1. General Scheme for Working Group Objectives Physiological/Biogeochemical Responses Organisms and Communities Ecosystem Effects How would changes in populations of calcifying organisms affect ecosystems? Experimental manipulations Organism Effects How would the response affect species? Earth System Functioning Carbon cycle, CO 2 uptake, feedbacks Modeling Paleorecords Monitoring majority of studies

2. Pressing Questions Session 1 Ecophysiological Responses of Calcifiers to Increased pCO 2 - Current Knowledge and Pressing Questions Controls on calcification (only briefly review these if necessary) Taxonomic differences Technological considerations Standardization of measurements

3. Controls on calcification (only briefly review these if necessary) Taxonomic differences Technological considerations Standardization of measurements What is evidence that CO 2 chemistry controls calcification in nature? Is calcification response to CO 3 2– linear, or asymptotic? What are the relative roles of HCO 3 – and CO 3 2– in the calcification process? What is the relationship between photosynthesis and calcification? What is the impact of temperature/light/nutrients on calcification? Pressing Questions Session 1 Ecophysiological Responses of Calcifiers to Increased pCO 2 - Current Knowledge and Pressing Questions

4. Controls on calcification Taxonomic differences Technological considerations Standardization of measurements Do we need experimental data from more species, or across more groups? Can we expect calcifiers to adapt to rising pCO 2 and if so, by what mechanisms? Over what time scales? Pressing Questions Session 1 Ecophysiological Responses of Calcifiers to Increased pCO 2 - Current Knowledge and Pressing Questions

5. Controls on calcification Taxonomic differences Technological considerations Standardization of measurements What are the technological capabilities and challenges for CO 2 system measurements and calcification measurements? What questions are best addressed in field studies, lab studies, or mesocosms? What questions can be addressed through modeling? What important ecophysiological parameters are not currently included in models because of lack of data? Pressing Questions Session 1 Ecophysiological Responses of Calcifiers to Increased pCO 2 - Current Knowledge and Pressing Questions

6. What are the advantages/disadvantages of existing research designs, sampling, manipulation of CO 2 chemistry, etc? Can we recommend “standards” within this arena? How can different measures of calcification be related/standardized? Controls on calcification Taxonomic differences Technological considerations Standardization of measurements Pressing Questions Session 1 Ecophysiological Responses of Calcifiers to Increased pCO 2 - Current Knowledge and Pressing Questions

7. Pressing Questions Session 2 Ecosystem Response to Elevated pCO 2 : Existing and Future Filed Monitoring and Experimental Research Ecological responses Regional considerations

8. Ecological responses Regional considerations Will calcifying organisms be outcompeted by noncalcifiers? If so, What impacts to ecosystem structure and function might occur? What changes, if any, may occur in food webs and other species interactions? How could such ecological responses affect the cycling of organic and inorganic C? Pressing Questions Session 2 Ecosystem Response to Elevated pCO 2 : Existing and Future Field Monitoring and Experimental Research

9. What information can be obtained by conducting studies in regions with natural variability in pCO 2 ? What regions would be most promising in terms of better characterizing CO 2 -chemistry environment? Which regions do models indicate will likely experience the greatest changes in seawater carbonate chemistry? Over what time scales? Ecological responses Regional considerations Pressing Questions Session 2 Ecosystem Response to Elevated pCO 2 : Existing and Future Field Monitoring and Experimental Research

10. Pressing Questions Session 3 What experimental designs are needed to address the pressing questions? What can be done now, with existing technology (both pelagic and neritic regions)? What can be done within next 5-10 years, with emerging technology? What are the coastal needs/concerns, versus those of open ocean (e.g., precision, contamination, etc.)? Can we capitalize on existing monitoring/research efforts to obtain more/better data? where? how? How can we measure dissolution within the water column and within sediments? What is the role of dissolution in buffering the system? How can we focus paleoclimatology, isotopic analyses, etc. to address questions about CO 2 affects on calcification? How can remote sensing be integrated into the overall monitoring and experimental designs? Are there pressing needs to develop new remote sensing technology? Experimental Design

11. Pressing Questions Session 4 What are the priorities in modeling the CO 2 -calcification questions? (carbon cycle? ecosystem/community interactions? physiological modeling? sediment/water interactions? etc.)? What important questions can be addressed with existing models? Which will require model development? Which modeling questions would be well constrained versus poorly constrained by existing data? Modeling

12. Ecology Habit & domain Response to nutrient, light, temperature changes Biodiversity Food webs & species interactions Capacity to adapt to elevated pCO 2 Calcification Production cycle/generation times Mineralogy CaCO 3 production and net accumulation Carbonate System Behavior pCO 2 variability Influence of sedimentary processes Carbon Cycling Role in the carbon cycle Planktonic versus Benthic Calcifiers

13. Possible Functions of CaCO 3 in Organisms FunctionPlanktonicBenthic ProtectionAll groups Buoyancy regulationcoccolithophores foraminifera Light modificationcoccolithophorescorals Provide protons for conversion of HCO 3 – to CO 2 for photosynth. coccolithophorescalcareous algae? Facilitate bicarbonate-based photosynthesis coccolithophores Aid in capture of preyforaminifera Reproductionpteropodscorals? Prevention of osmotically induced volume changes coccolithophores Extension into hydrodynamic regime corals, calc. algae, bryozoans Anchoring to substratecorals, calc. algae, bryozoans Competition for spacecorals, calc. algae, bryozoans

14. mm Ecosystem Effects experimental manipulations Earth System Carbon Cycle modeling paleorecords monitoring 10 3 10 2 10 1 10 0 10 –1 10 –2 10 –3 10 –4 10 –5 10 –6 10 –4 10 –3 10 –2 10 –1 10 0 10 1 10 2 10 3 10 4 10 5 ywhdmo km m cm Time (days) Space (km) m Physiology Organism remote sensing