Ammonia‐oxidizing Bacteria of the Nitrosospira cluster 1 dominate over ammonia‐oxidizing Archaea in oligotrophic surface sediments near the South Atlantic Gyre. Issue 3 (8th April 2015)

• Record Type: Journal Article
• Authors: Lagostina, Lorenzo; Goldhammer, Tobias; Røy, Hans; Evans, Thomas W.; Lever, Mark A.; Jørgensen, Bo B.; Petersen, Dorthe G.; Schramm, Andreas; Schreiber, Lars
• Is Part Of: Environmental microbiology reports. Volume 7:Issue 3(2015)
• Page Start: 404
• Page End: 413
• Publication Date: 2015-04-08
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; Electronic journals; 579.17
• DOI: 10.1111/1758-2229.12264
• Languages: English
• ISSNs: 1758-2229

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>Sediments across the Namibian continental margin feature a strong microbial activity gradient at their surface. This is reflected in ammonium concentrations of < 10 μM in oligotrophic abyssal plain sediments near the South Atlantic Gyre compared with ammonium concentrations of > 700 μM in upwelling areas near the coast. Here we address changes in apparent abundance and structure of ammonia‐oxidizing archaeal and bacterial communities (AOA and AOB) along a transect of seven sediment stations across the Namibian shelf by analysing their respective ammonia monooxygenase genes (<italic>amoA</italic>). The relative abundance of archaeal and bacterial <italic>amoA</italic> (g<sup>−1</sup> DNA) decreased with increasing ammonium concentrations, and bacterial <italic>amoA</italic> frequently outnumbered archaeal <italic>amoA</italic> at the sediment–water interface [0–1 cm below seafloor (cmbsf)]. In contrast, AOA were apparently as abundant as AOB or dominated in several deeper (> 10 cmbsf), anoxic sediment layers. Phylogenetic analyses showed a change within the AOA community along the transect, from two clusters without cultured representatives at the gyre to <italic>N</italic><italic>itrososphaera</italic> and <italic>N</italic><italic>itrosopumilus</italic> clusters in the upwelling region. AOB almost exclusively belonged to the <italic>N</italic><italic>itrosospira</italic> cluster 1. Our results suggest that this predominantly marine AOB lineage without cultured representatives can thrive at low ammonium concentrations and is active in the marine nitrogen cycle.</p> </abstract>