Algae Blooms in Ponds
Algae is a group of microorganisms that make their way into water bodies of all sizes. Algae cells can be carried to water by bird, land animal, boat, fishing gear, and even the air! The proliferation of algae depends on nutrients and sunlight to grow.
Types of pond algae
- Filamentous Algae
- Planktonic Algae
- Macroalgae (Chara)
Filamentous Algae
Filamentous algae is commonly called string algae, hair algae, or pond scum. String algae begins growth at the bottom of the pond. There are many species of filamentous algae so not all algae blooms will look the same.
String algae can look like green mossy mats, slime or long hair-like strands. The color of filamentous algae is normally bright green to dark green. Pithophora is a type of filamentous algae that has a cotton-like consistency. Spirogyra feels like wet silky hair.
As string algae matures it eventually releases to the surface of the pond. Why does algae float at the surface?Filamentous algae becomes buoyant from the oxygen it is producing.
Is string algae bad for a pond?
While filamentous algae may not be visibly appealing, it can provide some benefit to the pond. Algae is an essential part of a pond's ecosystem. It is a food source for invertebrates, protozoans, and fish.
If algae is covering the majority of the surface, this is nature's indicator that excess nutrients are present. Steps should be taken to reduce nutrients levels within the pond or lake. Find Out How
Planktonic Algae
Planktonic algae is commonly referred to as green water algae or pea soup algae. This single celled algae float freely throughout the pond. Coloration of planktonic algae forms can be green, yellow, blue-green or brown.
Planktonic algae blooms can be a sign of a serious imbalance in water. If visibility of pond measures less than 18 inches from the surface, steps should be taken to improve water conditions.
Chara Nitella
Chara and nitella are types of macro-algae. They are commonly misclassified as submerged weeds but are forms of algae. Chara is also known as muskgrass.
Chara algae produces stems with leaves growing in whorls around the stems. There is a gritty calcified outer coating. Chara has a skunk-like odor. It is typically found in hard water.
Nitella has similar looking growth to chara but lacks the gritty calcified coating and has no odor. Nitella algae is more delicate than chara. Nitella is typically found in acidic or soft water.
There is no root system with macroalgae forms. Just like string algae, growth begins at the bottom of the pond and then releases to the surface in mats.
Common Causes of Excessive Algae
High Nutrient Levels: Primarily phosphorus and nitrogen from fertilizers, waste runoff, and decomposing organic matter.
Sunlight Exposure: Extended sunlight promotes photosynthesis and algae proliferation.
Poor Aeration: Insufficient oxygen circulation fosters favorable conditions for algae growth.
Negative Impacts of Algae Blooms
Oxygen Depletion: Large blooms consume oxygen during decomposition, stressing or killing fish.
Toxins: Certain species, especially cyanobacteria, produce harmful toxins affecting humans and animals.
Aesthetic and Recreational Damage: Algae can drastically reduce the visual and recreational appeal of water bodies.
How Can Algae Blooms Cause Fish Kills
All forms of algae produce oxygen during the day, but algae also consumes oxygen at night. A heavy bloom can result in a fish kill from oxygen uptake at night. These kills can also occur when there are consecutive overcast days. When sunlight is blocked, the algae consumes oxygen during the day instead of producing it.
Effective Algae Control Strategies
Non-chemical algae control
Beneficial Bacteria: Products like Pond Cleanse, Muck Remover, and Phosphate Eliminator reduce overall nutrients in the pond, which reduces growth over time.
Pond Dye: Aquatic dyes can be utilized to limit sunlight penetration from reaching the pond bottom, where filamentous algae and chara begin growth.
Algaecide treatments
Algaecides: Provide immediate relief from algae blooms without harming beneficial aquatic life. There are a number of algaecide options depending on the type of growth you're encountering. Cutrine Granular is ideal for growth at the bottom of the pond. For floating mats, Algae Control Pack provides a thorough kill. For ponds with senstitive fish species like trout, Phycomycin is a copper-free alternative that will control all types of algae
Aeration
Aeration Systems: Efficient aeration systems reduce stagnant water and improve overall oxygen, which improves overall water quality.