The RV Melville joins up with an iceberg and the RV Revelle!

Jump to the log entry from the RV Melville

REVELLE @ 1/29/02 05:00Z, 

-66 20.238, -172 5.418

MELVILLE @ 1/29/02 05:00Z, 

-66 20.0, -171 57.0

So. Patch In Drifter @ 1/29/02 04:51Z, 

-66 20.8098, -171 51.9978 (this is at east side of patch)

So. Patch Out Drifter @ 1/29/02 04:51Z, 

1815 January 29, 2002, At sea

Hey, MELVILLE pulled into Dodge City.  Just 15 minutes ago on a picture perfect, sunny afternoon. We’ve been concerned they would bring the bad weather with them. So far so good. Best weather they’ve seen, we hear from them.

They’re going right to work with an 'In the Patch' station. Just in time, as things are starting to grow in the fertilized patch.  Chlorophyll concentrations are clearly up: over 50% in the fertilized patch. Things are so uniform in the waters around the patch that we can be quite sure that this is a result of the iron addition. We’re starting to see trends in the other parameters that are generally consistent: nitrate is down a 'smidge', PCO2 is starting down in the proper ratio as well. Both the changes correspond to what we would expect from the chlorophyll increase. Now if I told you (the scientists anyway) how much these 'smidges' are you wouldn’t believe that we can see these trends.  However, the chemical sensors on the In Patch drifter are operating so well that we almost do believe the trends. A few more days and we’ll be sure.  

Very cool if it all works: we could remotely monitor multiple experiments at the same time. Heaven forbid, we could also repeat our experiments on the same trip. The only problem is that the drifters really don’t stick perfectly in the patch. We had a pretty good blow last night and both the In Drifter and the In PIT have slipped off to one side. They look like they’re coming  back now, but we may have to reposition them. 

So not everything works perfectly: we launched two PIT’s last night. The first went off just as planned. The second had an extra radio transmitter on its mast.  OOPS...too much weight up too high. Over she went. We had to recover and add weight to the bottom.

Well, that’s all, except the next contestant in the Shackleton lookalike contest.  Here’s Joe Jennings: he and I were graduate students together at Oregon State. 

January 29, 2002

Local time: 0940

Ship’s Position: 65 degrees, 18 minutes South, 171 degrees, 21 minutes West

Continuing on our way south we are now in iceberg alley with over 15 contacts on the radar. The larger icebergs light up brightly, both visually and on the radar. No problem avoiding these. It is the smaller pieces that one must be watchful of and lucky for us, we are in almost 24 hour daylight now. Still the watch must stand vigilant and it is tedious business trying to figure out the difference between a white cap and a small bergie bit.

Silicate is very high as we crossed the Antarctic Polar Front Zone. Surface water temperatures have dropped (thus the increase in icebergs) and we have heard from Revelle that the deployment region to the south is stable and in good shape. The patch is drifting slowly, and there has been no geochemical signal to develop just yet. This means we won’t miss the party

The crew aboard Melville have been working hard to reinstall a surface seawater pump during the transit south. This has meant welding new brackets for a pump in the bow, installing new piping and power, as the ship pitched over 15 foot waves. We are up and running again and the engineers are happy to get off their e-ticket ride.

A reassessment of the Northern Patch results indicate a very successful experiment there. We do not know if we will be able to find it when we return, but the optical drifter buoys deployed for Mark Abbot (Oregon State University) and the autonomous profiling floats deployed for Jim Bishop (Lawrence Berkeley Laboratories) should be able to tell us how the patch develops and where it goes.

- Kenneth Coale

Figure: