How much do we know about marine metazoan biodiversity? Recent disclosures using second generation sequencing.

In response to contemporary threats to biodiversity, accurate and objective methods of species or operational taxonomic unit (OTU) assessment are fundamental to our understanding of mechanistic links among ecosystem components and resilience. Second generation sequencing approaches have been especially insightful for biodiversity analyses of the microbial biosphere, but to date, such approaches have not been used to study Metazoan phyla. Here, we utilize second generation sequencing for interpreting the relative richness of multiple metazoan phyla inhabiting the marine benthos. We identify (a.) comparative and substantial levels of unrecorded richness, that refute currently accepted paradigms of phylum rank abundance, (b.) ecosystem-level community composition at fine level spatial hierarchical scales and (c.) sequences derived from putative metazoan taxa that bear little genetic resemblance to any phylum that has been sequenced previously. These findings suggest that such techniques will provide a valuable addition to the exploratory tool-box for rapidly and simultaneously documenting the identity, composition and potential function of hitherto intractable, but ecologically important, communities.