RV Knorr Activites on Monday, 12-May-2008

Today there was much discussion between the Principal Investigators scales of variability in time and space. It was resolved to try to do more smaller bow tie surveys in the near future.

Activities today included:

1. Finished recovery the final four PELAGRA Lagrangian sediment traps around 6:30 Z. Of note, acantharian cysts were discovered in one trap. Acantharia are unique protozoans that produce skeletons composed of strontium sulfate.
2. Completed Primary Productivity cast at Station 50a
3. Kept the RV Knorr moving for underway bio-optics (OSU, Westberry, Dall'Olmo)
4. Sighted Float 48 at surfacing and completed a calibration cast (CTD, but no O₂)
5. Began a new survey, forming a bow tie with 20 km edges. A portion of the survey (3 -> 4 -> 5) crosses an eddy where we expect to see high spatial variability, and also includes a repeat visit to portions of a previous 25 km survey. See also the 3-day surface current plot from the Knorr ADCP
   
6. With the help of Eric D'Asaro at UW/APL and Toby Westberry aboard the RV Knorr, took a quick look at the underway ship fluorescence measurements. We did see some daily variation (see blue-ish lines) but often the daily variation was overshadowed by spatial variation. We expect to see large spatial variation along the route from 3 -> 4 -> 5.