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As peatlands are a major terrestrial sink in the global carbon cycle, gaining an understanding of their development and changes throughout time is essential in order to predict their future carbon budget and potentially mitigate the adverse outcomes of climate change. With this aim to understand peat development, many studies have investigated the paleoecological dynamics by analyzing various proxies, including pollen, macrofossil, elemental, and biomarker analyses. However, as each of these proxies is known to have its own benefits and limitations, examining them in parallel allows for a deeper understanding of these paleoecological dynamics at the peatland and a systematic comparison of the power of these individual proxies. In this study, we therefore analyzed peat cores from a peatland in Germany (Beerberg, Thuringia) to (a) characterize the vegetation dynamics over the course of the peatland development during the late Holocene and (b) evaluate to what extent the inclusion of multiple proxies, specifically pollen, plant macrofossils, and biomarkers, contributes to a deeper understanding of those dynamics and interaction among factors. We found that, despite a major shift in the regional forest composition from primarily beech to spruce as well as many indicators of human impact in the region, the local plant population in the Beerberg area remained stable over time following the initial phase of peatland development up until the last couple of centuries. Therefore, little variation could be derived from the paleobotanical data alone. The combination of pollen and macrofossil analyses with the elemental and biomarker analyses enabled further understanding of the site development as these proxies added valuable additional information, including the occurrence of climatic variations, such as the Little Ice Age, and more recent disturbances, such as drainage. [ABSTRACT FROM AUTHOR]

Purpose: Spatial and temporal patterns of past erosional events are a useful and needed information to explain observed soil patterns in different landscapes. Soil thickness reflects the overall expression of pedogenesis and erosion. Forested soils of Northern Germany exhibit varying soil thicknesses with thin soils on crest positions and buried soils at the footslope. The aim of this study is to reconstruct the complex soil mass redistribution and soil patterns of this forested area due to different periods of erosion and stability. Methods: We explored the explanatory power of both 10Be (in situ and meteoric) on a hillslope and we 14C-dated buried horizons at different depths. Results: The 10Be depth profiles did not show an exponential decrease with depth. They had a 'bulge' shape indicating clay translocation and interaction with oxyhydroxydes (meteoric 10Be), bioturbation and soil mass redistribution (in situ 10Be). The combined application of both 10Be and 14C dating revealed progressive and regressive phases of soil evolution. Although Melzower Forest is protected (same vegetation) since the past 250 years, both 10Be clearly indicated major soil mass redistribution along the investigated catena. Conclusion: A strong erosion impulse must have occurred between 4.5 and 6.8 kyr BP indicating an earlier human impact on soil erosion than previously postulated (~ 3 kyr earlier). Our findings correlate in fact with the first settlements reported for this region (~ 6.8 kyr BP) and show their immediate effect on soils. The overall soil redistribution rates in this forest are surprisingly similar to those obtained from a nearby agricultural area. [ABSTRACT FROM AUTHOR]

Two principal groups of processes shape mass fluxes from and into a soil: vertical profile development and lateral soil redistribution. Periods having predominantly progressive soil forming processes (soil profile development) alternate with periods having predominantly regressive processes (erosion). As a result, short‐term soil redistribution – years to decades – can differ substantially from long‐term soil redistribution; i.e. centuries to millennia. However, the quantification of these processes is difficult and consequently their rates are poorly understood. To assess the competing roles of erosion and deposition we determined short‐ and long‐term soil redistribution rates in a formerly glaciated area of the Uckermark, northeast Germany. We compared short‐term erosion or accumulation rates using plutonium‐239 and ‐240 (239+240Pu) and long‐term rates using both in situ and meteoric cosmogenic beryllium‐10 (10Be). Three characteristic process domains have been analysed in detail: a flat landscape position having no erosion/deposition, an erosion‐dominated mid‐slope, and a deposition‐dominated lower‐slope site. We show that the short‐term mass erosion and accumulation rates are about one order of magnitude higher than long‐term redistribution rates. Both, in situ and meteoric 10Be provide comparable results. Depth functions, and therefore not only an average value of the topsoil, give the most meaningful rates. The long‐term soil redistribution rates were in the range of −2.1 t ha‐1 yr‐1 (erosion) and +0.26 t ha‐1 yr‐1 (accumulation) whereas the short‐term erosion rates indicated strong erosion of up to 25 t ha‐1 yr‐1 and accumulation of 7.6 t ha‐1 yr‐1. Our multi‐isotope method identifies periods of erosion and deposition, confirming the 'time‐split approach' of distinct different phases (progressive/regressive) in soil evolution. With such an approach, temporally‐changing processes can be disentangled, which allows the identification of both the dimensions of and the increase in soil erosion due to human influence. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Plutonium (Pu) isotopes are attracting an increasing interest among fallout radionuclides (FRN) for their suitability as soil erosion/deposition tracer. Most of the recent studies were carried out on permanent grasslands and some in coniferous forests. One usually assumes that no erosion occurs in forested areas. However, this paradigm might be challenged because forest soils of Northern Germany in a hummocky ground moraine landscape exhibit sometimes a very shallow thickness on crest positions (Calcaric Regosols) and buried soils on slope positions (buried Ah as indicator). The question consequently is: Are these on-going or ancient processes? Therefore, a technique is needed that enables the determination of recent erosional process and a possibility to relate it to more long-term soil changes.In the present study, we measured the 239+240Pu stocks in a small, forested catchment (deciduous trees) that is characterised by a hummocky terrain including a kettle hole ("Melzower Forst"). Together with soil development depths, 239+240Pu stocks were correlated to relief parameters, e.g. the topographic position index (TPI). The TPI compares the elevation of each grid cell in a DEM with the mean elevation of a neighbourhood defined by a circle of a certain radius, in our study of 25 m.We compared the 239+240Pu stocks of fifteen different profiles and their relative erosion/accumulation rates to the TPI. Moreover, we used several mathematical models to evaluate the Pu-data and to quantify the erosion rates for the last 55 years. Our results show a very high spatial variability of the 239+240Pu stocks, from 35 to 70 Bq/m2, and no relationship to the TPI as has been demonstrated for arable land. Low annual rainfall, spatially distributed interception and stem flow might explain the high variability of the 239+240Pu stocks, giving rise to a patchy input pattern. The missing relationship between TPI and 239+240Pu stocks however demonstrated that no or negligible soil erosion has occurred during the last 55 years. As the forest has been protected for several hundreds of years, anthropogenic activities and maybe also natural events during the medieval times or earlier seemed to have caused strong erosional events which led to the soil pattern observed. [ABSTRACT FROM AUTHOR]

• No correlation between 239+240Pu inventories and forest landscape attributes exist. • Pu isotopes indicate no erosion for the last decades in the Melzower forest. • Forest soil thickness reveals strong ancient erosional and depositional processes. • 239+240Pu and soil morphology help to separate ancient from recent processes. Forested areas are assumed not to be influenced by erosion processes. However, forest soils of Northern Germany in a hummocky ground moraine landscape can sometimes exhibit a very shallow thickness on crest positions and buried soils on slope positions. The question consequently is: Are these on-going or ancient erosional and depositional processes? Plutonium isotopes act as soil erosion/deposition tracers for recent (last few decades) processes. Here, we quantified the 239+240Pu inventories in a small, forested catchment (ancient forest "Melzower Forst", deciduous trees), which is characterised by a hummocky terrain including a kettle hole. Soil development depths (depth to C horizon) and 239+240Pu inventories along a catena of sixteen different profiles were determined and correlated to relief parameters. Moreover, we compared different modelling approaches to derive erosion rates from Pu data. We find a strong relationship between soil development depths, distance-to-sink and topography along the catena. Fully developed Retisols (thicknesses > 1 m) in the colluvium overlay old land surfaces as documented by fossil Ah horizons. However, we found no relationship of Pu-based erosion rates to any relief parameter. Instead, 239+240Pu inventories showed a very high local, spatial variability (36–70 Bq m−2). Low annual rainfall, spatially distributed interception and stem flow might explain the high variability of the 239+240Pu inventories, giving rise to a patchy input pattern. Different models resulted in quite similar erosion and deposition rates (max: −5 t ha−1 yr−1 to +7.3 t ha−1 yr−1). Although some rates are rather high, the magnitude of soil erosion and deposition - in terms of soil thickness change - is negligible during the last 55 years. The partially high values are an effect of the patchy Pu deposition on the forest floor. This forest has been protected for at least 240 years. Therefore rather natural events and anthropogenic activities during medieval times or even earlier must have caused the observed soil pattern, which documents strong erosion and deposition processes. [ABSTRACT FROM AUTHOR]