ECo-MOAR investigated how changes in carbonate chemistry within seagrass beds affect community calcification. The project employed cutting-edge technologies developed by the Max Planck Institute for Marine Microbiology (MPI-MM) and the National Oceanography Centre (NOC). MPI-MM provided a pH and O₂ eddy covariance system, while NOC contributed autonomous in situ sensors to monitor carbonate parameters. The study examined how diurnal metabolic changes drive calcification and assessed the impact of ocean acidification near CO₂ vents. Measurements were conducted at high temporal resolution, across ecosystem-scale areas (tens of m²), and under natural environmental conditions, providing unprecedented insight into the biogeochemical dynamics of seagrass-associated calcifying communities.