Southern Ocean Iron Experiment (SOFeX) Cruise
January 5 - February 26, 2002
Skip to Log Entry from the R/V Melville
January 21, 2002: Day 17
PIT Drifter In North Patch: 55.682S 171.768W
PIT Drifter Out of North Patch: 55.821S 172.078W
Ship: -62 55.4538 S-170 27.8912 W
R/V Revelle Log Entry: We continue south with ice showing up again.Weve now had to pick our way through several fields of drifting icebergs. Its keeping the bridge crew on full alert.Here, Captain Tom Desjardins (right) and Bosun Victor (middle) are spotting ice with the bridge watch. This is not good if we have to operate in these conditions at the next patch. Picking a safe passage through the fields of ice shed by the big bergs is a cautious business. Conditions are nice, otherwise, with a clear sky, a steady 20 knot wind and a big swell coming out of the west - of course that puts us right in the trough as we head south and were starting to rock a bit. The boom of the swell breaking on the side of the ship adds to the drama as we pass through the ice.
We hope to be on site for the next fertilization experiment tomorrow morning. Were looking for water with high concentrations of silicon (Si). Most of the carbon moved from surface waters to the deep-sea is carried by sinking diatoms, a class of phytoplankton that makes a Si based shell. One of the major goals of our experiment is to assess how and when large diatom blooms export carbon from the surface waters into the deep-sea. The carbon carried into the deep-sea by diatoms is an important regulator of carbon dioxide in the atmosphere and the temperature of the earth. The North Patch experiment was intended to assess whether large amounts of carbon could be exported in low-Si waters where diatoms cannot grow. When we find high Si waters, we will spend several days surveying the area and collecting initial samples before iron is added.
We expect to find high Si waters near 65S. However, conditions are already quite different than those that were observed in 1998, when the JGOFS program was conducted in this area. Water temperature is 1C at 62S, which is several degrees colder than in 1998. We encountered water too warm as we came south - now its colder than expected.
We continue to analyze samples from the North Patch experiment.Primary production rates more than doubled in our last samples.But chlorophyll had stopped its rapid increase. What will MELVILLE find when they arrive tomorrow?
Ship:51 degrees, 49 minutes South, 177 degrees, 29 minutes West
R/V Melville Log Entry: Today we crossed the date line and went back to yesterday. Although we are keeping New Zealand time for the duration of the trip it was a noteworthy experience not possible many places on land. You saw our longitude change from East to West. It was also Julian Herndons 30th birthday, celebrated with a cake and congratulations from all.Julian (on the right) is a graduate student at San Francisco State University studying nitrogen cycling with Dr. Bill Cochlan (left) of the Romberg/Tiburon Center. More on this later.
The weather has calmed considerably from the day before and everyone is feeling well. We are almost ready for a test station following lots of problems with our biggest water sampler:the Trace Metal Clean Rosette. This is a device that enters the water with all the samplers in a closed position, then, upon command from a computer connected to the deck unit, the bottles open underwater. In this way, the sampler avoids contamination from the very surface of the water where contamination can accumulate in slicks and drippings from the ship. The sampler then descends to the maximum depth, and we trip the sample bottles closed at depths of interest on the way back up. The problem is that we have a new computer that is running old equipment, the computer keeps wanting to talk to the internet, but we cant just dial Microsoft from out here, the control cable had shorts in it, then the polarity was wrong, then the deck unit blew a fuse, then the computer died all together, etc. This is good training for our students. Going to sea is really about fixing things and finding ways to make things work. I call it McGuivers Oceanography and it characterizes much of what we do. So, our graduate students get to learn how to solder, weave safety stoppers out of Kevlar, use test equipment, run winches, build equipment from scraps they find lying around and advance our understanding of the world. In the image to the right, Nicolas Ladizinsky, Graduate Student at Moss Landing Marine Laboratories, fixes a slip ring connection on the Trace Metal Rosette winch.
We have gotten exciting news from Revelle about the patch that we are approaching. Already we are modifying our station plan to follow up on some of their findings. Soon we will get our chance to dip our samplers over the side and hopefully, everything will be working by then.