Tuesday, March 13, 2012

How a Sediment Trap Works

Dr Scott Nodder is a Marine Geologist who works at Niwa. He will be going out to the Chatham Rise on the Tangaroa with me checking on the Sediment Traps that are moored out there. Scott had a couple of these traps in the warehouse at Niwa. Here is a short video clip of him explaining how a Sediment Trap works. 

Sediment Traps look like a huge funnel and are put out just above the seabed to collect material falling from overhead — the Marine Snow) The traps can be placed anywhere in the water column, down to about 6000 m!
At the top end they are wide open so that they can catch all the material falling to the seafloor over an area of about 1 metre2. Anything that falls into the top of the funnel then slides down the smooth sloping walls of the funnel to the bottom and into a collecting bottle. Instead of having a single bottle at the bottom, the trap has 21 separate bottles on a rotating stage. At set intervals, the stage rotates, closing off the current bottle and positioning a new bottle under the funnel to collect a new sample.

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