Spatial variability of length-specific production in shell, somatic tissue and sexual products of Macoma balthica in the Lower St. Lawrence Estuary

1993 ◽  
Vol 115 (3) ◽  
pp. 421-433 ◽  
Author(s):  
M. Harvey ◽  
B. Vincent ◽  
Y. Gratton
Keyword(s):  
Spatial Variability ◽  
Macoma Balthica ◽  
Somatic Tissue ◽  
Specific Production ◽  
Lawrence Estuary ◽  
St Lawrence Estuary

scholarly journals Spatial variability of surface-water pCO<sub>2</sub> and gas exchange in the world's largest semi-enclosed estuarine system: St. Lawrence Estuary (Canada)

2017 ◽  
Author(s):  
Ashley Dinauer ◽  
Alfonso Mucci
Keyword(s):  
Surface Water ◽  
Spatial Variability ◽  
Published Data ◽  
Estuarine System ◽  
Lower Estuary ◽  
Subarctic Region ◽  
Environmental Diversity ◽  
Lawrence Estuary ◽  
Spatial Coverage ◽  
St Lawrence Estuary

Abstract. The incomplete spatial coverage of partial pressure of CO2 (pCO2 ) measurements across estuary types represents a significant knowledge gap in current regional- and global-scale estimates of estuarine CO2 emissions. The Estuary and Gulf of St. Lawrence (EGSL) at the lower limit of the subarctic region in eastern Canada is the largest estuarine system in the world, and is characterized by an exceptional richness in environmental diversity. It is among the world's most intensively studied estuaries, yet there are no published data on its surface-water pCO2 distribution. To fill this data gap, a comprehensive dataset was compiled from direct and indirect measurements of carbonate system parameters in the surface waters of the EGSL during the spring or summer of 2003–2016. The calculated pCO2 ranged from 435–765 μatm in the shallow, partially mixed Upper Estuary, 139–578 μatm in the deep, stratified Lower Estuary, and 207–478 μatm along the Laurentian Channel in the Gulf. Overall, at the time of sampling, the St. Lawrence Estuary served as a weak source of CO2 to the atmosphere, with an area-averaged CO2 degassing flux of 1.00 to 2.06 mmol C m−2 d−1 (0.37 to 0.75 mol C m−2 yr−1). A preliminary analysis of factors controlling the spatial variability of surface-water pCO2 reveals that respiration (Upper Estuary), photosynthesis (Lower Estuary), and temperature (Gulf) are dominant controls.

scholarly journals Spatial variability in surface-water <i>p</i>CO<sub>2</sub> and gas exchange in the world's largest semi-enclosed estuarine system: St. Lawrence Estuary (Canada)

2017 ◽  
Vol 14 (13) ◽  
pp. 3221-3237 ◽  
Author(s):  
Ashley Dinauer ◽  
Alfonso Mucci
Keyword(s):  
Surface Water ◽  
Spatial Variability ◽  
Dissociation Constants ◽  
Published Data ◽  
Estuarine System ◽  
Lower Estuary ◽  
Environmental Diversity ◽  
Lawrence Estuary ◽  
Spatial Coverage ◽  
St Lawrence Estuary

Abstract. The incomplete spatial coverage of CO2 partial pressure (pCO2) measurements across estuary types represents a significant knowledge gap in current regional- and global-scale estimates of estuarine CO2 emissions. Given the limited research on CO2 dynamics in large estuaries and bay systems, as well as the sources of error in the calculation of pCO2 (carbonic acid dissociation constants, organic alkalinity), estimates of air–sea CO2 fluxes in estuaries are subject to large uncertainties. The Estuary and Gulf of St. Lawrence (EGSL) at the lower limit of the subarctic region in eastern Canada is the world's largest estuarine system, and is characterized by an exceptional richness in environmental diversity. It is among the world's most intensively studied estuaries, yet there are no published data on its surface-water pCO2 distribution. To fill this data gap, a comprehensive dataset was compiled from direct and indirect measurements of carbonate system parameters in the surface waters of the EGSL during the spring or summer of 2003–2016. The calculated surface-water pCO2 ranged from 435 to 765 µatm in the shallow partially mixed upper estuary, 139–578 µatm in the deep stratified lower estuary, and 207–478 µatm along the Laurentian Channel in the Gulf of St. Lawrence. Overall, at the time of sampling, the St. Lawrence Estuary served as a very weak source of CO2 to the atmosphere, with an area-averaged CO2 degassing flux of 0.98 to 2.02 mmol C m−2 d−1 (0.36 to 0.74 mol C m−2 yr−1). A preliminary analysis revealed that respiration (upper estuary), photosynthesis (lower estuary), and temperature (Gulf of St. Lawrence) controlled the spatial variability in surface-water pCO2. Whereas we used the dissociation constants of Cai and Wang (1998) to calculate estuarine pCO2, formulations recommended for best practices in open ocean environments may underestimate pCO2 at low salinities, while those of Millero (2010) may result in overestimates.

Seasonal variations of cold tolerance in intertidal mollusks and relation to environmental conditions in the St. Lawrence Estuary

1983 ◽  
Vol 61 (6) ◽  
pp. 1193-1201 ◽  
Author(s):  
Edwin Bourget
Keyword(s):  
Cold Tolerance ◽  
Seasonal Variations ◽  
Macoma Balthica ◽  
Mya Arenaria ◽  
Tidal Period ◽  
Lawrence Estuary ◽  
Cold Tolerant ◽  
St Lawrence Estuary ◽  
Large Adult ◽  
Selection Of

Seasonal variations of cold tolerance of Mytilus edulis, Mya arenaria, Macoma balthica, and Acmaea testudinalis were examined. The lower median lethal temperature (MLT) of all species was low throughout the year, with reduced seasonal variation. High MLT values, between −10 and −15 °C, were observed for Acmaea testudinalis and Mya arenaria, while low values, between −12.5 and −20 °C, were observed for Macoma and Mytilus. Seasonal variations of MLT are partly explained by the seasonal variations of water salinity. Small (juveniles) Mytilus, Mya, and Macoma showed less cold tolerance than large (adult) Mytilus, Mya, and Macoma (MLT between −8.0 and −12.5 °C). The possibility of genetic adaptation due to the selection of cold tolerant individuals is discussed. Cold tolerance determinations of animals subjected to cyclic emersions of various durations to a "sublethal" temperature of −8 °C every 12.4 h (one tidal period) showed a cumulative and significant effect of repeated mild cold stress. The ecological significance of the results is discussed in relation to the conditions prevailing along the shores of the St. Lawrence Estuary.

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

2013 ◽  
Vol 10 (11) ◽  
pp. 7609-7622 ◽  
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.

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)

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

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

2021 ◽  
Author(s):  
Yves Paradis ◽  
Marc Pépino ◽  
Simon Bernatchez ◽  
Denis Fournier ◽  
Léon L’Italien ◽  
...  
Keyword(s):  
Lawrence Estuary ◽  
St Lawrence Estuary ◽  
Acipenser Oxyrinchus

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

1984 ◽  
Vol 62 (4) ◽  
pp. 778-794 ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document