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Transcriptomic responses of Emiliania huxleyi to Ocean Acidification Sebastian D. Rokitta, Uwe John and Björn Rost.

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Presentation on theme: "Transcriptomic responses of Emiliania huxleyi to Ocean Acidification Sebastian D. Rokitta, Uwe John and Björn Rost."— Presentation transcript:

1 Transcriptomic responses of Emiliania huxleyi to Ocean Acidification Sebastian D. Rokitta, Uwe John and Björn Rost

2 Ocean Acidifcation CO 2 pH DIC Year [CO 3 2- ] 300 250 150 100 50 0 200 185019002100195020502000 pH SWS 7.8 8.2 8.1 8.0 7.9 2400 1600 1200 800 400 2000 0 [DIC] [µmol kg -1 ] CO 3 2- [CO 2 ] 35 30 20 15 5 0 25 10 [µmol kg -1 ] After Wolf-Gladrow et al. (1999)

3 Photo: NASA, PML Coccolithophores

4 Biological carbon pumps

5 OA-responses in E. huxleyi Modified from Hoppe et al. (2011)

6 Energization?

7 The matrix approach Light vs. pCO 2 50 µmol photons m -2 s -1 300 µmol photons m -2 s -1 380 µatm 1000 µatm Acclimation data (µ, POC, PIC) Physiology (C i acquisition, light reactions) Transcriptomics (gene expression)

8 Phenomenology Rokitta & Rost (2012) PIC production drops (especially under low light!) POC production is boosted (especially under low light!) TPC production is insensitive

9 Physiology Rokitta & Rost (2012) More POC despite less pigmentation and O 2 evolution  Improved energy efficiency under OA

10 Gene expression?

11 Transcriptomics Low-light acclimation 1172 ↑ 861 ↓ High-light acclimation 1082 ↑ 814 ↓ OA responsive genes

12 Low-light specific 447 ↑ 236 ↓ High-light specific 357 ↑ 189 ↓ 725 ↑ 625 ↓ Core OA-response Transcriptomics

13 # of genes; sign denotes regulation (+ ↑ ; - ↓ ) Carbon metabolism Light physiology Signalling Ion fluxes Core OA-response LL specific OA-response HL specific OA-response -40-2002040-40-2002040-40-2002040 Organellar shuttling ↑ Pentose phosphate pathway ↑ Glycolysis ↓ Fatty Acid & Glucan anabolism ↑ Energy dissipation ↑ Lipid and IP 3 signaling ↑ Membrane potentials ↑ Regulation of C fluxes ↑ Energy dissipation ↑ Transcriptomics

14 OA re-wires carbon fluxes NADPHNADH

15 OA affects the redox hub Carbon metabolism Trx XC Asc GSH Chloro- plast EMS NADP/NADPH NAD/NADH... Mitochon- drium

16 Conclusions OA causes a shunting of carbon from calcification towards biomass production OA-Responses are modulated by energy availability and typically attenuated by high light OA affects cellular signaling and the redox hub and thereby re-wires carbon flux networks


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