May 23, 2001
Today we learned there is not a secret 5th
engine on the WESTERN
FLYER. There is a secret, extra fuel tank. The WESTERN FLYER
is making 11 knots through almost flat calm seas, instead of the planned
speed of 8 knots for maximum fuel economy. There is hardly a ripple on the
ocean, just a long swell running. So we are "making extra speed in
case the weather turns." This must prove that we live a more virtuous
life than the geologists, who fought high winds, high seas and high
currents on their three legs of the expedition.
Yesterday evening we occupied our first station at
the Hawaii Ocean Time series (HOT) site (http://hahana.soest.hawaii.edu/hot/hot_jgofs.html
). It was the first cast with a brand new rosette/CTD that had not been
wet before. We were still pulling tags and warning labels off as it went
overboard. This system is designed to give uncontaminated samples for iron
from deep water. Everything worked flawlessly and we left station 30
minutes ahead of schedule after a cast to 1500 meters. We’re just
running the first samples for dissolved iron now and things look good. A
10-year long record of ocean biogeochemical processes has been accumulated
at the HOT site – check their web site for a nice, on line data system
with all of their measurements. We hope to contribute to the understanding
of this system with our work on Surface Ocean/Lower Atmosphere Studies in
this region.
Our next hydrocast comes this evening at the Dive
8 station of the outbound leg. Between stations, we’re pulling our trace
metal pumping system behind the ship. This system pulls uncontaminated
seawater up to the ship from a few meters depth with a TeflonÔ pump and
then distributes it through the wet lab. If anything comes unplugged in
this system, then "distribution of water through the wet lab" is
the perfect description. We analyze trace metals by Flow Injection
Analysis with chemiluminescence detection for iron and with fluorescence
detection for aluminum. Iron reacts with the organic chemical luminol, in
the analytical system, creating a photon of light. Our instruments
patiently collect the very few photons generated at the extremely low iron
concentrations (~100 picomoles/liter – a few parts per million of a part
per million) found in this remote area and then report the concentration
of iron every 15 minutes. We spend our time keeping two instruments happy
measuring iron and one measuring aluminum, which is far more work than it
sounds. In between we collect samples to analyze for particulate metals at
Moss Landing Marine Laboratories and samples of phytoplankton to assess
the impacts of dust iron on the ecosystem. To learn more about Flow
Injection Analysis visit the MBARI Chemical Sensor home page - http://www.mbari.org/chemsensor/sensorhome.htm
.
Well, I hear the aluminum system is not very happy
right now, and I’m off to investigate.
-Ken J.