Continental Coastal Interactions: Integration of models across terrestrial, inland water, and coastal ocean ecosystems for diagnosis, attribution, and management of carbon processes Breakout 2 Chairs: Paul del Giorgio (Université du Québec à Montréal) Steve Lohrenz (UMass Dartmouth)

Objective Examine approaches for coupling terrestrial, inland water, and coastal ocean ecosystem models and their utility for assessment and prediction of carbon cycle exchanges and their relationships to human activities and climate- related forcing

Guiding questions 1) What is the state-of-the-art for models characterizing the dynamics of carbon (storage, emissions and export) in terrestrial, inland water and coastal environments? 2) Can current budgeting gaps and uncertainties be addressed by integrating the terrestrial and aquatic components of the landscapes? 3) Where are the critical interfaces among the different models for terrestrial, inland water and coastal ecosystems, and what are potential strategies for integrating modeling efforts across these boundaries?

Short presentations Proposed “intensive” Gulf study presented by Ken Davis – deployment of a network of towers Comparison of terrestrial models by Hanqin Tian – DLEM, SPARROW, SWAT, NEWS Boreal lake carbon processes and upscaling of aquatic carbon cycles – Paul del Giorgio Relative importance of the potential fates of NEE in boreal aquatic systems - Yves Prairie

Gulf coast tower deployment plan Ken Davis

Modeling Complexity of processes governing lateral fluxes of DOC, DIC and POC and other constituents Still very few models that incorporate lateral fluxes in an explicit manner Varying degrees of grid/resolution and types of variables Not only amount of carbon but also the nature of carbon that enters aquatic systems and is ultimately transported downstream and to ocean/coastal environments

Conceptual Model of DLEM Coupling of biogeochemical and hydrological cycles (C,N,P,H 2 O) in DLEM Tian et al., poster 241

Approach: SABGOM Hoffman et al., Ann. Rev., 2011; Fennel et al., 2011 and in prep. He et al., poster 242

Lack of accounting for aquatic carbon processes in terrestrial ecosystem models Boreal northern Quebec

Landscape drivers Watershed size, cover, slope Scaling lake CO 2 emissions fluxes Lake drivers DOC, production, morphometry Lake pCO 2 CO 2 flux Physical drivers of gas exchange (K) Geographic configuration Total lake CO 2 emissions Climate

Where does terrestrial NEE go? Terrestrial NEE Increase in biomass Soil C accumulation Lateral transport (DIC, PIC, DOC, POC) ?

Net C balance of boreal landscape From Teodoru et al. (2012)

Tidal wetlandsEstuaries Continental shelf NPPDegassing Burial River input BPP Air-water exchange POC export The carbon cycle of the coastal ocean POC DOC DIC Respiration (R) Resuspension NPP, R POC DOC DIC Sediments Advective exchange Open Ocean Najjar et al. plenary presentation

Conclusions Extremely valuable dialogue between the terrestrial, aquatic and coastal disciplines Key point – if you manage carbon in one space it can have “downstream” impacts Need to be able to propagate the impacts of lateral transport of carbon and other materials to the coastal areas receiving the materials Need to account for not only the amounts but also the nature of carbon and other components Inland waters are a continuation of terrestrial carbon processes and are integrally coupled Fluxes mediated by inland waters are regionally significant Better understanding of these processes across different sectors can help each of us do a better job of constraining estimates within specific ecosystem types