Figure 1. Fraction of the year that picophytoplankton (Prochlorococcus + "Synechococcus") are the most abundant phytoplankton (PHYSAT data from Alvain et al. 2005 for 2000-2001).
| Dynamic Green Ocean Project |
Laboratory based biological oceanography
TITLE. Picophytoplankton physiology and the microbial loop.
PhD project of Beate Stawiarski.
SUPERVISOR & CO-SUPERVISOR(S)
Erik Buitenhuis, Corinne Le Quéré (UEA and BAS)
Phd to be held at the University of East Anglia (UEA)
PROJECT DESCRIPTION.
Picophytoplankton make up 34% of the oceanic chlorophyll (Uitz et al. 2006, see also figure 1). Based on the high turnover rates in the microbial loop one would expect their contribution to primary production to be even higher. The high grazing rates of microzooplankton suppress picophytoplankton from forming blooms, and thus their biomass is relatively more constant in space and time than of the larger phytoplankton. However, from their small size and lack of ballast one would expect their contribution to export to be smaller. Because of their small size (big surface to volume ratio) they grow well at low nutrient and light conditions. This specialisation in poor conditions probably also contributes to their relatively constant biomass. The physiology of cyanobacteria is relatively well studied, but much less is known about picoeukaryotes.
The aim of this project is to improve the representation of picophytoplankton in a global ocean biogeochemical model. In combination with an ongoing project on the representation of microzooplankton (Buitenhuis et al. submitted) and the recent inclusion of bacteria in the PlankTOM10 model (Le Quere et al. in prep.), the overall aim is to better represent the microbial loop. In this project the PhD student would combine data synthesis of published physiological information (maximum growth rate, nutrient and light physiology, nutrient stoichiometries and DOC production) with laboratory experiments to fill in the gaps. With these data, the following questions will be addressed:
Figure 1. Fraction of the year that picophytoplankton (Prochlorococcus + "Synechococcus") are the most abundant phytoplankton (PHYSAT data from Alvain et al. 2005 for 2000-2001).
Funding: This project will be funded by the EU initial training network Greencylces II from October 2010.
How to apply: If you are interested in this project, please contact Erik Buitenhuis. See also the extra guidance notes for PhD students.