Chemosphere, Vol.26,Nos.1-4,pp 623-632, 1993 0045-6535/93$6.00+ 0.00 Printedin Great Britain PergamonPressLtd. METHANE EMISSION FROM WOOD-FEEDING TERMITES IN AMAZONIA C. Martius 1., R. Wassmann 2, U. Thein t, A. Bandeira 3, H. Rennenberg 2, W. Junk 1, W. Seiler z 1 Max-Planck Institute for Limnology Work Group Tropical Ecology Postfach 165, D-2320 P1/Sn, Germany 2 Fraunhofer-Institut ffir Atmosphfirische Umweltforschung (IFU) Postfach 1343, D-8100 Garmisch-Partenkirchen, Germany 3 Instituto Nacional de Pesquisas da Amaz6nia (INPA) Caixa Postal 478, 69.011 Manaus, Brazil (Received in USA 18 December 1991; accepted 27 March 1992) ABSTRACT The contribution of termites to the global methane budget has been controversely discussed in the last decade. We measured methane emissions from nests of wood-feeding termite species (Nasutitermes spp.) of primary and secondary forests of Amazonia. The methane emission rates from single termite nests varied in a broad range between 0.01 and 9.4 mg CH 4 hour -1 nest -l (average = 2.0 -- 2.4 mg CH 4 hour -1 nest-l), as termite colonies vary considerably in size (biomass). Consequently, data given as methane emission per nest are unsuitable for interspecific comparison. In seek for an appropriate unit the methane flux was related to the biomass of the termites dwelling in the nest. On this basis, the variation between the methane emissions of the nests was far lower (0.4 - 4.9 ~g hour -l g termites-l). Biomass-related methane emission rates averaged 3.0 _ 1.3 ~g hour -1 g termites-i, which means that Amazonian termites release significantly (at p = 0.01%) more methane than species from other regions. By extrapolating these emission rates to the estimated global biomass of termites we calculated a total emission of 26 Tg CH 4 year -l, which represents about 5 % of the annual methane flux from all sources to the world atmosphere. Termites are unlikely to contribute essentially to the global budget of the "greenhouse gas" methane. 1. INTRODUCTION The role of termites in the global budget of methane and, in particular, their contribution to the recent increase of tropospheric concentrations of this "greenhouse gas" have been controversely discussed in the last decade (Zimmerman et al., 1982; Zimmerman and Greenberg, 1983 Rasmussen and Khalil, 1983; Seller et al., 1984; Fraser et al., 1986). By extrapolating emission rates obtained with small laboratory groups of termites to the global termite population, Zimmerman et al. (1982) calculated a total emission of 150 Tg CH4 year -1 (Tg = 1012g) from termites, corresponding to approximately 30 % of the global source strength 623