Within each transect, algal mats were visually identified as either orange, red, black, or green. Not all types of algal mats were found within every t ransect. A maximum of five algal samples of each color were collected from each transect using a #13 cork borer (diameter = 17 mm, area = 227 square mm). Algal samples were preserved in 10% formalin for laboratory identifications. A maximum of five additional algal samples of each color were collected for ash-free dry mass analyses. Moss samples were also collected using the same method as for algae samples. Samples for ash-free dry mass measurements were filtered through GF/C glass fiber filters and frozen. The samples were dried (100 degrees C) for 24 hours, weighed, ashed (450 degrees C) for 4 hours, rehydrated with water, dried for 24 hours, and reweighed.