In this study, we used 13C and 15N labeled substrates to assess the carbon (C) and nitrogen (N) assimilation by detecting 13C and 15N in proteins from microorganisms in the phototrophic microbial mats in a soda lake on the Cariboo Plateau, British Columbia, Canada. Metagenomic database used for protein identification and metagenome assembled genome membership had been previousl generated in Zorz et.al. (2019).