1. Bergen mesocosm experiment 2011 Gisle Nondal, Richard Bellerby, Anna Silyakova, Helene Frigstad and Emanuele Reggiani London 29.09.11

2. Raunefjorden, Norway

4. 9 mesocoms deployed and moored each 25 m long with a volume of ca. 75 m 3 Initially open at top and bottom covered by nets with 3 mm mesh size enclosed water exchanging for 3 days (Courtesy of Ulf Riebesell, IFM-GEOMAR)

5. Set-up 3 mesocosms moored in a row With anchor weights at each end anchor weights (old railway wheels) set of 3 mesocosms (Courtesy of Ulf Riebesell, IFM-GEOMAR)

6. Target fCO 2 1 2 3 4 5 6 7 8 9 180 280 390 560 840 1120 1400 2000 3000 µatm glacial pre- present 2x p.i. 3x p.i. 4x p.i. 5x p.i. industrial CO 2 Enrichment

7. (Courtesy of Ulf Riebesell, IFM-GEOMAR)

8. After 3 days: Closing sediment traps Pulling up upper bags Adding salt (volume determination) Homogenizing CO 2 enrichment (in 4 steps) Nutrient addition (once) (Courtesy of Ulf Riebesell, IFM-GEOMAR)

9. Sampling procedure: Sampling at the Mesocoms with zodiacs

10. Gas samples directly taken on “Wassermann” Integrating water sampler

13. Carbonate chemistry In situ measurements of: Total inorganic carbon (DIC) DIC= [CO 2 (aq)]+[H 2 CO 3 ]+[HCO 3 - ]+[CO 3 2- ] DIC= [CO 2 (aq)]+[H 2 CO 3 ]+[HCO 3 - ]+[CO 3 2- ] Total alkalinity A t =[HCO 3 - ] +2[CO 3 2- ]+[B(OH) 4 - ]+ [OH - ]+[HPO 4 2 ]+2[PO 4 3 ]+ [SiO(OH) 3 - ]+ [HS - ]+[NH 3 ]-[H + ]-[HSO 4 - ]-[HF]-[H 3 PO 4 ] A t =[HCO 3 - ] +2[CO 3 2- ]+[B(OH) 4 - ]+ [OH - ]+[HPO 4 2 ]+2[PO 4 3 ]+ [SiO(OH) 3 - ]+ [HS - ]+[NH 3 ]-[H + ]-[HSO 4 - ]-[HF]-[H 3 PO 4 ] pH pH = -log[H + ] pH = -log[H + ] Overdetermination!!