Photosynthetic rates of Antarctic sea-ice algae

From the abstract of one of the papers:

Oxygen microelectrodes were used to measure the photosynthetic rates of Antarctic fast ice algal mats. Using the oxygen flux across the diffusive boundary layer below the fast ice at Davis, a productivity range of 0-1.78mg C per square metre per hour was measured. This is at the lower end of fast ice productivity estimates and suggests that conventional carbon 14 techniques may overestimate sea ice algal mat productivity. Photosynthetic capacity (P max) approached 0.05 mg per C.(mg chlorophyl a) per hr. Onset of photosynthesis saturation, E k, was found at about 14 micromol photons per square metre per second. The irradiance of photoinhibition onset, E inh, was about 20 micromol photons per square metre per second and the irradiance at the compensation point, E c, was 4 micromol photons per square metre per second.