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Updated: Feb 22, 2026

Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors
Published on: December 6, 2018
nirS-type denitrifying bacterial assemblages respond to environmental conditions of a shallow estuary
Jessica A Lisa1, Amal Jayakumar2, Bess B Ward2
1Department of Biological Sciences, Virginia Institute of Marine Science, College of William & May, Gloucester Point, VA, USA.
Abstract:
Molecular analysis of dissimilatory nitrite reductase genes (nirS) was conducted using a customized microarray containing 165 nirS probes (archetypes) to identify members of sedimentary denitrifying communities. The goal of this study was to examine denitrifying community responses to changing environmental variables over spatial and temporal scales in the New River Estuary (NRE), NC, USA. Multivariate statistical analyses revealed three denitrifier assemblages and uncovered 'generalist' and 'specialist' archetypes based on the distribution of archetypes within these assemblages. Generalists, archetypes detected in all samples during at least one season, were commonly world-wide found in estuarine and marine ecosystems, comprised 8%-29% of the abundant NRE archetypes. Archetypes found in a particular site, 'specialists', were found to co-vary based on site specific conditions. Archetypes specific to the lower estuary in winter were designated Cluster I and significantly correlated by sediment Chl a and porewater Fe2+ . A combination of specialist and more widely distributed archetypes formed Clusters II and III, which separated based on salinity and porewater H2 S respectively. The co-occurrence of archetypes correlated with different environmental conditions highlights the importance of habitat type and niche differentiation among nirS-type denitrifying communities and supports the essential role of individual community members in overall ecosystem function.
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