European Project on Ocean Acidification (EPOCA) 10 th- 13 th June 2008, La Maison du Séminaire, Nice (France) Theme 2 – Scientific Highlight “Linking individual responses to impacts on ecosystems” Dr Steve Widdicombe

Introduction Examples of impact on marine organisms. Whole organism impacts and trade-offs Interactions between species Impacts on communities and ecosystem function Predicting biodiversity

Research at PML – Impact Experiments PML has developed a range of experimental systems the can provide large quantities of CO 2 acidified seawater Large systems successfully used to look at impacts of large organisms and sediment cores. Small systems used for small organisms and larvae. Water pump for circulation Control box pH & temp sensor CO 2 gas Regulator LAN / internet connection Natural seawater Acidified seawater Widdicombe & Needham (2007) Mar Ecol Prog SerFindlay et al (in press Aquatic Biology)

Impact on IndividualsPhysiological Response to High CO 2 Sea urchin (Miles et al Mar. Pollut. Bull. 54, 89-96) Crab (Spicer et al Mar. Biol. 151, )

Impact on Animal Health

Impact on Animal Health – Immune Response Seawater acidification reduced immune response in mussels (Bibby et al Aquatic Biology 2, ) Seawater acidification also reduced mussel general heath status (NRR assay) (Beesley et al. in press Climate Change) Normal Abnormal

Whole Organism Impacts FEEDING ORGANISM METABOLISM GROWTH REPRODUCTION OUTPUTS Calcium content Arm regrowth Egg size & condition O 2 uptake MAINTENANCEINPUT Key Survival Processes

Whole Organism Physiology Reduced pH caused a significant increase in oxygen consumption Length of arm regrown significantly longer at lower pH Reduced pH significantly increased the calcium content in regrown arms Regrown arms had significantly higher calcium content than existing arms Wood et al. (2008) Proceedings of the Royal Society B

The Biological Cost control control control 7.3 control control 6.8 Regrowing arms Established arms Wood et al Proceedings of the Royal Society B

Behaviour and Interactions Green Shore Crab Carcinus maenas Chemical cue Edible Periwinkle Littorina littorea HELP! There are crabs in this habitat, I must thicken my shell In a future ocean where the availability of bicarbonate ions are reduced, snails may be less able to thicken their shells and could therefore be more vulnerable to predation. Phenotypic plasticity Bibby et al Biology Letters 3:

Community Structure & Biodiversity Communities made up of species with a range of tolerance to high CO 2 Polychaetes – Crustaceans – Molluscs – Echinoderms Differences seen within and between taxonomic groups Mud and sand communities showed different tolerances Prediction will come from knowing the mechanisms that underpin organism tolerance Long term experiments needed Widdicombe et al. Submitted. Mar. Ecol. Prog. Ser

7.6 CONTROL Why do changes in communities matter? Bulldozers Different types of animals with different behaviours have different impacts on ecosystem function. Will functional diversity be maintained? Burrow builders Nitrate μmol.m -2.h (Widdicombe & Needham, 2007)(Widdicombe et al., in prep)

Impacts: Sediment Fluxes

What do we need to know to predict biodiversity response? Species diversity What are the mechanisms that make acidification detrimental to the survival of individuals and the long term sustainability of populations? How do these mechanisms vary between species? How will acidification interact with other climate change stressors to set biogeographical limits? What will be the impact on biological control (predation, competition, ecosystem engineers, keystone species)? Will adaptation mitigate the effects of ocean acidification? Taxonomic (or phylogenetic) diversity Is an organism’s tolerance related to its phylogeny or its ecology? Functional diversity What is it that different organisms do for ecosystem function? What is the relationship between biodiversity and ecosystem function anyway? (Widdicombe & Spicer. In press. Predicting the impact of Ocean acidification on benthic biodiversity: What can physiology tell us? Journal of Experimental Marine Biology and Ecology)

References S Widdicombe & JI Spicer. In press. Predicting the impact of ocean acidification on benthic biodiversity: What can physiology tell us? Journal of Experimental Marine Biology and Ecology HL Wood, JI Spicer & S Widdicombe. In press. Ocean Acidification may increase calcification rates- but at a cost. Proceedings of the Royal Society B A Beesley, DM Lowe, C Pascoe & S Widdicombe. In press. Impact of CO 2 induced seawater acidification on the health of Mytilus edulis. Climate Change R Bibby, S Widdicombe, H Parry, JI Spicer & R Pipe Impact of ocean acidification on the immune response of the blue mussel Mytilus edulis. Aquatic Biology 2: R Bibby, P Cleall-Harding, S Rundle, S Widdicombe & J Spicer Ocean acidification disrupts induced defences in the intertidal gastropod Littorina littorea. Biology Letters 3: S Widdicombe & HR Needham Impact of CO 2 induced seawater acidification on the burrowing activity of Nereis virens and sediment nutrient flux. Marine Ecology Progress Series 341: JI Spicer, A Raffo & S Widdicombe, Influence of CO 2 -related seawater acidification on extracellular acid-base balance in the velvet swimming crab Necora puber. Marine Biology 151: H Miles, S Widdicombe, JI Spicer & J Hall-Spencer, Effects of anthropogenic seawater acidification on acid-based balance in the sea urchin Psammechinus miliaris. Marine Pollution Bulletin 54: S Widdicombe, et al., in prep. The response of Brissopsis lyrifera and Echinocardium cordatum to CO 2 induced sweater acidification.