Figure 4.
Annual air-sea CO2 flux at the boreal site determined by the bulk formula method. Units: μmol-C m−2 s−1. Negative fluxes (influx of CO2 into seawater) are indicated by blue, and positive fluxes by red. The annual average of the air-sea CO2 flux at the boreal site was negative (−1.76 × 10−2 ±1.50 × 10−2 μmol-C m−2 s−1), the indication being that the boreal site was a net sink of atmospheric CO2. The growing season for seagrasses is from May to August, and the decay season is from September to November at the site (unpublished data). The seawater was frozen from December to April at the site.