IPCC 2007 Les îles bleues dans un océan vert: Les systèmes aquatiques boréaux et leur rôle dans le bilan régional de C Paul del Giorgio et Y. T. Prairie Université du Québec à Montréal Why aren t surface waters included in regional C models and sink/source assessments? Why aren t surface waters included in regional C models and sink/source assessments? -Assumed to be either unimportant or accounted for in terrestrial flux and stock measurements 1
Why aren t surface waters included in regional C models and sink/source assessments? -Assumed to be accounted for in terrestrial flux and stock measurements -Few practical tools to incorporate them to landscape or climate models A large variety and high density of lakes and rivers NSERC / HQ Industrial Research Chair Carbon Biogeochemistry in Boreal Aquatic Systems CarBBAS Establish the baseline patterns of carbon accumulation and green house gas emissions in boreal lakes, streams and rivers Integrate and scale up these processes at the regional level Place these integrated aquatic C processes in the context of landscape C budget 10Km 2
Research program of the CarBBAS Chair: An integrated exploration of C dynamic in boreal inland waters Alochthonous C Inputs and Cycling Upland Riparian Stream Lake pco 2 > atm. CO 2 Litter Fall DOC POC DOC Adapted from Aufdenkampe and Mayorga (2000) Adapted from Richey 2005 Alochthonous C Inputs and Cycling Alochthonous C Inputs and Cycling Upland Riparian Stream Lake Upland Riparian Stream Lake pco 2 > atm. CO 2 pco 2 > atm. CO 2 Litter Fall DOC POC Litter Fall DOC POC CO 2 DOC DOC S S Adapted from Aufdenkampe and Mayorga (2000) Adapted from Richey 2005 Adapted from Aufdenkampe and Mayorga (2000) Adapted from Richey 2005 3
CO 2 emissions from boreal lakes and rivers The Eastmain River region? All aquatic systems are supersaturated in CO 2 and emit C to the atmosphere 4000 Streams and rivers 1400 Lakes Surface water pco 2 (µatm) 3500 3000 2500 2000 1500 1000 Surface water pco 2 (µatm) 1200 1000 800 600 500 Rivers Short streams Long streams 400 Large lakes Small lakes 4
Upscaling lake C evasion Upscaling stream C evasion Lake size (km 2 ) = integrated lake C flux Streams (>700) (1 km 2 ) Upper Mean Integrated stream flux CO 2 [mg C m -2 d -1 ] 6020 2750 CH 4 Lower 1115 Teodoru et al. 2009 (GBC) 5
50000 km2 Net Biome Aquatic C Evasion (NBACE) 970 km 2 Teodoru et al. (in prep) Total aquatic area (km 2 ) Total aquatic C emissions (t C yr -1 ) 400 TAA = -22.7 + 0.56 Alt r 2 = 0.28 350 300 250 200 150 100 50 6400 5600 4800 4000 3200 2400 1600 800 0 0 5 10 15 20 25 30 35 40 % aquatic surface Surface water pco 2 (µatm) 4000 3500 3000 2500 2000 1500 1000 To summarize: The integrated aquatic CO 2 fluxes result from the interaction between patterns in aquatic C biogeochemistry and in geography These integrated aquatic fluxes are thus a property of the landscape, the same as net C exchange or soil C accumulation Are these fluxes regionally significant? 0 150 200 250 300 350 400 450 500 Average altitude above sea-level (m) Teodoru et al. (in prep) 500 Rivers Short streams Long streams 6
Eastmain-1 Reservoir Project: The net C footprint of a boreal reservoir Methods: terrestrial fluxes Terrestrial fluxes (M. Garneau, I. Stratham, N. Roulet) Areal C flux (mg C m -2 d -1 ) Teodoru et al. 2012 GBC (in press) 7
Terrestrial fluxes (M. Garneau, I. Stratham, N. Roulet) Areal C flux (mg C m -2 d -1 ) What happens when we incorporate the aquatic C emissions? Results of combining terrestrial, wetland and aquatic fluxes: The net landscape C balance g C m -2 yr -1 8
The distribution of net landscape C flux between watersheds Net landscape C balance Average is 2.5 g C m -2 yr -1, i.e. carbon-neutral About 50% of catchments are nearly in carbonneutral balance (± 5 g C m -2 yr -1, Does this calculated integrated net balance correspond to long-term accumulation? From Paré et al. 2011 (Ecosystems 14: 533 546) Soils: 10 kg m -2 Peatlands: 112 kg m -2 Weighted average: 27 kg m -2 Over 7400 years, this corresponds to about 3.6 g C m -2 yr -1 Does this calculated integrated net balance correspond to long-term accumulation? From Paré et al. 2011 (Ecosystems 14: 533 546) Soils: 10 kg m -2 Peatlands: 112 kg m -2 Weighted average: 27 kg m -2 Over 7400 years, this corresponds to about 3.6 g C m -2 yr -1 Our mean net balance for this region is remarkably close at 2.5 g C m -2 yr -1 To summarize: The inclusion of aquatic fluxes helps bridge the gap between contemporary net ecosystem exchange and long-term terrestrial C accumulation Aquatic fluxes thus help us close the terrestrial C budget The integrated aquatic CO 2 emissions are one of the key factors that determine whether these boreal watersheds act as net sources or sinks of C What about other aquatic ecosystems? 9
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Local abundance of beaver across Québec (from Jerema et al. 2009). Local abundance of beaver across Québec (from Jerema et al. 2009). Research program of the CarBBAS Chair 10 4 CO 2 flux (mmol m -2 d -1 ) 1000 100 10 1 Lakes Reservoir Rivers Beaver 11
Forêt d enseignement du Lac du Parquet (UQAT) Beaver «habitat» comprises 2-3% of territory 1000 CH 4 flux (mmol m -2 d -1 ) 100 10 1 0.1 0.01 Lakes Reservoir Rivers Beaver Aquatic fluxes scaled to the entire 120 km 2 block of territory (expressed per m 2 of watershed) CO 2 flux g C m -2 y -1 CH 4 flux g C m -2 y -1 Total flux g C m -2 y -1 Lakes (8% total area) 5.5 0.2 5.7 Rivers (0.3% total area) 0.6 0.6 1.2 Beaver dams (2.5% of total area) 4.2 5.6 9.8 Total 10.3 6.4 16.7 Aquatic fluxes scaled to the entire 120 km 2 block of territory (expressed per m 2 of watershed) CO 2 flux g C m -2 y -1 CH 4 flux g C m -2 y -1 Total flux g C m -2 y -1 % of total aquatic flux Lakes (8% total area) 5.5 0.2 5.7 34% Rivers (0.3% total area) 0.6 0.6 1.2 7% Beaver dams (2.5% of total area) 4.2 5.6 9.8 59% Total 10.3 6.4 16.7 12
The greenhouse gas potential of beaver dam emissions in central Québec Beaver dam emissions extrapolated over central Québec (150,000 km 2 ) are in the order of 60 x 10 6 tons of CH 4 Expressed as CO 2 equivalents, this amounts to approximately 0.14 Pg C per year This represents around 4% of the global terrestrial C sink So to conclude: Inland waters represent an important component of the regional C balance in boreal landscapes The C lost via CO2 and CH 4 fluxes is significant relative to terrestrial processes and is not considered in most regional budgets These aquatic systems are hot spots of biogeochemical activity and of exchange The regional importance of these systems is likely to increase with climate change Collaborators Yves Praire (UQÀM) Beatrix Beisner (UQÀM) Alison Derry (UQÀM) Jeff Cardille (UdeM) Roxanne Maranger (UdeM) Milla Rautio (UQÀC) Grad students : Audrey Campeau François Guillemette Marie-Eve Ferland Jean-François Lapierre Dominic Vachon Mingeng Li Lennie Boutet Matt Bogart Juan Pablo Niño Acknowledgments Postdocs Cristian Teodoru Martin Berggren Research professionals Annick St Pierre Alice Parkes Finance and logistics : NSERC Hydro-Québec GRIL 13
Beaver distribution is predicted to greatly expand northwards in the coming decades From Jerema et al. 2009 14