|
|||||
|
|
Depth matters: Microbial eukaryote diversity and community structure in the eastern North Pacific revealed through environmental gene libraries |
|
| Authors: | Astrid Schnetzer Stefanie D MoorthiPeter D Countway Rebecca J GastIlana C Gilg David A Caron |
| Institution: | a Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, 90089-0371 CA, USA b Institute for Chemistry and Biology of the Marine Environment (ICBM-Terramare), University of Oldenburg, 26382 Wilhelmshaven, Germany c Biology Department, Woods Hole Oceanographic Institution, Woods Hole, 02543 MA, USA d Bigelow Laboratory for Ocean Sciences, 180 McKown Point Rd, West Boothbay Harbor, 04575 ME, USA |
| Abstract: | Protistan community structure was examined from 6 depths (1.5, 20, 42, 150, 500, 880 m) at a coastal ocean site in the San Pedro Channel, California. A total of 856 partial length 18S rDNA protistan sequences from the six clone libraries were analyzed to characterize diversity present at each depth. The sequences were grouped into a total of 259 Operational Taxonomic Units (OTUs) that were inferred using an automated OTU calling program that formed OTUs with approximately species-level distinction (95% sequence similarity). Most OTUs (194 out of 259) were observed at only one specific depth, and only two were present in clone libraries from all depths. OTUs were obtained from 21 major protistan taxonomic groups determined by their closest BLAST matches to identified protists in the NCBI database. Approximately 74% of the detected OTUs belonged to the Chromalveolates, with Group II alveolates making up the largest single group. Protistan assemblages at euphotic depths (1.5, 20 and 42 m) were characterized by the presence of clades that contained phototrophic species (stramenopiles, chlorophytes and haptophytes) as well as consumers (especially ciliates). Assemblages in the lower water column (150, 500 and 800 m) were distinct from communities at shallow depths because of strong contributions from taxa belonging to euglenozoans, acantharians, polycystines and Taxopodida (Sticholonche spp. and close relatives). Species richness (Chao I estimate) and diversity (Shannon index) were highest within the euphotic zone and at 150 m, and lowest for protistan assemblages located in the oxygen minimum zone (500 and 880 m). Multivariate analyses (Bray-Curtis coefficient) confirmed that protistan assemblage composition differed significantly when samples were grouped into shallow (≤150 m) and deep water assemblages (≥150 m). |
| Keywords: | Protistan community structure Protistan depth distribution Species richness Diversity 18S clone libraries North Pacific |
| 本文献已被 ScienceDirect 等数据库收录！ | |