I'm going to try and do a series on our research operations over the next several days whenever I can spare some time. It's been consistently busy for the past week. We have been sampling every 30-40 miles or so, which gives us about 3-4 hours of down time between stations. This made the shifts go by dreadfully slow, but it gave me time to work on my thesis. The distances between stations depends on what the lead scientist, Jim Ledwell, feels is best for detection of the tracer, which was injected into a specific density layer on last years cruise. From what I've deduced is that the stations are longer along the zonal, east/west, lines and closer together for the meridional, north/south, lines. For obtaining the water samples a large cylindrical steel frame is used known as a rosette. This is used to house the niskin bottles, which are the long gray cylindrical tubes encased within the inner circumference of the rosette for collecting the individual water samples at predetermined depths. These depths are chosen to coincide with the density level at which the tracer was injected to see how it has spread both zonally and meridionally as well as vertically. The CDT, which stands for conductivity, depth, and temperature, is an instrument used to measure just that. Then the density is calculated from the temperature and salinity (from conductivity) and then we can determine the depths where the density layer containing the tracer is. They are triggered to close electronically from the computer lab inside the ship by sending a signal through the winch wire, which has electrical wire encased so that each bottle can be triggered individually at the correct depth. There is also an ADCP, or Acoustic Doppler Current Profiler, which measures the currents. My duties are to safely deploy and retrieve the rosette at the stations. First we have to prep the bottles so that they are open on the way down. Then for deployment we wheel out the rosette onto the side deck where we attach tag lines to to control it as the winch picks it up and puts it over the railing.
For retrieval we used hooks that slide into the end of a 20 foot pole. We then hang them over the edge and try our best to hook the rosette frame as soon as it breaks the surface of the water. What may seem like a simple operation becomes exponentially more difficult when you add in 30-40 mph winds and 20+ seas, as well as rain/snow. If the tag lines aren't there quickly the rosette becomes a 1500 lb wrecking ball!! Although it does tend to make things interested when the weather isn't ideal, which is a good portion of the time. I almost feel like I'm on Deadliest Catch sometimes when waves are breaking over the sides and water is rushing over my knees on deck! You really feel pretty insignificant when a wave goes by and blocks the horizon as it rolls by about 3 or 4 feet over your head and you aren't sure whether or not it's going to come over the rail or not! Hopefully this wasn’t too nerdy or boring or both!
-J
