July 14 - 2005 part 2 Options

[Betty_Carvellas]

July 14, 2005

I've already told you about Rebecca Woodgate's work with moorings, and I'll have pictures for you within a few days. Before that, however, Bill Floering will be picking up a mooring he set out last year and putting two more in. Bill is a field operations scientist with NOAA/PMEL/FUCI, based in Seattle, Washington. That all translates to National Oceanographic and Atmospheric Administration, Pacific Marine Environmental Lab, and Fisheries Oceanography Coordinated Investigation. It's all a way to tie in the fisheries part of NOAA with the Oceanographic part.

One of the moorings that Bill will set out will be similar, in terms of instruments, to the one he is retrieving. The difference is that the mooring he's retrieving has been out since last year's Laurier cruise, and the one he is setting out will be picked up in October when a new one will be put down to replace it for the winter months. This first mooring will be set at a depth of approximately 74 meters, and will contain a set of instruments to measure salinity, conductivity, temperature and depth (similar to the CTD) and a fluorometer to measure chlorophyll, an indication of the phytoplankton in the water. The second mooring he's planning to deploy has an ADCP (Acoustic Doppler Current Profiler) on the top. If you read my July 12 journal about Rebecca Woodgate's moorings, you might remember that the ADCP sends out a sonar signal that bounces off material in the water and returns, thus giving readings which translate into speed and direction of the current. Although the mooring anchor will be at a bottom depth of about 72 meters, the ADCP sits higher on the chain at about 60 meters, where it will provide data every four meters for the water column above it. By combining data from both moorings, scientists gather information about both the physical and chemical properties of the water column.



I asked Bill if he had long term data for this mooring site, and he told me that the mooring he is retrieving is the second placed in that location; the first was lost to the ice. I remember that, on last year's Laurier cruise, we were unable to locate one of the moorings, and they thought that one had been lost to ice as well. Bill said that ice is the most common reason for mooring failures and losses, but some are lost to fishermen's nets or, rarely, to barge tow lines. Occasionally the release mechanism fails, but that's usually in much deeper water.

Bill will not be downloading the data from the retrieved mooring, because he is leaving the Laurier at Gambel, on St. Lawrence Island, in order to join a ship leaving Kodiak on the 18th. Instead, the instruments will remain on board to be brought back to Seattle in October. Bill's work keeps him in the field approximately six months of the year, primarily in the Gulf of Alaska and the Bering Sea. Although he's working on moorings on the Laurier cruises, he also does a variety of other work, including CTD casts and plankton tows. When I asked him what he does in his time off, he told me he does not go on a cruise ship, and he definitely does not go north!