Distribution, diversity and biomass of summer zooplankton from the coastal Canadian Beaufort Sea

Abstract

Composition, abundance, biomass and distribution of zooplankton in the coastal Canadian Beaufort Sea were studied in the summer of 2005 and 2006. Data were collected from two cross-shelf transects (11 stations in each). Sampling was conducted with vertical hauls using a conical net of 153-μm mesh size. Our results revealed that there are three ecological zones, Intense Plume, Diffuse Plume and oceanic, which are primarily shaped by the highly variable Mackenzie River plume. The Intense Plume Grouping was located at stations influenced greatly by the Mackenzie River, where Podon leuckarti, Pseudocalanus spp., Copepoda nauplii and Limnocalanus macrurus were most abundant. The Diffuse Plume Grouping, that was located in the transitional zone between the river plume and the ocean, had the highest diversity. This grouping was characterised by high abundance of Copepoda nauplii, Polychaeta larvae, Pseudocalanus and L. macrurus. The Oceanic Grouping, located farthest from shore beyond the 85-m depth contour, was mainly inhabited by marine taxa—Calanusglacialis, C. hyperboreus, Triconia (Oncea) borealis and Microcalanus spp.—and had the greatest overall zooplankton abundance and biomass of all groupings.