Protistan Microbial Observatory in the Cariaco Basin


Thursday, October 20, 2011
Redfield Auditorium - 12:00 Noon
Dr. William Orsi
Postdoctoral Fellow, WHOI, Department of Geology & Geophysics

The largest dataset of eukaryotic Sanger sequenced ribosomal RNA (18S rRNA) genes was combined with 454 pyrosequencing to investigate protistan diversity in the Cariaco Basin, the worlds largest truly marine anoxic basin.  Parametric statistical estimations of richness combined with multivariate statistical analyses reveal a restriction of many taxa to biogeochemical niches in the anoxic water column and to different sites in the Basin.  Estimates of richness for the Basin are an order of magnitude higher than the observed richness, which suggests that the anoxic waters of the Basin house a significant number of undetected and potentially novel taxa.  This is supported by the observation that the majority of protists in the anoxic waters do not hybridize with a universal rRNA probe, as well as the discovery of a new class of ciliates, the Cariacotrichea, with an apparent restriction to suboxic and anoxic marine environments