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Ontogenetic Shift in Crayfish δ 13C as a Measure of Land-Water Ecotonal Coupling
Vol. 107, No. 2 (1996), pp. 239-242
Stable URL: http://www.jstor.org/stable/4221329
Page Count: 4
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Although ontogenetic changes in the carbon isotope ratios of marine fauna have been well studied those of freshwater organisms have not. As a result, we may have a less than adequate assessment of the incorporation of allochthonous detritus into freshwater food-webs. This study found a δ 13C range of 9‰ for crayfish (Orconectes virilis) from oligotrophic Canadian Shield lakes. Much (60-83%) of this variability was explained by body size. A simple isotopic mixing model suggests that by their third year of life, crayfish in these lakes rely more substantially upon terrestrial detritus than epilithic algae for energy.
Oecologia © 1996 Springer