Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

Abstract

Abstract. An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and Halobacteria) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria within Proteobacteria phylum, and also members of Bacteroidetes phylum. The second most abundant lineages were Actinobacteria and Firmicutes at the Gulf of Lion site and Chloroflexi at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: Alpha-, Gammaproteobacteria, Firmicutes and Actinobacteria. In molecular surveys, the Betaproteobacteria group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea levee. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were Bacteroidetes and, to a lesser extent, Betaproteobacteria. At both site, the detection of Betaproteobacteria coincided with increased terrestrial Published by Copernicus Publications on behalf of the European Geosciences Union. 3492M.-C. Ciobanu et al.: Sedimentological imprint on subseafloor microbial communities inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary.

Effect of Sewage and Industrial Effluents on Bacterial and Archaeal Communities of Creek Sediments in the Taihu Basin

“…Halobacteria belonging to the phylum Euryarchaeota was dominant at all sites of both creeks, and showed no significant positive correlation with the environmental factors. However, previous studies indicated that Halobacteria exists in highly saline aquatic environments [87,88]. The second most abundant archaea in the sediment of the two creeks belonged to Thaumarchaeota.…”

Effect of wastewater disposal on the bacterial and archaeal community of sea sediment in an industrial area in China

“…In the three WWTPs, all the dominant classes belong to the phylum Euryarchaeota . The dominant class at GB and SY, Methanomicrobia , exists widely in wastewater treatment systems (Lin et al ., ; Shi et al ., ; Dungan & Leytem, ) and certain freshwater environments (Green et al ., ); the dominant class at YT (with 20 g L −1 sulfate in the aerobic tank), Halobacteria , is habituated to high‐salinity aquatic environments, such as the ocean (Yan et al ., ; Dorador et al ., ; Ciobanu et al ., ) and salt ponds (Moune et al ., ). In the effluent‐receiving area at HZW, the first dominant class, Marine_Group_I , is classified in the phylum Thaumarchaeota , and commonly exists in the marine environment (Durbin & Teske, ; Nitahara et al ., ; Giovannelli et al ., ); the second dominant class, Thermoplasmata , is classified in the phylum Euryarchaeota , and is regarded as methanogenic Archaea (Iino et al ., ) found in shallow marine areas (Schneider et al ., ).…”

Holocene paleodepositional changes reflected in the sedimentary microbiome of the Black Sea

“…For example, microbial life in 20‐Ma‐old coal‐bearing sediments located up to 2.5 km below the ocean floor was found to resemble organotrophic bacterial communities typically found in forest soils (Inagaki et al., ). Similarly, microbial communities likely of terrestrial origin were recovered from Mediterranean turbidites (Ciobanu et al., ). Downcore changes in microbial communities in radiocarbon‐dated Baltic Sea sediments were shown to mirror temporal changes in sea surface salinity (Lyra, Sinkko, Rantanen, Paulin, & Kotilainen, ).…”