ESTIMATION TEST OF GASEOUS EMISSIONS FROM FISHPONDS WITH CONTRASTED INPUTS
Résumé
Daily operations in fishponds induce gas emissions, mainly of carbon dioxide (CO2 ), oxygen (O2 ), ammonia (NH3 ), methane (CH4 ), nitrous oxide (N2O) and nitrogen (N2 ). Estimating the effect of management practices on ammonia and greenhouse gas emissions is a new challenge for the sustainable development of fish farming and increased productivity of fishponds. Experiments were performed on eight fishponds at the aquaculture experimental platform of the University of Dschang, Cameroon. Gases were collected using a small static chamber floating on the pond surface for 24 hours. Results show that CO2 gradients related to fish densities in the fishponds and to organic inputs. CH4 emissions measured in the ponds related to higher oxygen levels in the water due to higher photosynthesis and a large deposit of dead plankton on the bottom. NH3 and N2O gradients were significantly correlated, while no correlation was detected between NH3 and CO2 . It is assumed that higher N input (urea) or higher fish population (higher N exc retion) induced higher NH 3 emissions and higher N turn-over, inducing limited N2O emissions and nitrite accumulation below toxic levels. Further work in cont rolled conditions could provide more reliable emission measurements and confirm the observed trends
Domaines
Sciences du Vivant [q-bio]
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Efole_Ewoukem2013_Texte_Thomas_emili2012_book_{905E51E2-D5CA-43A6-8E1A-6049E677481F}.pdf (167.66 Ko)
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