Figure 3. Location of low-salinity Free Ocean Carbon Enrichment (FOCE) experiments in the Severn River, Maryland (USA) in June-July 2011.

(A) Individual CO₂ diffusers (white) generated halos of high CO₂/low pH conditions (5 cm and 40 cm distances in grey; 100 cm locations in green; 500 cm ambient sites in blue.) The FOCE system instrument package was located on shore (B,D) and maintained high CO₂/low pH conditions within mixed-species meadows of widgeon grass (Ruppia maritima) and redhead grass (Potamogeton perfoliatus) (C).