The astronauts would then eat that carbon-rich crop and exhale the carbon out in the form of carbon dioxide, which would then be captured by the microbes, to create a nutritious crop, which then would be exhaled in the form of carbon dioxide by the astronauts.
Então, os astronautas comeriam  do cultivo rico em carbono e expirariam o carbono  na forma de dióxido de carbono, que seria capturado pelos micróbios, para criar um cultivo nutritivo, que então seria expirado na forma de dióxido de carbono pelos astronautas.