Flocculation alters the distribution and flux of melt-water supplied sediments and nutrients in the Arctic: A case from Disko Fjord, West Greenland

TY - CONF

T1 - Flocculation alters the distribution and flux of melt-water supplied sediments and nutrients in the Arctic

T2 - Ocean Sciences Meeting

AU - Markussen, Thor Nygaard

AU - Andersen, Thorbjørn Joest

AU - Ernstsen, Verner Brandbyge

AU - Becker, Marius

PY - 2014

Y1 - 2014

N2 - In the Arctic, thawing permafrost and increased melting of glaciers are important drivers for changes in fine-grained sediment supply and biogeochemical fluxes from land to sea. Flocculation of particles is a controlling factor for the magnitude of fluxes and deposition rates in the marine environment but comparatively little is known about the flocculation processes in the Arctic. We investigated flocculation dynamics from a melt-water river in the inner Disko Fjord, West Greenland. A novel, laser-illuminated camera system significantly improved the particle size measurement capabilities and settling tubes were sampled to enable sub-sampling of different floc size fractions. Flocculation was observed during periods with low turbulent shear and also at the front of the fresh water plume resulting in significant volumes of large sized flocs at depth below the plume. The floc sizes and volumes were correlated with particulate and dissolved C, Fe and N concentrations. The observed flocculation dynamics highlight the potential for redistributing sediments and nutrients in the water column, which is important for understanding these environments and ecosystems in the past and future.

AB - In the Arctic, thawing permafrost and increased melting of glaciers are important drivers for changes in fine-grained sediment supply and biogeochemical fluxes from land to sea. Flocculation of particles is a controlling factor for the magnitude of fluxes and deposition rates in the marine environment but comparatively little is known about the flocculation processes in the Arctic. We investigated flocculation dynamics from a melt-water river in the inner Disko Fjord, West Greenland. A novel, laser-illuminated camera system significantly improved the particle size measurement capabilities and settling tubes were sampled to enable sub-sampling of different floc size fractions. Flocculation was observed during periods with low turbulent shear and also at the front of the fresh water plume resulting in significant volumes of large sized flocs at depth below the plume. The floc sizes and volumes were correlated with particulate and dissolved C, Fe and N concentrations. The observed flocculation dynamics highlight the potential for redistributing sediments and nutrients in the water column, which is important for understanding these environments and ecosystems in the past and future.

M3 - Poster

Y2 - 21 February 2014 through 28 February 2014

ER -