Pigmentation is one method employed by a variety of plants as a form of photoprotection. For example, in Antarctica, native mosses of green color can be found naturally shaded by rocks or other physical barriers while red colored mosses of the same species are likely to be found in wind and sun exposed locations. This variation in color is due to light intensity. Photoreceptors in mosses, phytochromes (red wavelengths) and phototropins (blue wavelengths), assist in the regulation of pigmentation. To better understand this phenomenon, Waterman et al. conducted an experiment to analyze the photoprotective qualities of UVACs (Ultraviolet Absorbing Compounds) and red pigmentation in antarctic mosses. Moss specimens of species "Ceratodon purpureus, Bryum pseudotriquetrum" and "Schistidium antarctici" were collected from an island region in East Antarctica. All specimens were then grown and observed in a lab setting under constant light and water conditions to assess photosynthesis, UVAC and pigmentation production. Moss gametophytes of red and green varieties were exposed to light and consistent watering for a period of two weeks. Following the growth observation, cell wall pigments were extracted from the moss specimens. These extracts were tested using UV–Vis spectrophotometry which uses light from the UV and visible spectrum to create an image depicting light absorbance. UVACs are typically found in the cytoplasm of the cell; however, when exposed to high-intensity light, UVACs are transported into the cell wall. It was found that mosses with higher concentrations of red pigments and UVACs located in the cell walls, rather than intracellularly, performed better in higher intensity light. Color change in the mosses was found not to be due to chloroplast movement within the cell. It was found that UVACs and red pigments function as long-term photoprotection in Antarctic mosses. Therefore, in response to high-intensity light stress, the production of UVACs and red pigmentation is up-regulated.