Thurs 15-May

• Finished 20 km bow tie survey



• Aborted the Biofloat 47 Deployment when check out test revealed that one (out of three) drogue motors was not working properly. After consultation with PI Eric D'Asaro and float engineer Mike Ohmart in Seattle, we decided to go ahead and deploy with two working motors and a slightly gimpy drogue.



• Completed a calibration cast in sight of Biofloat 48, including O₂, HPLC pigment analysis, and a_p (spectral particulate absorption).

Picked up PELAGRA sediment traps. This was no small feat because prior to deployment, some how the id's of the ARGOS transmitters got scrambled. In the end, two of the three traps were unable to transmit their latitude and longitude upon reaching the surface. With a bit of luck, a bit of predictive modelling of the float tracks at depth, and the GONIO 400 radio direction finder giving us a bearing and range (the later via relative signal strength), all three PELAGRA traps were recovered between between 21:30 and 23:45 Z. As you can see, in only 24 hours, the 600 m trap was chock full of "diatom dump", including heavily salicified resting spores.


• Following the retrieval of the sediment trap, a microscope fest ensued, where many of us view resting chaetoceros spores found at 300 , 600, 800 m.
  
  Using epifluorescence, it was observed that the many particles were full of chloroplasts (red fluorescence). Also, unknown phycoerthrin fluorescence cells were observed (yellow/orange fluorescers), perhaps belonging to synechocystis, a nitrogen-fixing cyanobacteria. A more detailed story on changing community composition will be posted soon with more photomicrographs. (Microscopy and photo ourtesy of Michael Sieracki, Bigelow Laboratory.)
  

Friday 16-May

• Completed a large evening surface "Zag" for Toby Westberry and Giorgio Dall'Olmo underway bio-optical measurements of spectral absorption, attenuation, backscattering and particle size distribution.



• Later, we steamed to the predicted location of Biofloat48. There we successfully redeployed Biofloat47 in quiet calm water. Biofloat 47 sucessfully completed it's first profile, sending back data (including nitrate estimates from ISUS). The graph below shows nearly coincident potential temperature, salinity and oxygen from yesterday's nearly simultaneous profiles of Biofloat 47 and 48. Chlorphyll and beam-c diverge more. To date, the chlorophyll fluorometers have been cross calibrated using pre-bloom chlorphyll measurements at very low concentrations. Also, we have not attempted to cross calibrate the beam transmissometers yet.




• We completed a calibration cast in sight of Biofloat 48, including O₂, HPLC pigment analysis, a_p (spectral particulate absorption), radiometry and measurement of inherent optical properties (IOPs).

Sat, 17 -May

• Midnight started new 20 Km bow tie survey, on going at the time of this report.



• The usual mid-day primary productivity casts were taken, where Kristinn Gudmunsson (Iceland's Marine Research Institute) and Mike Sauer carry out short term ¹⁴C incubations under varying light conditions. From these, we get curves of phytosynthesis (mole C m^-3 d^-1 ) vs. irradiance (mole photons m^-2 s^-1.
• Dave Checkley served Calanus sp. hors d'oeuvres from a recent plankton tow.