1. WP 11 - Biogeochemical Impacts - Kick-off meeting Nice 10 – 13/06/2008

2.  Objectives:  Determine impacts of ocean acidification on C and other key element cycles as well as climate relevant gases (CO2, DMS, N2O) from regional to global scales.  Assess the impact of emission scenarios on simulated ecosystem structure and function.  Quantify the changing role of marine sediments as sinks and sources of macro- and micro-nutrients (P, Fe) under future ocean acidification and climate change scenarios and investigate the impact of these changes on shelf and open ocean ecosystems and biogeochemistry.  Assess the potential of different long-term observation approaches (radionuclides, alkalinity changes, sediment traps) for detecting impacts due to ocean acidification. Kick-off meeting Nice 10 – 13/06/2008

3.  Approach: Use a hierarchy of regional to global biogeochemical-ecosystem models, some of which include not only the water column but also couple that to an interactive benthic compartment Kick-off meeting Nice 10 – 13/06/2008  Tasks: 1/3  Model Development: to incorporate new process knowledge from WP9 in order to better evaluate how ocean acidification affects individual processes and improve 3-D ocean biogeochemical and ecosystem models.  Where we start from: pH sensitive processes taken into account in large scale models …

4. BIOLOGICAL PUMPS CaCO 3 COUNTER PUMP ORGANIC C PUMP SOLUTION PUMP AIR SURFACE OCEAN TWILIGHT ZONE DEEP OCEAN       cold fresh warm haline SOLUBILITY HIGH LOW PHOTO- SYNTHESIS Nutrient &CO 2 uptake REMINERALISATION Nutrient &CO 2 release SEDIMENT BENTHIC REMIN. Nutrient & CO 2 release CALCIFICATION CO 2 release ALK consumption CaCO 3 dissolution ALK release BENTHIC DISS. ALK release POC flux CaCO 3 flux

5.  Tasks: 2/3  Model Performance Assessment: to evaluate the capability of models to reproduce existing and new datasets of dissolved properties (e.g., carbonate system parameters [WP10], O2, nutrients); Kick-off meeting Nice 10 – 13/06/2008 + Model output will be compared to relevant data, particularly where model domains overlap (e.g. the North West African upwelling system). + New data for the biogeography of calcifying organisms from WP3 will be exploited.

6.  Tasks: 3/3  Model-based assessment of impacts of ocean acidification on key biogeochemical and ecosystem processes, including sediment biogeochemistry - remineralization of organic - particle aggregation - ballasting - CaCO3 dissolution - rain ratio - bioavailability of nutrients (including sediment source) - ecosystem structure & productivity - stoichiometry of C fix - export production - CaCO3 production - air-sea fluxes CO 2 N 2 O DMS

7.  Deliverables: Link to monitoring :  Report on potential methods for detecting the impact of ocean acidification on marine particle fluxes (rain ratio effect) Model perfomance assessment :  Report evaluating the performance of all models and their developments in terms of their capability to reproduce past and present observations Impacts of ocean acidification :  … on the global fluxes of climate relevant gases  … and climate change on the sea floor as a source of macro- and micro- nutrients to the oceans (P, Fe)  … on individual biogeochemical processes at the regional, basin & global scales : report on future uncertainties and thersholds (input to WP13) Impacts of anthropogenic C emissions (past, present, future) : … on ocean biogeochemistry and ecosystems Kick-off meeting Nice 10 – 13/06/2008

8.  Participation teams : (1)shelf seas : ETH Zürich Plymouth Marine Laboratory Universiteit Utrecht (2) regional scale : Alfred Wegener Institut für Polar- u. Meeresforschung ETH Zürich (3) global scale/ : Laboratoire des Sciences et de l’Environnement and Earth Syst.University of Bergen Universität Bern Max-Planck-Institut für Meteorologie University of Bristol (model of intermediate complexity) Kick-off meeting Nice 10 – 13/06/2008

10.  Tasks:  Model-based assessment of impacts of ocean acidification on key biogeochemical and ecosystem processes, including sediment biogeochemistry: (i) the photic zone: ecosystem structure and productivity, stoichiometry of C fixation and export production, CaCO3 production, global fluxes of climate relevant gases, changes in bioavailability of macro-and micronutrients including sediment biogeochemistry in shelf areas (ii) the aphotic zone (remineralization of organic carbon, particle aggregation and ballasting, CaCO3 dissolution, and the rain ratio). The relative importance of physical versus biological-biogeochemical processes and their uncertainties will be identified by using sensitivity studies and probabilistic approaches. Kick-off meeting Nice 10 – 13/06/2008