Mercury in Marine Mussels from the St. Lawrence Estuary and Gulf (Canada): A Mussel Watch Survey Revisited after 40 Years

Various species of marine mussels have been used, in the last 50 years, as sentinel organisms for monitoring metal contamination along marine coasts. There are two main reasons for this: these mollusks concentrate metals in their soft tissue and they are geographically widespread. In practice, trace metal concentrations in mussel soft tissue reveal (after some correction for biotic effects) the contamination level of their surrounding environment. We present the results of a mercury (Hg) survey in Mytilus spp. collected in the summers of 2016, 2018, and 2019 at 51 stations distributed along the coasts of the Estuary and Gulf of St. Lawrence. Mercury concentrations ranged from 0.063 to 0.507 µg g−1 (dry weight, dw), with a grand mean of 0.173 ± 0.076 µg g−1 dw (±1 standard deviation), and a median of 0.156 µg g−1 dw for the 504 individuals analyzed. Mercury contents per individual mussel were significantly (p < 0.01) related to shell length and dry tissue weight, with the smaller individuals having the highest Hg concentrations. To take into account these biotic effects, we normalized Hg concentrations of the mussel soft tissue for constant shell length (L) and soft tissue weight (TW) based on the log-log relationships between Hg content and L or TW. The normalized Hg contents of mussels varied from 10.9 to 66.6 ng per virtual individual of 35 mm length and 0.17 g dry weight. A similar normalization procedure applied to 1977–1979 data, yielded a very similar range: 12 to 64 ng. This observation suggests that the Hg bioavailable to marine mussels in the study area did not change over a span of 40 years. Regional Hg distribution patterns indicate a gradual decrease of Hg content in mussels downstream from freshwater discharges to the St. Lawrence Estuary and the Baie des Chaleurs, suggesting that rivers constitute a significant Hg source in these estuarine systems. Atmospheric Hg deposition and concentration in marine waters of the Atlantic Ocean are known to have decreased in the last decades. However, in coastal environments, the response to these changes does not seem to be rapid, probably because of the long residence time of Hg in soils before being exported to coastal areas.

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Fat reserves and condition indices in greater snow geese

Canadian Journal of Zoology ◽

10.1139/z85-050 ◽

1985 ◽

Vol 63 (2) ◽

pp. 331-333 ◽

Cited By ~ 15

Author(s):

G. Gauthier ◽

J. Bédard

Keyword(s):

Subcutaneous Fat ◽

Dry Weight ◽

Condition Index ◽

Lawrence Estuary ◽

Fat Reserves ◽

Snow Geese ◽

Ether Extraction ◽

Total Fat ◽

Condition Indices ◽

St Lawrence Estuary

We evaluate several external condition indices as predictors of total fat reserves (TFR) in greater snow geese. In 1979 and 1980, we collected 373 adult geese during their spring staging halt along the St. Lawrence estuary, Québec, and determined their fat content by ether extraction. Body weight (BW) alone and BW divided by various morphometric measurements are relatively poor predictors of TFR (maximum r2 = 0.56). The thickness of subcutaneous fat (measured externally with an adiposimeter) combined with BW is the best predictor of TFR (R2 = 0.65). This condition index can be useful in predicting the average condition of living geese, provided a reasonable sample size is available. We also examined some internal condition indices. Of these, the dry weight of abdominal fat is the easiest to apply and one of the most reliable (r2 = 0.86).

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Temporal variability of zooplankton biomass (ATP content and dry weight) in the St. Lawrence Estuary: Advective phenomena during neap tide

Marine Biology ◽

10.1007/bf00392250 ◽

1983 ◽

Vol 73 (3) ◽

pp. 247-255 ◽

Cited By ~ 6

Author(s):

Y. Maranda ◽

G. Lacroix

Keyword(s):

Temporal Variability ◽

Neap Tide ◽

Dry Weight ◽

Zooplankton Biomass ◽

Atp Content ◽

Lawrence Estuary ◽

St Lawrence Estuary

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Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation

Biogeosciences ◽

10.5194/bg-10-7609-2013 ◽

2013 ◽

Vol 10 (11) ◽

pp. 7609-7622 ◽

Cited By ~ 13

Author(s):

M. Alkhatib ◽

P. A. del Giorgio ◽

Y. Gelinas ◽

M. F. Lehmann

Keyword(s):

Organic Matter ◽

Dissolved Organic Nitrogen ◽

Organic Nitrogen ◽

Bottom Water ◽

Estuarine Sediments ◽

Internal Source ◽

Lawrence Estuary ◽

Element Partitioning ◽

Sediment Porewaters ◽

St Lawrence Estuary

Abstract. The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 μmol m−2 d−1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5–6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

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Pre-exposure to Cu2+ and CuO NPs leads to infection of caged blue mussels, Mytilus edulis L., by pathogenic microalga: Pilot study in the Lower St. Lawrence Estuary (Québec, Canada)

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2021.112180 ◽

2021 ◽

Vol 166 ◽

pp. 112180

Author(s):

Michael Zuykov ◽

Galina Kolyuchkina ◽

Graeme Spiers ◽

Michel Gosselin ◽

Philippe Archambault ◽

...

Keyword(s):

Pilot Study ◽

Mytilus Edulis ◽

Lawrence Estuary ◽

Blue Mussels ◽

Cuo Nps ◽

St Lawrence Estuary

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Movement of sturgeons ( Acipenser oxyrinchus oxyrinchus and A. fulvescens ) in the St. Lawrence Estuary: A 35‐year tagging study

Journal of Applied Ichthyology ◽

10.1111/jai.14234 ◽

2021 ◽

Author(s):

Yves Paradis ◽

Marc Pépino ◽

Simon Bernatchez ◽

Denis Fournier ◽

Léon L’Italien ◽

...

Keyword(s):

Lawrence Estuary ◽

St Lawrence Estuary ◽

Acipenser Oxyrinchus

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A Current-Induced Ekman Spiral in the St. Lawrence Estuary

Journal of Physical Oceanography ◽

10.1175/1520-0485(1983)013<1540:aciesi>2.0.co;2 ◽

1983 ◽

Vol 13 (8) ◽

pp. 1540-1543 ◽

Cited By ~ 4

Author(s):

Clifford L. Trump

Keyword(s):

Lawrence Estuary ◽

St Lawrence Estuary ◽

A Current

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Marine tube-dwelling diatoms of eastern Canada: descriptions, checklist, and illustrated key

Canadian Journal of Botany ◽

10.1139/b84-114 ◽

1984 ◽

Vol 62 (4) ◽

pp. 778-794 ◽

Cited By ~ 19

Author(s):

Christopher S. Lobban

Keyword(s):

New Species ◽

Northwest Territories ◽

Common Species ◽

Bay Of Fundy ◽

Eastern Canada ◽

Lawrence Estuary ◽

The Common ◽

Living Material ◽

St Lawrence Estuary ◽

A New Species

From a study of living materials and specimens in several regional herbaria, a list has been drawn up of all the common and several of the rarer tube-dwelling diatoms of eastern Canada. Descriptions, illustrations of living material and acid-cleaned valves, and a key to the species are provided. Most specimens were from the Atlantic Provinces and the St. Lawrence estuary, but a few were from the Northwest Territories. By far the most common species is Berkeleya rutilans. Other species occurring commonly in the Quoddy Region of the Bay of Fundy, and sporadically in space and time elsewhere, arc Navicula delognei (two forms), Nav. pseudocomoides, Nav. smithii, Haslea crucigera, and a new species, Nav.rusticensis. Navicula ramosissima and Nav. mollis in eastern Canada are usually found as scattered cohabitants in tubes of other species. Nitzschia tubicola and Nz. fontifuga also occur sporadically as cohabitants.

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A biophysical model of the interaction between vertical migration of crustacean zooplankton and circulation in the Lower St. Lawrence Estuary

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f99-095 ◽

1999 ◽

Vol 56 (12) ◽

pp. 2420-2432 ◽

Cited By ~ 15

Author(s):

Bruno A Zakardjian ◽

Jeffrey A Runge ◽

Stephane Plourde ◽

Yves Gratton

Keyword(s):

Population Dynamics ◽

Vertical Migration ◽

Horizontal Distribution ◽

Calanus Finmarchicus ◽

Biophysical Model ◽

Crustacean Zooplankton ◽

Simple Formulation ◽

Lawrence Estuary ◽

Circulation Patterns ◽

St Lawrence Estuary

As an essential step in modeling the influence of circulation on the population dynamics of marine planktonic copepods, we define a simple formulation of swimming behavior that can be used in both Eulerian and Lagrangian models. This formulation forces aggregation of the population toward a preferential depth and can be stage specific and time varying, thus allowing description of either diurnal or seasonal vertical migration. We use the formulation to examine the interaction between the circulation and vertical distribution in controlling horizontal distribution of the common planktonic copepod Calanus finmarchicus in the Lower St. Lawrence Estuary, Canada. We first introduce diel migration into a simple one-dimensional model and then into a model of residual two-dimensional circulation patterns representative of conditions encountered in the Lower St. Lawrence Estuary. Results from the latter indicate that interactions between circulation and stage-specific swimming behaviors are the main mechanisms for aggregation of planktonic crustaceans at the head of the Laurentian Channel and highlight the implications of flushing of the surface-dwelling young stages for the population dynamics of C. finmarchicus in the Lower St. Lawrence Estuary.

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