Delphine Lannuzel, PhD student at the Université Libre
de Bruxelles (ESA-ULB)
explains about her stay at the University of Tasmania (Dr Andrew
Bowie, Hobart, Australia,
at the end of 2006. She will be trained in analytical techniques
of trace metals.
‘I just graduated from my PhD thesis at
the Université Libre
de Bruxelles. The scope was to study iron (Fe) biogeochemistry
in the Antarctic sea ice environment in a climate change perspective.
I have then been offered to take part to SAZ-SENSE campaign
(Jan-Feb 2007) aboard the RV Aurora Australis in the Antarctic
polar zone in the frame of the BELCANTO project.
Why would we want to measure Fe in the Southern
Ocean waters? Well, Fe is a key element in the study of ocean-atmosphere
interactions as it is an essential element for phytoplankton
growth, and hence is involved in marine primary productivity
and carbon export. This micro-nutrient has been shown to be
limiting in “High-Nutrient,
Low-Chlorophyll” areas such as the Southern Ocean where
its input are typically very low.
Because of the low Fe concentrations
encountered, it is a tricky business to collect and analyse
Fe in Antarctic surface waters: until thirty years ago Fe concentrations
in seawater may have been overestimated mainly because of contamination
problems upon sampling (type of containers used, human manipulation,
cables from the ship, material for CTDs…) and lack of
analytical performances.
Thanks to a huge international effort
via for example inter-calibration exercises, sampling and
analytical strategies for trace metal study in the ocean waters
have been greatly improved over the past 3 decades. Although
more datasets on Fe concentrations in Antarctic waters are
becoming now available, many questions remain unsolved as to
date. Clear characterization of Fe biogeochemical cycle in
the Southern Ocean marine ecosystem still needs to be assessed,
in order to understand how this can affect ocean-atmosphere
gas exchanges.
During the 4 years of my PhD thesis as part
of the SIBClim Belgian
project, I have been used to experience high Fe levels in
Antarctic sea ice (up to two orders of magnitude as compared
to the under-ice seawater). Now, measuring Fe levels in the
Southern Ocean open waters is a whole new world for me. Onboard
the SAZ-SENSE 2007 cruise that is planned from January 14th
to February 17th, I will be in charge of measuring Fe concentrations
in the collected seawater samples. I will be using the Flow
Injection Analysis (FIA) instrument that belongs to Dr. Andrew
Bowie (ACE-CRC, University of Tasmania, Hobart).
We indeed
need to spend a bit of time together in his laboratory before
the SAZ-SENSE cruise starts, so that Andrew can teach me
how his FIA instrument is working and also that I can help
preparing cargo for a successful campaign. I will thus be in
Hobart on December 2nd 2006 for this purpose;
This is where
the Be-Poles grant becomes a key contributor to this work,
as I need funds for this travel scholarship. This fellowship
will broaden my sea ice background to open seawater realm,
and thus certainly help me to answer the many questions I still
have regarding my current work on the Antarctic sea ice ecosystem.’
