Phylogenetic composition and distribution of picoeukaryotes in the hypoxic northwestern coast of the Gulf of Mexico
Article first published online: 27 DEC 2012
© 2012 The Authors. MicrobiologyOpen published by Blackwell Publishing Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 2, Issue 1, pages 130–143, February 2013
How to Cite
MicrobiologyOpen 2013; 2(1): 130–143
- Issue published online: 13 FEB 2013
- Article first published online: 27 DEC 2012
- Manuscript Accepted: 12 NOV 2012
- Manuscript Revised: 28 OCT 2012
- Manuscript Received: 26 JUL 2012
- University Grants Committee Areas of Excellence Scheme. Grant Number: AoE/P-04/04
- Research Grants Council. Grant Numbers: 661809, 661610
- TUYF Charitable Trust. Grant Number: TUYF10SC08
- MALV I and II;
- rDNA environmental sequences
Coastal marine hypoxic, or low-oxygen, episodes are an increasing worldwide phenomenon, but its effect on the microbial community is virtually unknown by far. In this study, the community structure and phylogeny of picoeukaryotes in the Gulf of Mexico, which are exposed to severe hypoxia in these areas was explored through a clone library approach. Both oxic surface waters and suboxic bottom waters were collected in August 2010 from three representative stations on the inner Louisiana shelf near the Atchafalaya and Mississippi River plumes. The bottom waters of the two more western stations were much more hypoxic in comparison to those of the station closest to the Mississippi River plume, which were only moderately hypoxic. A phylogenetic analysis of a total 175 sequences, generated from six 18S rDNA clone libraries, demonstrated a clear dominance of parasitic dinoflagellates from Marine alveolate clades I and II in all hypoxic waters as well as in the surface layer at the more western station closest to the Atchafalaya River plume. Species diversity was significantly higher at the most hypoxic sites, and many novel species were present among the dinoflagellate and stramenopile clades. We concluded that hypoxia in the Gulf of Mexico causes a significant shift in picoeukaryote communities, and that hypoxia may cause a shift in microbial food webs from grazing to parasitism.