Title

Bacterial community dynamics in the hyporheic zone of an intermittent stream

Author ORCID Identifier

https://orcid.org/0000-0002-3570-3588 : Catherine Febria

Document Type

Article

Publication Date

5-1-2012

Publication Title

ISME Journal

Volume

6

Issue

5

First Page

1078

Keywords

bacterial communities, hyporheic zone, intermittent streams, operational taxonomic unit (OTU), stream sediments, terminal-restriction fragment length polymorphism (T-RFLP)

Last Page

1088

Abstract

The dynamics of in situ bacterial communities in the hyporheic zone of an intermittent stream were described in high spatiotemporal detail. We assessed community dynamics in stream sediments and interstitial pore water over a two-year period using terminal-restriction fragment length polymorphism. Here, we show that sediments remained saturated despite months of drought and limited hydrologic connectivity. The intermittency of stream surface water affected interstitial pore water communities more than hyporheic sediment communities. Seasonal changes in bacterial community composition was significantly associated with water intermittency, phosphate concentrations, temperature, nitrate and dissolved organic carbon (DOC) concentrations. During periods of low- to no-surface water, communities changed from being rich in operational taxonomic units (OTUs) in isolated surface pools, to a few OTUs overall, including an overall decline in both common and rare taxa. Individual OTUs were compared between porewater and sediments. A total of 19% of identified OTUs existed in both porewater and sediment samples, suggesting that bacteria use hyporheic sediments as a type of refuge from dessication, transported through hydrologically connected pore spaces. Stream intermittency impacted bacterial diversity on rapid timescales (that is, within days), below-ground and in the hyporheic zone. Owing to the coupling of intermittent streams to the surrounding watershed, we stress the importance of understanding connectivity at the pore scale, consequences for below-ground and above-ground biodiversity and nutrient processing, and across both short- and long-time periods (that is, days to months to years). © 2012 International Society for Microbial Ecology All rights reserved.

DOI

10.1038/ismej.2011.173

ISSN

17517362

E-ISSN

17517370

PubMed ID

22158391

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