NITROGEN AND PHOSPHORUS EXCRETION AND ITS ECOLOGICAL EFFECT BY SEVERAL BIVALVES AND FOULING ANIMALS
暂无分享,去创建一个
Nitrogen and phosphorus excretion by several filter feeding mollusks,including Chlamys farreri,Argopecten irradians,Mytilus edulis,Crassostrea gigas,Ruditapes philippinarum and fouling organisms (Styela clave,Ciona intestinalis,Balanus amphitrite and Trapezium liratum) collected from coastal culture areas,were studied.NH 4 N was the predominant nitrogenous excretory product,which accounted for more than 70% (mean 70 8%-80 1%)of TN excreted by these organisms.Amino acids are the second main nitrogenous component excreted by all of the studied organisms,which constituted 10%-25% of TN product.Other nitrogenous components excreted by the species were urea,nitrite and nitrate,but no significant amount of uric acid was measured in these bivalve species.Organic phosphorus constituted 15%-27% of the total phosphorus excreted by these organisms.The calculated everyday excretion rates of N and P of all raft cultured bivalves in Sishili Bay in summer could provide 44% and 40% respectively of N and P demands for pelagic primary production.The raft cultured bivalves played an important role in nutrient regeneration in a coastal aquaculture ecosysten.