Community metabolism in shallow coral reef and seagrass ecosystems, lower Florida Keys

Seagrass and coral reef sites showed diurnal variations of NEP and NEC, with positive values at near-seafloor light levels >100-300 µEinstein/m**2/s. During daylight hours, we detected an average NEP of 12.3 and 8.6 mmol O2/m**2/h at the seagrass and coral reef site, respectively.

At night, NEP at the seagrass site was relatively constant, while on the coral reef, net respiration was highest immediately after dusk and decreased during the rest of the night. At the seagrass site, NEC values ranged from 0.20 g CaCO3 /m**2/h during daylight to -0.15 g CaCO3/m**2/h at night, and from 0.17 to -0.10 g CaCO3/m**2/h at the coral reef site. There were no significant differences in pH and aragonite saturation states (Omega ar) between the seagrass and coral reef sites.