1. François M. M. Morel Slides by Ja-Myung Kim

2. Years before 2010 330 µatm 400 µatm Vostok paleo Petit et al. 1999, Keeling et al. Mauna Loa from ice core & modern data Changes in atm. CO 2 concentration pCO 2 (µatm) 400 µatm

3. Seawater pCO 2 time-series monitoring stn.ESTOC (1995-2009) BATS (1983-2009) ALOHA (1988-2009)

4. Decadal changes at time-series stations ESTOC (1995-2009) BATS (1983-2009) ALOHA (1988-2009) 400 350 300 250 200 1985 1990 1995 2000 2005 2010 Year pCO 2 (µatm) ALOHA (1988-2009) ESTOC (1995-2009) Bates NR, Byrne RH, Dore JE, Feely RA, Gonzalez-Davila M, Karl DM, Lee K, Kleypas JA, Orr J (IPCC ARS) 400 350 300 250 200 1985 1990 1995 2000 2005 2010 Year pCO 2 (µatm) BATS (1983-2009)

5. Atlantic 0 1000 2000 3000 Pressure (db) 60°50°40°30°20°10°0°10°50° 60° N40°30°20° IndianPacific 0 1000 2000 3000 Pressure (db) 60°50°40°30°20°10°0°10°50°40°30°20° 60°50°40°30°20°10°0°10°20° Latitude 0 1000 2000 3000 Pressure (db) Latitude Vertical distributions of CO 2 in the ocean Anthropogenic CO 2 conc. (μmol kg -1 ) 50403020100 “Half of the CO 2 stored in the oceans is found in the upper 10% of the ocean” Sabine et al. 2004

6. Anthropogenic carbon emissions are increasing atmospheric CO 2 Ocean is a CO 2 sink Why and How does that affect ocean chemistry ? Ocean acidification

7. CO 2 (aq) HCO 3 - CO 3 2- + H 2 O+HCO 3 - H+H+ CO 2 (aq) CO 2 (g) Effect of CO 2 on carbonate system H+H+ + CO 2 increases CO 3 2- decreases H+H+ increases (pH decreases)

8. ESTOC (1995-2009) BATS (1983-2009) ALOHA (1988-2009) Decadal changes of pH & CO 3 2- at time-series monitoring stn. pH decrease: 0.0013 - 0.0018 yr -1 CO 3 2- decrease : 0.5 - 0.9 µmol kg -1 yr -1

9. CO 3 2- pH CO 2 CO 3 2- What biological consequences ? Photosynthesis Calcification Other physiological effects

10. What biological consequences ? Photosynthesis Calcification Other Physiological effects CO 3 2- pH

11. Experimental approaches Molecular mechanisms Lab cultures Coastal in-situ perturbation Open ocean monitoring Bottles Big bags Natural env.

12. Open ocean monitoring

13. Univ. of Bergen Univ. of Washington EPOCA POSTECH Mesocosm

14. Open ocean mesocosm, Baltic sea U. Riebesell (GEOMAR) In situ ecosystem-based CO 2 perturbation experiment MESOCOSM

15. Laboratory cultures Low CO 2 High CO 2 Mechanismstudy

16. What biological consequences ? Photosynthesis Calcification Other Physiological effects CO 3 2- pH

17. Photosynthesis CH 2 O Organic matter Light reaction Dark reaction e-e-e-e- photons H2OH2OH2OH2O O2O2O2O2 CO 2

18. Sediments Atmosphere Org C Phytoplankton Surface Ocean CO 2 500 1000 1500 2000 Depth (m) 0 20 40406060 CO 2 (µM) Biological pump

19. Photosynthesis Light reaction Dark reaction e- e- e- e- H2OH2OH2OH2O O2O2O2O2 CO 2 CH 2 O organic matter RubisCO Poor affinity for CO 2 K m ≈ 50 µM >> [CO 2 ] seawater

20. Carbon concentrating mechanism Chloroplast CO 2 80 µM HCO 3 - CO 2 10 µM HCO 3 - CA CH 2 O CA RubisCO 2 mM

21. CA Skeletonema costatum 0 2000 CA activity U (mg Chl a) -1 1000 1803601800 ppm Enzyme Rost et al. 2003 Response of CCM to increasing CO 2 Growth rates Labculture 280 720 ppm 3.0 2.0 0 1.0 Growth rate (d -1 ) Skeletonema costatum Rost et al. 2003 Growth rates 280 720 ppm 1.5 1.0 0 0.5 Growth rate (d -1 ) Skeletonema costatum 40% In-situ Kim et al. 2006 Growth rates 100 800 ppm Growth rate (d -1 ) Natural assemblage Ocean 2.0 1.0 0 0.5 1.5 Tortell et al. 2000 Growth rates Low CO 2 High CO 2 Growth rate (d -1 ) 2.0 1.0 0 0.5 1.5 ? Future growth rate

22. What biological consequences ? Photosynthesis Calcification Other Physiological effects CO 3 2- pH

23. Calcium carbonate (CaCO 3 ) production & dissolution Main overall reaction: +Ca 2+ CO 3 2- CaCO 3 (s) [CO 3 2- ] > [CO 3 2- ] sat [CO 3 2- ] < [CO 3 2- ] sat Calcite Aragonite

24. Future projection for saturation state Turley et al. 2010 [CO 3 2- ] = [CO 3 2- ] sat [CO 3 2- ] / [CO 3 2- ] sat Aragonite [CO 3 2- ] / [CO 3 2- ] sat Calcite

25. Tropical corals Coraline algae Molluscs Pteropods Coccolithophores Responses of marine calcifiers to increasing CO 2

26. Mussels & Oysters Gazeau et al. 2007 Mussels (Mytilus edulis) Oysters (Crassostrea gigas)

27. Coccolithophores 4.0 3.8 3.6 3.4 3.2 Low CO 3 2- Ambient CO 3 2- High CO 3 2- Coccolith size (µm) Coccolith Engel et al. 2005

28. Adapted from Doney et al. 2009 Major groups Tropical corals Coraline red algae Molluscs Pteropods Coccolithophores Responses at increasing CO 2 Different responses of marine calcifiers to increasing CO 2

29. Poor understanding of the mechanisms responsible for the sensitivity Seawater pH Calcifying pH 8.5 8.0 7.5 7.0 7.58.08.5 Seawater Skeleton inside H+H+H+H+ Ca 2+ CaCO 3 CO 3 2- + HCO 3 - + H + + H + CO 3 2- Seawater Venn et al. 2013 Stylophora pistillata (reef coral)

30. What biological consequences ? Photosynthesis Other Physiological effects pH Calcification CO 3 2-

31. l all pH homeostasis External enzymes Metalavailability Physiologicalprocesses pH

32. l allPhysiologicalprocesses pH Metal availability Fe(OH) 3 + H + Fe pH homeostasis External enzymes

33. Photosynthesis Light reaction Dark reaction e-e-e-e- H2OH2OH2OH2O O2O2O2O2 CO 2 Fe Organic matter

34. Effect of pH on Fe chemistry CaFe + 2H + → + Fe(OH) 2 + + 2H + → Ca-EDTAFe-EDTA + 2H + + Y → Bound Fe Free Fe + 2H + + Y → Bound Fe

35. Shi et al. 2010 Thalassiosira weissflogii kton The rate of Fe uptake by phytoplankton + 2H + + Y → Bound Fe Free Fe + 2H + + Y → Bound Fe 10 3 10 2 10 1 10 0 10 1 10 2 10 3 Total Fe (nM) µmol Fe mol C -1 day -1 pH 7.7 pH 8.1 10 1 Free Fe (pM) 10 2 10 3 10 4 1:1 pH 8.6 Fe uptake rate

36. pH effect depends on mature of chelator Shi et al. 2010

37. Weak effect of pH on Fe uptake in field Shi et al. 2010

38. Complications of OA research Time scales Adaptation Ocean warming Temperature Mixing CO 3 2- pH

39. Phytoplankton Succession Phytoplankton Succession Photochemistry C-fixation Transporter Enzyme Expression Enzyme Expression Cell Growth Competition Acclimation Adaptation Genetic mutation Lab. cultures Field monitoring Predictions Time scales Log 10 Days geological epoches nano seconds years centuries 10 -14 10 -5 0.01110010 5 10 8 Timescales secondsdays

40. Today Year 2100 + 2 to 6°C Mixing Nutrient input Irradiance Stratification Surface temperature ++++/- Ocean warming: Temperature & Mixing Temperature

41. Morel Group Ja-Myung Kim

42. Biologically complicated… Chemically simple,