Fine-grained sediment flocculation below the Hubbard Glacier meltwater plume, Disenchantment Bay, Alaska

A study in Disenchantment Bay, Alaska, demonstrates that fine sediment beneath a meltwater plume is flocculated and that floe sizes and fraction of mass bound within floes exhibit a pronounced increase with depth rather than down fjord. This spatial pattern of variability likely is due to the longer depositional timescale of floes compared to their horizontal advection timescale within the meltwater plume. The flux of mass within floes also increases with depth. These observations have implications for sedimentation models as sedimentation rates estimated from surface waters underestimate those at depth, and could result in the inaccurate prediction of the position of suspension depocenters. The results also may explain the behavior of fine sediment in more complex environments where floe properties are difficult to observe. (C) 2003 Elsevier B.V. All rights reserved.