“What does it do?” asked Neil, as he
inspected the arrangement of tubing and whirring pumps.
“It measures radioactivity that’s escaped from
the seafloor” I replied.
Having just heard
myself, I clarified “Natural radioactivity.
It’s found throughout the ocean, especially near the seafloor where much of it
comes from”.
“Oh right” said Neil, “why do you want to do that then?”
 |
| MAPs being prepared for their first deployment. Photo credit: Torben Stichel. |
I was glad
Neil asked why, I could answer that, but
how, is still pretty new to me. I just
had my crash course in how to measure the activity of Radium when our ship was
in Southampton dockyard. The expert, Amber Annett, walked me through her method
before she disembarked, and passed me the baton for this DY030 expedition.
I want to
learn how to measure Radium because I have a new instrument that will sample it
from just above the seafloor. This bit of the ocean is a real mystery for us
ocean chemists. Routinely the equipment we depend on cannot collect water samples
just above the seabed for risk of smashing it as it dangles from a long wire.
This means we struggle to measure the changes in chemical properties in this
zone – we struggle to map the chemistry of ocean bottom waters.
My idea is to
design new sampling equipment that can rest directly on the seabed, and DY030
has offered me the chance to try the newly built Miniature Autonomous Pumps
(MAPs) for the first time. I have only made the first step; test MAPs ability
to filter particles and collect the scarce quantities of radioactive elements that
pass been the seabed and the overlying ocean, but the results are promising.
 |
| Neil deploying MAPs on DY030. Photo credit: Torben Stichel |
MAPs have
been funded through a NERC Fellowship at University of Oxford, and designed and
built in collaboration with the Ocean Engineering and Technology Group at NOC Southampton. For this cruise, MAP missions are on a borrowed ‘Lander’ from NOC
Liverpool. Yesterday the bright orange Lander held two MAPs a metre above the
seabed, where they automatically pumped seawater, filtered particles, scavenged
elements, and monitored and recorded their performance. Samples recovered on
deck have been divided for various analyses –nutrients, and ‘trace’
concentration elements including Iron and Radium - that will feed in to the
programmatic goals of UK SSB.
Will Homoky
is a NERC Fellow and Anniversary Ambassador at University of Oxford. For more
information follow Will on twitter or visit his home page.
