The Dual Nature of Algae in Hydroponics

Algae are a diverse group of photosynthetic organisms found in various aquatic environments that range from freshwater to marine systems. They can be single-celled microalgae like phytoplankton, or multicellular forms like seaweeds and kelps.

Algae are also known for their rapid growth and short life cycles because of their efficient photosynthetic capabilities and high reproductive rates. They can quickly take over nutrient-rich environments, especially in conditions with plenty of sunlight and warm temperatures, leading to explosive population increases known as algal blooms. However, this rapid growth often results in a rapid depletion of essential nutrients and oxygen in the water which creates unfavorable conditions for their survival. Additionally, environmental stressors such as changes in light, temperature, and water quality and predation by microorganisms contribute to their quick demise. 

Beneficial Role

In natural ecosystems, algae provide numerous advantages. Through the process of photosynthesis, they generate a significant portion of the world’s oxygen, thereby supporting aquatic life and contributing to the maintenance of atmospheric oxygen levels. 

Furthermore, they play an important role in recycling nutrients by absorbing them from the water and incorporating them into their biomass, which subsequently serves as a food source for other organisms. Moreover, algae can function as indicators of water quality, with their presence and health reflecting the levels of nutrients and overall condition of aquatic environments.

In hydroponic systems, algae can also offer certain initial benefits. Photosynthetic algae can produce oxygen during daylight hours which helps prevent anaerobiosis in the lettuce’s root system [1]. Additionally, certain algae species can inhibit harmful microorganisms’ growth by competing with them for resources or releasing toxic substances, thereby providing biological control within the system. Also, in the past decade, numerous reports have surfaced regarding the release of growth-promoting substances by algae in plant cultivation systems, encompassing plant growth regulators like auxins, cytokinins, gibberellins, abscisic acid, and ethylene [2].

Harmful Impacts

Algae can pose a significant problem in hydroponic systems, particularly when they die and decompose. A primary concern is the competition for nutrients because algae flourish in nutrient-rich hydroponic solutions which directly rival lettuce for essential nutrients [3]. This leads to stunted lettuce growth and reduced yields. 

Furthermore, algae can cause obstructions and blockages within pipes, pumps, and emitters which hinder water flow and nutrients, resulting in uneven water distribution and increased maintenance requirements. 

The depletion of oxygen is also another issue, as the decomposition of dead algae consumes oxygen from the water, it creates an environment devoid of oxygen which can harm plant roots [4]. This low oxygen level can contribute to root diseases and poor nutrient absorption.

In addition to that, algal blooms can trigger pH imbalances since large-scale blooms alter the pH of the hydroponic solution [5]. Rapid changes in pH can stress plants, disrupt nutrient availability, and lead to deficiencies or toxicities. 

To counteract the detrimental effects of algae in hydroponic systems, a range of tactics can be utilized. Controlling light is key because algae need it for photosynthesis; by covering nutrient reservoirs and using opaque materials for pipes and tanks, we can limit light exposure and reduce algal growth.

Consistently monitoring and maintaining water quality, including nutrient levels and pH, helps prevent conditions that facilitate algal proliferation. Implementing physical barriers, such as screens or filters, can prevent algae from infiltrating the primary components of the hydroponic system. 

NutriHydro’s hydrogen peroxide is an effective method to combat algae infestation in hydroponic systems. It acts as an oxidizer that breaks down into water and oxygen, which helps to sterilize the water and kill algae without leaving harmful residues. By adding a diluted solution of hydrogen peroxide to the nutrient reservoir, growers can control algae growth and maintain a clean and healthy hydroponic environment. But, above all, it is important to use the correct concentration and application frequency to avoid damaging plant roots while effectively managing algae populations.

References:

[1] Schwarz, D., & Gross, W. (2004). Algae affecting lettuce growth in hydroponic systems. the Journal of Horticultural Science & Biotechnology, 79(4), 554–559. https://doi.org/10.1080/14620316.2004.11511804 

[2] Mazur, H., Konop, A., & Synak, R. (2001). Indole-3-acetic acid in the culture medium of two axenic green microalgae. Journal of Applied Phycology, 13(1), 35–42. https://doi.org/10.1023/a:1008199409953 

[3] Huo, S., Liu, J., Addy, M., Chen, P., Necas, D., Cheng, P., Li, K., Chai, H., Liu, Y., & Ruan, R. (2020). The influence of microalgae on vegetable production and nutrient removal in greenhouse hydroponics. Journal of Cleaner Production, 243, 118563. https://doi.org/10.1016/j.jclepro.2019.118563 

[4] The effects: dead zones and harmful algal blooms | US EPA. (2024, January 3). US EPA. https://www.epa.gov/nutrientpollution/effects-dead-zones-and-harmful-algal-blooms#:~:text=The%20overgrowth%20of%20algae%20consumes,for%20aquatic%20life%20to%20survive. 

[5] Wallace, J., Champagne, P., & Hall, G. (2016). Multivariate statistical analysis of water chemistry conditions in three wastewater stabilization ponds with algae blooms and pH fluctuations. Water Research, 96, 155–165. https://doi.org/10.1016/j.watres.2016.03.046