Rising Atmospheric CO 2 & Ocean Acidification

1. Rising Atmospheric CO2 & Ocean Acidification Scott Doney Woods Hole Oceanographic Institution International SOLAS Open Science Conference (May 2012) Talk Outline -Ocean CO2 Uptake & Seawater Chemistry -Biological, Ecological & Biogeochemical Effects -Socio-economic Impacts Special Thanks To: Alan Barton, Wei-Jun Cai, Sarah Cooley, Richard Feely, HaukeKite-Powell, Noelle Lucey, RikWanninkhof

2. Rising Atmospheric CO2 Ice core data -strong evidence for human causation -highest level in at least last million years -rapid change in CO2 relative to natural trends “Thus human beings are now carrying out a large scale geophysical experiment…” Revelle and Suess, Tellus, 1957

3. Ocean Acidification H+ + CO3 2- H+ + HCO3 HCO3 - - CO2 + CO3 + H2O 2- CO2 + H2O H2CO3 2HCO3 - 2000 30% acidity 16% [CO3 ] [CO2] CO3 2− 50 300 > < 8.2 40 240 2100 pH − − − − 100−150% 8.1 30 180  50% 2− pH μmol kg−1 8.0 20 120 [CO3 ] 7.9 2− 10 60 CO2(aq) 0 0 7.8 1800 1900 2000 2100 Year Wolf-Gladrow et al. (1999)

4. Hawaii Ocean Time-Series -Observed rising CO2 & declining pH Doney et al. Ann. Rev. Mar. Sci. 2009 Dore et al. PNAS 2009

5. CO2 Effects on CaCO3 Saturation aragonite = [Ca2+][CO32-] / Ksp Δ[CO32-] = [CO32-]obs - [CO32-]sat Present 2100 Orr et al. Nature 2005; Steinacher et al. Biogeosci. 2009

6. Anthropogenic Fluxes of CO2, N and S Anthro CO2 SO2 & H2SO4 HNO3 NH4 Doney et al. PNAS 2007

7. Nutrient Eutrophication & Hypoxia more nutrients Cai et al. Nat. Geosci. 2011 -organic matter respiration lowers pH & O2 -coastal & estuarine waters low pH& buffering capacity -high natural variability

8. Open Ocean Open Ocean Antarctic High Frequency Natural Variability Estuarine/near shore Upwelling Kelp Forest Coral Reef Hofmann PLoS 2011

9. Corals: warm & cold-water Possible Biological Impacts • -Reduced shell formation • corals, mollusks, some plankton, (crustaceans) • -Habitat loss • coral & oyster reefs • -Less food for predators • humans, fish, whales • -More seagrasses& algae • -Finfish sensory & behavior • -Open questions • organism ability to adapt • food-webs & ecosystems lobsters, crabs some plankton cold-water corals pteropods planktonic snails scallops, clams, oysters

10. Meta-Analysis of Biological Impacts Kroeker et al. Ecology Letters 2010

11. Natural High CO2Laboratories ‘low pCO2’: pH ∼8.1 ‘high pCO2’: pH 7.8–8.0 intense vents: pH <7.7 Hall-Spenser et al. Nature 2008; Fabriciuset al, Nature Clim. Change 2011

12. Potential Food Web Impacts Coccolithophores ARCOD@ims.uaf.edu Copepods Barrie Kovish Pacific Salmon V. Fabry Vicki Fabry Pteropods

13. Reduced pH Impairs Sensory Responses & Alters Behavior -Sense of smell & hearing -Predator avoidance & mortality -Change in acid-base balance alters effects of neurotransmittor control CO2 Munday et al. PNAS (2009); Dixson et al. Ecol. Lett. (2010); Nilsson et al. Nature Climate Change (2012)

14. Biogeochemical Impacts in Planktonic Systems • -Nitrogen cycle • N2 fixation (++) • Nitrification (-) • -Carbon cycle • Photosynthesis (+) • Calcification (- -) • CaCO3 dissolution (++) • -Export production • Carbon/nutrient ratio (-) or (+) • Particle ballasting (?) • Subsurface oxygen (-) or (?) • -Trace gases • DMS (?) • N2O (+) or (?) • Organohalogens (?) • -Trace metal speciation Hutchins et al. Oceanogr. 2009 Gehlen et al.; Hopkins et al.; and Riebesell & Tortell in Gattuso & Hansson 2011

15. Social & Economic Impacts • -Marine fisheries& aquaculture • food supply • jobs, livelihoods & trade • -Coral reefs • reef fisheries • tourism • shoreline protection • -Globally, largest impacts may be on developing island and coastal nations • exposure, sensitivity & adaptive capacity Cooley et al. Oceanography(2009) Cooley & Doney,Environmental Research Letters (2009) Cooley et al. Fish & Fisheries (2012)

16. Regional Impacts: Pacific NW Oysters -Coastal upwelling => Low oxygen & acidification -Commercial oyster hatcheries a $100M industry (3000 Jobs) -But no natural Pacific oyster recruitment in WA state for past decade & many hatchery failures

17. Upwelling Winds Reduced Larval Production During Upwelling Events Temperature Oyster Larval Production vs. Saturation State pH Saturation State Barton Limnology & Oceanography 2012

18. Synergies with Other Human Perturbations Doney Science 2010

19. Summary & Future Directions • -Seawater Chemistry • Well understood for open-ocean • Additional factors in coastal waters • Emerging observing systems • -Ocean Biological Impacts • Impact corals & mollusks • Ability to acclimate & adapt? • Habitat decline & food-web effects • Synergies with other stressors (e.g. climate change, overfishing) • -Biogeochemical Cycles • Nitrogen, carbon & trace gases • -Socio-economic Impacts • Wild fisheries & aquaculture • Recreation, tourism, ecosystem & cultural services Special Thanks To: Alan Barton Hauke Kite-Powell Rik Wanninkhof Scott Doney Woods Hole Oceanographic Institution sdoney@whoi.edu

20. Rising CO2 & Ocean Acidification • -About 1/3rd of human carbon dioxide emissions end up in the ocean • -Locally enhanced in some coastal waters by atm. deposition, excess nutrient inputs, circulation • -Well-understood changes in seawater chemistry: • more acidic (lower pH) • higher aqueous CO2 • lower carbonate ion • -Rates of change fast, ~100x faster than natural