Ocean acidification M. Debora Iglesias-Rodriguez Based on “An International Observational Network for Ocean Acidification” by Feely et al, and other stories. Hoegh-Guldberg et al. 2007

Time series of atmospheric CO2 Mauna Loa data: Dr. Pieter Tans, NOAA/ESRL (http://www.esrl.noaa.gov/gmd/ccgg/trends) HOTS/Aloha data: Dr. David Karl, University of Hawaii (http://hahana.soest.hawaii.edu) (modified after Feely, 2008).

Emerging and established ocean acidification programmes The Federal Ocean Acidification Research and Monitoring (FOARAM) Act passed Congress (March 25, 2009) NERC Ocean Acidification Programme The Natural Environment Research Council and the Department for Environment, Food & Rural Affairs are developing a collaborative 5 year research programme of ~ £12m.

Central Issues Interactions between biota and water chemistry Effects of ocean acidification on marine calcifiers Quantify synergistic effects from other environmental variables, (e.g., temp) What determines the capacity of organisms to adapt to ocean acidification? Threshold levels (tipping points) at the organism and community level Societal impacts (socio-economics of ocean acidification) - e.g., effect of declining pteropod populations on fish stock? from Pörtner et al., 2004)

Some facts about ocean acidification Since industrialization, pCO2 has increased from 280 to 387 ppm: decrease of ~0.1 units at a rate of ~0.0018 yr-1 (Caldeira & Wickett, 2003, 2005; Bates & Peters, 2007; Santana-Casiano et al., 2007). pCO2 will reach >800 ppm circa 2100: additional decrease (0.3 pH units). Present pCO2 is higher than experienced on Earth for the last 800,000 yrs Continuing pCO2 rise will lead to significant temperature increases

Chemistry of ocean acidification Increasing carbon dioxide (CO2) in seawater causes the formation of carbonic acid (H2CO3), which causes acidification. Effects: [CO2] increase   photosynthesis [HCO3-] increase: CO2 + H2O  H2CO3  H+ + HCO3-  2H+ + CO32-   calcification [CO32–] decrease, and the ocean’s saturation state with respect to CaCO3 (calcite/aragonite) ():  = f{[CO32–], [Ca+2]}  calcification ?

Chemistry of ocean acidification Increasing carbon dioxide (CO2) in seawater causes the formation of carbonic acid (H2CO3), which causes acidification. Effects: [CO2] increase   photosynthesis [HCO3-] increase: CO2 + H2O  H2CO3  H+ + HCO3-  2H+ + CO32-   calcification [CO32–] decrease, and the ocean’s saturation state with respect to CaCO3 (calcite/aragonite) ():  = f{[CO32–], [Ca+2]}  calcification ?

? Carbonic anhydrase Carbonic anhydrase Ca+2 ATPase Carbonic anhydrase CO2 H2O HCO3-

pH in intracellular compartments: 7. 2 - 7 pH in intracellular compartments: 7.2 - 7.8 for cytosol, nucleoplasm, mitochondria, plastid stroma (Raven, pers com). Carbonic anhydrase ? ~30’’ Carbonic anhydrase CO32- ~2’’ CO32- Ca+2 ATPase Carbonic anhydrase CO2 H2O HCO3-

Phytoplankton functional type adaptation Diatoms Coccolithophores Riebesell et al., Nature, 2000. Langer et al., G32006. Iglesias-Rodriguez et al., Science, 2008.

carbonate bicarbonate Adaptation???

Acclimation - how? Adaptation - who wins?

Main questions What is the long term adaptation to fast rate of change? What is the susceptibility of organisms to changes in pH? Can we build an ocean observation network that can accounts for biological complexity? Can we improve our knowledge on cell physiology and adaptation with the current experimental approaches? What is the effect of functional group dominance on biogeochemistry? So far: - Lab experiments - Mesocosm experiments - Field observations and monitoring - what latitudes?

Calcium carbonate saturation Royal Society report on ocean acidification, 2005 St. Petersburg report on ocean acidification, 2007 Orr et al., 2005.

CO2 sampling system attached to one of NOAA's Integrated Coral Observing Systems (ICON) in the Bahamas Joanie Kleypas, NCAR Lead Scientist; 
Chris Langdon, and colleagues at the Rosentiel School of Oceanography, University of Miami; 
James Hendee and Rik Wanninkhof, NOAA.

Regional organismal and ecosystem response to increased CO2 from shipboard surveys Just completed 1st August 2009: On-deck mesocosm ecosystem perturbations with gradients of pH and organic carbon Responses of phytoplankton and zooplankton to increased CO2 and changing stoichiometry of food supply Assessment of regional ”natural” stoichiometry of production and export Richard Bellerby and Frede Thingstad

Community requirements A coordinated regional and global network of observations, process studies, manipulative experiments and modelling. Identify natural variability of carbonate chemistry. Identify whether or not there are geochemical thresholds for ocean acidification that will lead to irreversible effects on species and ecosystems over the next few decades. Investigate long-term adaptation. Strategy: Repeat surveys of chemical and biological properties Time-series measurements at stations and on floats & gliders

Measurement Requirements for the Ocean Acidification Observational Network DIC, pCO2, TA and pH Particulate inorganic carbon (PIC), particulate organic carbon (POC) and bio-optical measurements Oxygen Other biological measurements (specific DNA sequences for marine bar-coding, physiological rates, genomics and proteomics) Nutrients, salinity Suspended [PIC] (MODIS/ Terra). (a) January–March. (b) April–June. (c) July–September. (d) October–December (after Balch et al, 2007).

Time Series Measurements on Moorings, Gliders and Floats Carbon and pH sensors on time-series moorings can resolve short space-time scale variability of the upper ocean - OceanSITES time-series. Some of these locations: intensified process studies: e.g. open ocean mesocosm experiments, coastal mesoscale CO2 release experiments. Coastal sites: effect of upwelling, riverine input - biogeochemical models that address specifically ocean acidification. These monitoring systems can provide verification for the models: open ocean large-scale biogeochemical models and coastal data will verify nested high resolution coastal models. Carbon system sensors could also be deployed on floats and gliders to resolve shorter space-time scale variability of the upper ocean. Potential ocean acidification monitoring sites (coral reefs)

Underway Volunteer Observing Ship Network Ships equipped with carbon system sensors and ancillary technologies (e.g. autonomous water samplers, nutrient analyzers) for ocean acidification should be added to the present carbon network. These should be supported with technology to study OA (DNA sensors, PIC and POC production rates, supported by satellite measurements).

New ‘-omics’ approaches Dupont et al., 2008.

If cells are in the water, what are they doing? Meta-approaches Diversity of marine microbial communities: ‘metagenomics’ (Venter et al. 2004, Delong et al. 2006, Sogin et al. 2006) Functional properties of marine communities: ‘proteomics’ (Jones, Edwards, Skipp, O’Connor, Iglesias-Rodriguez, 2009) If cells are in the water, what are they doing? Genome Genes Static Proteome Phenes Evolving proteomics

Sampling: Sampling: Sampling: 385 or 1500 ppm CO2 2.4L 14L 14L 2-3 days in exponential 5/6 generations 3/4 generations Sampling: Sampling: Sampling: Before adding culture Before transfer to 14L culture Before starting bubbling Before adding culture Before transfer to 14L culture Before starting bubbling Before adding culture Final harvest SEM Nutrients pH Salinity Temperature DIC/Alk Nutrient pH Salinity Temperature DIC/Alk Nutrient pH Salinity Temperature DIC/Alk Nutrient pH Salinity Temperature PIC POC SEM FRRF DIC/Alk Nutrient pH Salinity Temperature DIC/Alk Nutrient pH Salinity Temperature DIC/Alk Nutrient pH Salinity Temperature PIC POC SEM FRRF Proteins for iTRAQ

OA impact on coccolithophores Subcellular location by protein cluster Biological process by protein cluster Jones, Edwards, Skipp, O’Connor, Iglesias-Rodriguez, Proteomics, 2009

Improve understanding allows building a range of new models Alex Kahl, Oscar Schofield and Debora Iglesias-Rodriguez Photosynthetic carbon fixation Carbon Biosynthesis Carbon Reserves Light (E) Nutrients Low C:N exudate High C:N POC = C PIC is ½ of the POC when nutrient saturate POC can vary with nutrients PIC is constant Cs CR : NR CB : NB CP : NP fPB fPR fBP fBS fRB fN fE1 fE2

Future challenges for the next ten years Assess long term adaptation of functional groups. Improve basic knowledge of carbon physiology - adaptation to bicarbonate-rich ocean. Observations - coupling between biogeochemistry, physiology, and modelling. Building a global time series to assess changes in chemistry and biology. Extrapolate from experimental results to natural condition

Acknowledgements Richard Bellerby, University of Bergen. Richard Feely, NOAA, Seattle, U.S.A. Jean-Pierre Gattuso, Laboratoire de Villefranche, France. Richard Lampitt, National Oceanography Centre, Southampton, U.K. John Raven, University of Dundee, U.K.