Modern dinoflagellate cyst assemblages in surface sediments of Nunatsiavut fjords (Labrador, Canada)

In order to document long-term climate cycles and predict future climate trends for the Arctic, geological records archived in ocean sediments can help establish the link between historical and pre-historical sea-surface parameters. Dinoflagellate cysts (dinocysts) are used as proxy indicators of sea-surface parameters (temperature, salinity, sea-ice cover, primary productivity) jointly with transfer functions and a modern dinocyst reference database, to reconstruct the evolution of sea-surface conditions at decadal and millennial timescales. Here we present the surface distribution of recent dinocyst assemblages in 13 surface samples collected in four Nunatsiavut fjords (northern Labrador, Canada) along a latitudinal gradient, and their relationship with various environmental and biological parameters. Dinocyst concentrations in surface sediments increased from the inner to the outer part of each fjord and also from the northernmost to the southernmost fjords. There was also a southward increase in the species diversity with an occurrence and a dominance of cysts from autotrophic dinoflagellates. The presence of cysts of the calcareous dinoflagellate species Scrippsiella cf. S. crystallina in Anaktalak Fjord, where mining activities are underway, appears to be an indicator of human-related pollution within the fjord.