Spatiotemporal heterogeneity of actual and potential respiration in two contrasting floodplains

Mori, Nataša; Simčić, Tatjana; Brancelj, Anton; Robinson, Christopher T.; Doering, Michael

doi:10.1002/hyp.11211

Cited by 10 publications

(2 citation statements)

References 76 publications

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“…As previously reported, streambed sediments are completely exposed to the atmosphere under persistent dry conditions and may acquire characteristics similar to those of the adjacent soils (Steward et al ., ; Morandi et al ., ; Arce et al ., ). A longer dry phase and modifications in the frequency of the dry–wet cycle in river ecosystems often determine the degree of similarity between streambed and terrestrial habitats (Harms and Grimm, ; Mori et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Multi‐model assessment of hydrological and environmental impacts on streambed microbes in Mediterranean catchments

Gionchetta

Artigas

Arias-Real

et al. 2020

Environmental Microbiology

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Summary Microbes inhabiting intermittent streambeds are responsible for controlling and developing many biogeochemical processes essential for the ecosystem functions. Although streambed microbiota is adapted to intermittency the intensification of water scarcity and prolonged dry periods may jeopardise their capacity to cope with hydrological changes. This study aims to evaluate whether, and to what extent, the duration of dry periods affects streambed microbial density, diversity, composition (16S rRNA gene diversity) and functions (extracellular enzyme activities and respiration). Our results highlight the fact that hydrology modulates the community composition and, to some extent, the functions carried out under different environmental conditions. The relative abundance of certain taxa inhabiting the driest intermittent communities differs significantly from those found at sites with continuous flow. Microbial functional metrics revealed a progressive increase in recalcitrant carbon degradation activity at sites with an extended dry phase. In contrast, bacterial density and diversity were mainly influenced by the catchment land use, agriculture enhanced density but reduced diversity, and the presence of riparian vegetation supported greater streambed bacterial diversity. From this perspective, a combination of prolonged dryness with reduced riparian vegetation and increased agricultural land cover could compromise the ecosystem functioning by threaten microbially mediated processes linked to the carbon cycle.

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Section: Discussionmentioning

confidence: 97%

Multi‐model assessment of hydrological and environmental impacts on streambed microbes in Mediterranean catchments

Gionchetta

Artigas

Arias-Real

et al. 2020

Environmental Microbiology

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show abstract

“…As intermittent streams dry out, streambeds becomes "terrestrialized" by acquiring structural and functional features of the nearby soils (Arce et al 2019), the similarity likely depending on the duration of the dry phase and inundation frequency (Harms and Grimm 2012;Mori et al 2017). Whether such convergence of conditions directs similar decomposition dynamics is largely unknown.…”

Section: Introductionmentioning

confidence: 99%

Annual patterns of litter decomposition in the channel and riparian areas of an intermittent stream

et al. 2021

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Intermittent streams, dominant in arid and semi-arid regions, are suggested to be more representative of the global river network than perennial rivers. Even so, the impacts of constant changes in hydrological regime on the functioning of these streams and riparian areas remain to be elucidated. In this study, two native deciduous litter species were used to compare microbialdecomposition patterns between the channel of an intermittent stream and its riparian area over one year. Overall, the stream channel presented higher decomposition rates and fungal biomass than the riparian area, for both litter species. Despite a prolonged absence of streambed surface water (254 days), differences in hydrological conditions in the wetter seasons (autumn and winter) led to lingering effects, shaping and differentiating decomposition dynamics in both zones throughout the whole hydrological cycle. As the present results highlight the importance of the "hydrological imprint" for the leaves degradation process, long term studies seem to be advisable over short-term ones to better understand the functioning of intermittent streams.

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Response of hyporheic biofilms to temperature changes and dissolved organic carbon enrichment: a mesocosm study

Simčič,

Poklukar,

Mori

2024

J Soils Sediments

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Purpose Hyporheic biofilms are the central site for biogeochemical cycling in streams and rivers. In view of global warming and increasing human pressures, this study aimed to compare the response of hyporheic biofilm biomass and activities from an unpolluted reference stream reach surrounded by forest with those from a stream reach exposed to agricultural and urban land use using a mesocosm experiment in which the water temperature and dissolved organic carbon (DOC) contents were manipulated. Methods Hyporheic sediments collected in the field from the two study reaches (i.e. reference and impacted) were incubated in the laboratory at two different temperatures (10 °C, 14 °C) and wetted with three types of synthetic water (control [C] – 0 mg L−1; low DOC – 5 mg L−1; high DOC – 30 mg L−1) for four weeks. The responses of the hyporheic biofilms were measured weekly using structural (total protein content [TPC] as a proxy for biofilm biomass) and functional measures (electron transport system activity [ETSA] and community-level physiological profiling [CLPP]). Results The response of hyporheic biofilms to temperature changes and DOC enrichment was site-specific for all studied measures (TPC, ETSA and CLPP, including measured average well colour development [AWCD]). The addition of DOC to biofilms from the pristine stream reach significantly heightened the responses at 10 °C, a temperature within the normal environmental temperature ranges of the reference location, but not at 14 °C, which was here, a temperature outside normal environmental range. On the other hand, biofilms from the impacted stream reach exhibited increased responses following DOC enrichment under both temperature regimes, with a particularly pronounced response at 14 ºC, in this case, both experimental temperatures were within the normal environmental temperature ranges of the study locations. Conclusion Hyporheic biofilms were shown to be, like benthic biofilms, sensitive to temperature changes and organic enrichment, but their response to temperature changes and enrichment caused by climate change and/or other anthropogenic pressures (i.e. point and non-point pollution, removal of the riparian zone, hydromorphological modifications, etc.) was not simply linear but site-specific. The intensity of the response, characterized by increased activity and biomass production, appears to be constrained within the temperature ranges prevalent in the environment from which the biofilms originate. These findings emphasize the importance of site-specific considerations in predicting the impacts of climate change and anthropogenic pressures on these critical components of river and stream ecosystems.

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Spatiotemporal heterogeneity of actual and potential respiration in two contrasting floodplains

Cited by 10 publications

References 76 publications

Multi‐model assessment of hydrological and environmental impacts on streambed microbes in Mediterranean catchments

Multi‐model assessment of hydrological and environmental impacts on streambed microbes in Mediterranean catchments

Annual patterns of litter decomposition in the channel and riparian areas of an intermittent stream

Response of hyporheic biofilms to temperature changes and dissolved organic carbon enrichment: a mesocosm study

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