Title

The Ratio of Calcareous and Organic Shell Components of Freshwater Sphaeriid Clams in Relation to Water Hardness and Trophic Conditions

Document Type

Article

Publication Date

1979

Publication Source

Journal of Molluscan Studies

Abstract

Shells from 14 populations of sphaeriid clams including Sphaerium striatinum, S. simile, Pisidium walkeri, Musculim partumeium and M. iransversum were analyzed for organic carbon (μgC mg−1 shell), nitrogen (μg,N mg−1 shell) and CaCOs (%CaCO3 of total clam dry weight). Habitat waters were assessed for total hardness (expressed as ppm CaCo3), ppm Ca, ppm Mg, conductivity (μmho) and suspended organic Carbon (μgCl−1). For all populations, shell organic C and N are positively correlated and there is an inverse relationship between the amounts of shell CaCO3 and shell organic carbon. Trophic considerations give the best correlation with shell type at the generic level of consideration since species of Musculium are found at the opposite end of the trophic scale (eutrophic) from all other populations studied. For S. striatinum, the most extensively studied species, the amount of shell CaCO3 is inversely related to water hardness. The selection of shells in the Sphaeriidae is discussed in relation to structural-functional needs and habitat conditions.

Inclusive pages

312-321

ISBN/ISSN

Online ISSN 1464-3766; Print ISSN 0260-1230

Publisher

Malacological Society of London

Volume

45

Issue

3


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