Inorganic N and P dynamics of Antarctic glacial meltwater streams as controlled by hyporheic exchange and benthic autotrophic communities

McKnight, Diane M.; Runkel, Robert L.; Tate, Cathy M.; Duff, John H.; Moorhead, Daryl L.

doi:10.1899/0887-3593(2004)023<0171:inapdo>2.0.co;2

Cited by 122 publications

(172 citation statements)

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“…Background SRP concentrations in our study streams were intermediate or high in comparison to most published literature on stream P uptake (Mulholland et al 1985, McKnight et al 2004; but see Bernot et al 2006), and the efficiency of nutrient assimilation (as quantified by v f ) typically decreases with increasing background nutrient concentration (e.g., Mulholland et al 2008). For these reasons, measurement of v f at high nutrient concentrations can sometimes be hindered by analytical limits.…”

Section: Discussionmentioning

confidence: 71%

“…Instead, employing nonlinear least squares estimation, we used the OTIS model to fit a second suite of conservative transport parameters (D, A, A s , and α) from pulse tracer data and λ pulse from background-corrected SRP taken over the time course of the nutrient pulse at upstream and downstream stations. McKnight et al (2004) and Tank et al (2008) used similar dynamic approaches for quantifying nutrient uptake. We then calculated pulse nutrient uptake metrics from λ pulse , yielding S w-pulse , v f-pulse , and U pulse .…”

Section: Materials and Proceduresmentioning

confidence: 99%

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Quantifying phosphorus uptake using pulse and steady‐state approaches in streams

Powers

Stanley

Lottig

2009

Limnology & Ocean Methods

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Steady-state approaches to the study of stream nutrient processing have several limitations. Dynamic (time series) approaches are more flexible, and allow interpretation of nutrient additions introduced as unsteady slugs (pulses). We compared soluble reactive phosphorus (SRP) uptake metrics from experimental nutrient pulses modeled dynamically with those from continuous injections modeled with a steady-state approach. For six southern Wisconsin streams, uptake metrics from these two methods were similar despite low nutrient demand. Linear regression of paired-pulse versus steady-state estimates of the first-order uptake coefficient (λ; r 2 = 0.84, slope = 1.21) and uptake velocity (v f ; r 2 = 0.95, slope = 1.03) were highly significant. There was a tendency for slightly higher uptake with pulses, possibly due to P sorption. Sampling across five stations of one stream yielded a similar longitudinal pattern between experimental pulse SRP flux and steady-state (plateau) SRP concentration. Conservative transport parameters for pulse and continuously injected tracer data were also similar. These results suggest that unsteady nutrient amendments can provide usable nutrient uptake values, even in low-uptake situations for which uncertainty is high. The flexibility of dynamic approaches to nutrient spiraling facilitates research in poorly understood situations, including conditions of high water residence time, high discharge, and changing discharge or background chemistry.

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Section: Discussionmentioning

confidence: 71%

Section: Materials and Proceduresmentioning

confidence: 99%

Quantifying phosphorus uptake using pulse and steady‐state approaches in streams

Powers

Stanley

Lottig

2009

Limnology & Ocean Methods

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“…These structures exhibit great variety in morphology and composition and may include diverse biofilms of immobilized microorganisms (Bauld, 1984). Cyanobacteria and diatoms are emphasized as the key organisms comprising microbial mats in spring habitats (Esposito et al, 2006;Stal, 2012;Cantonati et al, 2012Cantonati et al, , 2015Cantonati et al, , 2016, where these prokaryotic-eukaryotic interactions play an important role in microbial mat development by enabling significant photosynthetic activity (Elster and Komárek, 2003) and nutrient cycling and acquisition (Gooseff et al, 2004;McKnight et al, 2004;Mueller and Vincent, 2006). Their remarkable adaptability, through which they can overcome the extremity of environmental conditions prevailing in many carbonate-rock springs, makes them one of the key components in terms of ecology, management and conservation of spring ecosystems .…”

Section: Introductionmentioning

confidence: 99%

Microbial mats as shelter microhabitat for amphipods in an intermittent karstic spring

Žutinić

Petrić

Gottstein

et al. 2018

Knowl. Manag. Aquat. Ecosyst.

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-Microbial mats represent complex communities where cyanobacteria and diatoms as key organisms provide shelter for diverse assemblages of aquatic invertebrates, like the small stygophilous amphipod Synurella ambulans. Studies addressing such communities in the karst springs have rarely examined springheads, and have ignored intermittent springs. During high flow conditions the stygophilic crustaceans are flushed to the surface of a temporary stream Krčić where microbial mats prevent their drift and enables their successful retreat into underground in the periods of drought. The objective of this study was to characterize the microbial mat community of the Krčić Spring as a shelter for S. ambulans during strong current and high water level. Representative samples for diatom and cyanobacterial species identification and composition, as well as the fresh mat material for potential animal activity and cyanobacterial phylogenetic analysis were collected. The most dominant diatom was Achnanthidium minutissimum, whilst Fragilaria capucina, Meridion circulare, Navicula cryptocephala and Nitzschia palea had abundance greater than 0.5%. Morphological observations of cyanobacteria revealed that Phormidium favosum was the most dominant, with Hydrocoleum muscicola as a subdominant. Cyanobacterial phylogenetic relationship revealed two distinct clusters: (i) "Phormidium cluster", confirming morphological observations in both winter and spring samples, and (ii) "Wilmottia cluster", a first report for Croatia and found exclusively in the winter sample. Laboratory observations revealed a small stygophilic amphipod S. ambulans, hiding and feeding inside the pockets of fresh microbial mat. The intermittent Krčić Spring as a predator-free and competitor-free ecosystem provides a spatiotemporal conformity between microbial mat and stygophilous amphipod.Keywords: Microbial mat / cyanobacteria / diatoms / amphipods / karstic spring Résumé -Le tapis microbien comme microhabitat refuge pour les amphipodes dans une source karstique intermittente. Le tapis microbien représente des communautés complexes où les cyanobactéries et les diatomées, en tant qu'organismes clés, abritent divers assemblages d'invertébrés aquatiques, comme les petits amphipodes stygophiles Synurella ambulans. Les études portant sur ces communautés dans les sources karstiques ont rarement examiné ces têtes de ruisseaux et ont ignoré les sources intermittentes. Dans les conditions d'écoulement fort, les crustacés stygophiles sont chassés à la surface d'un ruisseau temporaire Krčić où les tapis microbiens empêchent leur dérive et permettent leur retrait dans le sous-sol en période de sécheresse. L'objectif de cette étude était de caractériser la communauté du tapis microbien de la source Krčić comme abri pour S. ambulans lors de forts courants et de niveaux d'eau élevés. La diatomée la plus dominante était Achnanthidium minutissimum, tandis que Fragilaria capucina, Meridion circulare, Navicula cryptocephala et Nitzschia palea avaient une abondance supérieure à ...

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“…In the streambed, enhanced geochemical and biological processes alter the water chemistry and create distinct gradients of solutes that are sensitive to oxidation-reduction (redox) conditions [Champ et al, 1979;Triska et al, 1989;Jones et al, 1995;Baker et al, 2000;Morrice et al, 2000;Lautz and Fanelli, 2008]. Hyporheic exchange can influence surface water quality by chemically processing nutrients and pollutants in the streambed and by reintroducing chemically altered water back to the stream [McKnight et al, 2004]. Hyporheic exchange also maintains the health of aquatic species in the hyporheic zone, such as subsurface macroinvertebrate communities and fish embryos, by introducing stream water into benthic sediments and creating heterogeneous geochemical habitats in the streambed [Brunke and Gonser, 1997;Boulton et al, 1998].…”

Section: Introductionmentioning

confidence: 99%

Spatial patterns of hyporheic exchange and biogeochemical cycling around cross‐vane restoration structures: Implications for stream restoration design

Gordon

Lautz

Daniluk

2013

Water Resources Research

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[1] Natural channel design restoration projects in streams often include the construction of cross-vanes, which are stone, dam-like structures that span the active channel. Vertical hyporheic exchange flux (HEF) and redox-sensitive solutes were measured in the streambed around four cross-vanes with different morphologies. Observed patterns of HEF and redox conditions are not dominated by a single, downstream-directed hyporheic flow cell beneath cross-vanes. Instead, spatial patterns of moderate (<0.4 m d À1 ) upwelling and downwelling are distributed in smaller cells around pool and riffle bed forms upstream and downstream of structures. Patterns of biogeochemical cycling are controlled by dissolved oxygen concentrations and resulting redox conditions, and are also oriented around secondary bed forms. Strong downwelling into the hyporheic zone (0.5-3.5 m d À1 ) was observed immediately upstream of structures, but was limited to an area 1-2 m from the cross-vane; these hyporheic flow paths likely rejoin the stream at the base of cross-vanes after residence times too short to alter nitrate concentrations or accumulate reaction products. Total hyporheic exchange volumes are $0.4% of stream discharge in restored reaches of 45-55 m. Results show that shallow hyporheic flow and associated biogeochemical cycling near cross-vanes is primarily controlled by secondary bed forms created or augmented by the cross-vane, rather than by the cross-vane itself. This study suggests that cross-vane restoration structures benefit the stream ecosystem by creating heterogeneous patches of varying HEF and redox conditions in the hyporheic zone, rather than by processing large amounts of nutrients to alter in-stream water chemistry.Citation: Gordon, R. P., L. K. Lautz, and T. L. Daniluk (2013), Spatial patterns of hyporheic exchange and biogeochemical cycling around cross-vane restoration structures: Implications for stream restoration design, Water Resour.

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Inorganic N and P dynamics of Antarctic glacial meltwater streams as controlled by hyporheic exchange and benthic autotrophic communities

Cited by 122 publications

References 39 publications

Quantifying phosphorus uptake using pulse and steady‐state approaches in streams

Quantifying phosphorus uptake using pulse and steady‐state approaches in streams

Microbial mats as shelter microhabitat for amphipods in an intermittent karstic spring

Spatial patterns of hyporheic exchange and biogeochemical cycling around cross‐vane restoration structures: Implications for stream restoration design

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