National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 2019

Patterns of flow in the canyons of the northern Gulf of Alaska

Mordy, C.W., P.J. Stabeno, N.B. Kachel, D. Kachel, C. Ladd, M. Zimmerman, A.J. Hermann, K. Coyle, and M.J. Doyle

Deep-Sea Res. II, 165, 203–220, doi: 10.1016/j.dsr2.2019.03.009, View online (2019)

The continental shelf around Kodiak Island is incised with numerous submarine canyons, which play an important role in the cross-shelf transport of heat, salt, and nutrients, and the transport of ichthyoplankton of deep-spawning fish from the slope region into the shallow nursery grounds surrounding Kodiak Island. To explore the pathways and variability of flow, and the extent of tidal mixing within the canyons, moorings were placed in the Chiniak, Barnabas, and Amatuli troughs, and off the shelf from Resurrection Bay (Seward Line) and the Kenai Peninsula (Gore Point). In the troughs, intensified flow was evident near the trough walls, and flow was directed by bathymetry with inflow along the upstream (northern) side and outflow along the downstream (southern) side. The presence of mesoscale eddies in the gulf had no unique influence on currents or salinity in the troughs. Tidal mixing was strongest in Chiniak Trough, and this introduced cold, nutrient-rich bottom waters into the upper water column. Intensified bottom flow associated with the Alaskan Coastal Current was evident along the Seward Line and Gore Point, and directed toward the Kennedy-Stevenson Entrances, which are also regions of strong tidal mixing. Observations of tidal mixing were consistent with model results and satellite images showing cooler, phytoplankton-rich water in summer in the nursery grounds that surround Kodiak Island. Patterns of flow within the troughs and in Shelikof Strait were consistent with the springtime advance of ichthyoplankton across the shelf.

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