Title

Characterizing seasonal changes in physicochemistry and bacterial community composition in hyporheic sediments

Author ORCID Identifier

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

Document Type

Article

Publication Date

6-1-2010

Publication Title

Hydrobiologia

Volume

647

Issue

1

First Page

113

Keywords

Bacterial community composition, Dissolved organic carbon, Hyporheic zone, Microbial ecology, Physicochemistry, Stream sediments, TRFLP

Last Page

126

Abstract

The hyporheic zone of stream ecosystems is a critical habitat for microbial communities. However, the factors influencing hyporheic bacterial communities along spatial and seasonal gradients remain poorly understood. We sought to characterize patterns in bacterial community composition among the sediments of a small stream in southern Ontario, Canada. We used sampling cores to collect monthly hyporheic water and sediment microbial communities in 2006 and 2007. We described bacterial communities terminal-restriction fragment length polymorphism (TRFLP) and tested for spatial and seasonal relationships with physicochemical parameters using multivariate statistics. Overall, the hyporheic zone appears to be a DOC, oxygen, and nitrogen sink. Microbial communities were distinct from those at the streambed surface and from soil collected in the adjacent watershed. In the sediments, microbial communities were distinct between the fall, spring, and summer seasons, and bacterial communities were more diverse at streambed surface and near-surface sites compared with deeper sites. Moreover, bacterial communities were similar between consecutive fall seasons despite shifting throughout the year, suggesting recurring community assemblages associated with season and location in the hyporheic zone. Using canonical correspondence analysis, seasonal patterns in microbial community composition and environmental parameters were correlated in the following way: temperature was related to summer communities; DOC (likely from biofilm and allochthonous inputs) influenced most fall communities; and nitrogen associated strongly with winter and spring communities. Our results also suggest that labile DOC entering the hyporheic zone occurred in concert with shifts in the bacterial community. Generally, seasonal patterns in hyporheic physicochemistry and microbial biodiversity remain largely unexplored. Therefore, we highlight the importance of seasonal and spatial resolution when assessing surface- and groundwater interactions in stream ecosystems. © Springer Science+Business Media B.V. 2009.

DOI

10.1007/s10750-009-9882-x

ISSN

00188158

E-ISSN

15735117

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