Coastal Bacterioplankton Community Dynamics in Response to a Natural Disturbance

Abstract

In order to characterize how disturbances to microbial communities are propagated over temporal and spatial scales in aquatic environments, the dynamics of bacterial assemblages throughout a subtropical coastal embayment were investigated via SSU rRNA gene analyses over an 8-month period, which encompassed a large storm event. During non-perturbed conditions, sampling sites clustered into three groups based on their microbial community composition: an offshore oceanic group, a freshwater group, and a distinct and persistent coastal group. Significant differences in measured environmental parameters or in the bacterial community due to the storm event were found only within the coastal cluster of sampling sites, and only at 5 of 12 locations; three of these sites showed a significant response in both environmental and bacterial community characteristics. These responses were most pronounced at sites close to the shoreline. During the storm event, otherwise common bacterioplankton community members such as marine Synechococcus sp. and members of the SAR11 clade of Alphaproteobacteria decreased in relative abundance in the affected coastal zone, whereas several lineages of Gammaproteobacteria, Betaproteobacteria, and members of the Roseobacter clade of Alphaproteobacteria increased. The complex spatial patterns in both environmental conditions and microbial community structure related to freshwater runoff and wind convection during the perturbation event leads us to conclude that spatial heterogeneity was an important factor influencing both the dynamics and the resistance of the bacterioplankton communities to disturbances throughout this complex subtropical coastal system. This heterogeneity may play a role in facilitating a rapid rebound of regions harboring distinctly coastal bacterioplankton communities to their pre-disturbed taxonomic composition.

Restructuring of the Aquatic Bacterial Community by Hydric Dynamics Associated with Superstorm Sandy

“…Stormwater influx and sediment in freeflowing water during storm progression were possible factors causing such a shift in bacterial community structure. Spatial and temporal analyses of natural disturbance effect on coastal bacterial communities have shown differences in bacterial communities between storm and nonstorm conditions (59). Stream water conductivity, pH, salinity, and TDS measurements increased as the storm ended and baseline flow rate returned, indicating that different abiotic characteristics could influence bacterial composition.…”

Seasonal and interannual variability of the marine bacterioplankton community throughout the water column over ten years

“…Community structure measured over 4 years at SPOT at 500 m has been shown to be quite stable relative to spatial data sets spanning large regions of the ocean (Hewson et al, 2006a). Temporal variation occurs in the context of spatial variability, which is stronger than temporal variability in some (Fortunato et al, 2011;Yeo et al, 2013) but not in other sites (Nelson et al, 2008).…”

“…Marine bacterial communities at the ocean's surface vary globally (Rusch et al, 2007;Pommier et al, 2007), at mesoscales (10-100 km), across ocean fronts (Pinhassi et al, 2003;Hewson et al, 2006b), at smaller scales between river plumes, bays and estuaries and their surrounding environments (Casamayor et al, 2002;Crump et al, 2004;Fortunato et al, 2011;Yeo et al, 2013) and even down to the micrometer scale (Long and Azam, 2001); however, within a given water mass, at least up to several kilometre wide, communities are coherent (Hewson et al, 2006b).…”

Phylogenetic Differences in Attached and Free-Living Bacterial Communities in a Temperate Coastal Lagoon during Summer, Revealed via High-Throughput 16S rRNA Gene Sequencing

“…Recently, high-throughput sequencing has been used to test whether attached and free-living communities are taxonomically distinct, and results have tended to indicate that along estuarine salinity gradients, the two communities differ when salinities are lower but are similar at higher oceanic salinities (15,16). Highthroughput 16S rRNA gene surveys have also tended to support the notion that bacteria are strongly influenced by estuarine salinity gradients (17,18), and the question arises as to whether there are true marine bacteria that form attached communities or whether they are fundamentally pelagic bacteria that are temporarily associated with particles; if this were the case, all or the majority of attached bacteria would be represented in the pelagic community in systems where such salinity gradients did not exist (19). Alternatively, attached communities that formed in coastal versus open oceans could be fundamentally different.…”