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Use of carbon and nitrogen isotope ratios in termite research
Author(s) -
Tayasu Ichiro
Publication year - 1998
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1046/j.1440-1703.1998.00268.x
Subject(s) - isotopes of nitrogen , isotopes of carbon , carbon fibers , nitrogen , termitidae , isotope , stable isotope ratio , environmental chemistry , isotope analysis , carbon to nitrogen ratio , humus , δ15n , ecology , chemistry , δ13c , biology , soil water , total organic carbon , materials science , physics , organic chemistry , quantum mechanics , composite number , composite material
In this paper, I review carbon and nitrogen isotopic (natural abundance levels) studies of termites. The carbon isotope ratio of CH 4 emitted from termites, together with the emission rates of CO 2 , CH 4 and H 2 , showed several trends corresponding to the kinds of symbiotic microbes and feeding habits. The fraction of methane oxidized in the nest structure was estimated by comparing carbon isotope ratio of CH 4 emitted from the nest with that produced by termites in the nest. Symbiotic nitrogen fixation in the gut of termites has been shown to have a significant contribution to the nitrogen economy in some wood‐feeding termites. The carbon isotope ratio distinguishes between C4 from C3 plants, and the fractional contribution of grass in the diet can thereby be estimated. The carbon and nitrogen isotope ratios in termites are discernible among soil‐feeders, fungus cultivators and wood‐feeders. Wood/soil‐interface feeders have intermediate values between wood‐ and soil‐feeders, and thus carbon and nitrogen stable isotope ratios are assumed to characterize the degree of humification of the material consumed by termites. It is suggested that carbon and nitrogen isotope ratios are useful indicators of the functional position of termites in the decomposition process. A similar isotope pattern has been obtained in earthworms, suggesting that isotope signatures might be useful parameters in investigating detritivorous animals in general.