Fluorescence (chlorophyll a fluorescence) activity measurements were recorded for selected plants for about three weeks to determine if the photosystems of lichen or mosses are active in differing levels of light. Fibre optic probes were fixed to rocks at Botony Bay, Granite Harbour in such a way that the chlorophyll a fluorescence from an adjacent lichen or moss could be monitored. The ends of ... the fibre optics were attached to bamboo markers and elevated above ground level. The free ends were used to monitor the activity of the lichens and mosses under the snow. In the 00-01 season the area was covered with 20-50 cm of snow.The chlorophyll activity was monitored at two hour intervals for approximately 5 weeks from 5 November ? 8 December 2000. In addition several temperature and photosynthetic photon flux denisty (PPFD) sensors were installed in the vicinity of the samples. In vivo photosynthetic activity was also measured by attaching the fibre optics to a chlorophyll a fluorometer.