| Abstract: | A recently introduced approach far estimating the photosynthetic quantum efficiency (φ) of a freshwater or marine phytoplankton community has been applied for the first time to high latitude polar ecosystems, namely four lakes of southern Victoria Land, Antarctica. Values for φ at various depths ranged from 0.0022–0.1560 when calculated using a recommended mean extinction coefficient for phytoplankton (i.e. k?c= 0.016). By contrast, φ ranged from 0.0037–0.0760 when calculated using an empirically estimated value for k?c of 0.0328. If the recommended k?c= 0.016 more closely approaches an accurate estimate, then the φ valves indicate that the phytoplankton convert light to organic carbon more efficiently than elsewhere. However, if the empirically derived k?c= 0.0328 more closely approaches an accurate estimate, then the φ values indicate the phytoplankton trap light more efficiently than elsewhere. Although we have not resolved whether light conversion (φ) or light trapping are more efficient, the results show that the phytoplankton of these Antarctic lakes are well adapted to performing photosynthesis under extremely low light conditions. |
