emitted, but also in the bulk. Integrating the geodesic equations for the null geodesics along which gravitons propagate and using conservation equations for the energy-momentum tensor in the bulk, we find the form of the energy-momentum tensor in the bulk.

Using the obtained energy-momentum tensor in the bulk, we show that in the period of late cosmology in the Friedmann equation corrections to the leading-order terms due to graviton emission are small, and the perturbative approach is consistent.

Graviton emission changes cosmological evolution of matter on the brane. Time (temperature) dependence of of the Hubble function determined from the Friedmann equation which includes the terms due to graviton emission is different from that in the standard cosmological model. This, in turn, results in a change of abundances of light elements produced in primordial nucleosynthesis [@steig]. We find that the difference of abundances of ${}^4 He$ produced in primordial nucleosynthesis calculated in the models with and without the graviton production is a small number, much smaller than that estimated in [@heb; @lan1; @lan2]. A crude estimate of the graviton production in the early cosmological period, which takes ito account the bounce of produced gravitons back to the brane [@lan2], does not 