Abstract
Seasonal dynamics of ocean prokaryotic communities in the free-living fraction have been widely described, but less is known about the seasonality of prokaryotes inhabiting marine particles. We describe the seasonality of bacterial communities in the particulate matter continuum by sampling monthly over two years in a temperate oligotrophic coastal ecosystem and using a serial filtration (including six size-fractions spanning from 0.2 to 200 μm). We observed that bacterial communities in the particulate matter continuum had annual changes following harmonic seasonal oscillations, where alpha, beta, and gamma diversity increased during the warm period and decreased during the cold period. Communities in each size-fraction changed gradually over time, being the communities in larger size-fractions the ones with stronger annual changes. Annual community changes were driven mainly by day length and sea surface temperature, and each size-fraction was additionally affected by other variables (e.g., smaller size-fractions by dissolved PO4 and larger size-fractions by turbidity). While some taxonomic groups mantained their preference for a given size fraction during most of the year, others varied their distribution into different size fractions over time, as e.g., SAR11, which increased its presence in particles during the cold period. Our results indicate that the size-fractionation scheme provides novel seasonal patterns that are not possible to unveil by analyzing only free-living bacteria, and that help to better understand the temporal dynamics of prokaryotes.
Highlights
Ecological communities are dynamic (e.g., Magurran et al, 2010) and, in particular, aquatic microbial communities are known to vary over different temporal scales (e.g., Fuhrman et al, 2006; Kara and Shade, 2009; Gilbert et al, 2012; Jones et al, 2012; Hatosy et al, 2013)
Samples were taken monthly between June 2011 and June 2013 at the Blanes Bay Microbial Observatory (BBMO), an oligotrophic coastal station (20 m depth) placed 0.5 miles offshore (41◦40’N, 002◦48’E) in the NW Mediterranean Sea, which has regularly been sampled for microbial ecology studies during the last decades (Gasol et al, 2012, 2016)
This study was performed at the BBMO, an oligotrophic temperate coastal site, characterized by a strong seasonal forcing, with warm summers and relatively cold winters
Summary
Ecological communities are dynamic (e.g., Magurran et al, 2010) and, in particular, aquatic microbial communities are known to vary over different temporal scales (e.g., Fuhrman et al, 2006; Kara and Shade, 2009; Gilbert et al, 2012; Jones et al, 2012; Hatosy et al, 2013). During winter and spring the mixing of the water column promotes bacterial communities dominated by Flavobacteria, Roseobacter, and some Gammaproteobacteria (Teeling et al, 2012; Buchan et al, 2014; Taylor et al, 2014). All these studies have described only the temporal changes of FL bacteria, and much less is known on the annual variability of the bacterial communities attached to particles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
