A significant and urgent challenge faced by the aquaculture industry is to meet the escalating demand for food, while preserving critical habitats and biodiversity1. In this context, nanobubbles have emerged as a promising technology that can help transform the industry, with several benefits ranging from increased production yields to improved water quality and reduced environmental impact.
To understand the potential of nanobubbles in aquaculture, one must first comprehend the role of oxygen in this industry. Dissolved oxygen is a critical factor that limits stocking density and production yields in aquaculture. Traditional aeration methods, such as paddlewheels and airstones, have been used to infuse oxygen into water. However, these methods have limitations, including a low oxygen transfer efficiency of about 3% per foot of water, and a tendency for oxygen to concentrate in the topmost layers of water, leaving bottom layers oxygen-deprived2
Nanobubbles represent an innovative solution to this problem. These are very small bubbles, about 2,500 times smaller than a grain of salt, that can remain suspended in the water column for months, saturating chosen levels of water with oxygen. This is achieved by diffusing compressed oxygen into fast-flowing water, which further spreads and dissolves bubbles. Notably, nanobubble generators have an oxygen transfer efficiency of up to 85%, nearly 30 times the rate of traditional aerators2.
The use of nanobubbles in aquaculture offers several advantages. First, nanobubbles can increase stocking densities without compromising water quality. Traditional aeration systems typically allow the culture of up to 40 kilos of seafood per cubic metre, but with nanobubble technology, this can be raised to 80 kilos or more2. Further, a study published in Aquaculture and Fisheries in 2020 found that the use of a nanobubble generator in shrimp farms doubled production while improving survival and feed conversion rates2.
Second, nanobubbles can help to control disease or pathogens by avoiding dead zones with low saturated oxygen and removing biofilm surface deposits, thereby reducing pathogens, specifically fungi and bacteria2. There is also evidence to suggest that nanobubbles can reduce infectious bacteria in shrimp, leading to fewer deaths and better yields2.
Lastly, nanobubble technology holds potential for bioremediation, a process that uses natural organisms to break down hazardous substances into less toxic or non-toxic substances. A case in point is a project in Yokohama, Japan, where nanobubble technology was applied to a degraded seabed. Within six months, fish, shrimp, and seaweed had returned to an area that had previously been devoid of most lifeforms2.
Nanobubble technology, therefore, offers a path for the aquaculture industry to meet the dual challenge of increasing production to meet the demands of a growing global population while also enhancing sustainability. The industry, as a part of the broader food system, must continue to innovate and implement such transformative solutions to ensure a sustainable future for people, nature, and climate1.
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