Proteomics involves using mass spec

Proteomics involves using mass spectrometry to generate mass spectra for the proteins in an environmental sample, which are then matched to those from protein libraries (VerBerkmoes et al. 2009). This approach allows quantification of the protein level (e.g., as a fraction of all spectra) as well as taxonomic matching. For example, Georges et al.(2014) used proteomics to observe an increase in organic substrate (e.g., amino acid) transport proteins from winter to spring in Bedford Basin, Canada, and a spatial survey in the South Atlantic revealed an increase in some proteins, such as nitrate permeases, in the open ocean (Morris et al.2010).