2. Trichodesmium cultures grown under different CO 2 and temperatures Hutchins et al. (2007) Meta analysis (Findlay et al. 2011) on E. huxleyi cultures shows that after pCO 2 and TA, P concentration controls PIC:POC response

3. StudyPIC:POCGrowth rateDaylength Iglesias-Rodriguez et al. (2008) ↑↓ 12h Unpub. data, Bretherton ↔↓ 14h Hoppe et al. (2011) ↓↔ 18h Shi et al. (2009) ↓↔ 24h

5. Fv/Fm decreases slightly in continuous light cultures – stress?

6. 14h daylight period: calcification maintained, but at the cost of growth rate 24h daylight period: no change in growth rate, but cultures produce excess coccolithes

7. SpeciesStrain Date of isolation Location of isolation Emiliania huxleyiPML 70-302/07/2011Northern North Sea Emiliania huxleyiPML 124-325/06/2011Bay of Biscay Emiliania huxleyiRCC96229/10/2004French Polynesia Gephyrocapsa oceanica RCC180409/12/2008Sipadan, Malaysia Coccolithus pelagicus PLY 1821958English Channel Ochrosphera sp.RCC136622/02/1998Palau, Micronesia

11. Species/Strain14h24h E. huxleyi NZEH Calcification ↔ µ ↓ µ ↔, produces lose lithes E. huxleyi 962 Thin coccosphere calcification ↔ µ ↓ µ ↔, produces lose lithes G. oceanica Calcification ↓ µ ↓ µ ↓, produces lose lithes Shipboard experiments from the Arctic Circle and Southern Ocean Meta-analysis of all OA literature to see whether or not L:D controls the observed response

12. L:D cycle is an important consideration for OA experiments Discrepencies in OA response can be explained by L:D cycle Local changes in L:D cycles in nature as climate changes

13. Acknowledgements Supervisors Dave Suggett and Tracy Lawson Richard Geider the Algal Research Group at University of Essex Mark Moore and Alex Poulton I am in the third year of my PhD and looking for more research opportunities! lmjbre@essex.ac.uk