Similar Datasets
Project description:Seamounts, often rising hundreds of metres above the surrounding seafloor, obstruct the flow of deep-ocean water. While the resultant entrainment of deep-water by seamounts is predicted from ocean circulation models, its empirical validation has been hampered by the large scale and slow rate of the interaction. To overcome these limitations we use the growth of planktonic bacteria to assess the interaction rate. The selected study site, Tropic Seamount, in the North-Eastern Atlantic represents the majority of isolated seamounts, which do not affect the surface ocean waters. We prove deep-water is entrained by the seamount by measuring 2.3 times higher bacterial concentrations in the seamount-associated or ‘sheath’ water than in deep-ocean water unaffected by seamounts. Genomic analyses of the dominant sheath-water bacteria confirm their planktonic origin, whilst proteomic analyses indicate their slow growth. According to our radiotracer experiments, the doubling time of sheath-water bacterioplankton is 1.5 years. Therefore, for bacterioplankton concentration to reach 2.3 times higher in the ambient seawater, the seamount would need to retain deep-ocean water for more than 3.5 years. We propose that turbulent mixing of the retained sheath-water could stimulate bacterioplankton growth by increasing the cell encounter rate with the ambient dissolved organic molecules. If some of these molecules chelate hydroxides of iron and manganese, bacterioplankton consumption of the organic chelators would result in precipitation of insoluble hydroxides. Hence precipitated hydroxides would form ferromanganese deposits as a result of the bacterioplankton-mediated deep-water seamount interaction.
2020-05-27 | PXD016702 | Pride
Project description:Polyamines, such as putrescine and spermidine, are aliphatic organic compounds with multiple amino groups. They are found ubiquitously in marine systems. However, compared with the extensive studies on the concentration and fate of other dissolved organic nitrogen compounds in seawater, such as dissolved free amino acids (DFAA), investigations of bacterially-mediated polyamine transformations have been rare. Bioinformatic analysis identified genes encoding polyamine transporters in 74 of 109 marine bacterial genomes surveyed, a surprising frequency for a class of organic nitrogen compounds not generally recognized as an important source of carbon and nitrogen for marine bacterioplankton. The genome sequence of marine model bacterium Silicibacter pomeroyi DSS-3 contains a number of genes putatively involved in polyamine use, including six four-gene ATP-binding cassette transport systems. In the present study, polyamine uptake and metabolism by S. pomeroyi was examined to confirm the role of putative polyamine-related genes, and to investigate how well current gene annotations reflect function. A comparative whole-genome microarray approach (Bürgmann et al., 2007) allowed us to identify key genes for transport and metabolism of spermidine in this bacterium, and specify candidate genes for in situ monitoring of polyamine transformations in marine bacterioplankton communities.
2008-12-31 | GSE13781 | GEO
Project description:Supplementary raw metabolomics files for "Ecological stochasticity and phage induction diversify bacterioplankton communities at the microscale," Rachel E. Szabo et al.
2021-09-24 | MSV000088151 | MassIVE
Project description:<p>Marine dissolved organic matter (DOM) varies in its recalcitrance to rapid microbial degradation. DOM of varying recalcitrance can be exported from the ocean surface to depth by subduction or convective mixing and oxidized over months to decades in deeper seawater. Carboxyl-rich alicyclic molecules (CRAM) are characterized as a major component of recalcitrant DOM throughout the oceanic water column. The oxidation of CRAM-like compounds may depend on specific bacterioplankton lineages with oxidative enzymes capable of catabolizing complex molecular structures like long-chain aliphatics, cyclic alkanes, and carboxylic acids. To investigate the interaction between bacteria and CRAM-like compounds, we conducted microbial remineralization experiments using several compounds rich in carboxyl groups and/or alicyclic rings, including deoxycholate, humic acid, lignin, and benzoic acid, as proxies for CRAM. Mesopelagic seawater (200 m) from the northwest Sargasso Sea was used as media and inoculum and incubated over 28 days. All amendments demonstrated significant DOC removal (2 – 11 µmol C L-1) compared to controls. Bacterioplankton abundance increased significantly in the deoxycholate and benzoic acid treatments relative to controls, with fast-growing <em>Spongiibacteracea</em>, <em>Euryarcheaota</em>, and slow-growing SAR11 enriched in the deoxycholate treatment and fast-growing <em>Alteromonas</em>, <em>Euryarcheaota</em>, and <em>Thaumarcheaota</em> enriched in the benzoic acid treatment. In contrast, bacterioplankton grew slower in the lignin and humic acid treatments, with oligotrophic SAR202 becoming significantly enriched in the lignin treatment. Our results indicate that the character of the CRAM proxy compounds resulted in distinct bacterioplankton removal rates and affected specific lineages of bacterioplankton capable of responding.</p>
2024-02-20 | MTBLS3512 | MetaboLights