Abundance and Vertical Distribution of the Phytobenthic Community within a Pool and Riffle Sequence of an Alpine Gravel Stream

Müllner, Alexandra N.; Schagerl, Michael

doi:10.1002/iroh.200390022

Cited by 24 publications

(24 citation statements)

References 60 publications

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“…Cyanobacteria can be abundant components of benthic biofilms [43] and they are well known for allelopathy as a competitive strategy [46]. The spatial variation of cyanobacterial abundance throughout our study streams may therefore further contribute to the network scale pattern of alpha diversity.…”

Section: Discussionmentioning

confidence: 98%

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Headwaters are critical reservoirs of microbial diversity for fluvial networks

et al. 2013

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Streams and rivers form conspicuous networks on the Earth and are among nature's most effective integrators. Their dendritic structure reaches into the terrestrial landscape and accumulates water and sediment en route from abundant headwater streams to a single river mouth. The prevailing view over the last decades has been that biological diversity also accumulates downstream. Here, we show that this pattern does not hold for fluvial biofilms, which are the dominant mode of microbial life in streams and rivers and which fulfil critical ecosystem functions therein. Using 454 pyrosequencing on benthic biofilms from 114 streams, we found that microbial diversity decreased from headwaters downstream and especially at confluences. We suggest that the local environment and biotic interactions may modify the influence of metacommunity connectivity on local biofilm biodiversity throughout the network. In addition, there was a high degree of variability in species composition among headwater streams that could not be explained by geographical distance between catchments. This suggests that the dendritic nature of fluvial networks constrains the distributional patterns of microbial diversity similar to that of animals. Our observations highlight the contributions that headwaters make in the maintenance of microbial biodiversity in fluvial networks.

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Section: Discussionmentioning

confidence: 98%

“…As streambed geomorphology can influence benthic biofilm communities [24,43], we tested whether physical changes (e.g. water depth, velocity, channel slope or Froude number) explain the observed drop in alpha diversity and evenness across confluences.…”

Section: Discussionmentioning

confidence: 99%

Headwaters are critical reservoirs of microbial diversity for fluvial networks

et al. 2013

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“…Due to the lack or paucity of primary production in the subsubstratum (Mu¨llner & Schagerl, 2003), invertebrates probably feed on detritus and biofilms derived mainly from allochthonous inputs and on the associated microflora: fine particulate organic matter sustains a high number of collectorgatherers while coarse organic matter attracts shredders. We found that some large shredders (e.g.…”

Section: Discussionmentioning

confidence: 99%

Colonisation patterns and vertical movements of stream invertebrates in the interstitial zone: a case study in the Apennines, NW Italy

Cucco

Fenoglio

et al. 2006

Hydrobiologia

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We examined vertical migration and colonisation patterns of stream macroinvertebrates within the substratum of an Apennine creek in NW Italy. Macrobenthos was sampled at three depths in the streambed (0-5, 5-10, 10-15 cm) by means of artificial baskets filled with natural substratum. We placed 42 traps (5Â5Â15 cm), i.e. 21 top-opened (T-traps) and 21 bottom-opened (B-traps), each composed of three overlapping baskets (high-H, medium-M and low-L), to evaluate differences in the vertical movements. We also collected Surber samples to compare interstitial assemblages with streambed communities. The multilevel traps yielded 42 taxa, compared with 60 taxa in the natural riverbed. Interstitial traps were rapidly colonised; both taxa richness and organism number increased during the 42-day study period. We found active migration in both vertical directions, but there were more invertebrates in the top-opened traps than in the bottom-opened traps. In the T-traps the most colonised baskets were those placed at the H level, while in the B-traps the L level baskets were more rapidly colonised. The interstitial assemblages differed markedly from the streambed communities in both composition and functional organisation, with more collector-gatherers and predators in the interstitial zone and more filterers and scrapers in the natural riverbed. In Apennine lotic systems, the interstitial zone is an important habitat for stream macrobenthos, although it may not be used by all species.

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“…due to the calcareous geology of the catchment, and stream water is saturated in oxygen even down to 2 m in the streambed. Photosynthetically active radiation (PAR) can be seasonally high, allowing benthic diatoms and cyanophytes to develop notable biomass [Müllner and Schagerl, 2003] (Figure 1b). …”

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confidence: 99%

Scales and drivers of temporal pCO₂ dynamics in an Alpine stream

et al. 2014

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The role of inland waters for the global carbon cycle is now recognized and evidence increasingly suggests that stream ecosystems disproportionately contribute to the carbon cycle. Understanding the dynamics and drivers of stream water partial pressure of CO 2 (pCO 2 ) and CO 2 evasion fluxes from streams to the atmosphere is imperative for assessing the role of climate change on the carbon cycle in stream ecosystems. Monitoring pCO 2 over 3 years, we here report on the seasonal, diurnal, and event-driven dynamics of pCO 2 in the hyporheic zone and stream water of an Alpine stream and assess possible drivers of these dynamics. Our findings suggest that both catchment-derived CO 2 delivered by shallow groundwater into the stream and in-stream respiration continuously build up pCO 2 in the hyporheic zone. Depending on stream water temperature and assumedly on primary production (inferred from photosynthetically active radiation), hyporheic CO 2 contributes to stream water pCO 2 and ultimately to CO 2 outgassing to the atmosphere. Diurnal patterns of stream water pCO 2 increasingly built up during extended base flow and streambed-scouring storms caused the collapse of these diurnal patterns. Post storm recovery of the diurnal pCO 2 patterns was generally rapid. Our findings suggest that decreasing gas exchange velocity related to receding discharge drives recovery dynamics. We found that average CO 2 outgassing fluxes during night exceeded those during day by up to 1.8 times. Our study highlights temperature and hydrology-key components of climate change-as major drivers of pCO 2 dynamics in Alpine streams. They also underscore the necessity to consider day-night differences in CO 2 outgassing fluxes to properly establish carbon budgets and regional estimates of CO 2 outgassing to the atmosphere.

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Abundance and Vertical Distribution of the Phytobenthic Community within a Pool and Riffle Sequence of an Alpine Gravel Stream

Cited by 24 publications

References 60 publications

Headwaters are critical reservoirs of microbial diversity for fluvial networks

Headwaters are critical reservoirs of microbial diversity for fluvial networks

Colonisation patterns and vertical movements of stream invertebrates in the interstitial zone: a case study in the Apennines, NW Italy

Scales and drivers of temporal pCO₂ dynamics in an Alpine stream

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Abundance and Vertical Distribution of the Phytobenthic Community within a Pool and Riffle Sequence of an Alpine Gravel Stream

Cited by 24 publications

References 60 publications

Headwaters are critical reservoirs of microbial diversity for fluvial networks

Headwaters are critical reservoirs of microbial diversity for fluvial networks

Colonisation patterns and vertical movements of stream invertebrates in the interstitial zone: a case study in the Apennines, NW Italy

Scales and drivers of temporal pCO2 dynamics in an Alpine stream

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Scales and drivers of temporal pCO₂ dynamics in an Alpine stream