Assessment of the Importance of Nutrient Recycling by Seabirds in the St. Lawrence Estuary

1980 ◽  
Vol 37 (4) ◽  
pp. 583-588 ◽  
Author(s):  
J. Bédard ◽  
J. C. Therriault ◽  
J. Bérubé
Keyword(s):  
Nutrient Recycling ◽  
Vertical Mixing ◽  
Nutrient Budget ◽  
Somateria Mollissima ◽  
Nutrient Regeneration ◽  
Lawrence Estuary ◽  
Nitrogenous Compounds ◽  
The One ◽  
Excretion Rates ◽  
St Lawrence Estuary

Feeding and excretion rates of the herring, great black-backed, and ring-billed gulls (Larus argentatus, L. marinus, and L. delawarensis), and of the common eider (Somateria mollissima) were measured in captive individuals and the concentration of soluble nutrients in their excreta was established.The bird population in a 30.6-km2 coastal study area varied between 2500 and 12 500 individuals between early May and mid-November. These birds excreted a seasonal total of 5.8, 4.2, and 48.1 kg-at. of soluble silicate, phosphate, and nitrogenous compounds, respectively. Such quantities, when introduced in the nutrient budget of the coastal area studied, are found to be negligible, considering the levels of nutrients generally recorded in these waters on the one hand, and the relative importance of alternate sources such as land drainage and vertical mixing on the other. Thus, the seabirds can hardly be viewed, except perhaps under the most special circumstances, as important agents in the dynamic nutrient regeneration processes of marine coastal waters of the St. Lawrence Estuary.Key words: nutrient recycling, seabirds, St. Lawrence Estuary

scholarly journals Distribution of common eiders Somateria mollissima during the brood-rearing and moulting periods in the St. Lawrence Estuary, Canada

2011 ◽  
Vol 17 (2) ◽  
pp. 124-134 ◽  
Author(s):  
Hélène Diéval ◽  
Jean-François Giroux ◽  
Jean-Pierre L. Savard
Keyword(s):  
Somateria Mollissima ◽  
Lawrence Estuary ◽  
Brood Rearing ◽  
Common Eiders ◽  
St Lawrence Estuary

The food and feeding of common eiders in the St. Lawrence estuary in summer

1974 ◽  
Vol 52 (3) ◽  
pp. 319-334 ◽  
Author(s):  
M. Cantin ◽  
J. Bédard ◽  
H. Milne
Keyword(s):  
Intertidal Zone ◽  
Maximum Growth ◽  
Somateria Mollissima ◽  
Lawrence Estuary ◽  
Common Eiders ◽  
Feeding Activities ◽  
Food And Feeding ◽  
South Shore ◽  
Natural Foods ◽  
St Lawrence Estuary

The study was conducted in the St. Lawrence estuary during 1969 and 1970. The food abundance in the intertidal zone was measured in four Sampling stations located on the south shore of the river; the measurements revealed that over 95% of the available food of the common eider (Somateria mollissima) consisted of Littorina spp., Mytilus edulis, and Gammarus oceanicus. Both adult and young birds showed a distinct rhythm of feeding activities associated with tidal level. During the prenesting period, herring eggs and Nereis virens made up most of the food of adult common eiders. When accompanying ducklings, females ate mostly Littorina spp. and amphipods. Littorina spp. made up between 30 and 97% of the diet of the ducklings, the importance of this gastropod growing with age of the bird. Energy requirements during maximum growth were evaluated at about 460 kcal/bird per day on ducklings (age 54 days) fed natural foods, while between week 3 and week 8 it stood at about 520 kcal/bird per day in ducklings fed "turkey starter." These figures were used to assess the importance of the food removed by the eiders from the intertidal zone during the summer. We conclude that between 10 and 30% (according to the area) of the standing-crop biomass of Littorina alone (in July) is removed by the ducklings and the females accompanying them. At various moments through the season, these birds remove between 40 and 100 metric tons of mollusks per day from the intertidal zone.

scholarly journals Winter observations alter the seasonal perspectives of the nutrient transport pathways into the lower St. Lawrence Estuary

Ocean Science ◽  
2021 ◽  
Vol 17 (5) ◽  
pp. 1509-1525
Author(s):  
Cynthia Evelyn Bluteau ◽  
Peter S. Galbraith ◽  
Daniel Bourgault ◽  
Vincent Villeneuve ◽  
Jean-Éric Tremblay
Keyword(s):  
Vertical Mixing ◽  
Coast Guard ◽  
Tidal Mixing ◽  
Mixing Processes ◽  
Transport Pathways ◽  
Nutrient Analysis ◽  
Near Surface ◽  
Lawrence Estuary ◽  
Order Of Magnitude ◽  
St Lawrence Estuary

Abstract. The St. Lawrence Estuary connects the Great Lakes with the Atlantic Ocean. The accepted view, based on summer conditions, is that the estuary's surface layer receives its nutrient supply from vertical mixing processes. This mixing is caused by the estuarine circulation and tides interacting with the topography at the head of the Laurentian Channel. During winter when ice forms, historical process-based studies have been limited in scope. Winter monitoring has been typically confined to vertical profiles of salinity and temperature as well as near-surface water samples collected from a helicopter for nutrient analysis. In 2018, however, the Canadian Coast Guard approved a science team to sample in tandem with its ice-breaking and ship escorting operations. This opportunistic sampling provided the first winter turbulence observations, which covered the largest spatial extent ever measured during any season within the St. Lawrence Estuary and the Gulf of St. Lawrence. The nitrate enrichment from tidal mixing resulted in an upward nitrate flux of about 30 nmol m−2 s−1, comparable to summer values obtained at the same tidal phase. Further downstream, deep nutrient-rich water from the gulf was mixed into the subsurface nutrient-poor layer at a rate more than an order of magnitude smaller than at the head. These fluxes were compared to the nutrient load of the upstream St. Lawrence River. Contrary to previous assumptions, fluvial nitrate inputs are the most significant source of nitrate in the estuary. Nitrate loads from vertical mixing processes would only exceed those from fluvial sources at the end of summer when fluvial inputs reach their annual minimum.

scholarly journals Nutrient transport pathways in the Lower St. Lawrence Estuary: seasonal perspectives from winter observations

2021 ◽  
Author(s):  
Cynthia Evelyn Bluteau ◽  
Peter S. Galbraith ◽  
Daniel Bourgault ◽  
Vincent Villeneuve ◽  
Jean-Éric Tremblay
Keyword(s):  
Vertical Mixing ◽  
Coast Guard ◽  
Tidal Mixing ◽  
Mixing Processes ◽  
Transport Pathways ◽  
Nutrient Analysis ◽  
Near Surface ◽  
Lawrence Estuary ◽  
Order Of Magnitude ◽  
St Lawrence Estuary

Abstract. The St. Lawrence Estuary connects the Great Lakes with the Atlantic Ocean. The accepted view, based on summer conditions, is that the Estuary's surface layer receives its nutrient supply from vertical mixing processes. This mixing is caused by the estuarine circulation and tidal-upwelling at the Head of the Laurentian Channel (HLC). During winter when ice forms, historical process-based studies have been limited in scope. Winter monitoring has been typically confined to vertical profiles of salinity and temperature and near-surface water samples collected from a helicopter for nutrient analysis. In 2018, however, the Canadian Coast Guard approved a science team to sample in tandem with its icebreaking and ship escorting operations. This opportunistic sampling provided the first winter turbulence observations, which covered the largest spatial extent ever measured during any season within the St. Lawrence Estuary and Gulf. The nitrate enrichment from tidal mixing resulted in an upward nitrate flux of about 30 nmol m−2 s−1, comparable to summer values obtained at the same tidal phase. Further downstream, deep nutrient-rich water from the Gulf was mixed into the subsurface nutrient-poor layer at a rate more than an order of magnitude smaller than at the HLC. These fluxes were compared to the nutrient load of the upstream St. Lawrence River. Contrary to previous assumptions, fluvial nitrate inputs are the most significant source of nitrate in the Estuary. Nitrate loads from vertical mixing processes would only exceed those from fluvial sources at the end of summer when fluvial inputs reach their annual minimum.

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

scholarly journals Trophic Trait Evolution Explains Variation in Nutrient Excretion Stoichiometry among Panamanian Armored Catfishes (Loricariidae)

Diversity ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 88
Author(s):  
Eric K. Moody ◽  
Fernando Alda ◽  
Krista A. Capps ◽  
Oscar Puebla ◽  
Benjamin L. Turner
Keyword(s):  
Significant Variation ◽  
Trophic Position ◽  
Nutrient Recycling ◽  
Trophic Niche ◽  
Relative Importance ◽  
Closely Related Species ◽  
Trait Evolution ◽  
Nutrient Excretion ◽  
Nutrient Mineralization ◽  
Excretion Rates

Variation in nutrient excretion rates and stoichiometric ratios (e.g., nitrogen to phosphorus) by consumers can have substantial effects on aquatic ecosystem function. While phylogenetic signals within an assemblage often explain variation in nutrient recycling rates and stoichiometry, the phylogenetically conserved traits that underlie this phenomenon remain unclear. In particular, variation in nutrient excretion stoichiometry across a phylogeny might be driven by phylogenetic patterns in either diet or body stoichiometry. We examined the relative importance of these traits in explaining variation in nutrient recycling rates and stoichiometry in a diverse family of Neotropical-armored catfishes, Loricariidae, in Panamanian streams. We found significant variation in nutrient mineralization traits among species and subfamilies, but variation in nutrient excretion stoichiometry among species was best explained by trophic position rather than body stoichiometry. The variation in trophic position among Panamanian species was consistent with variation in the trophic niche of their genera across South America, suggesting that phylogenetic patterns underpin the evolution of trophic and nutrient excretion traits among these species. Such geographical variation in nutrient mineralization patterns among closely related species may be common, given that trophic variation in fish lineages occurs widely. These results suggest that information on trophic trait evolution within lineages will advance our understanding of the functional contribution of animals to biogeochemical cycling.

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

1983 ◽  
Vol 13 (8) ◽  
pp. 1540-1543 ◽  
Author(s):  
Clifford L. Trump
Keyword(s):  
Lawrence Estuary ◽  
St Lawrence Estuary ◽  
A Current
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