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Ammonia‐oxidizing B acteria of the N itrosospira cluster 1 dominate over ammonia‐oxidizing A rchaea in oligotrophic surface sediments near the S outh A tlantic G yre
Author(s) -
Lagostina Lorenzo,
Goldhammer Tobias,
Røy Hans,
Evans Thomas W.,
Lever Mark A.,
Jørgensen Bo B.,
Petersen Dorthe G.,
Schramm Andreas,
Schreiber Lars
Publication year - 2015
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12264
Subject(s) - ammonia monooxygenase , upwelling , ammonium , sediment , transect , archaea , bacterioplankton , oceanography , environmental chemistry , anoxic waters , biology , anammox , ocean gyre , ecology , subtropics , chemistry , phytoplankton , denitrification , bacteria , geology , nitrogen , nutrient , paleontology , denitrifying bacteria , organic chemistry , genetics
Summary Sediments across the N amibian 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 S outh A tlantic G yre 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 N amibian shelf by analysing their respective ammonia monooxygenase genes ( amoA ). The relative abundance of archaeal and bacterial amoA (g −1 DNA ) decreased with increasing ammonium concentrations, and bacterial amoA frequently outnumbered archaeal amoA 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 N itrososphaera and N itrosopumilus clusters in the upwelling region. AOB almost exclusively belonged to the N itrosospira 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.