Prediction of Holocene Mercury Accumulation Trends by Combining Palynological and Geochemical Records of Lake Sediments (Black Forest, Germany)

Abstract

Forest vegetation plays a key role in the cycling of mercury (Hg) and organic matter (OM) in terrestrial ecosystems. Litterfall has been indicated as the major transport vector of atmospheric Hg to forest soils, which is eventually transported and stored in the sediments of forest lakes. Hence, it is important to understand how changes in forest vegetation affect Hg in soil and its biogeochemical cycling in lake systems. We investigated the pollen records and the geochemical compositions of sediments from two lakes (Schurmsee and Glaswaldsee) in the Black Forest (Germany) to evaluate whether long-term shifts in forest vegetation induced by climate or land use influenced Hg accumulation in the lakes. We were particularly interested to determine whether coniferous forests were associated with a larger export of Hg to aquatic systems than deciduous forests. Principal components analysis followed by principal component regression enabled us to describe the evolution of the weight of the latent processes determining the accumulation of Hg over time. Our results emphasize that the in-lake uptake of Hg during warm climate periods, soil erosion after deforestation and emissions from mining and other human activities triggered changes in Hg accumulation during the Holocene stronger than the changes caused by forest vegetation alone.

Why productive lakes are larger mercury sedimentary sinks than oligotrophic brown water lakes

“…S3), which is consistent with the higher concentration of chlorine in the water phase, which may be attributed to the use of road salt during winter (Supporting Information Table S4). However, notable concentrations of copper were also observed in a sediment trap of the Black Forest, which is consistent with the geochemical signals found in the lake sediment of medieval mining activities near the lake catchments (Schütze et al 2018).…”

“…Similarly, a higher percentage of peatlands in the catchment is related to both higher DOM and higher Hg concentrations in lake water (Laudon et al 2004; Wiener et al 2006). Previous studies on Holocene palynological and geochemical data derived from lake sediments indicate a significant increase in Hg concentrations when catchment vegetation shifted from deciduous to coniferous vegetation during the Holocene (Rydberg et al 2015; Schütze et al 2018).…”

Insights into the factors influencing mercury concentrations in tropical reservoir sediments

“…In our PCA analysis, the degree of forest cover surrounding the reservoirs was also related to THg for PC1 (Figure 4). Furthermore, the amounts of Hg exported to downstream systems may depend on the type of vegetation present, as vegetation type may lead to large differences in the amount of THg accumulated, retained in, and export from, the watershed 46,47 . The reservoirs included in this study are located in regions with three different biomes: Savanna, Atlantic Forest and Amazon.…”

Mercury in the sediments of selected peatlands in Małopolska region

“…Palaeogeographic studies show that the greatest amounts of mercury were introduced into the natural environmentand particularly into the atmospherearound the mid-20th century. This is reflected in the metal's content not only in bog sediments (Benoit et al 1998;Martinez-Cortizas et al 1999;Roos-Barraclough et al 2002;Biester et al 2002Biester et al , 2006Steinnes, Sjøbakk 2005;Farmer et al 2009;Zaccone et al 2009;Rydberg et al 2010;Zuna et al 2012;Allan et al 2013;Coufalík et al 2013;Küttner et al 2014;Talbot et al 2017) but also in lacustrine sediments (Lockhart et al 1998;Santos et al 2001;Cannon et al 2003;Ribeiro-Guevara et al 2010;Thevenon et al 2011;Hermanns, Biester 2013;Lacerda et al 2017;Schütze et al 2018;Guédron et al 2019;Péres-Rodrígues et al 2019;Okupny et al 2020;Juśkiewicz, Gierszewski 2022) and marine sediments (Hare et al 2010;Leipe et al 2013;Ignatavičius et al 2022).…”