Suspended Sediment Character and Distribution in McBeth Fiord, Baffin Island

Abstract

Sediment concentration, particle-particle morphology and size data are used to identify the processes that control the distribution and dynamics of suspended sediment during the open water season in the McBeth Fiord, Baffin Island. Dominant processes include hemipelagic sedimentation below river plumes and sediment resuspension by wind-driven waves, internal waves and bottom currents, including those related to deep-water renewal. Suspended particles are composed of unflocculated mineral grains, planktonic detritus - such as from diatoms, radiolarian and dinoflagellates - and large particles of marine snow composed of mucoid stringers, fecal pellets, floccules, agglomerates and resuspended clay clasts. Strong offshore winds are capable of temporarily removing the surface seasonal layer in the fiord. That in turn may initiate the autumn cycle of deep-water exchange. Replacement of deep water within McBeth Fiord by water from the Baffin Shelf can also introduce shelf sediment to the fiord and cause the resuspension of sediment covering the outer sill complex. Alternatively, strong onshore winds can push the surface layer to the head of the fiord and significantly increase the surface layer volume of the inner fiord. Internal wave trains associated with such a surface layer surge and travelling in a landward direction can impact on the front of the delta situated at the head of the fiord and initiate resuspension of bottom sediments.

Key words: Arctic,fiord, McBeth Fiord, suspended sediment, oceanography, wind events, resuspension