Microbiomes are communities of microorganisms that inhabit diverse ecological niches from the human gut to the water column of the ocean. The effects of microbiomes on their habitat are only now being appreciated with recent studies demonstrating the role of the human gut microbiome in surprising areas of human health (i.e., blood pressure) or the water column microbiome in biogeochemical processes. Metagenomics is able to evaluate the presence of different taxa or specific genes while transcriptomics is able to define levels of gene expression, but proteomics seeks to identify and measure the translated end products of the microbiome (and its host/environment depending on the method). Metaproteomics is the attempt to characterize the proteome of a community of microorganisms using mass spectrometry (bottom-up, top-down or targeted analysis). Results provide insight into the activity of different taxa leading to a clearer functional understanding of microbiomes. Although using high-resolution fast duty cycle mass spectrometers have made this analysis possible, there are still looming problems related to the inherently large search space and to comparing results temporally or between laboratories. This project seeks to provide metaproteomic data related to standardized materials, benchmark bioinformatics workflows of standardized data, and facilitate, and/or participate in inter-laboratory/inter-calibration studies. Due to the nature of this project, we are seeking applicants from the fields of microbiology, mass spectrometry (proteomics) or bioinformatics.