Bacterial communities from shoreline environments (costa da morte, northwestern Spain) affected by the prestige oil spill.
ABSTRACT The bacterial communities in two different shoreline matrices, rocks and sand, from the Costa da Morte, northwestern Spain, were investigated 12 months after being affected by the Prestige oil spill. Culture-based and culture-independent approaches were used to compare the bacterial diversity present in these environments with that at a nonoiled site. A long-term effect of fuel on the microbial communities in the oiled sand and rock was suggested by the higher proportion of alkane and polyaromatic hydrocarbon (PAH) degraders and the differences in denaturing gradient gel electrophoresis patterns compared with those of the reference site. Members of the classes Alphaproteobacteria and Actinobacteria were the prevailing groups of bacteria detected in both matrices, although the sand bacterial community exhibited higher species richness than the rock bacterial community did. Culture-dependent and -independent approaches suggested that the genus Rhodococcus could play a key role in the in situ degradation of the alkane fraction of the Prestige fuel together with other members of the suborder Corynebacterineae. Moreover, other members of this suborder, such as Mycobacterium spp., together with Sphingomonadaceae bacteria (mainly Lutibacterium anuloederans), were related as well to the degradation of the aromatic fraction of the Prestige fuel. The multiapproach methodology applied in the present study allowed us to assess the complexity of autochthonous microbial communities related to the degradation of heavy fuel from the Prestige and to isolate some of their components for a further physiological study. Since several Corynebacterineae members related to the degradation of alkanes and PAHs were frequently detected in this and other supralittoral environments affected by the Prestige oil spill along the northwestern Spanish coast, the addition of mycolic acids to bioremediation amendments is proposed to favor the presence of these degraders in long-term fuel pollution-affected areas with similar characteristics.
Full-textDOI: · Available from: Marc Viñas, May 29, 2015
SourceAvailable from: Gunther Kletetschka[Show abstract] [Hide abstract]
ABSTRACT: Ancient living halotolerant bacteria and ancient DNA have been reported from bedded marine halite, but seldom from lacustrine halite of the geological age. A halotolerant bacterium (Haloalkaliphilic bacterium, designated as 3-4) was isolated from primary halite with abundant fluid inclusions. Primary halite crystallized in lacustrine Yunying Depression located in the northeastern Jianghan Basin of central China. Yunying Depression is an inland salt paleolake residing in a faulted basin formed during late Cretaceous/early Tertiary. Brine inclusions from the same layer of the salt that housed Haloalkaliphilic bacterium 3-4 are the middle-late Eocene primary halite crystals and have homogenization temperatures between 5.8 and 43.3 °C. The estimated age is between 33.9 and 48.6 Ma years old for these fluid inclusions, and this represents the long-term survivability of this microorganism Haloalkaliphilic bacterium 3-4. Sequence analysis of the partial fragment of 16S ribosomal DNA showed that the organism is similar to the lineage of Haloalkaliphilic bacterium and Oceanobacillus sp. The isolation of the microbe reinforces the long-term preservation possibility of life in extreme environment such as the fluid inclusions in halite.Carbonates and Evaporites 01/2015; DOI:10.1007/s13146-014-0227-0 · 0.31 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Dormancy is a life history trait that may have important implications for linking microbial communities to the functioning of natural and managed ecosystems. Rapid changes in environmental cues may resuscitate dormant bacteria and create pulses of ecosystem activity. In this study, we used heavy-water (H(18) 2O) stable isotope probing (SIP) to identify fast-growing bacteria that were associated with pulses of trace gasses (CO2, CH4, and N2O) from different ecosystems [agricultural site, grassland, deciduous forest, and coniferous forest (CF)] following a soil-rewetting event. Irrespective of ecosystem type, a large fraction (69-74%) of the bacteria that responded to rewetting were below detection limits in the dry soils. Based on the recovery of sequences, in just a few days, hundreds of rare taxa increased in abundance and in some cases became dominant members of the rewetted communities, especially bacteria belonging to the Sphingomonadaceae, Comamonadaceae, and Oxalobacteraceae. Resuscitation led to dynamic shifts in the rank abundance of taxa that caused previously rare bacteria to comprise nearly 60% of the sequences that were recovered in rewetted communities. This rapid turnover of the bacterial community corresponded with a 5-20-fold increase in the net production of CO2 and up to a 150% reduction in the net production of CH4 from rewetted soils. Results from our study demonstrate that the rare biosphere may account for a large and dynamic fraction of a community that is important for the maintenance of bacterial biodiversity. Moreover, our findings suggest that the resuscitation of rare taxa from seed banks contribute to ecosystem functioning.Frontiers in Microbiology 01/2015; 6:24. DOI:10.3389/fmicb.2015.00024 · 3.94 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Symbiotic associations can be disrupted by disturbance or by changing environmental conditions. Endophytes are fungal and bacterial symbionts of plants that can affect performance. As in more widely known symbioses, acute or chronic stressor exposure might trigger disassociation of endophytes from host plants. We tested this hypothesis by examining the effects of oil exposure following the Deepwater Horizon (DWH) oil spill on endophyte diversity and abundance in Spartina alterniflora - the foundational plant in northern Gulf coast salt marshes affected by the spill. We compared bacterial and fungal endophytes isolated from plants in reference areas to isolates from plants collected in areas with residual oil that has persisted for more than three years after the DWH spill. DNA sequence-based estimates showed that oil exposure shifted endophyte diversity and community structure. Plants from oiled areas exhibited near total loss of leaf fungal endophytes. Root fungal endophytes exhibited a more modest decline and little change was observed in endophytic bacterial diversity or abundance, though a shift towards hydrocarbon metabolizers was found in plants from oiled sites. These results show that plant-endophyte symbioses can be disrupted by stressor exposure, and indicate that symbiont community disassembly in marsh plants is an enduring outcome of the DWH spill.PLoS ONE 04/2015; 10(4):e0122378. DOI:10.1371/journal.pone.0122378 · 3.53 Impact Factor