Nannochloropsis

These organisms are autotrophic, meaning they rely on photosynthesis to produce energy. They lack any parasitic mechanisms and do not infect or damage the tissues of higher plants.

In scientific terms, Nannochloropsis is widely studied in biotechnology and aquaculture for its ability to produce high levels of lipids and omega-3 fatty acids.

Misunderstandings regarding its status as a "disease" arise because, in hydroponic or aquaponic systems, they can colonize nutrient solutions if lighting is improperly managed.

Therefore, it should not be categorized as a pathogen or a plant pest, but rather as an opportunistic microorganism that competes for resources in artificial cultivation setups.

The growth of Nannochloropsis requires high light intensity, carbon dioxide, and an abundance of mineral nutrients such as nitrogen and phosphorus in an aqueous solution.

Optimal growth temperatures for these microalgae range from 20°C to 25°C. Outside of this range, metabolic rates decrease significantly, limiting their proliferation.

The species prefers an alkaline environment with a pH between 8.0 and 8.5. It does not typically thrive in the acidic conditions common in many standard soil-based horticultural substrates.

Continuous agitation or aeration of the water is necessary to prevent cell sedimentation and to ensure an uniform distribution of nutrients and light availability.

In greenhouses, entry points such as open water tanks or improperly sealed irrigation lines can allow these algae to contaminate systems if direct sunlight reaches the nutrient fluid.

Nannochloropsis causes no direct damage to crops. It does not secret phytotoxins, nor does it form infections that compromise the physiological integrity of plants.

The primary concern is resource competition. Dense algal blooms consume significant amounts of nitrogen and phosphorus intended for the crop, potentially causing nutrient imbalances.

Thick layers of algal biomass can physically clog irrigation emitters, filters, and valves, leading to irregular water delivery and increased maintenance requirements.

When algae cover the surface of a hydroponic substrate, they can block essential oxygen exchange, potentially stressing the root zone of the crops.

The rapid decomposition of accumulated algal cells within closed-loop irrigation systems can create an environment conducive to secondary bacterial growth, which might pose a risk to the plants.

The most effective strategy to control Nannochloropsis is light exclusion. Using opaque materials for reservoirs and piping prevents the photosynthesis required for algae growth.

Regular maintenance, including mechanical cleaning of tanks and the use of fine filtration systems (under 1 micron), is highly effective at removing cells from the water supply.

Maintaining strict nutrient balance and avoiding phosphorus excess helps reduce the suitability of the irrigation water for opportunistic algal colonization.

If colonization occurs, applying approved disinfectants such as hydrogen peroxide at low doses can successfully eliminate the biomass without harming the crop's root system.

Ensuring clean input water and maintaining high hygiene standards during system setup are the most reliable ways to prevent the introduction of algae into the greenhouse environment.