Influence of diel biogeochemical cycles on carbonate equilibrium in a karst river

Montety, Véronique de; Martin, Jonathan B.; Cohen, Matthew J.; Foster, C. R.; Kurz, Marie J.

doi:10.1016/j.chemgeo.2010.12.025

Cited by 63 publications

(96 citation statements)

References 62 publications

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“…Previous work summarizing gage estimated flows (Heffernan et al 2010a) suggests that spring inputs exceed downstream river flow by an average of 10%. However, continuous measures of hydraulic head gradients at multiple locations in the river suggest persistent gaining conditions (de Montety et al 2011; M. J. Kurz, J. B. Martin, and M. J. Cohen, unpublished manuscript), consistent with the presence of small springs and seeps along the entire river.…”

Section: Site Descriptionmentioning

confidence: 78%

“…Fluxes of both N and P are dominated by mineral forms: NO 3 represents .90% of N flux, with concentrations ranging from 250 to 880 lg NO 3 -N/L across springs, while soluble reactive phosphorus (SRP) represents .95% of total P, with concentrations between 35 to 65 lg P/L. Spring water emerges oversaturated with CO 2 (de Montety et al 2011), and undersaturated with DO (Heffernan and Cohen 2010). Spring water is also exceedingly clear (Duarte et al 2010), with negligible inputs and only modest longitudinal accumulation of dissolved organic matter, facilitating high primary production and dense beds of both vascular plants (principally Sagittaria kurziana and Vallesnaria americana) and filamentous benthic algae (principally Lyngbya wollei and Vaucheria spp.…”

Section: Site Descriptionmentioning

confidence: 99%

“…Moreover, the extended duration of high-frequency measurements enabled detection of day-to-day effects of primary production on subsequent denitrification. Likewise, Liu et al (2008) andde Montety et al (2011) used high-resolution measurements of temperature, specific conductance, and pH to document the diel dynamics of calcite precipitation-dissolution reactions in karst systems, which, in turn, exerts an important influence on numerous element cycles. This emerging capacity to disentangle the interactions between autotrophic, heterotrophic, and geochemical removal pathways illustrates the potential of in situ sensing of multiple solutes to address fundamental questions about ecosystem dynamics.…”

Section: Introductionmentioning

confidence: 99%

“…During these and previous deployments, we observed coherent diel variation in SpC, consistent with reduced ion activity during the day. Given that the alkalinity of the spring inflows is constant, that bicarbonate is the predominant anion in these waters, and that spring vent water is oversaturated with respect to calcite (de Montety et al 2011), but not other minerals, this diel SpC signal implies daytime calcite precipitation. Specifically, daytime decreases were observed in SpC ranging between 6 and 15 lS/cm from a nighttime maximum that consistently matched the flowweighted springs inputs (;338 lS/cm).…”

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confidence: 99%

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Diel phosphorus variation and the stoichiometry of ecosystem metabolism in a large spring‐fed river

Cohen

Kurz

Heffernan

et al. 2013

Ecological Monographs

107

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Abstract. Elemental cycles are coupled directly and indirectly to ecosystem metabolism at multiple time scales. Understanding coupling in lotic ecosystems has recently advanced through simultaneous high-frequency measurements of multiple solutes. Using hourly in situ measurements of soluble reactive phosphorus (SRP), specific conductance (SpC), and dissolved oxygen (DO), we estimated phosphorus (P) retention pathways and dynamics in a large (discharge, Q ' 7.5 m 3 /s) spring-fed river (Ichetucknee River, Florida, USA). Across eight multi-day deployments, highly regular diel SRP variation of 3-9 lg P/L (mean ;50 lg P/ L) was strongly correlated with DO variation, suggesting photosynthetic control directly via assimilation, and/or indirectly via geochemical reactions. Consistent afternoon SRP maxima and midnight minima suggest peak removal lags gross primary production (GPP) by ;8 hours. Two overlapping processes were evident, one dominant with maximum removal near midnight, the other smaller with maximum removal near midday. Hourly [Ca] measurements during three 24-hour deployments showed consistent afternoon minima, suggesting that calcite precipitates as GPP increases pH and mineral saturation state. Resulting P coprecipitation was modeled using SpC as a [Ca] proxy, yielding a diel P signal adjusted for the primary geochemical retention pathway. P assimilation, the dominant diel signal, was computed by interpolating between daily concentration maxima, both with and without geochemical adjustment, and converting concentration deficits to fluxes using discharge and benthic area. Adjusting for calcite co-precipitation yielded assimilation rates (13.7 6 5.8 mg PÁm À2 Ád À1) strongly correlated with GPP, accounting for 72% 6 9% of gross removal, and ecosystem C:P stoichiometry (466 [6 12]:1) consistent with dominant vascular autotrophs (478 [6 24]:1). Without adjusting for co-precipitation, covariance with GPP was weaker, and C:P implausibly high. Consistent downstream P accumulation, likely from P-rich porewater seepage, varied across deployments (3-22% of total flux) and co-varied with discharge and respiration. Asynchronous N and P assimilation may arise from differential timing of protein and ribosome production, with the latter requiring maximal carbohydrate stores and minimal photolytic interference. This study demonstrates direct and indirect coupling of biological, hydrological, and geochemical processes and the utility of high-resolution time series of multiple solutes for understanding these linkages.

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Section: Site Descriptionmentioning

confidence: 78%

Section: Site Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Diel phosphorus variation and the stoichiometry of ecosystem metabolism in a large spring‐fed river

Cohen

Kurz

Heffernan

et al. 2013

Ecological Monographs

107

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“…Thus far, these data have been mostly acquired during limited periods of time such as single storm events or a day (Beck et al, 2009;Brick and Moore, 1996;Chapman et al, 1997;Gammons et al, 2007;Kurz et al, 2013;Liu et al, 2008;Morel et al, 2009;de Montety et al, 2011;Neal et al, 2002;Nimick et al, 2011Nimick et al, , 2005Takagi, 2015;Tercier-Weaber et al, 2009). Although these studies clearly highlighted the wealth of information provided by sampling rivers at sub-hourly frequency, they underestimate the legacy of past hydrological episodes (Kirchner, 2006;Jasechko et al, 2016;Rode et al, 2016) and are of limited use when mass budgets are to be calculated for a typical hydrological cycle.…”

Section: P Floury Et Al: the Potamochemical Symphonymentioning

confidence: 99%

The potamochemical symphony: new progress in the high-frequency acquisition of stream chemical data

Floury¹,

Gaillardet²,

Gayer³

et al. 2017

Hydrol. Earth Syst. Sci.

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Abstract. Our understanding of hydrological and chemical processes at the catchment scale is limited by our capacity to record the full breadth of the information carried by river chemistry, both in terms of sampling frequency and precision. Here, we present a proof-of-concept study of a "lab in the field" called the "River Lab" (RL), based on the idea of permanently installing a suite of laboratory instruments in the field next to a river. Housed in a small shed, this set of instruments performs analyses at a frequency of one every 40 min for major dissolved species (Na + , K + , Mg 2+ , Ca 2+ , Cl − , SO 2− 4 , NO − 3 ) through continuous sampling and filtration of the river water using automated ion chromatographs. The RL was deployed in the Orgeval Critical Zone Observatory, France for over a year of continuous analyses. Results show that the RL is able to capture long-term fine chemical variations with no drift and a precision significantly better than conventionally achieved in the laboratory (up to ±0.5 % for all major species for over a day and up to 1.7 % over 2 months). The RL is able to capture the abrupt changes in dissolved species concentrations during a typical 6-day rain event, as well as daily oscillations during a hydrological low-flow period of summer drought. Using the measured signals as a benchmark, we numerically assess the effects of a lower sampling frequency (typical of conventional field sampling campaigns) and of a lower precision (typically reached in the laboratory) on the hydrochemical signal. The highresolution, high-precision measurements made possible by the RL open new perspectives for understanding critical zone hydro-bio-geochemical cycles. Finally, the RL also offers a solution for management agencies to monitor water quality in quasi-real time.

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Organic and inorganic carbon dynamics in a karst aquifer: Santa Fe River Sink‐Rise system, north Florida, USA

et al. 2014

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Spatiotemporal variations in dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), major ions concentrations and other geochemical parameters including stable carbon isotopes of DIC (δ 13 C DIC ), were measured in surface water and deep and shallow well water samples of the SantaFe River Sink-Rise eogenetic karst system, north Florida, USA. Three end-member water sources were identified: one DOC-rich/DIC-poor/δ 13 C DIC -depleted, one DOC-poor/DIC-rich/δ 13 C DIC -enriched, and one enriched in major ions. Given their spatiotemporal distributions, they were presumed to represent soil water, upper aquifer groundwater, and deep aquifer water sources, respectively. Using assumed ratios of Na + , Cl, and SO 4 2À for each end-member, a mixing model calculated the contribution of each water source to each sample. Then, chemical effects of biogeochemical reactions were calculated as the difference between those predicted by the mixing model and measured species concentrations. In general, carbonate mineral dissolution occurred throughout the Sink-Rise system, surface waters were net autotrophic and the subsurface was in metabolic balance, i.e., no net DOC or DIC production or consumption. However, there was evidence for chemolithoautotrophy, perhaps by hydrogen oxidizing microbes, at some deep aquifer sites. Mineralization of this autochthonous natural dissolved organic matter (NDOM) led to localized carbonate dissolution as did surface water-derived NDOM supplied to shallow well sites during the highest flow periods. This study demonstrates linkages between hydrology, abiotic and microbial processes and carbon dynamics and has important implications for groundwater quality, karst morphologic evolution, and hydrogeologic projects such as aquifer storage and recovery in karst systems.

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Influence of diel biogeochemical cycles on carbonate equilibrium in a karst river

Cited by 63 publications

References 62 publications

Diel phosphorus variation and the stoichiometry of ecosystem metabolism in a large spring‐fed river

Diel phosphorus variation and the stoichiometry of ecosystem metabolism in a large spring‐fed river

The potamochemical symphony: new progress in the high-frequency acquisition of stream chemical data

Organic and inorganic carbon dynamics in a karst aquifer: Santa Fe River Sink‐Rise system, north Florida, USA

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