of Emiliania huxleyi to Ocean Acidification Sebastian D. Rokitta, - - PowerPoint PPT Presentation

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of Emiliania huxleyi to Ocean Acidification Sebastian D. Rokitta, - - PowerPoint PPT Presentation

Oct 21, 2022 183 likes •362 views

Transcriptomic responses of Emiliania huxleyi to Ocean Acidification Sebastian D. Rokitta, Uwe John and Bjrn Rost Ocean Acidifcation 2- 2- ] [CO [CO 2 ] pH pH SWS [CO [CO 3 [DIC] [DIC] SWS [ mol kg mol kg -1 -1 ] [ mol kg mol kg -1

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SLIDE 1

Transcriptomic responses

  • f Emiliania huxleyi

to Ocean Acidification

Sebastian D. Rokitta, Uwe John and Björn Rost

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SLIDE 2

Ocean Acidifcation

CO CO2 pH pH DIC DIC

Year Year

[CO [CO3

2- 2-]

300 300 250 250 150 150 100 100 50 50 200 200 185 1850 190 1900 210 2100 195 1950 205 2050 200 2000

pH pHSWS

SWS

7. 7.8 8. 8.2 8. 8.1 8. 8.0 7. 7.9 240 2400 160 1600 120 1200 800 800 400 400 200 2000

[DIC] [DIC] [μmol kg mol kg-1

  • 1]

CO CO3

2- 2-

[CO [CO2]

35 35 30 30 20 20 15 15 5 25 25 10 10

[μmol kg mol kg-1

  • 1]

After Wolf-Gladrow et al. (1999)

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SLIDE 3

Photo: NASA, PML Photo: NASA, PML

Coccolithophores

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SLIDE 4

Biological carbon pumps

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SLIDE 5

OA-responses in E. huxleyi

Modified from Hoppe et al. (2011)

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SLIDE 6

Energization?

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SLIDE 7

The matrix approach

Light vs. Light vs. pCO pCO2 50 50 μmol

mol photon hotons m-2

  • 2 s-1
  • 1

300 300 μmol

mol photon hotons m-2

  • 2 s-1
  • 1

380 380 μatm

atm

1000 1000 μatm

atm

  • Acclimation data (μ, POC, PIC)
  • Physiology (Ci acquisition, light reactions)
  • Transcriptomics (gene expression)
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SLIDE 8

Phenomenology

Rokitta & Rost (2012)

  • PIC production drops

(especially under low light!)

  • POC production is boosted

(especially under low light!)

  • TPC production is insensitive
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SLIDE 9

Physiology

Rokitta & Rost (2012)

  • More POC despite less pigmentation and O2 evolution

 Improved energy efficiency under OA

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SLIDE 10

Gene expression?

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SLIDE 11

Transcriptomics

Low-light acclimation 1172 ↑ 861 ↓ High-light acclimation 1082↑ 814 ↓

OA responsive genes

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SLIDE 12

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

Transcriptomics

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SLIDE 13

# of genes; sign denotes regulation (+ (+ ↑; - ; - ↓)

Carbon Carbon metabolism metabolism Light physiology Light physiology Signalling Signalling Ion fluxes Ion fluxes

Core Core OA-res OA-respo ponse LL specif LL specific OA-res OA-respo ponse HL sp HL specific ific OA-res OA-respo ponse

  • 40
  • 40 -20

20 20 40

  • 40

40 -20

  • 20

20 20 40 40

  • 40
  • 40 -20

20 20 40

Organellar shuttling Organellar shuttling ↑ Pentose Pentose phosphate hosphate pathway pathway ↑ Glyco Glycolysis ↓ Fatt Fatty Acid cid & Glucan anabo Glucan anabolism↑ Energ Energy dissipation dissipation ↑ Lipid and Lipid and IP3 signaling signaling ↑ Membrane potentials Membrane potentials ↑ Regulation of Regulation of C C fluxes fluxes ↑ Energ Energy dissipation dissipation ↑

Transcriptomics

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SLIDE 14

OA re-wires carbon fluxes

NADPH NADH

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SLIDE 15

OA affects the redox hub

Carbon Carbon metabolism metabolism

Trx XC Asc GSH

Chloro- Chloro- plast plast EMS EMS

NADP/NADPH NADP/NADPH NAD/NADH NAD/NADH

...

Mitochon- tochon- driu drium

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SLIDE 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