Disturbance and resilience of a granitic critical zone submitted to acid atmospheric influence (the Ringelbach catchment, Vosges Mountains, France): Lessons from a hydrogeochemical survey in the nineties

Abstract

The chemistry of precipitations and stream waters in the critical zone of a small granitic catchment mainly covered by grassland has been investigated backward (period 1990-1997). Major elements concentrations, fluxes and budgets at annual and seasonal scales allowed evaluating the catchment response to variation trends in atmospheric deposition and hydrological patterns. Acid precipitation was efficiently buffered by soil cations exchange and mineral weathering processes, as attested by the dominance of Ca and HCO 3 in stream waters. A decrease of sulfate acidity in precipitation following clean air measures was accompanied by an increase of alkalinity and a decrease of sulfate in stream waters. Waters of short residence time from water-saturated areas in the valley bottom and rapid shallow circulations within slopes were a very effective diluted weathering endmember contributing to stream outlet in high flow conditions, whereas evapotranspiration from saturated areas and/or deep waters with long residence time influenced the stream water concentration pattern in low flow conditions. Water discharge controlled the variations of the annual and seasonal budgets of major elements, except for nitrate and sulfate, mainly stored during summer. Soil legacy sulfate was mainly released during the first autumn stormflows, with high peak concentrations decreasing rapidly from 1990 to 1992 and disappearing afterwards. The output water flux was the main driver of the weathering rate in the acidification recovery period 1993-97, contrary to the first period 1990-92 when acidification was still under way, as attested by the weathering plateau (constant Si/ΣBC ratio). At that time, the intense weathering testifies the disturbance caused by acidification process. However, this critical zone was resilient enough to allow rapid and significant recovery over a few years following sulfur atmospheric abatement. For the future, the atmospheric nitrogen deposition pressure remains still challenging in a global change context, which argues for the necessity of long-term observatories.

A Forty-Year Karstic Critical Zone Survey (Baget Catchment, Pyrenees-France): Lithologic and Hydroclimatic Controls on Seasonal and Inter-Annual Variations of Stream Water Chemical Composition, pCO2, and Carbonate Equilibrium

“…Lastly, the rise in ion concentrations observed in stream water during autumn with the first stormflow events occurring after the strong summer evaporation period, is supposed to come from soil horizons and epikarst drainage. This "flushing effect" was evidenced by Walling and Foster [145] and later on by several authors on catchment draining various lithologies and under various climate conditions: on silicate basins such as the Mont-Lozère, the Strengbach and Ringelbach [72,111], the silicate-rich Chari-Logone River catchment in Chad [146], the Vantaa River boreal catchment in southern Finland [147], the Heidingzi agricultural catchment in China [137], and also on calcareous basins such as the Oka River forested catchment in Spain [148], the Middle Bussento Karst System in Italy [149], and the Chenqi agricultural karstic catchment [150].…”

“…Consequently, strong acid inputs also result in a decrease of the stream water alkalinity, mainly composed by HCO 3 − [72,111]. This acidification process due to strong acids can be estimated by the decrease of alkalinity.…”

“…Carbonate dissolution can also be carried out by chemical agents other than carbonic acid. Anthropic disturbances such as agricultural practices using N-fertilizers [66][67][68], atmospheric deposition from long-distance sources of air pollution [69][70][71][72] and acid mine drainage [73,74], are potential sources of sulfuric and nitric acids that can add to or substitute carbonic acid in carbonate dissolution process. Likewise, there are also natural sources of sulfuric acid from volcanoes and hot springs as well as sulfur minerals in soils and sediments [75,76].…”

Long and short-term trends of stream hydrochemistry and high frequency surveys as indicators of the influence of climate change, agricultural practices and internal processes (Aurade agricultural catchment, SW France)

“…5). Following these conditions, the first storm event loaded and carried elements accumulated in soils by concentration (elements from mineral weathering or dissolution such as Ca, Mg, Na and/or from fertiliser input, K, Cl, SO 4 ,NO 3 ) and adsorption/desorption processes, particularly obvious for sulphate as described in many catchments (Piñol et al, 1992;Probst et al, 1990;Probst and Ambroise, 2019). This high concentration was described as "the washout effect" (Piñol et al, 1992)or a"flush" effect (Reynolds and Edwards, 1995).…”

Twenty-five year record of chemicals in open field precipitation and throughfall from a medium-altitude forest catchment (Strengbach - NE France): An obvious response to atmospheric pollution trends

“…Among the anthropogenic perturbations, acid rain and more generally atmospheric acid deposition have impacted, sometimes deeply, the biogeochemical cycles of several elements (C, N, S, P, Al, H and other nutrients such as Ca and Mg; Paces, 1985;Cosby et al, 1985;Martin and Harr 1988;Landman and Bonneau (eds) 1995;Norton et al, 2000;De Vries et al, 2003;Hruska and Kram, 2003;Oulehle et al, 2006;Vanguelova et al, 2010;Norton et al, 2014;McHale et al, 2017;Oulehle et al, 2017;Probst and Ambroise, 2018). The acidification of surface waters and soils degraded the quality of stream and spring waters, lakes and soils, notably by increasing the release of base cations and metals, leading to nutrient imbalances and causing forest decline, fish death, eutrophication of lakes and corrosion of monuments and water pipes (Likens and Bormann, 1974;Charlson and Rodhe, 1982;Schulze, 1989;Probst et al, 1990aProbst et al, ,b, 1995aLikens et al, 1996;Dambrine et al, 1998a;Evans et al, 2001;Jenkins et al, 2003;Watmough and Dillon, 2003;Moldan et al, 2004;Zhang et al, 2007).…”