Southern Ocean Iron Experiment (SOFeX) Cruise
January 5 - February 26, 2002

February 15, 2002: Day 42

R/V Melville:
Position: 66 degrees, 1 minutes South, 172 degrees, 7 minutes West

Dr. Bob Bidigare opens his filter sandwich from 15 m to find it is clogged with phytoplankton.

R/V Melville Log Entry: Arrival of US Coast Guard Icebreaker Polar Star marked the third chapter of the South Patch experiment. Dr. Ken Buesseler from Woods Hole Oceanographic Institution is leading a team of scientists on what would have been a transit leg for the Polar Star from McMurdo to Argentina. Ken was able to get funding to assemble group of scientists whose expertise in some measure compliment those aboard the Revelle and Melville that will allow us to extend the observational period of the South Patch bloom progression. After a challenging, but very productive week, and some very difficult transects, it was with a mixture of relief and apprehension that we watched Polar Star cross our bow at 0600 this morning. Yes we have grown pretty attached to this station and believe the best is yet to come.

ctdtrace.jpg (45864 bytes)

We spent the whole day at an Inside Patch station in some of the greenest water we have ever seen. Although we have seen small areas with higher values, the chlorophyll was the highest we have seen it on station and stayed that way all day. It was a beautiful and fitting last station to a very productive few weeks. The fluorescence (a measure of plant pigments=chlorophyll) was uniformly distributed and high through the mixed layer (see photo of CTD trace from cast at our last In station. Y-axis is depth down to 300m, green trace is fluorescence, note maximum in surface decreasing with depth. Blue trace is temperature, note the smaller steps developing in the surface mixed layer.), filters clogged rapidly and the weather was mild. All casts went off without a hitch and (finally) the station plans I have been making up for the last few weeks, was executed flawlessly. Mike Landry and Cecilia Sheridans plankton nets came up with more stuff in it at 100 meters than at 50. Does this mean that the patch is beginning to sink out? This would be a very exciting development and one that Kens group would be well prepared to follow: The flux of carbon from the surface waters.

First CTD Cast of the morning with the Polar Star in the background.

The radio in the lab crackled all day with chatter between the scientists aboard both vessels as we tried to catch up and impart enough of what we have learned so that they could get off to a running start, and we could feel comfortable leaving. We sent (by Inmarsat/e-mail) over files, tables, graphs, maps and data Ken would need to get through the week. We offered to send transmitters, filters, reagents and standards, but it is difficult for Polar Star to pick things out of the water. Theyll be fine, we tell ourselves, the Patch is doing fine and will teach them all they need to know.


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