In situ oxygen profiles across the sediment-water interface in shallow salt marsh tidal ponds at 3 different times of the day; morning, afternoon and night, respectively

Optode microprofiling device from PreSens GmbH (Germany, www.presens.de) with an Automated Micromanipulator (AM), needle-type optodes for measurements of oxygen (PM-PSt7), pH (PM-HP5), and CO2 (PM-CDM1 prototypes). Depth \"0\" is defined as the top of the microphytobenthos layer at the sediment-water interface.