Tag carbon dioxide

Current deacidification techniques are limited to bench scale, highlighting need for sustained R&D before implementation is possible. 

Macroalgae aquaculture has benefits but improvements are needed in monitoring, reporting, verification standards and carbon uptake assessments. 

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. 

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. 

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. 

Total alkalinity is an important variable in water for aquaculture systems, and its concentration frequently fluctuates over time in many culture systems. 

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. 

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. 

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. 

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. 

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.