estuary acts as a leading line and a barrier for nocturnal passerine migrants, and likely shapes migration farther south in Canada and in the United States.

Geochemistry of zinc, copper and lead in the sediments of the estuary and Gulf of St. Lawrence

1978 ◽  
Vol 15 (5) ◽  
pp. 757-772 ◽  
Author(s):  
D. H. Loring
Keyword(s):  
Organic Material ◽  
Lower Estuary ◽  
Lawrence Estuary ◽  
Fine Grained ◽  
Elemental Concentrations ◽  
Suspended Particulate ◽  
Fine Grained Material ◽  
St Lawrence Estuary ◽  
Total Sedimentation ◽  
St Lawrence River

Total elemental concentrations (Zn, 8–215 ppm; Cu, 3–76 ppm; Pb, 9–66 ppm) vary texturally and regionally in the sediments of the St. Lawrence estuary and open Gulf of St. Lawrence.Chemical and mineralogical analyses indicate that 8–39% of the total Zn, 7–20% of the total Cu and 15–26% of the total Pb are weakly held by fine-grained organic material, oxide grain coatings, ion exchange positions and carbonates in the sediments. These concentrations are potentially available to the biota. The remaining concentrations (61–93% of the total) are not readily available but are locked up in fine-grained sulphide, oxide and silicate minerals.The highest concentrations of the detrital and non-detrital contributions occur in the pelites or muds of the upper estuary. Seaward these concentrations decrease as the natural and anthropogenic supply of dissolved and suspended particulate matter from the St. Lawrence River diminishes. The upper estuary acts as a sink for these elements because most of the non-detrital Zn, Pb and Cu supplied are removed here by adsorption onto fine-grained suspended terrestrial organic material from solution or before entry (Cu) and transferred to the bottom along with other fine-grained material in response to the present depositional conditions. Decreasing concentrations of these elements are deposited seaward and the sedimentation intensities of the non-detrital elements remain constant with fluctuations in total sedimentation intensity in the lower estuary and open Gulf of St. Lawrence.Biogeochemically, Zn is a contaminant and Pb and Cu are potential contaminants of the upper estuary sediments. Zn and Pb are potential contaminants in the lower estuary but all the elements are at or near natural levels in the open gulf sediments.

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