Dataset Information

Seamount sheath water: years-long retention of deep-ocean water traced by bacterioplankton

ABSTRACT: 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.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Unidentified Marine Bacterioplankton

SUBMITTER: Minia Antelo

LAB HEAD: Dörte Becher

PROVIDER: PXD016702 | Pride | 2020-05-27

REPOSITORIES: Pride

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Publications

Bacterioplankton reveal years-long retention of Atlantic deep-ocean water by the Tropic Seamount.

Giljan Greta G Kamennaya Nina A NA Otto Andreas A Becher Dörte D Ellrott Andreas A Meyer Volker V Murton Bramley J BJ Fuchs Bernhard M BM Amann Rudolf I RI Zubkov Mikhail V MV

Scientific reports 20200313 1

Seamounts, often rising hundreds of metres above surrounding seafloor, obstruct the flow of deep-ocean water. While the retention of deep-water by seamounts is predicted from ocean circulation models, its empirical validation has been hampered by large scale and slow rate of the interaction. To overcome these limitations we use the growth of planktonic bacteria to assess the retention time of deep-ocean water by a seamount. The selected Tropic Seamount in the North-Eastern Atlantic is representa ...[more]

PMID: 32170218

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Dataset Information

Seamount sheath water: years-long retention of deep-ocean water traced by bacterioplankton

Publications

Bacterioplankton reveal years-long retention of Atlantic deep-ocean water by the Tropic Seamount.

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