Correlating microbial community profiles with geochemical data in highly stratified sediments from the Arctic Mid-Ocean Ridge

Abstract

Microbial communities and their associated metabolic activity in marine sediments have a profound impact on global biogeochemical cycles. Their composition and structure are attributed to geochemical and physical factors, but finding direct correlations has remained a challenge. Here we show a significant statistical relationship between variation in geochemical composition and prokaryotic community structure within deep-sea sediments. We obtained comprehensive geochemical data from two gravity cores near the hydrothermal vent field Loki's Castle at the Arctic Mid-Ocean Ridge, in the Norwegian-Greenland Sea. Geochemical properties in the rift valley sediments exhibited strong centimeter-scale stratigraphic variability. Microbial populations were profiled by pyrosequencing from 15 sediment horizons (59,364 16S rRNA gene tags), quantitatively assessed by qPCR, and phylogenetically analyzed. Although the same taxa were generally present in all samples, their relative abundances varied substantially among horizons and fluctuated between Bacteria-and Archaea-dominated communities. By independently summarizing covariance structures of the relative abundance data and geochemical data, using principal components analysis, we found a significant correlation between changes in geochemical composition and changes in community structure. Differences in organic carbon and mineralogy shaped the relative abundance of microbial taxa. We used correlations to build hypotheses about energy metabolisms, particularly of the Deep Sea Archaeal Group, specific Deltaproteobacteria, and sediment lineages of potentially anaerobic Marine Group I Archaea. We demonstrate that total prokaryotic community structure can be directly correlated to geochemistry within these sediments, thus enhancing our understanding of biogeochemical cycling and our ability to predict metabolisms of uncultured microbes in deep-sea sediments.taxonomic profiling | ultraslow-spreading ridge | amplicon sequencing

Bacterial composition and spatiotemporal variation in sediments of Jiaozhou Bay, China

“…Certain geochemical background, such as sediment NH 3 , OrgC (Jorgensen et al 2012) and OrgN , mineral (Jorgensen et al 2012), salinity (Bolhuis and Stal 2011), and pH ; and many sedimentological factors, such as median grain size (Jackson and Weeks 2008) and the electrical conductivity, had also been identified as potentially the key regulators of the bacterial composition, community structure, abundance, and distribution in the marine sediment. Dang et al (2010a) found that the sedimentological factors dominated the geochemical and physicochemical factors for the distinction of sediment anammox bacterial community between station B2 and D1 in Jiaozhou Bay, and have significant impacts on the spatial distribution between B2 and the other stations.…”

The influence of vent systems on pelagic eukaryotic micro-organism composition in the Nordic Seas

“…4). Sea water and plume chemistry have been investigated thoroughly in other studies (Pedersen et al 2005;Sauter et al 2006;Pedersen et al 2010a;Schander et al 2010;Baumberger 2011;Tandberg et al 2011;Jørgensen et al 2012;Kongsrud and Rapp 2012;Stensland 2013), and further discussion related to chemistry will therefore follow below. Five groups dominated the three different water masses (Alveolata, Rhizaria, Protozoa, Metazoa and Heterokonta), but the internal proportion within a given sample varied.…”

“…Indeed, vent and seep systems can have a high productivity, both benthic and pelagic, compared to the surrounding water masses (Van Dover(2005) and Loki's Castle (2008); in addition, the cold seep Håkon Mosby Mud Volcano was included based on the high methane concentrations in the water column (online resource 2). Since the discovery, several studies (Pedersen et al 2005(Pedersen et al , 2010aLichtschlag et al 2010;Schander et al 2010;Baumberger 2011;Tandberg et al 2011;Jørgensen et al 2012;Kongsrud and Rapp 2012;Stensland 2013) have described the geochemistry, benthic fauna and prokaryote sediment community of both the hydrothermal vents and Håkon Mosby Mud Volcano. However, the protist community in these systems remains largely undescribed despite its importance as a link towards higher trophic levels.…”

River organic matter shapes microbial communities in the sediment of the Rhône prodelta

“…Organic carbon is one of the most fundamental factors shaping marine sediment microbial communities (Jorgensen et al, 2012). However, sediment organic matter (OM) is a complex and heterogeneous mixture of high-and low-molecular-weight organic carbon compounds derived from multiple sources (for example, marine or terrestrial) at different states of degradation.…”