Responses of microbial activity in hyporheic pore water to biogeochemical changes in a drying headwater stream
dc.contributor.author
dc.date.accessioned
2020-06-16T11:38:14Z
dc.date.available
2020-06-16T11:38:14Z
dc.date.issued
2019-04
dc.identifier.issn
0046-5070
dc.identifier.uri
dc.description.abstract
1. Microbial heterotrophic activity is a major driver of nutrient and organic matter
processing in the hyporheic zone of headwater streams. Additionally, the hypor‐
heic zone might provide refuge for microbes when surface flow ceases during
drought events.
2. We investigated chemical (organic and inorganic nutrients) and microbiological
parameters (bacterial cell concentration, live–dead ratios, and extracellular en‐
zyme activities) of surface and interstitial pore water in a period of progressive
surface-hyporheic disconnection due to summer drying. The special situation of
the chosen study reach, where groundwater mixing is impeded by the bedrock
forming a natural channel filled with sediment, allowed as to study the transfor‐
mation of these parameters along hyporheic flow paths.
3. The chemical composition of the hyporheic pore water reflected the connectivity
with the surface water, as expressed in the availability of nitrate and oxygen.
Conversely, microbiological parameters in all hyporheic locations were different
from the surface waters, suggesting that the microbial activity in the water
changes rapidly once the water enters the hyporheic zone. This feature was prin‐
cipally manifested in higher live–dead ratios and lower leucine aminopeptidase (an
activity related to nitrogen acquisition) in the hyporheic pore waters.
4. Overall, bacterial cell concentration and extracellular enzyme activities increased
along hyporheic flow paths, with a congruent decrease in inorganic nutrients and
dissolved organic matter quantity and apparent molecular size.
5. Our findings show two important functions of the hyporheic zone during drought: (1)
deeper (−50 cm) water-saturated layers can act as a refuge for microbial activity; and
(2) the hyporheic zone shows high rates of carbon and nitrogen turnover when water
residence times are longer during drought. These rates might be even enhanced by
an increase in living microbes in the remaining moist locations of the hyporheic zone
dc.description.sponsorship
FP7 People: Marie-Curie Actions, Grant/ Award Number: 607150; FP7 Environment, Grant/Award Number: 603629-ENV-6.2.1
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
Wiley
dc.relation.isformatof
Reproducció digital del document publicat a: https://doi.org/10.1111/fwb.13258
dc.relation.ispartof
Freshwater Biology, 2019, vol. 64, núm. 4, p. 735-749
dc.relation.ispartofseries
Articles publicats (D-CCAA)
dc.rights
Attribution 4.0 International
dc.rights.uri
dc.subject
dc.title
Responses of microbial activity in hyporheic pore water to biogeochemical changes in a drying headwater stream
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/openAccess
dc.relation.projectID
info:eu-repo/grantAgreement/EC/FP7/603629/EU/MANAGING THE EFFECTS OF MULTIPLE STRESSORS ON AQUATIC ECOSYSTEMS UNDER WATER SCARCITY/GLOBAQUA
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.identifier.idgrec
031612
dc.type.peerreviewed
peer-reviewed
dc.relation.FundingProgramme
dc.relation.ProjectAcronym
dc.identifier.eissn
1365-2427