An integrated multi-trophic aquaculture (IMTA) system is designed to cultivate tiger prawns (Penaeus monodon) alongside red sea lettuce (Ulva lactuca). The system recirculates marine water from the prawn ponds, through a biological filtration unit, and into channels containing the sea lettuce, before returning it to the prawns.
State the primary chemical form in which nitrogenous waste is excreted by aquatic invertebrates like prawns.
Explain why allowing high levels of uneaten organic feed and prawn faeces to accumulate in the ponds would lead to a rapid depletion of dissolved oxygen.
In modern recirculating aquaculture systems, ultraviolet (UV) sterilisers are frequently incorporated into the water loop. Explain how this treatment helps to maintain high prawn survival rates.
Describe how saprobionts (decomposers) and nitrifying bacteria in the biological filtration unit convert organic prawn waste into inorganic ions that promote the growth of Ulva lactuca.
Tiger prawns can exhibit cannibalistic behaviour. Suggest one practical method prawn farmers can use to minimise this form of intraspecific predation.
74 exam-style questions on Edexcel IGCSE Biology Food production. Each one has a worked solution and a mark scheme showing where the marks go.