Diversity patterns of benthic bacterial communities along the salinity continuum of the Humber estuary (UK)

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Vidal-Durà, A., Burke, I.T., Mortimer, R.J.G. ORCID: 0000-0003-1292-8861 and Stewart, D.I., 2018. Diversity patterns of benthic bacterial communities along the salinity continuum of the Humber estuary (UK). Aquatic Microbial Ecology, 81 (3), pp. 277-291. ISSN 0948-3055

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Official URL: http://doi.org/10.3354/ame01875

Abstract

Sediments from intertidal mudflats are fluctuating environments that support very diverse microbialcommunities. The highly variable physicochemical conditions complicate the understanding of the environmental controls on diversity patterns in estuarine systems. This study investigated bacterial diversity and community composition in surface (0-1 cm) and subsurface (5-10 cm) sediments along the salinity gradient of the Humber estuary (UK) using amplicon sequencing of the 16S rRNA gene, and it correlates variations with environmental variables. The sediment depths sampled were selected based on the local remobilisation frequency patterns. In general, bacterial communities showed similar composition at the different sites and depths, with Proteobacteria being the most abundant phylum. Richness of operationally defined taxonomic units (OTUs) was uniform along the Microbial Diversity of the Humber Estuary salinity gradient. However, Hill numbers, as bacterial diversity measures, showed that the common and dominant OTUs exhibited a decreasing trend from the inner towards the outer estuary sites. Additionally, surface and subsurface bacterial communities were separated by NMDS analysis only in the mid and outer estuary samples, where redox transitions with depth in the sediment profile were more abrupt. Salinity, porewater ammonium concentrations and reduced iron concentrations were the subset of environmental factors that best correlated with community dissimilarities. The analysis of the regional diversity indicated that the dataset may include two potentially distinct communities. These are a near surface community that is the product of regular mixing and transport which is subjected to a wide range of salinity conditions, and thus contains decreasing numbers of common and dominant OTUs seawards, and a bacterial community indigenous to the more reducing subsurface sediments of the mid and outer mudflats of the Humber estuary.

Item Type:

Journal article

Publication Title:

Aquatic Microbial Ecology

Creators:

Vidal-Durà, A., Burke, I.T., Mortimer, R.J.G. and Stewart, D.I.

Publisher:

Inter-Research

Date:

2018

Volume:

Number: