Ciliate communities in shallow groundwater: seasonal and spatial characteristics

Andrushchyshyn, Oksana P.; Wilson, Kevin P.; Williams, D. Dudley

doi:10.1111/j.1365-2427.2007.01806.x

Cited by 21 publications

(24 citation statements)

References 32 publications

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“…The microbial transformations of dissolved and particulate nutrients taking place in the HZ have been shown to influence both macroinvertebrate and algal assemblages and may play a fundamental role in the productivity of riparian vegetation (Brunke and Gonser, 1997;Boulton et al, 1998;Clarke, 2002). The microbial community is most likely to be associated within biofilms, comprising viruses, bacteria, protozoa and fungi (Feris et al, 2003a(Feris et al, ,b, 2004aBarlocher et al, 2006;Andrushchyshyn et al, 2007) and constitutes the majority of the biomass and activity in lotic ecosystems (Pusch et al, 1998;Fischer and Pusch, 2001;Craft et al, 2002), contributing up to 96% of the ecosystem respiration (Naegeli and Uehlinger, 1997). Feris et al (2003) noted that microbial transformations of dissolved and particulate nutrients in the HZ influenced both macroinvertebrate and algal communities and furthermore influenced the productivity in lotic systems and beyond (Pusch et al, 1998).…”

Section: Heat Exchange and Temperaturementioning

confidence: 97%

Inter‐disciplinary perspectives on processes in the hyporheic zone

et al. 2010

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International audienceThe interface between groundwater and surface water within riverine/riparian ecosystems--the hyporheic zone (HZ)--is experiencing a rapid growth of research interest from a range of scientific disciplines, often with different perspectives. The majority of the multi-disciplinary research aims to elucidate HZ process dynamics and their importance for surface water and groundwater ecohydrology and biogeochemical cycling. This paper presents a critical inter-disciplinary review of recent advances of research centred on the HZ and highlights the current state of knowledge regarding hydrological, biogeochemical and ecohydrological process understanding. The spatial and temporal variability of surface water and groundwater exchange (hyporheic exchange flows), biogeochemical cycling and heat exchange (thermal regime) are considered in relation to both experimental measurements and modelling of these phenomena. We explore how this knowledge has helped to increase our understanding of HZ ecohydrology, and particularly its invertebrate community, the processing of organic matter, trophic cascading and ecosystem engineering by macrophytes and other organisms across a range of spatial and temporal scales. In addition to providing a detailed review of HZ functions, we present an inter-disciplinary perspective on how to advance and integrate HZ process understanding across traditional discipline boundaries. We therefore attempt to highlight knowledge gaps and research needs within the individual disciplines and demonstrate how innovations and advances in research, made within traditional subject-specific boundaries (e.g. hydrology, biochemistry and ecology), can be used to enhance inter-disciplinary scientific progress by cross-system comparisons and fostering of greater dialogue between scientific disciplines

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Section: Heat Exchange and Temperaturementioning

confidence: 97%

Inter‐disciplinary perspectives on processes in the hyporheic zone

et al. 2010

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“…As a result, hydraulic conductivity can vary: longitudinally in pool-riffle sequences (Stanford & Ward, 1988); with depth into the sediments in areas of upwelling and downwelling; and can change over time (Hendricks & White, 1995;Robinson et al, 2002;. Some evidence suggests that localized hydrodynamics, such as in regions of lateral exchange, can also result in spatial gradients in microbial metabolism (Claret & Boulton, 2009) and microbial community structure (Battin, 2000;Halda-Alija et al, 2001;Andrushchyshyn et al, 2007;Iribar et al, 2008). However, the factors influencing hyporheic microbial community composition along spatial and seasonal gradients remain poorly understood.…”

Section: Introductionmentioning

confidence: 95%

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

2009

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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.

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“…However, the complex microbial communities in biofilms have been recognized as important contributors to critical ecological processes, such as auxotrophic primary production, nitrogen fixation, and nutrient cycling, and may underpin the function of stream food webs (31,45,61). The few studies which have investigated benthic habitats in lotic systems have found evidence of the existence of diverse communities of abundant ciliates (3,20,56) and shifts in community structure in response to ecophysiological parameters (30,42,43). With one exception, however, these investigations were based on aquatic sediments, and the organisms within epilithic biofilms have continued to receive little attention.…”

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confidence: 92%

Relative Diversity and Community Structure of Ciliates in Stream Biofilms According to Molecular and Microscopy Methods

Dopheide

Lear

Stott

et al. 2009

Appl Environ Microbiol

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Ciliates are an important component of aquatic ecosystems, acting as predators of bacteria and protozoa and providing nutrition for organisms at higher trophic levels. Understanding of the diversity and ecological role of ciliates in stream biofilms is limited, however. Ciliate diversity in biofilm samples from four streams subject to different impacts by human activity was assessed using microscopy and terminal restriction fragment length polymorphism (T-RFLP) analysis of 18S rRNA sequences. Analysis of 3 and 5 terminal fragments yielded very similar estimates of ciliate diversity. The diversity detected using microscopy was consistently lower than that suggested by T-RFLP analysis, indicating the existence of genetic diversity not apparent by morphological examination. Microscopy and T-RFLP analyses revealed similar relative trends in diversity between different streams, with the lowest level of biofilm-associated ciliate diversity found in samples from the least-impacted stream and the highest diversity in samples from moderately to highly impacted streams. Multivariate analysis provided evidence of significantly different ciliate communities in biofilm samples from different streams and seasons, particularly between a highly degraded urban stream and less impacted streams. Microscopy and T-RFLP data both suggested the existence of widely distributed, resilient biofilm-associated ciliates as well as ciliate taxa restricted to sites with particular environmental conditions, with cosmopolitan taxa being more abundant than those with restricted distributions. Differences between ciliate assemblages were associated with water quality characteristics typical of urban stream degradation and may be related to factors such as nutrient availability and macroinvertebrate communities. Microscopic and molecular techniques were considered to be useful complementary approaches for investigation of biofilm ciliate communities.Heterotrophic microeukaryotes such as ciliates are thought to be of considerable importance in aquatic ecosystems, as they are major predators of bacteria and constitute a nutritional resource for other protozoa, invertebrates, and probably fish larvae (9,22,36,52,62,63,71). In addition, protozoan bacterivory contributes to enhanced decomposition of leaf detritus-a vital nutrient resource in streams-by increasing turnover of bacterial populations through predation (57). It is not well understood, however, how ciliate diversity and community structure in streams are affected by changing environmental conditions, or how ciliate communities affect other stream biota and processes. The effects of various physical, chemical, and biological factors on freshwater protozoan communities have been considered by a number of studies, but most of these have focused upon planktonic organisms in lentic habitats (for example, see references 2, 11, and 44). However, the complex microbial communities in biofilms have been recognized as important contributors to critical ecological processes, such as auxotrophic primary ...

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Ciliate communities in shallow groundwater: seasonal and spatial characteristics

Cited by 21 publications

References 32 publications

Inter‐disciplinary perspectives on processes in the hyporheic zone

Inter‐disciplinary perspectives on processes in the hyporheic zone

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

Relative Diversity and Community Structure of Ciliates in Stream Biofilms According to Molecular and Microscopy Methods

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