Research
Ocean carbon levels and their influence on marine life
Voyage update 1 - From the log of Southern Surveyor' Chief Scientist,
Tom Trull, 3 April 2006.
PULSE Beats from Southern Surveyor Voyage SSS03/2006
Inspection of our recovered Sediment trap mooring revealed successful
collections by the two Mclane conical funnel traps, but not from
the IRS-Sinking Velocity Trap. The IRS-SVT collects particles on
a dimpled ball and then dumps them into a settling column above
a spinning carousel that separates them by sinking velocity.
Sinking velocity is a key parameter in the penetration of organic
carbon from the surface ecosystem to the deep sea - the faster a
particle sinks the further its organic carbon penetrates before
it is re-mineralized by bacteria.
Amazingly, sinking rates vary by more than 3 orders of magnitude
for typical oceanic particles - from 1m/day for phytoplankton to
>1000 m/day for mineral rich aggregates and compact faecal pellets.
Very little data has been collected, mainly from submarines and
remotely operated vehicles, so we were eager to get these results.
Sadly, a failed pressure-compensating membrane let seawater into
the motor that drives the rotating ball requiring repairs in Hobart,
so these results will have to await a future deployment.
We got the SAZ sediment trap mooring turned around and back in
the water by late Monday night and returned to triangulate the position
and thus precise depth of our PULSE mooring. This was made easy
by its first PULSE Beats - 3 Iridium network reports of GPS positions
from the surface float showing it on target and keeping its watch
circle of a few hundred metres about the anchor point.
Tuesday dawned calm and sunny and we launched the ship's boat to
obtain trace element clean samples from clear of the ship's contamination
wake.
This work is part of evaluating the possibility of using trace
element clean Helmond-Byrne bottles on the normal Rosette for at
least some elements.
Unfortunately after a succesful run with the boat we lost power
to the CTD during the comparison cast. We are switching to the aft
CTD wire now, and will keep fingers crossed for a successful result.
In any case this means an afternoon of cable reterminations - for
the CTD and also for Seasoar.
Meanwhile we will steam west to the location of an oxygen-optode-equipped
Argo profiling float. (www.argo.ucsd.edu)
The SS03/2006 Team.
< back | 1
| 2 >
« ocean carbon home
Last updated
6/01/12
|
