If you thought algae could be easily identified, you were wrong. Algae have a diverse group that cannot be easily identified or seen with the naked eye. Although they appear identical, algae come in various shapes, sizes, and roles in marine ecology. Thousands or even millions of identified and unidentified species can be found in fresh and marine waters around the world. Most species of freshwater algae float in water, while others attach to rocks, aquatic plants, and pond surfaces. However, some species of freshwater algae are harmless and manageable, while others cause problems and are difficult to control.
Algae normally serve as crucial organisms in the ecosystem of the lake or pond. They help balance the food chain that is important to marine life by providing food, energy, and shelter among fish, zooplankton, and other marine organisms. Also, they help absorb heavy metals trapped in ponds or lakes.
The most popular groups of freshwater algae are green algae, diatoms, and blue-green algae. Green algae are the largest and most varied group of algae. According to scientists, green algae come from land plants and contain bright green pigments. However, these guys can contaminate clean, healthy water in clouds of “cotton candy.”
Diatoms produce yellowish-green or yellowish-brown pigments in ponds or lakes. The cell wall of diatoms is made up of two separate valves or shells made of silica. Silica valves cause diatoms to appear in beautiful shapes and colors when viewed under a microscope. Diatoms multiply through cell division and produce offspring that can create new cell walls. Some types of diatoms release toxins called domoic acid. Domoic acid often attacks shellfish and is poisonous to humans and other marine animals. However, freshwater diatoms do not produce domoic acid.
Blue-green algae or cyanobacteria contain green, blue and red pigments. Excessive blue-green algae blooms cause problems in the environment of ponds and lakes. Other types of algae are euglenoids, dinoflagellates, brown algae, crabeaters, and desmids.
Yes, it is true that freshwater algae have some benefits in the pond or lake environment, but most people think of it as nothing more than a problem. Contrary to its benefits, freshwater algae are notable for their drawbacks. They can affect the health of human and marine life in that they cause fish kills, death and depletion of water systems.
Freshwater algae become a problem when excessive blooms occur. This usually happens during the summer when the weather is warm and nutrients are abundant for the freshwater algae to consume. Most pond or lake owners neglect the small population of freshwater algae in the belief that their occurrence is normal; however, these seemingly benign creatures could take the life out of your special possessions.
What are the signs that freshwater algae are becoming problematic? Freshwater algae normally start out with a small population, but with ample sunlight and the necessary nutrients, they gradually grow into large groups. They also produce “dross” and lead to discoloration of the water. If left untreated, these algae could suffocate fish and affect the entire marine environment.