Dr. Raissa Philibert
Postdoctoral Researcher
contact details:
Department of
Earth Sciences,
Stellenbosch
University, South Africa
Email: raiphilibert at gmail.com
Research interests: Marine biogeochemistry, Microbial
ecology, Nutrients cycling, trace metal chemistry
Biography:
I was born and grew up in Mauritius. I moved to Cape Town
in 2007 to start my undergraduate studies and never left! After a Bsc(hons) in
Chemistry at the University of Cape Town, I joined the Oceanography Department
in 2011 for a MSc and PhD investigating the nitrogen cycle in the Southern
Ocean and the Benguela upwelling system. and I will be graduating in
December 2015. Over the last year, while waiting for my PhD examination to be
complete, I joined the Earth Sciences department at Stellenbosch to
investigate how trace metals concentrations and light limitation affect
phytoplankton growth. When I’m not studying phytoplankton, I can be found
running and hiking.
Current project:
The aim of my current research project is to improve the
current understanding about the effects iron and light co-limitation on
Southern Ocean diatoms as this plays an important role in regulating the marine
carbon cycle, the marine food web and the Earth's climate. The Southern Ocean,
accounts for 4% of global carbon fluxes and is expected to play an important
role in the uptake of the anthropogenic carbon dioxide. However, the efficiency
of the biological pump (the mechanism through which carbon is removed from the
surface ocean due to the sinking and subsequent sequestration of organic matter
produced by phytoplankton) in this region is still debated. The efficiency of
the biological pump is affected by several factors such as the phytoplankton
community structure and the rate of primary productivity. For instance, larger
phytoplankton such as diatoms play a major role for the biogeochemical cycling
of carbon as well as other nutrients such as nitrogen and iron. Their growth is
regulated by light and nutrients availability. In the Southern Ocean, however,
phytoplankton are limited by the low iron availability (iron limitation) which
is considered to be the cause of the high nutrients, low chlorophyll conditions
observed in this region. This iron limitation might also be compounded by the
light conditions experienced by Southern Ocean phytoplankton. Given their
importance for the regulation of climate and biogeochemical cycling of
nutrients, the adaptation of Southern Ocean diatoms to iron and light
limitation will be studied by conducting incubation experiments of summer and
winter phytoplankton communities as well as laboratory culture experiments.
Publications:
- Philibert, R., Clark, D., and Waldron H, A regional and seasonal comparison
of nitrogen uptake by phytoplankton in the Southern Ocean, Ocean Science, 11,
251-267, Journal IF: 2.232
- Kuyper, B., Labuschagne, C., Philbert , R ., Moyo, N., Waldron, H., Reason
C., and Palmer, C., Development of a simplified, cost effective GC-ECD
methodology for the sensitive detection of bromoform in the troposphere,
Sensors, 2012, 12, 13583-13597, Journal IF 2.245
- Philibert, R., The importance of nitrification in the Southern Ocean and
in Southern Benguela upwelling system, 2014, SOLAS Newsletter, 16, 15-16,
available at http://www.solas-
int.org/archive.html
(not peer-reviewed)
Conference oral presentation list
- Philibert, R., Van Horsten, N., Mtshali, T., Roychoudhury, A., and Fietz,
S., Effects of iron and light co-limitation on Southern Ocean phytoplankton,
APECS 2015 Online International Conference,
- Philibert, R., Clark, D., and Waldron, H., A comparative study of nitrogen
cycling in the Southern Ocean and the Benguela upwelling system, Southern
African Marine Science Symposium, 2014, Stellenbosch, South Africa
- Philibert, R., Clark, D., Bellerby R., and Waldron, H., Importance of
nitrification for nitrogen cycling in the Southern Benguela Upwelling system,
EGU General Assembly 2014, Vienna, Austria.
- Gunputh R.,, Philibert, R. , and Ramessur, R., Ocean Economy within Climate
Compatible and Sustainable Development: Issues in Mauritius, ADDGASAT
Conference on Science, Technology, Gender and Sustainable Development, 2014,
Moka, Mauritius
- Philibert, R ., Clark, D., and Waldron, H., The importance of nitrification
in the Southern Ocean and in Southern Benguela upwelling system, SOLAS 6th
International summer school, September 2013, Xiamen, China (accompanied by a
poster)
- Bruun J.,, Rees, A., Stephens, J., Thomalla, S., Philibert , R., Waldron,
H., Somerfield, P., Jeansson, E., Bellerby, R., Moiseev, D., Assessment of
seasonal and decadal signals in the in-situ Atlantic plankton data, ICES Annual
General Meeting, September 2012, Bergen, Norway
Conference poster presentations:
- Philibert, R ., Clark, D., and Waldron, H., The importance of nitrification
in the Southern Ocean and in Southern Benguela upwelling system, SOLAS 6th
International summer school, September 2013, Xiamen, China (poster)
- Philibert, R ., Clark, D., and Waldron, H., Nitrogen regeneration and
assimilation rates in the euphotic zone of the Southern Benguela upwelling
system, ICES Annual General Meeting, September 2012, Bergen, Norway
(accompanied by a 2 minute presentation).
- Philibert, R ., Clark, D., and Waldron, H., Nitrogen regeneration and
assimilation rates in the euphotic zone of the Southern Benguela upwelling
system, UCT Postgraduate annual science symposium, September 2012, Cape
Town
Postgraduate student supervision:
Mhlangabezi Mdutyana (UCT) - Seasonal
comparison of nitrogen uptake and nitrification rates in the Southern Ocean.
