Presentation
Scientific director : Alfonso Mucci
Laboratory manager : Constance Guignard
Location :
GEOTOP-McGill
Department of Earth and Planetary Sciences
3450 University Street, Room 203
Montréal, QC H3A 2A7 - Canada
Contact : alfonso.mucci@mcgill.ca | constance.guignard@mcgill.ca
For the last 25 years, the aquatic and sediment geochemistry laboratory has been dedicated to studies of reactions and processes occurring in the water column and sediment as well as the biogeochemical cycles of trace metals and carbon in marine, coastal and estuarine environments. For example, since 2003, we participated to numerous national and international projects in the Canadian Arctic, especially in the Beaufort Sea and Northwest Passage. We used several geochemical and isotopic tracers to identify water masses and measured the CO2 partial pressure gradient across the air-sea interface. From the latter, we determined the direction of the CO2 flux and the magnitude of the surface ocean sink or source. In addition, we are pursuing a study of the factors that led to the development of persistent hypoxic bottom waters in the Lower St. Lawrence Estuary and the Gulf as well as their impact on sediment chemistry.
The geochemical characterization of sediments and the analysis of their porewaters allow us to identify the nature and kinetics of diagenetic reactions that control the remobilization and vertical distribution of elements in the sediment column. Most of these reactions are fueled by the microbial degradation of organic matter (catabolic reactions) that settles through the water column and is buried in the sediment.
