What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?

Hydrological variations hold a significant influence over the water chemistry in the karst systems within the critical zone. In this context, the Baget Catchment (BC) was monitored at high-resolution over 2 hydrological years. The high-frequency survey at the outlet of BC displayed multiple hydroche...

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Main Authors: Francesco Ulloa-Cedamanos, Anne Probst, Vanessa Dos-Santos, Jean-Luc Probst
Format: Article
Language:English
Published: MDPI AG 2020-11-01
Series:Environmental Sciences Proceedings
Subjects:
Online Access:https://www.mdpi.com/2673-4931/7/1/9
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author Francesco Ulloa-Cedamanos
Anne Probst
Vanessa Dos-Santos
Jean-Luc Probst
author_facet Francesco Ulloa-Cedamanos
Anne Probst
Vanessa Dos-Santos
Jean-Luc Probst
author_sort Francesco Ulloa-Cedamanos
collection DOAJ
description Hydrological variations hold a significant influence over the water chemistry in the karst systems within the critical zone. In this context, the Baget Catchment (BC) was monitored at high-resolution over 2 hydrological years. The high-frequency survey at the outlet of BC displayed multiple hydrochemical patterns in response to hydrological variations, mixing water sources, and biogeochemical processes. Among the major elements, sulfate exhibited the widest relative variation during flooding and showed a significant dilution, whereas calcium and bicarbonate revealed a chemostatic behavior as a result of carbonate dissolution in the karst. Hysteretic analysis evidenced the control of different hydrological reservoirs over the stream transport processes of dissolved elements. The concentration of dissolved organic carbon increased during the hydrograph rising limb and was controlled by surface runoff. The relationships between Ca<sup>2+</sup> and HCO<sub>3</sub><sup>−</sup> concentrations and stream discharge exhibited hysteresis patterns with counterclockwise loops, unlike all other elements, due to the carbonate weathering by biogenic CO<sub>2</sub>-rich water. Finally, high-frequency sampling during storm events improved the understanding of the factors controlling the hydrochemical dynamic of the Baget stream water. The relative contributions of the karst and epikarst zones, of rainwater, as well as the role of different biogeochemical processes and the hydrological conditions were highlighted.
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spelling doaj.art-7364a0298ff6406bb184b06a6c5ba1002023-11-17T10:58:41ZengMDPI AGEnvironmental Sciences Proceedings2673-49312020-11-0171910.3390/ECWS-5-08058What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?Francesco Ulloa-Cedamanos0Anne Probst1Vanessa Dos-Santos2Jean-Luc Probst3Laboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Auzeville Tolosane, 31326 Castanet Tolosan, FranceLaboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Auzeville Tolosane, 31326 Castanet Tolosan, FranceLaboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Auzeville Tolosane, 31326 Castanet Tolosan, FranceLaboratoire Écologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Auzeville Tolosane, 31326 Castanet Tolosan, FranceHydrological variations hold a significant influence over the water chemistry in the karst systems within the critical zone. In this context, the Baget Catchment (BC) was monitored at high-resolution over 2 hydrological years. The high-frequency survey at the outlet of BC displayed multiple hydrochemical patterns in response to hydrological variations, mixing water sources, and biogeochemical processes. Among the major elements, sulfate exhibited the widest relative variation during flooding and showed a significant dilution, whereas calcium and bicarbonate revealed a chemostatic behavior as a result of carbonate dissolution in the karst. Hysteretic analysis evidenced the control of different hydrological reservoirs over the stream transport processes of dissolved elements. The concentration of dissolved organic carbon increased during the hydrograph rising limb and was controlled by surface runoff. The relationships between Ca<sup>2+</sup> and HCO<sub>3</sub><sup>−</sup> concentrations and stream discharge exhibited hysteresis patterns with counterclockwise loops, unlike all other elements, due to the carbonate weathering by biogenic CO<sub>2</sub>-rich water. Finally, high-frequency sampling during storm events improved the understanding of the factors controlling the hydrochemical dynamic of the Baget stream water. The relative contributions of the karst and epikarst zones, of rainwater, as well as the role of different biogeochemical processes and the hydrological conditions were highlighted.https://www.mdpi.com/2673-4931/7/1/9carbonate dissolutionchemical weatheringwater chemistryflood eventshigh frequency monitoringhydrochemical survey
spellingShingle Francesco Ulloa-Cedamanos
Anne Probst
Vanessa Dos-Santos
Jean-Luc Probst
What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?
Environmental Sciences Proceedings
carbonate dissolution
chemical weathering
water chemistry
flood events
high frequency monitoring
hydrochemical survey
title What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?
title_full What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?
title_fullStr What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?
title_full_unstemmed What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?
title_short What Can Be Learned about the Relationships between Water Discharge and Composition during Flood Events in a Forested Karstic Catchment from the Pyrenees Mountains (Southwestern France)?
title_sort what can be learned about the relationships between water discharge and composition during flood events in a forested karstic catchment from the pyrenees mountains southwestern france
topic carbonate dissolution
chemical weathering
water chemistry
flood events
high frequency monitoring
hydrochemical survey
url https://www.mdpi.com/2673-4931/7/1/9
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