Bacterial community of oolitic carbonate sediments of the Bahamas Archipelago

Abstract

The present study characterized bacterial communities associated with oolitic carbonate sediments from the Bahamas Archipelago, ranging from high-energy 'active' to lower energy 'non-active' and 'mat-stabilized' environments. Bacterial communities were analyzed using terminal restriction fragment length polymorphisms (TRFLP), clone analyses of the 16S rRNA gene, confocal laser scanning microscopy (CLSM) and the quantitative phenol-sulfuric acid assay for extracellular polymeric substances (EPS). Confocal imaging of oolitic grains stained with cyanine dye-conjugated lectin and EPS quantification demonstrated that all 3 environments harbored attached biofilm communities, but densities increased from the active to the mat-stabilized environment. Bacterial communities associated with all 3 settings were highly diverse and dominated by Proteobacteria (50 to 61%). Analysis of similarity (ANOSIM) and similarity percentages (SIMPER) revealed significant differences among the 3 environments in the relative abundance of Proteobacteria, Planctomycetes, Cyanobacteria, Chlorobi, and Deinococcus-Thermus. Bacterial primary production in the active shoal environment was associated with Rhodobacteraceae, Ectothiorhodospiraceae, and Chlorobi, whereas the lower energy environments appear to harbor a more complex consortium of aerobic photoautotrophs and anaerobic/aerobic anoxygenic phototrophs. The ubiquitousness of photosynthetizers, along with the presence of aerobic/anaerobic heterotrophic microbes (e.g. denitrifiers, sulfate-reducers, biofilm producers/degraders) and the gradient increase in biofilm production on ooid grains from active to mat-stabilized environments, support the potential involvement of these communities in biomineralization and carbonate precipitation.KEY WORDS: Ooids · Carbonate sediment · Carbonate precipitation · 16S rRNA diversity · Bacterial community · Biofilm Resale or republication not permitted without written consent of the publisher Editorial responsibility: Ronald Kiene,

Functional gene diversity of oolitic sands from Great Bahama Bank

“…This is in agreement with Diaz et al . (), who documented a similar diversity trend using clone libraries of the 16S rRNA gene in the oolitic sediments of the Bahamas. The average Shannon–Weaver functional diversity index [H = 9.14], although lower than in the mangrove sediments from South China [average: H = 10.22] (Bai et al ., ), surpasses the levels reported by others using similar technology in the sediments from the Gulf of Mexico [average: H = 5.23] (Wu et al ., ) and Juan de Fuca hydrothermal vents [average: H = 5.75] (Wang et al ., ).…”

“…These findings are supported by Diaz et al . (), who documented similar taxonomic composition of primary producers in oolitic sediments from the Bahamas using terminal fragment length polymorphism (TRFLPs) and 16S rRNA clone analysis. Based on the ubiquitous presence of both oxygenic and anoxygenic phototrophs, all of which can drive the alkalinity toward carbonate precipitation by consuming CO 2 and increasing local pH (Bosak et al ., ; Dupraz et al ., ), we can infer these communities could have metabolic capabilities for carbonate precipitation as documented in systems, such as microbialites (Breitbart et al ., ); stromatolites (Dupraz & Visscher, ); and fresh‐water ooids (Pacton et al ., ).…”

“…Apart from recent molecular phylogenetic studies that shows marine oolitic grains harbor a remarkably diverse bacterial community, represented by Proteobacteria within the Alpha ‐ , Delta‐ and Gamma ‐lineages, Cyanobacteri a, Planctomycetes , and several other groups (Diaz et al ., ; Edgcomb et al ., ), little is known about the functional gene diversity and metabolic potential of these communities. To circumvent this, we employ a functional gene microarray, geochip 4.2 as well as EPS analysis on oolitic grains from high‐energy ‘active’ environments (tidal currents) to lower energy ‘non‐active’ and ‘microbially stabilized’ environments of the Bahamas.…”

Co‐existence of skeletal and ooid shoals as a result of antecedent topography—Cat cay shoal complex, Bahamas

“…Recently the change from skeletal to ooid formation has been considered an indicator of an environmental crisis caused by anoxic events based on the fact that microbial carbonates are indicators of environmental change (Whalen, Day, Eberli, & Homewood, ). The ooids in the Cat Cay ooid shoal harbour, like all ooids on Great Bahama Bank, a highly diverse microbial community with capabilities of carbonate precipitation (Diaz, Piggot, Eberli, & Klaus, ; Diaz et al, , ; Diaz, Eberli, Blackwelder, Phillips, & Swart, ; Edgcomb et al, ; O’Reilly et al, ). Microbial activities in tandem with the physicochemical conditions of the extracellular polymeric substances micro‐domains control the organomineralization processes in ooids through two distinct avenues: biologically induced and biologically influenced mechanisms (Diaz & Eberli, ; Harris et al, ).…”

Comments on "Estimating the impact of early diagenesis on isotope records in shallow-marine carbonates: A case study from the Urgonian platform in western Swiss Jura" by A. Godet et al. [Palaeogeography Palaeoclimatology Palaeoecology 454 (2016) 125-138]

“…There is evidence that microbial processes are actively involved at various stages in their mineralization (BREHM et al, 2004;EDGCOMB et al, 2013;DIAZ et al, 2013DIAZ et al, , 2014DIAZ et al, , 2015O'REILLY et al, 2016). For instance, some microbes may promote mineralization of ooids that takes place in extracellular polymeric substances (EPS) whereas others may alter the original mineralization of ooid cortices (DUGUID et al, 2010).…”