Definition. A fibroblast is a cell that manufactures and maintains connective tissue, the structural framework that supports the organs of all animals. Fibroblasts secrete fibrous proteins and ground substance, which together form the extracellular matrix that is the basis of connective tissue. fibroblast is a cell that manufactures and maintains connective tissue, the structural framework that supports the organs of all animals.
Therefore, there is very little chlorophyll in these tropical waters, keeping them clear. (As an aside, corals are symbioses where phytoplankton have evolved to survive in nutrient-poor tropical waters by living inside the bodies of the corals and obtaining nutrients directly from the waste products of the corals.
You can clean it off quite easily with bleach or a pressure washer. And a pressure washer is great fun. But if it's damp, you'll have difficulty stopping it from coming back. Shaded and damp, or bright and damp, it's the water that the algae needs.