Benthic Foraminiferal Assemblages from the Laurentian Channel in the Lower Estuary and Gulf of ST. Lawrence, Eastern Canada: Tracers of Bottom-Water Hypoxia

ABSTRACT Over the past century, an increase in temperatures and a decrease dissolved oxygen concentrations have been observed bottom waters of Laurentian Channel (LC), throughout Lower St. Lawrence Estuary (LSLE) Gulf (GSL), eastern Canada. To document impact these changes, we analyzed benthic foraminiferal assemblages geochemical signatures four sediment cores taken LC. Radiometric measurements (210Pb, 226Ra, 137Cs) indicate that studied encompass last 50 years sedimentation LSLE ∼160 GSL. The sedimentary record shows 60 to 65% taxonomic diversity LC since 1960s. An accelerated change is at approximately same time all sites, around late 1990s early 2000s, towards populations dominated by hypoxia-tolerant indicator taxa Brizalina subaenariensis, Eubuliminella exilis, Globobulimina auriculata. This evolution reflects incursions hypoxic zone into western GSL over decades. results our multivariate analyses highlight potential as proxy bottom-water hypoxia.