Thursday, January 29, 2015

Sampling the sea floor

Guy Gelfenbaum and Jackson Currie, both with the US Geological Survey, use a sediment grab off-shore of the Elwha River delta.

One of the fundamental data types used to track change in the coastal zone adjacent to the Elwha River mouth are sediment samples. Grain size data play a central role, for example, in our recently published paper documenting physical changes to the coastal environment in the first two years after dam removal.

Yesterday, associated with regular topography/bathymetry surveys of the Elwha River delta, I went out to help dredge up yet more dirt from the ocean floor. Check it out:

The day turned out to be pretty nice, with beautiful water conditions, so all in all not a bad way to spend a every sample we pulled up added a bit to our understanding of how sediment is moving around in the coastal environment. On top of it, we got to observe a veritable feeding frenzy occurring right off the river mouth, with possibly ~100 Harbor seal and California sea lions feeding (perhaps on some of the fish species observed just a few days earlier?) just a few feet outside the river mouth.

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