News features and technical articles about the evolution of aquaculture, one of the world’s fastest growing industries.

carbon dioxide

Aquafeeds

A new nutrient for aquaculture, from microbes that consume carbon waste

Biotechnology firm NovoNutrients aims to produce a line of nutraceutical aquafeed additives as well as a bulk feed ingredient that can supplement fishmeal. Its process includes feeding carbon dioxide from industrial gas to a “microbial consortium” starring hydrogen-oxidizing bacteria. 

Aquafeeds

Understanding the oxygen demand of aquafeeds

Manufactured aquafeeds, if improperly managed, can result in undesirable oxygen demand that can reduce dissolved oxygen levels and pollution through effluents, and stress cultured animals. 

Health & Welfare

The oft-overlooked water quality parameter: pH

Attention to pH, a numeric scale used to specify the acid or alkaline condition of an aqueous solution, is very important. Reducing biomass and feeding rates together with phytoplankton control and liming can often keep pH at desirable values. 

Responsibility

Assessing the carbon footprint of aquaculture

A carbon footprint is an estimate of the total carbon emissions resulting from the production, use and disposal of a product or service. Carbon footprints for aquaculture products result mainly from the use of manufactured feed and mechanical aeration. 

Health & Welfare

Dissolved oxygen requirements in aquatic animal respiration

Although carbon dioxide is not highly toxic, high levels in the blood have many negative physiological consequences. As carbon dioxide increases, higher dissolved oxygen tension is necessary to load hemoglobin with oxygen. 

Responsibility

Aquaculture ponds hold carbon

Although 16.6 million metric tons of carbon are annually buried in aquaculture ponds, estimated carbon emissions for culture species have approached several metric tons of carbon per metric ton of aquaculture product. 

Responsibility

Carbon dioxide: Waste, nutrient

Carbon dioxide is both a nutrient and a waste product in aquaculture. Some pond managers feel that application of organic matter to provide additional carbon dioxide can reduce pH and control blue-green algae. 

Health & Welfare

Misuses of sodium bicarbonate in pond aquaculture

Sodium bicarbonate is a useful chemical in recirculating aquaculture systems and fish transport tanks. However, two common uses of the compound in pond culture – to remove carbon dioxide and treat off-flavors – do not work.