Nitrogen excretion by the surf zone bivalves Donax serra and D. sordidus

Publisher Website
Google Scholar
Abstract
CT:nitrogen excretion by 2 surf zone bivalves, Donax serra and D. sordidus, was determined under laboratory and field conditions. Comparison of the forms of nitrogen excreted revealed only slight differences between species, with ammonia and amino acids constituting 70 to 78% and 21 to 30% of total dissolved nitrogen (TDN) respectively. During exposure at low tide, ammonia accumulated in D. serra mantle cavity fluid at 1 to 10% of the immersed excretion rates. On re-immersion, as initial uptake of ammonia was recorded with subsequent recovery to peak excretion rates within 2 h. Mass significantly influenced rate of ammonia excretion in both species. The effect of temperature on ammonia excretion rates is reflected in Q10 values of 2.2 (D. serra) and 2.3 (D. sordidus) for starved sand-mussels over the temperature range 15 to 25.degree.C. Mass-adjusted mean ammonia excretion rates of fed sand-mussels were significantly higher than ''starved'' excretion rates in both species. D. serra and D. sordidus recycle a total of 307 g N per m strip of surf zone per year which constitutes 2.3% of total phytoplankton nitrogen requirements in the surf zone.
Keywords

This publication has 1 reference indexed in Scilit: