| Dynamic Green Ocean Project |
Laboratory based biological oceanography
TITLE. Environmental conditions regulating the growth of coccolithophores in the ocean.
PhD project of Moritz Heinle
SUPERVISOR & CO-SUPERVISOR(S)
Erik Buitenhuis (UEA and BAS), Gill Malin (UEA)
Phd to be held at the University of East Anglia (UEA)
PROJECT DESCRIPTION.
Coccolithophores are important organisms for the oceanic carbon cycle. On annual time-scales, their dense coccospheres contribute to increasing the sinking velocity of organic particles (Buitenhuis et al. 2001, Ploug et al. 2008) particularly during blooms, thus isolating carbon from the atmosphere. On decadal to millennium time-scales, they control the distribution of alkalinity between the surface and the deep ocean. Very little is known about the physiology and environmental conditions which favor the presence and blooming conditions of coccolithophores. Satellite observations have identified large-scale large-scale blooms of coccolithophores in the high latitudes (Le Quere et al. 2005). For the Northern oceans and South West Atlantic, these blooms have been confirmed by local observations. For the Southern Ocean, there is conflicting evidence. The physiological information available from Emiliana huxleyi, the most studied species, shows slow growth at cold temperatures, but little work has been done on cold-water species such as Coccolithus pelagicus (Buitenhuis et al. 2008).
The current project would try to resolve the controversy regarding the presence of coccolithophores in the Southern Ocean. It would aim to identify what are the environmental conditions which favor the presence and blooming conditions of different species of coccolithophores in the ocean, and to identify where such conditions are observed in the present ocean, where they have been in the past ocean, and how they are expected to change in the future. Particular attention will be given to the role of temperature and light, and to determine if the conditions predicted for the future high-latitude oceans will favor or penalize coccolithophorid growth. The project will be based on a combination of laboratory work, data and model analysis. During the laboratory work the student will cultivate ~ 10 species of coccolithophores and test their growth rate under different temperature, nutrient and light conditions. Several such cultures are currently used for physiological research at UEA and thus the student would benefit from state-of-the-art experience in the field. The student will complete and analyse a database of the available coccolithophore concentrations and physiological rates starting from results from the European EurOceans and IRONAGES projects. He will perform sensitivity analysis of the model for the rates, and check for coherence with the concentrations and satellite data of CaCO3, and use the model results to verify if the changes in environmental conditions which trigger the presence of coccolithophores in models are consistent with his laboratory results.