Common Name: Filamentous Algae
Filamentous algae are single algae cells that form long visible chains, threads, or filaments. These filaments intertwine forming a mat that resembles wet wool. Filamentous algae starts growing along the bottom in shallow water or attached to structures in the water, like rocks or other aquatic plants. Filamentous Algae will often form mats that float on the surface of the pond resembling wet wool.
Most pond owners commonly refer to this type of algae as “pond scum”, but can often be called string algae, or floating algae. This is a very common type of algae found in ponds, but if left untreated can cover the entire surface of a pond.
Common Name: Chara Algae
Chara is often called muskgrass or skunkweed because of its foul, musty almost garlic-like odor. Chara is a gray-green branched multicellular algae that is often confused with submerged flowering plants. However, Chara has no flower, will not extend above the water surface, and often has a “grainy” or “crunchy” texture. Chara has cylindrical, whorled branches with 6 to 16 branchlets around each node.
Submerged portions of all aquatic plants provide habitats for many micro and macro invertebrates. These invertebrates in turn are used as food by fish and other wildlife species (e.g. amphibians, reptiles, ducks, etc.). After aquatic plants die, their decomposition by bacteria and fungi provides food (called “detritus” for many aquatic invertebrates. Chara is consumed by many species of ducks.
Common Name: Planktonic Algae
Planktonic algae are floating microscope plants that are normal and essential inhabitants of sunlit surface waters. There are literally millions of floating planktonic algae and these color pond water shades of green, blue-green, brown or variations in between. Planktonic algae that color the water is often called a “bloom” or “algae bloom”. Many species of algae are involved in algae blooms and these species change over time based on temperature, light, nutrients, and other factors.
Planktonic algae blooms are considered desirable as the beginning of the pond food chain. In fact, fertilization programs are often used to promote algae blooms and thereby support a larger fish population. Planktonic algae is desirable for shading the pond bottom (in areas over 2 feet deep). This shading suppresses the establishment of rooted aquatic plants. However, to much planktonic algae can cause oxygen depletions and fish kills.