Common water flea

Common water flea (Daphnia pulex) is a small crustacean belonging to the order Cladocera and the family Daphniidae. While often considered beneficial in natural ecosystems for their role in food chains, in intensive plant production and aquaculture systems, they are often viewed as bio-contaminants that interfere with technical processes.

The biology of Daphnia pulex is characterized by high reproductive efficiency through cyclical parthenogenesis. In favorable aquatic environments, females produce clones rapidly without fertilization. When resources become scarce or environmental conditions fluctuate, the population produces resting eggs (ephippia), which are highly resistant to desiccation and can persist in dried equipment or pipes until conditions improve again.

In a controlled agricultural environment, their primary harmfulness is nutrient sequestration. These crustaceans filter-feed on microscopic particles and nutrients, effectively competing with crops for essential minerals in hydroponic solutions. Their presence can disrupt the balanced chemical composition required for optimal plant growth and cause imbalances in pH levels and dissolved oxygen.

The physical damage caused by these organisms involves the clogging of drip irrigation lines, pumps, and fine-mesh filters. As their population density explodes, the accumulation of organic matter from dead individuals can lead to water turbidity, the development of biofilms, and an increased risk of fungal infections within the root zones of the cultivated plants.

Effective management strategies focus on preventing the entry and establishment of the population. Key measures include:

• Installing high-precision micron filters on intake pipes.
• Utilizing UV sterilization lamps to interrupt the reproductive cycle.
• Implementing rigorous sanitation protocols for all water storage tanks.
• Routine monitoring of nutrient solution turbidity.
• Treating source water to eliminate resting eggs (ephippia).