Microelectrode measurements of soft microbial mats in Laguna Pozo Bravo

Oxygen and sulphide profiles covering the upper 5–10 mm of soft microbial mats in Laguna Pozo Bravo were measured in situ in triplicate during both daytime (from 13:00 to 16:00) and nighttime (from 20:00 to 01:00) in January 2019. Clark-type oxygen and amperometric sulphide microsensors with a tip width of <50 µm were employed for these measurements. The microsensors were placed on a multisensor holder with a tip distance of ~0.5 cm for simultaneous measurements, with electricity supplied by a portable generator. Oxygen concentration was adjusted for salinity and temperature, according to specifications (Unisense), and values were determined assuming an atmospheric pressure of 1 bar.