Alternative Reference Frames in River System Science

Doyle, Martin W.; Ensign, Scott H.

doi:10.1525/bio.2009.59.6.8

Cited by 49 publications

(50 citation statements)

References 48 publications

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“…Nearly all of our understanding about riverscape dynamics has been from the Eulerian (place-based) frame of reference; an increasing need exists for data to be collected from the Lagrangian (individual-based) frame of reference as well (Doyle and Ensign, 2009). This frame of reference could be useful in areas such as mobile organisms, fluvial wood, and the mobility of individual sediment particles.…”

Section: Discussionmentioning

confidence: 99%

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Making riverscapes real

et al. 2012

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Section: Discussionmentioning

confidence: 99%

“…In addition to these in-situ techniques, new techniques are also allowing measuring of mobile objects and organisms. These 'Lagrangian frame of reference' (Doyle and Ensign, 2009) techniques include passive integrated transponder (PIT) tagging (e.g. Johnston et al, 2009), RFID -radio frequency identification (e.g.…”

Section: Mapping Riverscapesmentioning

confidence: 99%

Making riverscapes real

et al. 2012

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“…1 was located , 5 m upstream of the injection site) and worked in a downstream direction. This was not a Lagrangian approach of following a nutrient pulse in a specific water parcel; the addition was sustained to plateau in the traditional Eulerian-style solute addition typical of stream spiraling studies (Stream Solute Workshop 1990;Doyle and Ensign 2009). However, not having to wait for the furthest downstream station to reach plateau before commencing sampling at the upstream station allowed us to minimize the addition durations, and care was taken to avoid entering the stream or disturbing sediments as sampling occurred.…”

Section: Methodsmentioning

confidence: 99%

Distinguishing dynamics of dissolved organic matter components in a forested stream using kinetic enrichments

Lutz

Bernhardt

Roberts

et al. 2011

Limnology & Oceanography

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Traditional methods for investigating stream solute biogeochemistry measure longitudinal rates of uptake by increasing either the concentration or isotopic composition of solutes. These methods cannot be applied to dissolved organic matter (DOM) because we cannot replicate the heterogeneous native DOM pool. We explored an alternative approach, attempting to displace or enhance benthic uptake of native DOM by supplying an exogenous source of labile carbon or by enriching the stream with inorganic nitrogen. This approach allows us to measure uptake rates of enriched solutes, as well as changes in the concentration and composition of native DOM resulting from the experimental manipulations. We examined DOM composition using fluorescence characterization. We were able to elicit changes in the chemical composition of native DOM by differentially altering the dynamics of autotrophic production and heterotrophic uptake within the second-order reach of Walker Branch, a well-studied stream in eastern Tennessee. Supplying heterotrophs with labile carbon resulted in an increase in fluorescence associated with terrestrially derived DOM. Stimulating algae by adding inorganic nitrogen increased autochthonous production and indirectly displaced heterotrophic demand for terrestrial DOM due to increased in-stream production of bioavailable DOM. While we were able to alter the composition of the native DOM pool, we observed little change in DOM concentrations. The ability to differentiate between DOM subcomponents provides insight into processes controlling DOM production and consumption that cannot be gained by treating DOM as a single bulk pool.Dissolved organic matter (DOM) represents an important source of energy in stream ecosystems (Fisher and Likens 1973;Cummins 1974), fueling heterotrophic microbial production and establishing the foundation on which stream trophic structure and ecosystem function relies (Minshall et al. 1983;Webster and Meyer 1997). DOM, however, is a single term applied to an extremely heterogeneous pool of organic molecules, with independent subcomponents that can exhibit distinct dynamics. Understanding the role that DOM plays in stream ecosystems requires that we are able to elucidate the processes that govern the dynamics of different DOM subcomponents.The heterogeneity of native DOM in streams restricts our ability to manipulate DOM in an experimental context because we are unable to synthesize the native DOM pool in its entirety. Nutrient Spiraling Theory (NST; Newbold et al. 1981;Stream Solute Workshop 1990), which has been a powerful tool for investigating solute biogeochemistry in streams, cannot be directly applied because this approach requires that we are able to add the diversity of DOM molecules to a stream in order to measure rates of longitudinal uptake. While several studies have used NST with manipulations of specific subcomponents of the DOM pool, such as litter leachates (McDowell 1985;Wiegner et al. 2005;Bernhardt and McDowell 2008) or simple organic monomers (Bernhardt and ...

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“…Discharge also determines the transit time of water and its dissolved and particulate constituents along the river course. The effects of transit time on phytoplankton abundance may be viewed from a Lagrangian perspective that considers processes regulating growth and loss within a parcel of water moving along the longitudinal dimension of the river (Doyle and Ensign 2009). Under favorable conditions (growth exceeding loss), slower water velocities result in greater biomass accrual per unit of transit time or distance (Lucas et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Phytoplankton abundance and contributions to suspended particulate matter in the Ohio, Upper Mississippi and Missouri Rivers

et al. 2011

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Main channel habitats of the Ohio, Missouri, and Upper Mississippi Rivers were surveyed during the summers of 2004, 2005 and 2006 using a probability-based sampling design to characterize inter-annual and inter-river variation in suspended chlorophyll a (CHLa) and related variables. Large (fivefold) differences in CHLa were observed with highest concentrations in the Upper Mississippi (32.3 ± 1.8 lg L -1 ), intermediate values in the Missouri (19.7 ± 1.1 lg L -1 ) and lowest concentrations in the Ohio (6.8 ± 0.5 lg L -1 ). Inter-annual variation was small in comparison to inter-river differences suggesting that basin-specific factors exert greater control over river-wide CHLa than regional-scale processes influencing climate and discharge. The rivers were characterized by variable but generally low light conditions as indicated by depth-averaged underwater irradiance \4 E m -2 day -1 and high ratios of channel depth to euphotic depth ([3). Despite poor light conditions, regression analyses revealed that TP was the best single predictor of CHLa (R 2 = 0.40), though models incorporating both light and TP performed better (R 2 = 0.60). Light and nutrient conditions varied widely within rivers and were inversely related, suggesting that riverine phytoplankton may experience shifts in resource limitation during transport. Inferred grazing and sedimentation losses were large yet CHLa concentrations did not decline downriver indicating that growth and loss processes were closely coupled. The contribution by algae to suspended particulate organic matter in these rivers (mean = 41%) was similar to that of lakes (39%) but lower relative to reservoirs (61%).

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Alternative Reference Frames in River System Science

Cited by 49 publications

References 48 publications

Making riverscapes real

Making riverscapes real

Distinguishing dynamics of dissolved organic matter components in a forested stream using kinetic enrichments

Phytoplankton abundance and contributions to suspended particulate matter in the Ohio, Upper Mississippi and Missouri Rivers

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