Where sawgrass grows densely, few animals or other plants thrive, although alligators often choose these locations for nesting. Where there is more room, periphyton grows, appearing as mats or brown sausage-shaped chunks. Periphyton is predominantly algae, although over 100 different microorganisms help create it.[28] Larval insects and amphibians are supported by periphyton; these in turn provide food for birds, fish, and reptiles. Periphyton also absorbs calcium from the water, which creates marl where sawgrass takes root.[29]