1. NCP ( mmol O 2 m -2 d -1 ) BP (mmol C m 2 d -1 ) NET ECOSYSTEM METABOLISM IN THE NW IBERIAN UPWELLING SYSTEM ON AN ANNUAL CYCLE C.G.Castro, Arbones B, Alvarez-Salgado XA, Alonso-Pérez F, Froján M, Zúñiga D, Teixeira IG, and Figueiras FG Instituto de Investigaciones Marinas (CSIC) The 45 th International Liège Colloquium 13 th – 17 th May 2013

2. Aristegui Arístegui et al. 2009 CAIBEX: Shelf –ocean exchanges in the Canaries- Iberian Large Marine Ecosystem Background

3. Northern boundary of the Canary Current upwelling system Seasonal variation: Upwelling: April to September Downwelling: October to March MONTH Upwelling index (1987-2004) Courtesy of RMS from PML UPWELLING Background Courtesy of RMS from PML DOWNWELLING Upwelling index (10 3 m 3 s -1 Km -1 )

4. E Background High rates of primary production during the upwelling period (2.5 g C m -2 d -1 ), dominated by large – sized diatoms (Varela et al., 1991; Teira et al., 2001; Figueiras et al., 2001; Tilstone et al., 2003) Espinoza et al. 2012

5. Objectives To study the fate of fixed carbon based on direct measurements of gross primary production, pelagic respiration and vertical export of organic matter and explore the linkage between Production / Respiration balance and size structure and composition of the microbial plankton community.

6. Methods Courtesy of RMS from PML SEAWATER SAMPLES for: -Nutrients -Size –fractionated chlorophyll (0.2, 2, & 20 µm) -Pico-, Nano- and Microplankton biomass SEAWATER SAMPLES for: -Nutrients -Size –fractionated chlorophyll (0.2, 2, & 20 µm) -Pico-, Nano- and Microplankton biomass Net Community Production (NCP) and Community Respiration (CR) by in situ 24 ligh-dark bottle oxygen incubations Net primary production by in situ 24 incubations of C14 Bacterial production by leucine uptake Vertical fluxes of organic carbon by in situ 24h deployment of a multitrap

7. Temperature (°C) Nitrate (µmol kg -1 ) 20082009 Upwelling index (m 3 s -1 Km -1 ) Hydrographic conditions Results

8. 20082009 Total chlorophyll a (mg m -3 ) Primary production (mg m -3 d -1 ) 20082009 >20 μ m>2 μ m>0.2 μ m 57% 76% 32% Results

9. Microbial plankton biomass Integrated biomass (mg C m -2 ) Size class Contribution (%) 20082009 Pico-Nano-Micro- Results

10. Production / respiration balance NCP (mmol O 2 m -3 d -1 ) CR (mmol O 2 m -3 d -1 ) BP (mg C m -3 d -1 ) 20082009 Results

11. 20082009 Vertical Carbon Fluxes (mg C m 2 d -1 ) Organic carbon Phytoplanktonic carbon Diatom carbon Results

12. NCP ( mmol O 2 m -2 d -1 ) BP (mmol C m 2 d -1 ) NCP ( mmol O 2 m -2 d -1 ) BP (mmol C m 2 d -1 ) Conclusions

13. 6 0 4 2 1 0.5 NCP (g C m -2 d -1 ) Autotrophic biomass Heterotrophic biomass Conclusions

14. NCP 0.5 ±0.5 Respiration 0.5 ±0.3 Respiration 0.07 ±0.03 Carbon flux 0.29 ±0.02 DOWNWELLING SEASON 58% 50% 24% NCP 2.1 ±2.0 Respiration 0.9 ±1.0 Respiration 0.2 ±0.1 Carbon flux 0.4 ±0.2 UPWELLING SEASON aphotic zone photic zone 19% 70% 50% Conclusions g C m -2 d -1

15. Thank you for your attention