A possible sign of climate change is likely to be improved production and growth in plants. The response of net photosynthetic rates were measured on the large areas of relatively uniform moss cover at Cape Hallet through the summer season to get an estimate of the energy content, nutrient content, productivity and acclimation of mosses and lichens. The results are the first step to a full ... description of energy flow in the ecosystem. The photosynthetic behaviour of two moss species Bryum subrotundifolium and Bryum pseudotriqueterum was completed. Net photosynthesis responses to plant water content and to light were first constructed in order to optimise the experimental conditions. Sets of net photosynthesis response to light were then constructed through the season at a constant temperature of 12 degrees. Mosses were given different additions of fertiliser (macro-nutrients, micronutrients or no treatment) and sampled the following season in order to detect any nutrient limitation. An additional set of trials was carried out on Prasiola (alga) and optimal temperatures for photosynthesis of B. subrotundifolium were determined.