title: Processes governing the stable isotope composition of water in the St. Lawrence river system, Canada.
abstract: Linkages between δ(18)O-δ(2)H and hydrological processes have been investigated from isotopic time series recorded in the St. Lawrence River basin. Three stations were monitored from 1997 to 2008. They include the Ottawa River, the St. Lawrence River main channel at Montreal and the fluvial estuary. All sites depict seasonal isotopic cycles characterized by heavy isotope depletions during the snowmelt period and heavy isotope enrichments throughout the ice-free period. The data define δ(2)H-δ(18)O regression lines falling below the meteoric water line. In the Ottawa River, calculations suggest that approximately 8 % of the total inflow to the basin is lost through evaporation. In the St. Lawrence River main channel, seasonal isotopic fluctuations most likely reflect hydrological processes occurring within the Great Lakes and mixing with tributaries located downstream. In the St. Lawrence River fluvial estuary, isotopic data allow partitioning streamflow components and suggest that the recorded seasonal variations mainly respond to mixing processes.
authors.affiliation: a Geotop & Groundwater Research Group , Université du Québec en Abitibi-Témiscamingue , Amos , Quebec , Canada.|b Geotop & Sciences de la Terre et de l'atmosphère , Université du Québec à Montréal , Montreal , Quebec , Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Rosa
authors.affiliation: b Geotop & Sciences de la Terre et de l'atmosphère , Université du Québec à Montréal , Montreal , Quebec , Canada.
authors.forename: Claude
authors.initials: C
authors.lastname: Hillaire-Marcel
authors.affiliation: b Geotop & Sciences de la Terre et de l'atmosphère , Université du Québec à Montréal , Montreal , Quebec , Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Hélie
authors.affiliation: b Geotop & Sciences de la Terre et de l'atmosphère , Université du Québec à Montréal , Montreal , Quebec , Canada.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Myre
mesh_terms: D003903:Deuterium / Q000032:analysis*; D004784:Environmental Monitoring; D062070:Hydrology; D009864:Ontario; D010103:Oxygen Isotopes / Q000032:analysis; D011792:Quebec; D045483:Rivers / Q000737:chemistry*; D012621:Seasons
chemical_list: D010103:Oxygen Isotopes; D003903:Deuterium
keywords: Evaporation; St. Lawrence River; deuterium; isotope hydrology; oxygen-18; seasonality