Variations in Microbial Community Structure through the Stratified Water Column in the Tyrrhenian Sea (Central Mediterranean)

Journal of Marine Science and Engineering

Francesco Smedile¹  Simona Scarfi¹  Emilio De Domenico¹  Marc Garel³  Helen Glanville⁴  Gabriella Gentile²  Violetta La Cono²  Cristian Tamburini³  Laura Giuliano²  Michail Yakimov² 

[1] Department of Animal Biology and Marine Ecology, University of Messina S. ta Sperone 31, Messina 98166, Italy; E-Mails:;Institute for Coastal Marine Environment (IAMC), CNR, Spianata S. Raineri 86, Messina 98122, Italy; E-Mails:;Aix Marseille Université, CNRS/INSU, Université de Toulon, IRD, Mediterranean Institute of Oceanography (MIO) UM 110, Marseille 13288, France; E-Mails:;Ecosystems and Environment Group, Environment Centre Wales, Bangor University, Deiniol Road, Bangor, Gwynedd LL57 2UW, UK; E-Mail:

关键词: microbial communities;    Tyrrhenian Sea;    16S rDNA/16S rRNA clone libraries;    CARD-FISH;    marine Thaumarchaeota;   

DOI  :  10.3390/jmse3030845

来源: mdpi

【 摘 要 】

The central Mediterranean Sea is among the most oligotrophic habitats in the marine environment. In this study, we investigated the abundance, diversity and activity of prokaryoplankton in the water column (25–3000-m depth) at Station Vector (Tyrrhenian Sea, 39°32.050′ N; 13°22.280′ E). This specific water column consists of three different water masses (Modified Atlantic Water (MAW), Levantine Intermediate Water (LIW) and Tyrrhenian Deep Water (TDW), possessing a typical stratification of the Central Mediterranean basin. CARD-FISH showed that the metabolically-active fraction of bacterial populations exceeded the archaeal fraction along the whole water column, except at the deepest water masses. 16S rDNA and 16S rRNA clone libraries obtained from each type of water mass were used to analyse the prokaryoplankton community structure and to distinguish between active and “less active” microbial fractions. Our results showed that the rRNA-derived bacterial libraries seemed to be more depth specific compared to 16S rDNA-derived counterparts. Major differences were detected between the active fractions of bacterioplankton thriving in photic (25 m, MAW) and aphotic layers (500–3000 m, LIW and TDW respectively), whereas no statistically-significant differences were detected within the deep, aphotic layers (500–3000 m, LIW and TDW). Archaeal communities possessed more depth-specific distribution patterns with both total and active fractions showing depth stratification. Cyanobacteria and Marine Group II MAGII of Euryarchaea dominated the MAW prokaryoplankton. A notable fraction of Geitlerinema-related cyanobacteria was detected among the metabolically-active bacterial population recovered from the mesopelagic (500 m, LIW) aphotic layer, which is indicative of their mixotrophic behaviour. Heterotrophic Gammaproteobacteria and members of Marine Group 1.1a and the PSL12-related ALOHA group of Thaumarchaeota were both abundant in the aphotic layers (both LIW and TDW). Discrepancies observed between 16S rDNA- and 16S rRNA-based libraries are most likely linked to different physiological states of the prokaryoplankton community members recovered from different layers. Taking into account the relative homogeneity of the main physicochemical parameters throughout the whole water column, light and energy source are likely the most relevant environmental variables shaping microbial biodiversity through the Station Vector water column.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.