Volcanic deposits initially contain no fixed organic carbon and no available fixed organic or inorganic nitrogen. Yet in environments with adequate precipitation, such deposits can ultimately support complex ecosystems in decades to a few hundred years. Aspects of biogeochemical development and plant succession have been addressed in a number of volcanic environments, but relatively little is known about colonization and successional development by microbes, even though they can be critical determinants of plant colonization (e.g., by legumes).

Results from analyses of chronosequences on Kilauea volcano show that trace gases (CO, H2) derived from the ambient atmosphere play important roles in microbial activity on young, poorly vegetated or unvegetated deposits. Notably, CO-oxidizing bacteria are more abundant (greater total CO uptake capacity) in vegetated, well-developed deposits, even though CO likely plays a much less important role in them. This suggests that CO oxidizers are important throughout successional development, but that their functional roles may change.

While specific changes in functionality remain uncertain, analyses of CO oxidizer community structure and diversity across chronosequences and gradients of successional development reveal distinct patterns, with a trend for taxa in Firmicutes and Actinobacteria lineages to dominate in water-stressed unvegetated systems and taxa in Proteobacteria to dominate in vegetated systems.
Patterns in CO oxidizers are congruent with those for microbial communities as a whole, as evidenced by 16S rRNA gene sequence libraries, but patterns for both suggest that different forces (or variables) may shape systems developing on volcanic deposits versus those on continental soils.