Hutchins et al 2007 Trichodesmium cultures grown under

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

1. 4 1. 2 PIC: POC 1 0. 8 0. 6 0. 4 Long daylight period 0. 2 Short daylight period 0 0 500 1000 1500 p. CO 2 (µatm) Study PIC: POC Growth rate Daylength Iglesias-Rodriguez et al. (2008) ↑ ↓ 12 h Unpub. data, Bretherton ↔ ↓ 14 h Hoppe et al. (2011) ↓ ↔ 18 h Shi et al. (2009) ↓ ↔ 24 h

1 0. 8 0. 9 Ambient High CO 2 Coccosphere thickness (µm) 0. 8 0. 7 µ (d-1) Ambient 0. 6 0. 5 0. 4 0. 3 High CO 2 0. 4 0. 2 0 14 h 24 h -0. 2 -0. 4 0. 1 0 14 h L: D Cycle 24 h -0. 6 L: D Cycle

0. 6 Ambient High CO 2 0. 5 Fv/Fm decreases slightly in continuous light cultures – stress? Fv/Fm 0. 4 0. 3 0. 2 0. 1 0 14 h L: D Cycle 24 h

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

Species Strain Date of isolation Location of isolation Emiliania huxleyi PML 70 -3 02/07/2011 Northern North Sea Emiliania huxleyi PML 124 -3 25/06/2011 Bay of Biscay Emiliania huxleyi RCC 962 29/10/2004 French Polynesia Gephyrocapsa oceanica RCC 1804 09/12/2008 Sipadan, Malaysia Coccolithus pelagicus PLY 182 1958 English Channel Ochrosphera sp. RCC 1366 22/02/1998 Palau, Micronesia

0. 7 Ambient High CO 2 0. 6 0. 5 0. 4 µ (d-1) 0. 6 14: 10 h 0. 3 Ambient High CO 2 0. 3 0. 2 0. 1 0 0 E. huxleyi G. oceanica Species 24: 0 h E. huxleyi G. oceanica Species

0. 4 Ambient High CO 2 0. 3 0. 2 0. 1 0 0. 5 Coccosphere thickness (µm) 0. 5 14: 10 h 0. 4 Ambient High CO 2 0. 3 0. 2 0. 1 0 -0. 1 E. huxleyi G. oceanica -0. 2 -0. 3 -0. 4 E. huxleyi G. oceanica Species 24: 0 h Species

14: 10 h 0. 6 0. 5 0. 6 Ambient High CO 2 0. 5 Ambient High CO 2 0. 4 Fv/Fm 0. 4 24: 0 h 0. 3 0. 2 0. 1 0 0 E. huxleyi G. oceanica Species

Species/Strain E. huxleyi NZEH E. huxleyi 962 G. oceanica 14 h 24 h Calcification ↔ µ↓ µ ↔, produces lose lithes Thin coccosphere calcification ↔ µ↓ µ ↔, produces lose lithes 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

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

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 Ph. D and looking for more research opportunities! lmjbre@essex. ac. uk