Southern Ocean Iron Experiment (SOFeX) Cruise
January 5 - February 26, 2002
Logbook
Skip to Log Entry from the R/V Melville
January 20, 2002: Day 16
R/V Revelle:
North Patch: -55 49.26-171 52.92
Ship: -58 52.58-171 22.04
R/V Revelle Log Entry: Were on our way to 65 S, 170 W to begin a survey for our next experiment.We left the North Patch at 2300 last evening after spending most of the day sampling in the patch.We stopped 15 kilometers (10 miles) south of the patch for a control station and left there at 0300.That made a long day, as I was up at 0400 for the SeaSoar recovery.Of course, as things go, the CTD/Rosette started getting balky again for the last few casts, with enough noise on the signal lines that it wouldnt collect water samples.So, we had to repeat several casts and couldnt send the rosette below 150 m to collect all the samples that we wanted.Hmm boy, was I getting grumpy.No yelling yet, though.And no real reason to.
Weve left the North Patch with the experiment going great.MELVILLE is underway and should arrive on Tuesday.Our project will be alone for several days, but when MELVILLE arrives, they should find some really exciting results.Our sampling shows that the phytoplankton in the North Patch are growing like crazy.Some preliminary calculations show the growth rate is about near the theoretical maximum predicted by the 'Eppley Curve'.Dick Eppley is a pioneering biological oceanographer who calculated the maximum rates at which plankton can grow under different light and temperature conditions.If these results hold up to further analysis, then it is likely that iron addition has completely relieved the community growth limitation.Is it possible that Si limitation may not be as important as we think?
This is really just speculation.The trick now is for MELVILLE to find the patch and to then figure out what is happening.Weve marked the patch with several drifting buoys.These are equipped with GPS (Global Positioning System) receivers that determine their latitude and longitude and with ORBCOMM and Packet Radio transmitters.The ORBCOMM link reports position 4 times per day to a satellite communication network and we (and MELVILLE) then receive the positions by e-mail.The Packet Radios send the GPS positions at 30 minute intervals when a ship is near, but the Packet Radio range is only about 8 km, so you have to be quite close to find them.The drifting buoys have tracked the patch quite well for the past few days.
The weather continues to be 'moderate' which means cold, but little wind.A large swell is running and were on a course that puts us right in the trough - that means a rough ride. It must be Sunday since we are getting wine with dinner.Almost time for e-mail to go out and I have to send MELVILLE an update - bye.
R/V Melville:
Ship:47 degrees, 55 minutes South, 177 degrees, 51 minutes East
R/V Melville Log Entry: Hello from Melville, Steaming along at a heading of 142 degrees for the last 30 hours, we are now well out of the lee of New Zealand and beginning to pick up some of the roaring 40s and raging 50s. Although the weather is overcast and white-capped, it is not really very bad for us old-timers. You wouldnt know it from some of the green faces at todays fire and abandon ship drill, however, and the realities of oceanography are beginning to make an impression on our younger scientific crew. It was too rough and wet to put on our exposure suits on the boat deck, so a demonstration sufficed for this weeks drill. This is definitely an occupation that requires many different skills. By the time we were done loading, tightening chains on vans, climbing masts to place antennae, loading supplies, torquing down bolts, we mused that ALL oceanography is physical oceanography and our rubber bands and aching feet stood in strong support of this observation. Still, we are inspired by the results from the RV Revelle so far and looking forward to exercising our other head muscles on a very interesting and evolving experiment. At our first scientific meeting today, we outlined a draft station plan, designed to meet the sampling needs of all participants. It is interesting to observe that ones water requirements increases in anticipation of a successful experiment and it now looks like we will have to add several casts. This may preclude our original plan of doing two stations per day in lieu of meeting everyones sampling demands. I am a bit worried that sea level may drop somewhat from the efforts of our ambitious scientists.
- Kenneth