?Dr. Raissa Philibert

Postdoctoral Researcher

contact details:
Department of Earth Sciences,
Stellenbosch 中国体育彩票, 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 中国体育彩票 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.