In anaerobic systems, complex substrates often require cooperation to degrade. This is especially the case with environmentally relevant and recalcitrant biopolymers such as chitin, where there is a metabolic cascade between functional guilds from exoenzyme-producing fermenters to organic acid oxidizing respirers. How important are specific taxonomic groups such as species in this case? Will communities tend to result on the basis of taxonomy, or does functionality play a larger role? How does energy availability affect how communities assemble and interact? I am addressing these questions via laboratory incubations and downstream geochemical, metagenomic, and amplicon sequencing-based analyses.