Eelgrass campaign oxygen dynamics

Continuous measurements (every 10 min) of dissolved oxygen (DO) and water temperature were made with miniDOT oxygen optode loggers (Precision Measurement Engineering, Vista, CA, USA, in the following termed “oxygen logger”) at the three main sites. The chamber incubations were done in triplicates and at the three types of habitat in April, June and August, corresponding to mean temperatures of 9, 16 and 21°C, respectively. Chambers consisted of gas impermeable transparent plastic bags (19 x 42 cm; diameter x height = 12 L) attached to a hard PVC collar, which was secured firmly into the sediment with metal plugs. Incubations were made over a period of approximately 24 hours with logging of oxygen, temperature and light every 10 minutes by a oxygen logger and a light logger placed at a depth of about 30 cm above the seafloor inside each chamber fixed to a metal stick placed into the sediment.