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3 May 2012 - First deployment of the Owen Tube

May 3. We tried out the Owen tube for the first time today. Before casting we marked the wire every 1m so that we could roughly determine the depth during the cast. The Flood ETM was predicted for 0930. The Winched Profiler was in the water that morning and we detected an ETM with the FLNTU and the LISST sensors. We lowered the Owen Tube off the stern with the A-frame until we could feel the big 300lb weight touch the bottom and then raised it up slightly until the weight was off the bottom. This weight hangs ~1m below the Owen Tube. We then sent the messenger down the line and closed the tube, brought it back on deck, pushed the weight over to the Owen Tube, flipped the tube vertical, placed it in the rack, and started the stopwatch.

We collected fractions of water from the bottom of the Owen tube at specific time intervals:

1 min. 1.8 sec., 1500ml
5 min. 45 sec., 1500ml
12 min. 6 sec., 1500ml
19 min. 18 sec., 1500ml
40 min. 36 sec., 3000ml
Final 3000ml
We decided to combine fractions 1&2 and 3&4 giving us four ~3000ml fractions.
We carefully measured the volume of each fraction and then subsampled them for all of our standard measurements including DNA and RNA. This became the routine for all the other Owen Tube samples.