Evidence of Springwater Acidification in the Vosges Mountains (North-East of France): Influence of Bedrock Buffering Capacity

Investigations on springwater acidity were carried out in the Vosges mountains (north-eastern France). Acid or poorly buffered spring and streamwaters were detected in the same area. The proportion of acid springwaters (pH < 5.6) is about 20% among 220 springs. The springwater pH on granite are equally spread between 5.0 and 6.8 whereas on sandstone a majority of springs is in the range 5.6 to 6.2. As a whole, but mainly on sandstone, from the 1960's to 1990's, the shape of the pH distributions shifts toward greater acidity. In the sandstone area, trends in pH, alkalinity, total hardness (corresponding to divalent cations), sulfate and nitrate were considered over the 30 yr period (1963-1996) in relation to the bedrock chemical composition. Kendall seasonal tau coefficients indicate that decreasing trends were significant for the first three parameters. Linear regression on the smoothed mean value revealed 18 and 90% decrease for pH and alkalinity respectively, for springwaters draining poor-base cation sandstone whereas only 8 and 30% decrease respectively, was observed on clay-enriched sandstone. On silica-enriched sandstone, alkalinity began to decrease in the early 70's as well as pH. Loss of alkalinity only occurred in the early 80's for springs draining clay enriched sandstone. This can be interpreted as a titration process by acid atmospheric inputs of the buffering capacity of weathering and exchange processes in the soils and the catchment bedrock. The nitrate presents an increasing step in the early seventies but possibly as a result of change in analytical technics and/or increase in atmospheric inputs mainly resulting from increase in fertiliser inputs in agricultural areas or in car traffic. Surprisingly no change in sulfate was noticed in any groups of springs probably as a result of the adsorption/mobilisation in the soils. These long-term trends in spring waters (1963-1996) confirmed the soil and streamwater acidification trends already mentioned in this region, in relation to acid atmospheric inputs since no climate nor forestry practice changes have been detected over the period. Moreover, in spite of acid atmospheric input reductions, no recovery can presently be detected

Evaluation of streamwater composition changes in the Vosges Mountains (NE France): 1955–2005

n 1995, in the southwestern Vosges Mountains (NE France), 158 of 395 streams (40%) had a pH lower than 5.5 at baseflow. As elsewhere in Europe, acid deposition has decreased since the seventies, as has base cation deposition. In order to assess the response of streamwater to decreasing deposition, we compared their present chemical composition to their former composition. All comparisons showed a decrease in sulphate concentration, which was greater on granite than on sandstone. In addition calcium, magnesium and aluminium concentrations generally decreased. Acidity in streams draining granite decreased in spring, especially during the eighties, decreases were not observed on sandstone. Continuous monitoring of 5 streams since 1998 confirmed that Al concentrations decreased while changes in pH were small. Chemical trends in streams from the Vosges massif fell between those measured in Northern Europe and Central Europe. This study provides the first broad-scale overview of surface water acidification and recovery in France and emphasizes the need for continuous monitoring to assess long-term changes in aquatic ecosystems

Parcellaires et habitat antiques des forêts du plateau de Haye en Lorraine : bilan et perspectives

Les vestiges antiques conservés sous couvert forestier sur le plateau de Haye en Lorraine, principalement des vestiges agraires et parcellaires associés à de l'habitat, font l'objet de travaux depuis une quinzaine d'années, menés par une équipe d'archéologues et de chercheurs forestiers. Cet article vise à faire un rapide bilan de l'état d'avancement de ce dossier sous forme d'un état des lieux et en ouvrant sur les questions qui peuvent intéresser le programme RurLand

Acidification des eaux de source et saturnisme dans le Massif vosgien.

Les recherches menées à  l'occasion du programme DEFORPA ont montré que les dépôts acides et la sylviculture avaient directement contribué à une acidification des sols et des eaux de surface du Massif vosgien. L'étude de la variation de l'acidité des eaux de source depuis 30 ans a confirmé une acidification progressive de l'eau captée sur les roches les plus pauvres, comme le grès vosgien. Nous avons expérimentalement vérifié que cette acidification a considérablement augmenté la teneur en plomb de l'eau chez les résidents dont les canalisations d'eau potable sont en plomb. Le nombre élevé de cas de saturnisme hydrique observés par les médecins au cours des années 1980 dans le Massif vosgien est attribué directement à  cette acidification des eaux, et indirectement et pour partie à la pollution acide atmosphérique

Le massif forestier, objet pertinent pour la recherche archéologique. L’exemple du massif forestier de Haye (Meurthe-et-Moselle)

La forêt constitue un milieu avec un potentiel archéologique très fort, notamment du fait de la bonne conservation des vestiges, mais aussi de certaines propriétés chimiques des sols. En revanche, la forêt représente en elle-même un milieu très contraignant pour les études archéologiques, qui a parfois empêché ou ralenti ces études. Les nouveaux outils à la disposition des archéologues, notamment le LiDAR pour la télédétection, mais aussi les collaborations interdisciplinaires permettent aujourd'hui de réinvestir ce milieu en changeant d'échelle. Le massif forestier par sa grande surface a en effet une échelle pertinente pour aborder l'étude d'un terroir, pour peu qu'il soit assez ancien pour avoir fossilisé des vestiges antiques ou médiévaux par exemple. Ces questions sont abordées en se basant sur l’exemple du massif forestier de Haye, massif de 11600 ha localisé en périphérie de l’agglomération nancéienne, qui fait l’objet d’études interdisciplinaires depuis une dizaine d’années.Forests are areas of high archaeological potential, particularly because of the good preservation of the remains and also because of certain chemical properties of the soil. However, forest cover is a very restraining obstacle for archaeological surveys and has sometimes hindered or even stopped them. Archaeologists now possess new tools, in particular airborne laser (LiDAR) for remote sensing but also interdisciplinary collaborative work, that enable a rediscovery of this major part of the territory, at a new scale. Forest massifs (contiguous forest areas) are a relevant scale to tackle the study of a terroir due to their large surface area, particularly if the land is old enough to have fossilized antique or medieval remains for example. Here, we develop the historical analysis of the Haye forest, situated on the outskirts of Nancy and having a total area of 11600 hectares. It has been the subject of interdisciplinary studies for the last ten years, which allowed the discovery of one of the largest Roman agricultural landscape in France.Der Wald ist eine Umgebung mit einem sehr hohen archäologischen Potential, besonders wegen der guten Erhaltung der Überreste, aber auch aufgrund gewisser chemischer Eigenschaften des Bodens. Im Gegensatz dazu ist der Wald an sich eine sehr einschränkendes Milieu für archäologische Untersuchungen, das manchmal seine Untersuchung verhindert oder verlangsamt. Die neuen, den Archäologen zur Verfügung stehenden Werkzeuge, vor allem LiDAR zur Fernerkundung, aber auch die interdisziplinäre Zusammenarbeit erlauben nun dieses Milieu in anderem Maβstab zu erkunden. Der Waldkomplex durch seine große Oberfläche hat in der Tat den geeigneten Maßstab, um die Studien vor Ort anzugehen, wenn er nur alt genug ist, um zum Beispiel antike und mittelalterliche Überreste bewahrt zu haben. Diese Fragen werden am Beispiel des Waldes von Haye angegangen, einem Waldkomplex von 11 600 ha in der Nähe der Stadt Nancy, der seit zehn Jahren Gegenstand interdisziplinärer Studien ist

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.

This study concerned a 25 yr continuous record of bulk precipitation and throughfall composition in a medium-altitude forested environment. The 1986-2012 survey from the more intense acid rain period in the mid-eighties until the present allowed the quantification of the interaction between atmospheric deposition and vegetation and the long-term evolution following pollutant emission trends. The long-term monitoring evidenced some significant temporal trends (pH, conductivity, SO42-, Cl-, NO3-, Ca2+, Mg2+, and K+). Significant decreases in the concentrations and fluxes of several ions were observed (H+ and SO42-, Cl-, and Ca2+) in open field precipitation and throughfalls. The regular and strong decrease in protons and sulfate followed the decreases in anthropogenic SO2 and NOx (proton precursors) since the 1980s. The decrease in Cl- concentrations was weaker and could have been related to the regional reduction in HCl emissions and/or to changes in the precipitation regime. The annual calcium fluxes were reduced from approximately 15 to 9 and 6 to 2 kg.ha-1 under spruces and beeches, respectively, as a consequence of reductions in anthropogenic industrial dust. In such calcium-limited resource soils, the atmospheric Ca flux exceeded the Ca flux from mineral weathering and was highly bioavailable for vegetation growth. This decrease in nutrient input had strong consequences for soil nutrients and may thus have participated in forest decline. The two tree plantations had contrasting effects on the physico-chemical parameters of the incoming precipitation with higher water interception and chemical concentrations under spruces than under beeches, which underlined the role of tree species in atmospheric inputs to soils. The structure and persistence of spruce needles enhanced the capture of particles and water, accentuating the acidity of the deposition and leading to the intensification of acidification processes, nutrient leaching in soils and forest decline. In contrast, beech leaves were able to neutralize a portion of the atmospheric protons, which minimized and reduced the negative effects of acid rain. In addition, the throughfalls represented an important part of the biological cycle of trees for some elements such as K or N, as indicated by the contrasting patterns at year and long-term scales regarding the vegetation type. However, our study indicated that the influence of tree species might change over time with changes in atmospheric pollution, in precipitation regime, or in stand structure. This study outlined the importance of the long-term record of open field precipitation and throughfalls under various tree types to better evaluate the real inputs of elements to forest ecosystems and among them, essential mineral nutrients

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.

This study concerned a 25 yr continuous record of bulk precipitation and throughfall composition in a medium-altitude forested environment. The 1986-2012 survey from the more intense acid rain period in the mid-eighties until the present allowed the quantification of the interaction between atmospheric deposition and vegetation and the long-term evolution following pollutant emission trends. The long-term monitoring evidenced some significant temporal trends (pH, conductivity, SO42-, Cl-, NO3-, Ca2+, Mg2+, and K+). Significant decreases in the concentrations and fluxes of several ions were observed (H+ and SO42-, Cl-, and Ca2+) in open field precipitation and throughfalls. The regular and strong decrease in protons and sulfate followed the decreases in anthropogenic SO2 and NOx (proton precursors) since the 1980s. The decrease in Cl- concentrations was weaker and could have been related to the regional reduction in HCl emissions and/or to changes in the precipitation regime. The annual calcium fluxes were reduced from approximately 15 to 9 and 6 to 2 kg.ha-1 under spruces and beeches, respectively, as a consequence of reductions in anthropogenic industrial dust. In such calcium-limited resource soils, the atmospheric Ca flux exceeded the Ca flux from mineral weathering and was highly bioavailable for vegetation growth. This decrease in nutrient input had strong consequences for soil nutrients and may thus have participated in forest decline. The two tree plantations had contrasting effects on the physico-chemical parameters of the incoming precipitation with higher water interception and chemical concentrations under spruces than under beeches, which underlined the role of tree species in atmospheric inputs to soils. The structure and persistence of spruce needles enhanced the capture of particles and water, accentuating the acidity of the deposition and leading to the intensification of acidification processes, nutrient leaching in soils and forest decline. In contrast, beech leaves were able to neutralize a portion of the atmospheric protons, which minimized and reduced the negative effects of acid rain. In addition, the throughfalls represented an important part of the biological cycle of trees for some elements such as K or N, as indicated by the contrasting patterns at year and long-term scales regarding the vegetation type. However, our study indicated that the influence of tree species might change over time with changes in atmospheric pollution, in precipitation regime, or in stand structure. This study outlined the importance of the long-term record of open field precipitation and throughfalls under various tree types to better evaluate the real inputs of elements to forest ecosystems and among them, essential mineral nutrients

A spatial study of the relationships between streamwater acidity and geology, soils and relief (Vosges, northeastern France)

We have used a geographic information system (GIS) to study the relationships between streamwater pH and alkalinity at base flow with geology, soils and relief in 100 forested catchments located in the sandstone portion of the Vosges mountains. where atmospheric deposition and forest cover can be considered homogeneous. At base flow, streamwater acidity depends primarily on bedrock and soil content of weatherable minerals whose dissolution neutralizes acidity. Catchments are developed on three main stratigraphic levels, consisting of two sandstone layers rich in weatherable minerals, called "rich", at the upper and lower extremity of the stratigraphic sequence, and a quartzitic sandstone, called "poor", in between. Catchments were classified into three major groups in relation to the stratigraphic sequence: (1) only "poor" bedrock, (2) "rich" upstream and "poor" downstream, (3) "poor" upstream and "rich" downstream. Results showed that streamwater pH differed depending on the group. Within each group, the pH was related to bedrock, soil and relief characteristics of the catchments. The relative surface covered by the bedrock located in the lower part of the catchment explained more than 50% of the variability of pH. More than 20% of variability could be explained by soil types in catchments composed of poor' bedrock only. Soil type apparently did not influence streamwater pH in the other groups. The catchment area, probably related to the increase of soil volume and water residence time, explained up to 20% of pH variability, depending on the catchment type

Contribution à l'étude de la répartition et du fonctionnement des sols de haute montagne.Massifs des Aiguilles Rouges et du Mont Blanc

High mountain soils from the Mont Blanc area are discribed, and their biogeochemistry studied in relation to altitude.Cette thèse présente les sols de haute montagne sur terrain cristallin (massifs Aiguilles Rouges-Mont Blanc), leur répartition en fonction des principaux facteurs du milieu, et le fonctionnement biogeochimique d'une séquence altitudinale de 4 sols. Elle suggère que parmi l'ensemble des facteurs étudiés, la stabilité du milieu, qui conditionne la durée de la pédogénèse, est fondamentale