The release of phosphorus and nitrogen by living and decomposing snails

Strony 17-24 : ilustracje ; 27 cm

The excretion of P-PO4 and N-NH4 by snails (Lymnaea (Lymnaea) stagnalis, Lymnaea (Radix) auricularia and Planorbarius corneus) was measured in laboratory experiments. For L. (L.) stagnalis the release of these elements from decomposing animals and their faecal material were also determined. Amounts of nutrients excreted by the snails studied varied greatly in the ranges <1 to 70 µg P-PO4 and <2 to over 200 µg N-NH4 per individual. These amounts were very much related to the sizes of snails. The phosphorus and nitrogen contained in the tissues of L. (L.) stagnalis are released to the water very rapidly due to the rapid decomposition that the bodies of snails undergo. The release of phosphorus from freshly produced faecal matter is considerable -even greater than the excretion by live snails (expressed per unit weight). However, the limited mass of faeces produced as compared with the body weight of an snail, ensures that this still accounts for only 3% of daily excretion of phosphorus from the body of a live snail.

Bibliographical references (pages 23-24)

Pages 17-24 : illustrations ; 27 cm

Bibliografia na stronach 23-24