Southern Ocean Iron Experiment (SOFeX) Cruise
January 5 - February 26, 2002
Logbook
Skip to Log Entry from the USCGC Polar Star
February 16, 2002: Day 43
R/V Melville:
Position: 63 degrees, 24 minutes South, 171 degrees, 10 minutes West
R/V Melville Log Entry: Having begun a surface mapping survey the previous day, we finished it last night, realizing it is not exactly contemporaneous, but it is of great value for us to see the variability and covariation in the parameters we measure and, we are told, there is a satellite image on its way. These underway observations will be very useful in ground truthing these remote images and useful too, for Polar Star to understand the extent of the Patch. My last chance to share iceberg photos with you I am sending two from our last Out Station - it is the same iceberg that was on station with us the whole beautiful day.
We are headed north. Since many were up late from the sampling of the survey, it is quiet in the lab except for the creaking and shifting of equipment as the ship steers 0000, broadside to the Southern Ocean swell from the West. The transit from the South Patch to the North Patch will take about 2 days, 21 hours. In this region, the winds blow unimpeded by land masses around the Antarctic continent in a merry-go-round of wind and waves from the west to the east. In the trough through the waves of the 60s and 50s, this could be a long ride. We are thankful that we dont roll as badly as the Polar Star but we have taken some 30-degree rolls and in this swell, we all must develop strategies for working and sleeping in a constantly accelerating frame of reference.
Almost all the bunks are oriented fore and aft and one side of them is usually hard up against a wall. Some of the upper bunks have about 0.5 meters of overhead space, unless there is a pipe or something in the ceiling above the bed. Some bunks have rails or boards to keep one from coming out altogether, others do not. The roll period is about seven seconds. This means that the ships roll continually tries to push you into a bulkhead and alternately, dump you onto the floor every 7 seconds. A mate on the R/V Thompson, some 20 years ago showed me how to tie the corners of the sheets underneath the mattress making a secure pocket that one couldnt slip out of. This helps keep the feet in place. In my Chief Scientist stateroom on the 02 level (higher and more motion) I have found that I can stuff things under my mattress on the outboard side, making a trough that is hard to roll out of. This is the "soft taco" method (I dont think Beauty Rest makes one of these). Others brace themselves against the railing and wall in a "Bill the Cat" kind of sprawl, jamming knees into the rail and pushing the back up against a bulkhead. Some have taken to putting their mattress on the floor and sleeping athwart ships (not as much roll but the blood does rush alternately to the head and feet). You wouldnt expect that sleeping could be such a workout. Whatever the method, the sleepy faces at breakfast made me think that there is no perfect solution and nothing works better than calm seas or a comfortable course.
Sweet Dreams,
Kenneth Coale, Chief Scientist
USCGC Polar Star Log Entry: Weve had a busy couple of days here at the Southern Patch. We spent much of the first day conducting underway surveys, trying to establish the outer boundaries of our patch. Our primary method to track the patch, as with the earlier groups, is to look for the SF6 tracer in seawater. SF6 is an unreactive chemical marker added along with iron that even now, some 4 weeks after initiation can be readily detected in a half liter water sample. In addition, as mentioned in my last report, we can also look at the phytoplankton response to iron by measuring a property (Fv/Fm), or the photosynthetic competency.
I ended my last report with a photo of Ed Abraham, who measures Fv/Fm continuously from our surface running seawater intake. His map of Fv/Fm is shown here, with "hotter" colors along the cruise track indicating the locations that are showing the highest phytoplankton response as a result of iron fertilization.Along with this map, we have SF6, which was analyzed by Leah Houghten and Laura Goldson on samples collected every 15 minutes by our other team members. Sure enough, the images overlap nicely indicating that the changes in photosynthesic efficiency are due to the earlier iron additions traced by our SF6 marker.
Scientifically, we are also finding some patches of relatively high chlorophyll, or plankton biomass that are not tagged with SF6 or have especially high Fv/Fm. We hope to target some of these sites later in the cruise. What is it that naturally controls blooms in this area and does iron really enhance not just phytoplankton biomass, but also export to the deep ocean? Many of the samples we are collecting in and outside our study area will tell us just how much carbon and associated nutrients are taken up by these phytoplankton blooms and what fraction is exported to the deep ocean. We are also looking at the smaller critters, or the microbial community. Robert Daniels, shown here in the lab, is conducting a variety of studies of marine bacteria abundance and growth rates.
We are just starting to get used to life at sea with 150 Coasties on a ship that doesnt at first seem large enough to hold us all. We did see the excitement level rise today, as we had Saturday Pizza Night where some hot slices of pizza were offered along with hot Buffalo wings in the galley. No beer on this ship to wash it down with, but still quite a nice break from the regular fare.
Weve already celebrated one birthday among us (Happy Birthday Leah) with what else as a gift, but a USCG sweatshirt from the ship. Unfortunately, we had to live without a cake.The problem was that our science led us on a south to north cruise track (one of those shown above for Fv/Fm) just at the time the cooks were trying to bake the cake. So we were in the trough between swells rolling quite heavily, when the batter jumped out of the pan before it had time to set. This happened twice before the cooks who had so kindly offered to bake this surprise, had to give up. We settled for piling on some junk food and snacks for the B-day celebration which took place one night between 15 minute SF6 runs in the lab. So much for a day off on your birthday!
As of tonight, we are left on our own as the Melville heads North. We wish her well.
Outside, we still have a few icebergs around, and despite the roll of this round bottomed ship, its nice to know you are on an ice breaker when you see one of these go by. The weather has been near freezing and generally windy (10-20 knots), but not too bad. Last night we were working in the snow, lowering sample bottles one at a time over the side, and that does get chilly.Today the winds were less, and we were able to launch the more sophisticated CTD/Rosette sampler that lowers 24 sample bottles at a time. Within one hour, we had collected more water samples than all of our efforts last night in the snow. We are keeping our team and the USCG marine technical crew busy, and all parties are working hard to make these last days of the experiment a success.Cheers from the south.
- Ken Buesseler
