Data from: The Tara Oceans voyage reveals global diversity and distribution patterns of marine planktonic ciliates

Illumina reads of the SSU-rDNA-V9 region obtained from the circumglobal
Tara Oceans expedition allow the investigation of protistan plankton
diversity patterns on a global scale. We analyzed 6,137,350 V9-amplicons
from ocean surface waters and the deep chlorophyll maximum, which were
taxonomically assigned to the phylum Ciliophora. For open ocean samples
global planktonic ciliate diversity is relatively low (ca. 1,300 observed
and predicted ciliate OTUs). We found that 17% of all detected ciliate
OTUs occurred in all oceanic regions under study. On average, local
ciliate OTU richness represented 27% of the global ciliate OTU richness,
indicating that a large proportion of ciliates is widely distributed. Yet,
more than half of these OTUs shared <90% sequence similarity with
reference sequences of described ciliates. While alpha-diversity measures
(richness and exp(Shannon H)) are hardly affected by contemporary
environmental conditions, species (OTU) turnover and community similarity
(β-diversity) across taxonomic groups showed strong correlation to
environmental parameters. Logistic regression models predicted significant
correlations between the occurrence of specific ciliate genera and
individual nutrients, the oceanic carbonate system and temperature.
Planktonic ciliates displayed distinct vertical distributions relative to
chlorophyll a. In contrast, the Tara Oceans dataset did not reveal any
evidence that latitude is structuring ciliate communities.