Figure 3. Oxygen and calcium concentrations within the mat systems.

Depth profiles of oxygen (▪) and calcium (•) in the upper 8 mm of the sediments from site 10. Left hand side panels depict light incubations; right hand side panels represent dark incubations. Each profile corresponds to the average of three measurements. From top to bottom, measurements were taken after 12 h, 60 h, 108 h and 156 h, respectively. Average light intensities were 1613, 1241,1976, and 1846 µE m⁻² s⁻¹, during the 12 h, 60 h, 108 h, and 156 h afternoon O₂ measurements, respectively.