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1.
  • Abbaszadeh Shahri, Abbas, et al. (author)
  • Landslide susceptibility hazard map in southwest Sweden using artificial neural network
  • 2019
  • In: Catena (Cremlingen. Print). - : ELSEVIER. - 0341-8162 .- 1872-6887. ; 183
  • Journal article (peer-reviewed)abstract
    • Landslides as major geo-hazards in Sweden adversely impact on nearby environments and socio-economics. In this paper, a landslide susceptibility map using a proposed subdivision approach for a large area in southwest Sweden has been produced. The map has been generated by means of an artificial neural network (ANN) model developed using fourteen causative factors extracted from topographic and geomorphologic, geological, land use, hydrology and hydrogeology characteristics. The landslide inventory map includes 242 events identified from different validated resources and interpreted aerial photographs. The weights of the causative factors employed were analyzed and verified using accepted mathematical criteria, sensitivity analysis, previous studies, and actual landslides. The high accuracy achieved using the ANN model demonstrates a consistent criterion for future landslide susceptibility zonation. Comparisons with earlier susceptibility assessments in the area show the model to be a cost-effective and potentially vital tool for urban planners in developing cities and municipalities.
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2.
  • An, Yiming, et al. (author)
  • Temporal changes on soil conservation services in large basins across the world
  • 2022
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 209
  • Journal article (peer-reviewed)abstract
    • Soil erosion is one of the main drivers of land degradation across the world, thus soil conservation service has received increasing attention. Limited studies have focused on it, hence this study investigates spatial and temporal patterns on soil conservation service in four large representative basins globally (i.e., Amazon, Mississippi, Yangtze, and Yellow River Basins), between 2001 and 2018. Annual soil conservation service and soil erosion rate are estimated under RUSLE framework, and temporal trends are analyzed using Mann-Kendall test. Additionally, impacts of soil erosion factors on spatial distribution of soil conservation service are assessed through fitting stepwise regressions annually and calculating the factors' contributions. Furthermore, driving factors of temporal changes are identified as climate or land cover dominated, and combined effect of both, according to Z scores from Mann-Kendall test for soil conservation service, R and C factors. Results show the Yangtze River Basin produces the highest average annual erosion rate (mean values of 133.28 Mg ha(-1) yr(-1) in 2001 and 143.21 Mg ha(-1) yr(-1) in 2018) and average soil conservation service (mean values of 2663.57 Mg ha(-1) yr(-1) in 2001 and 3126.43 Mg ha(-1) yr(-1) in 2018). Amazon River Basin yields the lowest average annual soil erosion rate (15.96 Mg ha(-1) yr(-1) in 2001 and 21.30 Mg ha(-1) yr(-1) in 2018), whereas the Mississippi River Basin produces the lowest average soil conservation service (388.48 Mg ha(-1) yr(-1) in 2001 and 730.70 Mg ha(-1) yr(-1) in 2018). Over the study period, soil conservation service shows an increasing trend in the Yangtze and Yellow River Basins, with average changing rates of 27.23 Mg ha(-1) yr(-1) and 16.60 Mg ha(-1) yr(-1), respectively. Increasing soil conservation service is mainly driven by climate change (i.e., rainfall) and the combined effect of climate and land cover changes, but terrain conditions are the main spatial drivers.
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3.
  • Bhandari, Rajendra, et al. (author)
  • Bulk carbon and lignin fingerprinting of catchment sediments transported by mountain rivers in Nepal Himalayas
  • 2022
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 216
  • Journal article (peer-reviewed)abstract
    • The Himalayan rivers yield the most significant flux of continental sediments into the ocean. Organic matter (OM) transported by these rivers provides a peek at the influence of diverse geological terrains, soil types, vegetation, and climate on carbon cycling within a narrow boundary. We analyzed suspended and bedload sediments from four Himalayan rivers to trace their sources, elucidate their fate during fluvial transport, and estimate the organic carbon (OC) flux. Hence, total OC (TOC), dissolved organic carbon (DOC), C:N ratios, and lignin phenols were measured. Consistent with the erosional intensity in the rivers, suspended sediment load input followed the order: Kaligandaki > Myagdikhola > Aadhikhola > Tinahukhola. C:N values in rivers from the Lesser Himalayas and Siwalik indicate sediments from mixed biogenic sources. In contrast, high TOC and C/N values in the trans-Himalaya rivers flowing through barren landscapes reflect the erosion of catchment sediments yielding petrogenic carbon. The suspended matter in rivers from the Lesser Himalayas and Siwalik has higher lignin phenol concentrations than the trans-Himalaya and Higher Himalaya rivers. The lignin phenol ratios indicate higher degradation in rivers from the trans and Higher Himalaya sections. This implies that only a small fraction of the terrestrial OM transported by these rivers deposits in the ocean sink. In contrast, rivers from the Lesser Himalayas and Siwaliks sequester a significant amount of OM bound to their bedload. As a result, these rivers transferred lower particulate OC (POC) but higher DOC than similar rivers worldwide. Rivers from Lesser Himalayas and Siwaliks transfer > 90 % of annual POC flux during monsoons. Finally, although Himalayan rivers transport less OC than other global rivers traversing densely vegetated landscapes, the sheer number of these rivers has significant implications on the fate and transport of total OC from catchments sediments.
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4.
  • Chen, Peng, et al. (author)
  • Relationship between precipitation and Be-10 and impacts on soil dynamics
  • 2020
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 195
  • Journal article (peer-reviewed)abstract
    • Meteoric beryllium-10 (Be-10) is commonly used as a proxy of landscape dynamics (erosion and sedimentation rates) and soil development. Soil represents the first-stage reservoir of meteoric Be-10, and variability in the concentration of the isotope in soils may be affected by soil properties and atmospheric deposition. Although many investigations have targeted this issue, there are still problems in estimating the atmospheric input of the isotope in different soil environments. Here, we used Be-10 data measured in soils distributed across China to explore the potential influence of meteorological and pedological conditions on the isotope concentration and related applications. In addition, to determine the mechanisms controlling Be-10 concentrations in topsoil on a regional scale, the soil samples were sub-divided into 18 different catchments according to fluvial systems. The results indicated that there were significant negative correlations between precipitation and the soil Be-10 concentration in high-precipitation regions (> 1200 mm.y(-1)) and significant positive correlations for soils in low precipitation regions (< 1200 mm.y(-1)). The data also revealed that precipitation is the most important variable controlling the Be-10 concentration in soils of China when compared with the effects of soil properties such as grain size, mineralogy, pH, and cation exchange capacity. Land use and soil erosion may have limited impacts on the distribution of Be-10 in soils.
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5.
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6.
  • Gao, Fuyuan, et al. (author)
  • Rapid retreat of the East Asian summer monsoon on the western Chinese loess Plateau during the middle to late Holocene and its environmental and societal implications
  • 2023
  • In: Catena (Cremlingen. Print). - 0341-8162 .- 1872-6887. ; 231
  • Journal article (peer-reviewed)abstract
    • Spatiotemporal changes in the Holocene climate of the arid region of China were principally caused by shifts in the intensity and location of the East Asian summer monsoon (EASM). However, our knowledge of these EASM variations is limited, especially since the middle Holocene. We investigated two aeolian sedimentary sections (the Linxia/LX and Gulang/GL sections) on the western Chinese Loess Plateau (CLP), to explore the variations in the intensity and location of the EASM and their impact on the regional environment and human cultural development during the middle to late Holocene. The longitudes of these two loess sections are similar, but the GL section is located on the northern edge of the CLP, in the eastern Hexi Corridor, and it is situated further north than the LX section. The chronologies of both sections are based on accelerator mass spectrometry C-14 dating, and environmental magnetic parameters and grain size end-members were used to reconstruct their moisture histories. The results suggest that the climate at the LX section was relatively dry before 3.5 ka, after which it became wetter. In contrast, at the GL section, the climate was also relatively dry before 3.5 ka, with the wettest conditions occurring during 3.5-2 ka, but subsequently there was an abrupt shift to a dry climate. We suggest that these spatiotemporal patterns reflect the westward movement and rapid southward retreat of the EASM and the linked monsoon rainfall belt. TraCE-21 ka climate simulation results support our inference. We also found that, compared with other ancient cultures in the eastern Hexi Corrido, sites of the Shajing culture, dated to similar to 2.4-2.8 ka, are predominantly located in areas that are arid at the present-day, and relatively distant from rivers. We suggest that this distribution pattern reflected the occurrence of a humid climate during the period of the Shajing culture, thus demonstrating the impact of the EASM on cultural development in this region.
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7.
  • Ghaderi, Abdolvahed, et al. (author)
  • A visualized hybrid intelligent model to delineate Swedish fine-grained soil layers using clay sensitivity
  • 2022
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 214, s. 106289-
  • Journal article (peer-reviewed)abstract
    • In the current paper, a hybrid model was developed to generate 3D delineated soil horizons using clay sensitivity (St) with 1 m depth intervals in a landslide prone area in the southwest of Sweden. A hybridizing process was carried out using generalized feed forward neural network (GFFN) incorporated with genetic algorithm (GA). The model was conducted by means of seven variables consisting of the geographical coordinates and piezocone penetration test data (CPTu). The output of model (St) as a description of the effect of soil disturbance on shear strength plays a significant role in landslides in Sweden and thus can be applied for site-specific evaluation. Therefore, the use of St-based models to delineate soil layers can be a cost-effective solution to improve geoengineering design practices and assist in the reduction of related environmental risks, such as catastrophic landslide events or excavation failures. Evaluated model performance based on different applied soil classifications showed 4.38% improvement in the predictability level of GFFN-GA compared to optimum GFFN. Accordingly, delineated soil layers were evaluated using different criteria including previous landslides as well as supplementary geophysical and geotechnical investigations. The results show that the adopted hybrid GFFN-GA is an efficient tool that can potentially be applied to delineate soil horizons for the prediction of future events.
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8.
  • Kuhry, Peter, et al. (author)
  • Soil organic carbon stocks in the high mountain permafrost zone of the semi-arid Central Andes (Cordillera Frontal, Argentina)
  • 2022
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 217
  • Journal article (peer-reviewed)abstract
    • This study presents the first detailed soil organic carbon (SOC) inventory for a high mountain permafrost zone in the semi-arid Central Andes of South America. We describe plant cover and soil profiles at 31 sites representing the main land cover and landform types in the Veguitas catchment (Cordillera Frontal, Argentina), which ranges in elevation from c. 3000 to 5500 m. The vegetated area with soil development is largely confined to altitudes of < 3650 m and represents only 8.2% of the total catchment area. Mean SOC 0-100 cm storage for the vegetated portion of the catchment is 3.62 kg C m(-2), which is reduced to 0.33 kg C m(-2) if we consider negligible SOC stocks in the extensive bare ground and glaciated areas at higher elevations. Hotspots of SOC storage are wet meadow areas, with peat deposits up to 102 cm deep and a maximum observed total SOC storage of 53.07 kg C m(-2). These wet meadow areas, however, occupy only 0.11% of the total catchment area and their contribution to mean SOC storage is limited. Among soils at well-drained sites, highest mean SOC 0-100 cm storage is found on backslope positions of moraines that predate the Last Glacial Maximum (6.87 kg C m(-2)). Only 2% of all SOC stocks in the catchment are found in permafrost terrain and none are located in the permafrost layer itself. The main ecoclimatic control on SOC storage is plant cover, with vegetation limits being sensitive to ambient tem-perature. Projected increases in temperatures will not remobilize any frozen SOC stocks but will likely result in an upward shift of the upper vegetation belt with soil development creating new areas of phytomass carbon and SOC storage. The area is expected to represent a net C sink and thus a negative feedback on future global warming.
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9.
  • Lin, Qi, et al. (author)
  • Organic carbon burial in a large, deep alpine lake (southwest China) in response to changes in climate, land use and nutrient supply over the past ~100 years
  • 2021
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 202
  • Journal article (peer-reviewed)abstract
    • Inland waterbodies play an important role in the global carbon cycle, acting both as carbon sources with organic carbon (OC) mineralization and as sinks with OC burial in sediments. Under recent impacts of global warming, anthropogenic land-use change and nutrient supply, however, there is a limited knowledge regarding OC dynamics in sediments of large, deep lakes especially in subtropical alpine regions. Here, we studied the patterns of OC burial and the potential regulating factors using multiple sedimentary proxies and observational records in Lugu Lake (southwest China) over the past ~100 years. Comparisons of 15 sediment cores in different areas of the lake reveal similar temporal trends in OC content and other sediment parameters, indicating coherent patterns of whole-lake sedimentary environmental change dominated by watershed human perturbation. Based on C/N ratios and δ13Corg analyses, the sediment OC has primarily been autochthonous in source. OC accumulation rates (OCAR) increased during 1880–1980, from ~14 to 43 g C m−2 yr−1 in a central core (LGS), mainly resulting from elevated primary production under increased phosphorus input and soil erosion. Subsequently, OCAR decreased considerably to ~15 g C m−2 yr−1, although the phosphorus supply and lake primary productivity remained high. We infer the OCAR decline likely resulted from increased organic matter decomposition and OC mineralization in the water column because of climate warming and lake-water thermal stratification. This phenomenon might mask the positive contribution of primary production to OC burial. Our findings suggest that the commonly observed synergistically positive effects of warming and eutrophication on sediment OC burial may be impaired in deep lakes, which needs further investigations across ecological, climatic and land-use gradients.
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10.
  • Lin, Qi, et al. (author)
  • Spatial variation of organic carbon sequestration in large lakes and implications for carbon stock quantification
  • 2022
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 208
  • Journal article (peer-reviewed)abstract
    • Lakes are recognized as critical zones for carbon transformation and storage, and lacustrine sediments sequestrate considerable amounts of organic carbon (OC). Understanding sedimentation processes and OC burial patterns is crucial to clarifying lakes’ role in global carbon cycling. However, OC sedimentation may be quite spatially heterogeneous within an aquatic system, owing to the differences in OC production and sources, hydrodynamic conditions and underwater topography. The uncertainties in estimating OC sequestration in the world’s large lakes remain poorly constrained. This study takes the test case of two large lakes (50 and 249 km2) with different water depth and trophic status, using a multi-core paleolimnological technique, to identify the spatial variation in OC accumulation and its main influencing factors over the past century. Results of multi-core comparisons revealed similar temporal trends in major organic and nutrient parameters, suggesting coherent processes of whole-lake sedimentary environment changes for each lake. The OC preserved in sediments was primarily of autochthonous origin. However, OC standing stocks varied ∼3-fold spatially, and average OC accumulation rates ranged between 9.5–27.4 g m−2 yr−1 (post–1963 in oligo-mesotrophic deep-lake Lugu) and between 17.4–43.5 g m−2 yr−1 (post–1980 in eutrophic shallow-lake Erhai), respectively. These variations were primarily attributable to the spatial differences in aquatic primary production and terrestrial detritus supply relating to anthropogenic land-use change and phosphorus loading, rather than intra-lake sediment focusing-related transport and redistribution. The single central-core approach from Lugu Lake would overestimate whole-lake OC stock by 32% or underestimate the value by 48%, indicating spatial variability is an important source of uncertainty for OC stock quantification in similar large and/or morphometrically complex waterbodies. Therefore, spatial heterogeneity of OC accumulation in inland waters requires considerable research with well-placed multi-cores to provide a deeper understanding of carbon sequestration patterns and mechanisms.
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12.
  • Pietroń, Jan, et al. (author)
  • Extreme spatial variability in riverine sediment load inputs due to soil loss in surface mining areas of the Lake Baikal basin
  • 2017
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 152, s. 82-93
  • Journal article (peer-reviewed)abstract
    • Surface mining can contribute to increasing riverine loads of potentially metal-enriched sediments. However, the related human disturbances and natural processes reflect a great complexity, which hinders quantitative Understanding. We here consider the Zaamar Goldfield in Mongolia, one of the world's largest placer mining sites, located in the Tuul River basin (upper Lake Baikal basin). A main study aim is to investigate relations between patterns of increased sediment loads along the Tuul River and the (spatially variable) area coverage of active or recently abandoned placer mines in the river vicinity. Specifically, we compare observed loads derived from nested catchment areas with the output from spatially distributed soil erosion modelling. Results showed that riverine sediment loads in mining areas reflect soil losses both from soil erosion and direct human impacts (e.g. waste water discharge), which are two to three orders of magnitude higher than the input from natural areas dominated by soil erosion alone. Notably, the sediment load contributions from the mining areas were insensitive to changes in hydrometeorological conditions, whereas contributions from natural areas were much lower during drier periods (as expected when governed by soil erosion by water). Accordingly, the relative contribution to the total sediment load (TSL) of metal-enriched soil from mining areas is likely to be particularly pronounced (with estimated values of about 80% of TSL) under drier hydrometeorological conditions. This is consistent with observations of considerably elevated metal concentrations under low flow conditions and implies that if annual average discharge continues to decrease in the Tuul River as well as the entire Selenga River system, increased metal concentrations may be one of the consequences.
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13.
  • Plotzki, A., et al. (author)
  • Geomorphology and evolution of the late Pleistocene to Holocene fluvial system in the south-eastern Llanos de Moxos, Bolivian Amazon
  • 2015
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 127, s. 102-115
  • Journal article (peer-reviewed)abstract
    • In the Bolivian Amazon several paleochannel generations are preserved. Their wide spectrum of morphologies clearly provides crucial information on the type and magnitude of geomorphic and hydrological changes within the drainage network of the Andean foreland. Therefore, in this study we mapped geomorphological characteristics of paleochannels, and applied radiocarbon and optically stimulated luminescence dating. Seven paleochannel generations are identified. Significant changes in sinuosity, channel widths and river pattern are observed for the successive paleochannel generations. Our results clearly reflect at least three different geomorphic and hydrological periods in the evolution of the fluvial system since the late Pleistocene. Changes in discharge and sediment load may be controlled by combinations of two interrelated mechanisms: (i) spatial changes and re-organizations of the drainage network in the upper catchment, and/or (ii) climate changes with their associated local to catchment-scale modifications in vegetation cover, and changes in discharge, inundation frequencies and magnitudes, which have likely affected the evolution of the fluvial system in the Llanos de Moxos. In summary, our study has revealed the enormous potential which geomorphic mapping and analysis combined with luminescence based chronologies hold for the reconstruction of the late Pleistocene to recent fluvial system in a large portion of Amazonia.
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14.
  • Qin, Zhilian, et al. (author)
  • Vertical distributions of organic carbon fractions under paddy and forest soils derived from black shales : Implications for potential of long-term carbon storage
  • 2021
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 198, s. 1-8
  • Journal article (peer-reviewed)abstract
    • Black shales are characterized by a high content of organic carbon (C). Few studies have focused on the influence of land use on soil organic C (SOC) fractions from soils derived from black shale (black shale soils). The objective of this study was to elucidate the influence of land use on SOC fractions in black shale soils combining chemical determination and stable C isotope analysis techniques. Herein, we determined labile organic C (LOC), semilabile organic C (Semi-LOC), and recalcitrant organic C (ROC) fractions in various depths of soils in paddy fields (0-70 cm) and forests (0-120 cm) from black shale distribution region in Hunan province, China, and then investigated delta C-13 values of these soils. Results showed that the contents of LOC, Semi-LOC, and ROC in paddy soils (1.63-7.35 g kg(-1), 0.35-1.21 g kg(-1), and 3.75-14.8 g kg(-1), respectively) and forest soils (0.73-4.94 g kg(-1), 0.12-0.89 g kg(-1), and 1.44-8.96 g kg(-1), respectively) are significantly decreased with increasing depth. The contribution made by LOC to SOC in paddy soils was significantly lower than that in forest soils, while the contribution made by ROC to SOC was significantly higher in paddy soils than that in forest soils. In these two land uses, the delta C-13 values were higher in SOC compared to the ROC fraction, while the delta C-13 values were close in the ROC fraction below 20 cm soil depth. Our study indicated that i) new C is mainly limited to the surface soil layer (0-10 cm) in forests, while it can be leached along the soil profiles in paddy fields; ii) the estimated ROC pool is similar to 900 Pg within the 0-100 cm soil layer in terrestrial ecosystems, which should better represent the ability of soil C sequestration.
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15.
  • Rahmati, Omid, et al. (author)
  • Contribution of physical and anthropogenic factors to gully erosion initiation
  • 2022
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 210, s. 105925-105925
  • Journal article (peer-reviewed)abstract
    • Losses of large volumes of soil through gully formation lead to serious environmental, societal, and economic problems for human societies. This study establishes a framework based on an artificial intelligence approach to investigate the impact of geo-environmental and topo-hydrological factors on gully occurrences in the Biram region, Iran. The maximum entropy, random forest, and boosted regression trees machine-learning models were applied. The relative importance of variables (RIV) was then determined and gully erosion susceptibility maps were generated. Model results were evaluated using cutoff–dependent and –independent metrics. All models identified road construction as the main cause of gully formation in the study region (RVI ranged between 27% and 34%), and a medium contribution of distance from stream (RVI = 15–18%), lithology (RVI = 12–15%) and land use (RVI = 8–12%). Other factors such as drainage density, topographic wetness index, aspect, slope, profile curvature, elevation and plan curvature showed lower relative importance (RIV < 10%). Planners should pay attention to minimizing gully erosion along roads, so that river systems and downstream communities are adequately protected.
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16.
  • Ramage, Justine L., et al. (author)
  • Distribution of carbon and nitrogen along hillslopes in three valleys on Herschel Island, Yukon Territory, Canada
  • 2019
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 178, s. 132-140
  • Journal article (peer-reviewed)abstract
    • Thermokarst results from the thawing of ice-rich permafrost and alters the biogeochemical cycling in the Arctic by reworking soil material and redistributing soil organic carbon (SOC) and total nitrogen (TN) along uplands, hillslopes, and lowlands. Understanding the impact of this redistribution is key to better estimating the storage of SOC in permafrost terrains. However, there are insufficient studies quantifying long-term impacts of thaw processes on the distribution of SOC and TN along hillslopes. We address this issue by providing estimates of SOC and TN stocks along the hillslopes of three valleys located on Herschel Island (Yukon, Canada), and by discussing the impact of hillslope thermokarst on the variability of SOC and TN stocks. We found that the average SOC and TN 0-100 cm stocks in the valleys were 26.4 +/- 8.9 kg C m(-2) and 2.1 +/- 0.6 kg N m(-2). We highlight the strong variability in the soils physical and geochemical properties within hillslope positions. High SOC stocks were found at the summits, essentially due to burial of organic matter by cryoturbation, and at the toeslopes due to impeded drainage which favored peat formation and SOC accumulation. The average carbon-to-nitrogen ratio in the valleys was 12.9, ranging from 9.7 to 18.9, and was significantly higher at the summits compared to the backslopes and footslopes (p < 0.05), suggesting a degradation of SOC downhill. Carbon and nitrogen contents and stocks were significantly lower on 16% of the sites that were previously affected by hillslope thermokarst (p < 0.05). Our results showed that lateral redistribution of SOC and TN due to hillslope thermokarst has a strong impact on the SOC storage in ice-rich permafrost terrains.
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17.
  • Raúl Sitoe, Sandra, 1979-, et al. (author)
  • Paleo-environment and flooding of the Limpopo River-plain, Mozambique, between c. AD 1200-2000
  • 2015
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 126, s. 105-116
  • Journal article (peer-reviewed)abstract
    • Multi-proxy analysis was performed on a radiocarbon-dated core, collected from a relic oxbow lake in theLimpopo River-plain, Mozambique, with the aim to reconstruct paleo-environment and past flooding of thelower river system over the past c. 800 years. An additional objective was to evaluate and investigate the potentialuse of different proxies as recorders of paleo-flooding events and paleo-environmental variability within thefloodplain. The proxies applied in this study were: mineral magnetic properties, grain-size distribution, organiccarbon content and diatom microfossil assemblages.We found that sediment grain-size and mineral magneticproperties of the minerogenic fraction were the most sensitive proxies in terms of detecting signals from highintensityriver-discharge events. In the 800 year long sequence, variations in sand content, magnetic susceptibilityand saturation isothermal remnant magnetization suggest at least four major flooding events at the siteduring the reconstructed period; in the mid-1200, late-1300, mid-1500 AD and during the last century. Thediatom proxy reflects the development of the site from an open oxbow lake to a mainly terrestrial area. Thediatom assemblage indicates that open lake conditions prevailed at the site between c. AD 1200–1400, withperiodic inundation by marine water, most likely due to late Holocene sea-level changes. From c. AD 1400 andonwards, diatoms were rarely deposited at the site, which indicates drier conditions. This was a result of soilformation and gradual in-filling of the lake, a processwhich possiblywas accentuated by a regionally dry climatesituation. Our study shows that oxbow lakes and the proxies used here have great potential for reconstructingflooding events, a knowledge that is crucial for potential prediction and mitigation of flooding events inMozambique in the future. Although chronological uncertainties limit comparisons to other paleoenvironmentalrecords, it seems that the flooding events recorded at our site occurred both during regionallywet and dry periods. Our data infer however, that flooding was probably more clearly recorded during thelake-stages than during infilled stage, probably as the terrestrial environment was more exposed to erosion.
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18.
  • Ray, Sumit Kumar, et al. (author)
  • Modern analogue to past coseismic ground uplift in North Andaman, India
  • 2021
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 205
  • Journal article (peer-reviewed)abstract
    • Dynamics of surface geological processes, triggered by coseismic ground uplift following the 2004 Sumatra-Andaman earthquake (M-w > 9.2), provide a modern analogue for assessing the paleoseismic significance of an enigmatic subsurface peat occurrence within beach sands in the western coast of North Andaman Island. The megathrust earthquake uplifted vast stretches of coastal intertidal zones to supratidal levels. As a result, intertidal flora, including mangroves, desiccated and perished. Mass mortality of the flora continued even three years after the earthquake and generated a large volume of forest debris. Coastal waves pushed the debris to the high tide line where the accumulated debris would be gradually buried, and would subsequently transform into linear peat bodies keeping a record of the seismic event in 2004. Accordingly, we have interpreted a linear strand-parallel peat occurrence in beach sand as a record of earlier mass mortality of plants likely associated with a coseismic ground uplift. Stable isotope studies indicate that local intertidal flora is the source of the peat organic matter. Moreover, the 1817 CE calibrated mean AMS radiocarbon age of the peat suggests recurrence of a megathrust earthquake in the Andaman subduction zone about 200 years ago.
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19.
  • Rodrigues, Leonor, et al. (author)
  • Pre-Columbian agriculture in the Bolivian Lowlands : Construction history and management of raised fields in Bermeo
  • 2015
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 132, s. 126-138
  • Journal article (peer-reviewed)abstract
    • Recent archaeological research suggests that some parts of the Amazon Basin were significantly modified by pre-Columbian populations. One of the most impressive examples of such transformations is the raised fields of south-western Amazonia, in the Llanos de Moxos in the Bolivian Lowlands. Despite a growing interest in raised field agriculture, due to the important role it seems to have played in the development of pre-Columbian complex societies, very few field-based investigations have been performed in the Amazon Basin. As a result, there is limited knowledge of how these fields were constructed, managed and within which time-frame they were in use. This study provides a new interpretation of how pre-Columbian raised fields were managed and a chronological sequence of their utilisation and eventual abandonment. Fieldwork was carried out in the indigenous community of Bermeo, in the vicinity of San Ignacio de Moxos, where some of the best preserved fields in the Llanos Moxos are found. Magnetic susceptibility and the geochemistry of the sediments, combined with radiocarbon and optically stimulated luminescence dating, show that the raised fields were in intermittent use since as early as AD 570-770. The original surface on which the fields were built and distinct periods of construction and use have been identified. The data suggests that raised fields were built during a few separate construction events, probably linked to periods of more frequent and severe floods. The study challenges the most widely accepted theory that suggests that pre-Columbians were able to cultivate these fields on a continuous basis by transferring nutrient-rich sediments from the canals to the fields. We conclude that pre-Columbians built raised fields to overcome periods of increased flooding, with the main objective of improving drainage.
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20.
  • Rydberg, Johan, 1976-, et al. (author)
  • Biogeochemical cycling in a periglacial environment : a multi-element mass-balance budget for a catchment in West Greenland
  • 2023
  • In: Catena (Cremlingen. Print). - 0341-8162 .- 1872-6887. ; 231
  • Journal article (peer-reviewed)abstract
    • There is an increased awareness that the biogeochemical cycling at high latitudes will be affected by a changing climate. However, because biogeochemical studies most often focus on a limited number of elements (i.e., C, P and N) we lack baseline conditions for many elements. In this work, we present a 42-element mass-balance budget for lake dominated catchment in West Greenland. By combining site specific concentration data from various catchment compartments (precipitation, active layer soils, groundwater, permafrost, lake water, lake sediments and biota) with catchment geometries and hydrological fluxes from a distributed hydrological model we have assessed present-day mobilization, transport and accumulation of a whole suite of elements with different biogeochemical behavior. Our study shows that, under the cold and dry conditions that prevails close to the inland ice-sheet: i) eolian processes are important for the transport of elements associated with mineral particles (e.g., Al, Ti, Si), and that these elements tend to accumulate in the lake sediment, ii) that even if weathering rates are slowed down by the dry and cold climate, weathering in terrestrial soils is an important source for many elements (e.g., lanthanides), iii) that the cold and dry conditions results in an accumulation of elements supplied by wet deposition (e.g., halogens) in both terrestrial soils and the lake-water column, and iv) that lead and sulfur from legacy pollution are currently being released from the terrestrial system. All these processes are affected by the climate, and we can therefore expect that the cycling of the majority of the 42 studied elements will change in the future. However, it is not always possible to predict the direction of this change, which shows that more multi-element biogeochemical studies are needed to increase our understanding of the consequences of a changing climate for the Arctic environment.
  •  
21.
  • Siewert, Matthias Benjamin, et al. (author)
  • Landscape controls and vertical variability of soil organic carbon storage in permafrost-affected soils of the Lena River Delta
  • 2016
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 147, s. 725-741
  • Journal article (peer-reviewed)abstract
    • To project the future development of the soil organic carbon (SOC) storage in permafrost environments, the spatial and vertical distribution of key soil properties and their landscape controls needs to be understood. This article reports findings from the Arctic Lena River Delta where we sampled 50 soil pedons. These were classified according to the U.S.D.A. Soil Taxonomy and fall mostly into the Gelisol soil order used for permafrost-affected soils. Soil profiles have been sampled for the active layer (mean depth 58 ± 10 cm) and the upper permafrost to one meter depth. We analyze SOC stocks and key soil properties, i.e. C%, N%, C/N, bulk density, visible ice and water content. These are compared for different landscape groupings of pedons according to geomorphology, soil and land cover and for different vertical depth increments. High vertical resolution plots are used to understand soil development. These show that SOC storage can be highly variable with depth. We recommend the treatment of permafrost-affected soils according to subdivisions into: the surface organic layer, mineral subsoil in the active layer, organic enriched cryoturbated or buried horizons and the mineral subsoil in the permafrost. The major geomorphological units of a subregion of the Lena River Delta were mapped with a land form classification using a data-fusion approach of optical satellite imagery and digital elevation data to upscale SOC storage. Landscape mean SOC storage is estimated to 19.2 ± 2.0 kg C m− 2. Our results show that the geomorphological setting explains more soil variability than soil taxonomy classes or vegetation cover. The soils from the oldest, Pleistocene aged, unit of the delta store the highest amount of SOC per m2 followed by the Holocene river terrace. The Pleistocene terrace affected by thermal-degradation, the recent floodplain and bare alluvial sediments store considerably less SOC in descending order.
  •  
22.
  • Sun, Yuanhao, et al. (author)
  • Pollen-based reconstruction of total land-cover change over the Holocene in the temperate steppe region of China : An attempt to quantify the cover of vegetation and bare ground in the past using a novel approach
  • 2022
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 214
  • Journal article (peer-reviewed)abstract
    • Fossil pollen data are essential for reconstructing ancient vegetation and land-cover changes. Sugita's REVEALS model is the best method to estimate regional plant cover (in percentage cover) using pollen data from lakes. Such reconstructions imply that the sum of all plants' cover is 100%. However, land cover is not always represented by vegetation alone, the area of bare ground can be significant in many types of biomes, e.g., in alpine or steppe regions. Here we define "total land cover " as the sum of vegetation cover (VegC) and bare ground (BareC). In this study, we use the relationship between tree pollen percentages and both tree cover (TreeC) and VegC (=TreeC + herb cover (HerbC)) based on a dataset of modern pollen assemblages and related total land cover. This relationship is applied to estimate past "actual " vegetation cover (a-VegC) from fossil pollen percentages using the Modern Analogue Technique (MAT). The REVEALS (RV) model can then be applied to the same fossil pollen records to estimate regional cover of individual plant taxa (RV PlantC; e.g., RV PinusC, etc.), total tree cover (RV-TreeC) and total herb cover (RV-HerbC). These cover values can then be converted into RV aPlantC, RV a-TreeC and RV a-HerbC using the MAT-reconstructed a-VegC (e.g., RV PinusC x MAT a-VegC = RV aPinusC; RV-TreeC x MAT a-VegC = RV a-TreeC, etc.). The results of leave-one-out cross-validation indicates that the MAT reconstructions using the modern pollen assemblages provide values of a-TreeC, a-HerbC and BareC mostly very similar to the modern vegetation data. We further tested the method using pollen assemblages from lake surface sediments of 11 lakes and the results also suggest a good performance of MAT-based reconstruction. We then applied the proposed method (MAT-REVEALS) to four Holocene pollen records available from the study area to evaluate the feasibility of the strategy to reconstruct past actual plant cover. The results suggest that the method provides plausible estimates of vegetation cover for the sub-regions within the study area. The results from Lake Daihai over the last 10,000 years BP are interpreted and discussed in more details to evaluate the effects of possible departures from the approach assumptions.
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23.
  • Veit, Heinz, et al. (author)
  • The Southern Westerlies in Central Chile during the two last glacial cycles as documented by coastal aeolian sand deposits and intercalating palaeosols
  • 2015
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 134, s. 30-40
  • Journal article (peer-reviewed)abstract
    • Changes in the position and intensity of the Southern Westerly Winds (SWW) and related causal processes during the Quaternary are controversial and not well understood. Here, we present a record from continental Central Chile, based on coastal aeolian sand and dunes with intercalated palaeosols, reaching back 190 ka in time. Sixteen samples for luminescence dating and additional samples for geochemical procedures were analysed from three locations in the Norte Chico (La Serena, Los Vilos, Las Ventanas). Besides the recent Bw-horizons, four palaeosols (Btb1, Btb2, Btb3, Btb4) are identified. They formed in periods with stable surface conditions and a relatively dense vegetation cover, whereas sand accumulation reflects increased aeolian activity under dry conditions and, in parts, glacial sea level lowering. Three of these soils are well bracketed by luminescence data to <14 ka (Bw), 59-47 ka (Btb4) and 135-125 ka (Btb2). The formation of Btb1 and Btb3 tentatively occurred at 190-160 ka and 107-95 ka. Btb-horizons are interpreted to reflect wetter conditions than modern ones (Bw-horizons). Since the only way to bring wetter conditions to the coastal area of the Norte Chico are the SWW, the documented changes should reflect changes in paleo atmospheric circulation. The more humid periods appear to show a periodicity, dominated by the obliquity cycle. Increased Antarctic sea-ice during austral winter combined with a weak South Pacific Anticyclone at subtropical latitudes, seem to have favoured winter incursions of humid air masses from the Westerlies.
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24.
  • Vigiak, Olga, et al. (author)
  • A semi-empirical model to assess uncertainty of spatial patterns of erosion
  • 2006
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 66:3, s. 198-210
  • Journal article (peer-reviewed)abstract
    • Distributed erosion models are potentially good tools for locating soil sediment sources and guiding efficient Soil and Water Conservation (SWC) planning, but the uncertainty of model predictions may be high. In this study, the distribution of erosion within a catchment was predicted with a semi-empirical erosion model that combined a semi-distributed hydrological model with the Morgan, Morgan and Finney (MMF) empirical erosion model. The model was tested in a small catchment of the West Usambara Mountains (Kwalei catchment, Tanzania). Soil detachability rates measured in splash cups (0.48-1.16gJ(-1)) were close to model simulations (0.30-0.35gJ(-1)). Net erosion rates measured in Gerlach troughs (0.01-1.05kgm(-2) per event) were used to calibrate the sediment transport capacity of overland flow. Uncertainties of model simulations due to parameterisation of overland flow sediment transport capacity were assessed with the Generalized Likelihood Uncertainty Estimation (GLUE) methodology. The quality of the spatial predictions was assessed by comparing the simulated erosion pattern with the field-observed erosion pattern, measuring the agreement with the weighted Kappa coefficient of the contingency table. Behavioural parameter sets (weighted Kappa > 0.50) were those with short reinfiltration length (< 1.5m) and ratio of overland flow power a to local topography power close to 0.5. In the dynamic Hortonian hydrologic regime and the dissected terrain of Kwalei catchment, topography controlled the distribution of erosion more than overland flow. Simulated erosion rates varied from -4 to +2kgm(-2) per season. The model simulated correctly around 75% of erosion pattern. The uncertainty of model predictions due to sediment transport capacity was high; around 10% of the fields were attributed to either slight or severe erosion. The difficult characterisation of catchment-scale effective sediment transport capacity parameters poses a major limit to distributed erosion modelling predicting capabilities. Crown Copyright (c) 2006 Published by Elsevier B.V. All rights reserved.
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25.
  • Wei, Lezhang, et al. (author)
  • River morphology redistributes potentially toxic elements in acid mine drainage-impacted river sediments: Evidence, causes, and implications
  • 2022
  • In: Catena (Cremlingen. Print). - : ELSEVIER. - 0341-8162 .- 1872-6887. ; 214
  • Journal article (peer-reviewed)abstract
    • River morphology plays a vital role in the transport of substance within them. However, our understanding of how natural and artificial morphologies redistribute different potentially toxic elements in acid mine drainage (AMD)-contaminated rivers remains poor. In this study, we linked morphological river features and physicochemical sediment characteristics to trace the redistribution of various potentially toxic elements and elucidate their implications for remediating rivers prone to AMD pollution. A dense network of sediment/soil samples was collected from different river morphological units, such as channels, dam reservoirs, pools, floodplain sandbars and wetlands in an AMD-impacted river. The analyses showed that the contaminant levels in channel generally decreased downstream from the headwater mine site, however, local fluctuations in certain areas were observed due to the trapping effect of various dams along the river. The As and Pb concentrations were higher at floodplain sandbars, while river channels exhibited higher Cd and Zn contamination. The concentrations and geochemical fractions of As, Cd, Cu, Pb and Zn in sediment/soil cores from sandbar and river channel also varied. Additionally, structural equation modeling analysis indicated that spatial variations in contaminant distributions were directly affected by physicochemical properties (such as the soil/sediment Fe, Zn, and S concentrations, and pH), which are indirectly affected by river morphology. The diverse morphology of the river redistributed AMDderived contaminants and could be used to identify contamination hotspots. Our analyses suggested that the feasibility and efficiency of previously proposed countermeasures varied for contaminants in different geomorphological units. In river channels, As uptake from sediments by aquatic plants may be less efficient than Cd, Cu, and Zn uptake due to its lower bioavailability. Moreover, vegetation prevented contaminant enriched soil particle erosion more than it aided in the phytoremediation of As- and Pb-contaminated sandbars. Thus the finding of this study provide a theoretical foundation for further studies on the transport and storage of AMDderived contaminants in similar rivers, along with the development of targeted remediation methods.
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26.
  • Westerberg, Lars-Ove, et al. (author)
  • Geomorphology and pedology of the Engaruka archaeological environment, Tanzania, and the effects of the 1997-1998 El Nino flash-flood
  • 2018
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 163, s. 244-256
  • Journal article (peer-reviewed)abstract
    • Here we analyse geomorphic, pedologic and hydrologic processes of relevance to archaeological research on the pre-colonial irrigation system at Engaruka, Tanzania. Although archaeological studies have been carried out in Engaruka for several decades; geophysical processes have not been in focus, despite having the potential to contribute to the understanding of both the ancient irrigation system and the current land use in Engaruka. Geomorphology and pedology were explored through field surveys and mapping using air photos and satellite images. The effects of the flash-flood during the 1997-1998 El Nino were mapped and quantified in the field. Maximum flash-flood discharge in Engaruka River was estimated using Marming's Equation. The geomorphic study revealed that Engaruka is an environment where high-magnitude processes (debris flows, flash-floods, rock slides) dominate landform development. Low-magnitude processes (sheet-wash, wind erosion), transfer fine-textured sediment to low terrain, causing successive coarsening of soil texture in fields of the ancient irrigation system. Andisol occurrence in the dry environment is associated with current irrigation, indicating incremental improvement of arable land resulting from human land use. Andisols appear transient; discontinuation of irrigation has caused a reversion to Entisols, as water retention and structure deteriorate upon drying. A flash-flood during the 1997-1998 El Nino caused destruction of parts of the archaeological remains, with severe impact on current land use and settlements. Approximately 80 ha (4%) of the total area of the ancient remains were covered by debris flow deposits and alluvium, or scoured by new drainage lines of the water courses. The denudation caused by the single flash-flood is estimated to 9 mm in the catchment of Engaruka River. Manning's Equation yielded a least possible maximum discharge in Engaruka River, in the order of 270 m(3)/s, some 600-700 times higher than normal, dry season discharge.
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27.
  • Zarafshar, Mehrdad, et al. (author)
  • Scattered wild pistachio trees profoundly modify soil quality in semi-arid woodlands
  • 2023
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 224
  • Journal article (peer-reviewed)abstract
    • Scattered wild pistachio trees (Pistacia atlantica Dest.) support various ecological functions and services, including soil conservation, in semi-arid woodlands of the Irano-Turanian zone, but over-exploitation puts the populations at risk. The current paucity of information precludes a thorough assessment of the effect of wild pistachio trees on soil quality. Therefore, we quantified their role in soil quality of semi-arid woodlands domi-nated by a Pistachio-Amygdalus community. At three sites in the southern Irano-Turanian zone, we contrasted moisture, pH, electrical conductivity (EC), organic carbon (SOC), total nitrogen (TN) and nutrient concentrations of bare soil with below-crown soil. In addition, we examined soil microbial respiration (Rmic), substrate-induced respiration (SIR), microbial biomass carbon (Cmic) and nitrification potential to evaluate the influence of pis-tachio trees on soil microbial activity. Soil pH and C/N ratio were similar between bare and below-crown soils but significantly greater soil moisture (+41 %), EC (+13 %), SOC (+82 %) and TN (+75 %) were observed below pistachio crowns. Most soil nutrients were more abundant beneath tree crowns, especially zinc and manganese. Soil microbial activity was greater below crowns compared to bare soil as evidenced by significantly elevated Rmic (+11 %), SIR (+86 %), Cmic (+61 %) and nitrification potential (+49 %). SOC-normalization of microbial variables revealed that a SOC-driven increase in Cmic was largely responsible for the enhanced soil microbial activity below crowns. Microbial communities in bare soil showed a higher metabolic quotient (Rmic/Cmic) than in below-crown soil, suggesting low microbial efficiency and higher metabolic costs. Our findings indicate that the soils below wild pistachio crowns represent fertility islands, where soil quality and microbial activity are supported by an increased supply of organic matter and more favourable soil moisture conditions. The few woodlands that have remained relatively intact in this area urgently require conservation action while resto-ration planting of wild pistachio trees in degraded areas may help restore soil quality.
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28.
  • Zarafshar, Mehrdad, et al. (author)
  • The impact of stand composition and tree density on topsoil characteristics and soil microbial activities
  • 2024
  • In: Catena (Cremlingen. Print). - : Elsevier. - 0341-8162 .- 1872-6887. ; 234
  • Journal article (peer-reviewed)abstract
    • The assessment of long-term effects of forest management practices, particularly species mixing and stand density, provides valuable information for the forestry sectors. This study evaluated and compared the effect of stand composition and density on organic horizon (i.e., OL, OF, OH) and organo-mineral horizon characteristics of nine stands in the Orleans State Forest (France), seven years after the first thinning treatments. To this end, three triplets of stands of pure Quercus petraea Matt., pure Pinus sylvestris L. and a mixture of both species were selected. Each stand consisted of two plots with different tree densities: low and normal. Physicochemical variables were measured on the organic humus horizon (OH), while microbial biomass carbon (MBC) and nitrogen (MBN), and soil microbial metabolic profile were evaluated on the organo-mineral horizon; the abundance of soil microbial populations (i.e., bacteria, fungi and archaea) in each plot was also assessed by qPCR. The OH thickness consistently increased under pure pine stands (25-35 mm), while other OH characteristics showed no variation based on stand composition and tree density. Low-density plots exhibited changes in microbial biomass, with a significant decrease in both MBC and MBN. Moreover, the highest MBC was recorded under pure pine stands (1241 mg C.kg(- 1 )DW soil), and the highest MBN under pure oak stands (24-39 mg N.kg(- 1 ) DW soil). The highest C assimilation rates were recorded in the mixed stands, especially under low tree density. Bacteria and archea were similarly abundant across stand compositions and tree densities, while fungi tended to be more abundant in the mixed coniferous-broadleaf stands. Our findings should be considered by the forestry sectors of European countries where these two species are distributed, and suggest that EU forestry strategies should promote biodiversity in the context of tree plantations.
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29.
  • Zeng, Lin, et al. (author)
  • Long-term Pleistocene aridification and possible linkage to high-latitude forcing : New evidence from grain size and magnetic susceptibility from loess-paleosol record in northeastern China
  • 2017
  • In: Catena (Cremlingen. Print). - : Elsevier BV. - 0341-8162 .- 1872-6887. ; 154, s. 21-32
  • Journal article (peer-reviewed)abstract
    • Loess deposits are regarded as good indicators of the inception and development of arid and semi-arid climate in central Asia and northern China during the late Cenozoic. In northeastern China extensive loess deposits are found surrounding the Horqin and Otindag sand fields, and they have great potential for reconstructing the long-term aridification history of the region. However, these loess deposits are currently poorly understood. Here, we present a high-resolution magnetic susceptibility (MS) and grain-size record spanning the last 1.0 Ma from a 36.6-m-thick loess-paleosol sequence at Niuyangzigou site (NYZG) in NE China. The grain-size record reveals a long-term drying trend in NE China since ca. 1.0 Ma, punctuated by two significant abrupt drying events at similar to 0.65 Ma and similar to 0.3 Ma. These results demonstrate a process of stepwise intensification of drying in NE China over the past 1 Ma, and lend support to the hypothesis that global ice volume/temperature changes were the major driver of the long-term aridification of Asian dust source areas. However, unlike the widely studied loess deposits on the central Chinese Loess Plateau (CLP), the MS record in paleosol units Sl, S2 and S4 from the NYZG site do not show evidence of enhanced monsoon precipitation resulting from decreased global ice volume and the prolonged episodes of interglaciation after the Mid-Pleistocene Transition evident in the ice volume record. We hypothesize that this may be due to differences in the climatic sensitivity of the MS of Chinese loess deposits on a regional scale, rather than to in regional differences in monsoon intensity.
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30.
  • Bärring, Lars, et al. (author)
  • Wind erosion on arable land in Scania, Sweden and the relation to the wind climate - a review
  • 2003
  • In: Catena. - 0341-8162. ; 52:3-4, s. 173-190
  • Journal article (peer-reviewed)abstract
    • This paper addresses variations in the wind climate in relation to changes in the impact of wind erosion on agricultural lands with Scania, the southernmost province of Sweden, as an example. The literature concerning wind erosion in the region is reviewed and the conclusions are linked to recent analyses of the regional wind climate. Presently, wind erosion occasionally induces problems in light soil areas of the intensively cultivated Scania. It is not a new phenomenon that results from modem farming practice; it was documented already in the 18th century. This was an era of major land use changes because the increasing population required new and more vulnerable areas to be cultivated, which resulted in an ecological crisis due to increased wind erosion. Partly overlapping in time, a series of land amalgamation reforms transformed the land-use resulting in larger fields. Analyses of the frequency of wind directions indicate that variations in the large-scale wind climate occurred at that time. Wind erosion again became a topic of concern in the 20th century. Extensive analyses of several aspects of the wind climate (e.g., storminess and cyclone intensity) of Scandinavia and northwestern Europe show that there have been interdecadal variations but no sign of an overall long-term trend. The recurring periods of intensified wind erosion problems can best be explained as the combined result of a varying wind climate and the lack of appropriate long-term maintenance strategies for protective measures through the intervening periods of benign wind climate. (C) 2003 Elsevier Science B.V. All rights reserved.
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31.
  • Hamed Abd El Mageed, Yasser, et al. (author)
  • Comparison between rainfall simulator erosion and observed reservoir sedimentation in an erosion-sensitive semiarid catchment
  • 2002
  • In: Catena. - 0341-8162. ; 50:1, s. 1-16
  • Journal article (peer-reviewed)abstract
    • Estimating catchment scale soil loss based on rainfall simulators is often hampered by the difficulty to scale up simulator results. Our objective was to develop and test a method for estimating catchment scale soil loss based on observed rainfall using a variable intensity rainfall simulator in an erosion-sensitive catchment in semiarid Tunisia. A 7-year period, 1992-1999, with observed sedimentation amounts in a downstream reservoir was chosen to test a methodology. The methodology was based on (1) energy adjustment for the used simulator due to the difference in kinetic energy of simulated and natural rainfall at equal intensities and (2) upscaling of simulated erosion in which rill erosion was estimated by adjusting the difference between slope lengths for the plots versus the catchment after onset of runoff. The comparison between calculated soil loss from rainfall simulator experiments and observed sedimentation in the downstream reservoir displayed good overall results. Calculated soil loss was found to be about 96%, 36%, and 80% for different observed subperiods, respectively. The observed low value for the second period was probably due an exceptionally intense rainfall event during this period, which appears to have led to gully erosion, soil slide, and riverbank collapse. Therefore, during this event, siltation in the reservoir may essentially be due to unaccounted erosion processes such as gully erosion. Overall, however, it appears that plot-scale variable intensity rainfall simulators can rather successfully estimate catchment scale soil losses. (C) 2002 Elsevier Science B.V. All rights reserved.
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32.
  • Berglund, Örjan, et al. (author)
  • Carbon capture efficiency, yield, nutrient uptake and trafficability of different grass species on a cultivated peat soil
  • 2019
  • In: CATENA. - : Elsevier BV. - 0341-8162. ; 173, s. 175-182
  • Journal article (peer-reviewed)abstract
    • Loss of organic matter from cultivated peat soils is a threat to farmers, due to the surface subsidence associated with organic matter loss, and to the atmosphere, due to CO2 and N2O emissions from the soil. In a three-year field experiment (2015-2017) on a drained, cultivated fen peat in southern Sweden, we tested whether reed canary grass (Phalaris arundinacea L.) and tall fescue (Festuca arundinacea Schreb.) perform better on peat soils than the commonly grown timothy grass (Phleurn pratense L.), without increasing greenhouse gas emissions. In the experiment, we compared yield, nutrient uptake, penetration resistance and loss of organic matter measured as greenhouse gas emissions (CO2, N2O and CH4). Yield of timothy was significantly lower than that of reed canary grass and tall fescue in 2016, and lower than that of reed canary grass in 2017. Yield level increased over time, with total dry matter yield in 2017 of 11.7 Mg ha(-1) yr(-1) for timothy, 13.5 Mg ha(-1) yr(-1) for tall fescue and 14.3 Mg ha(-1) yr(-1) for reed canary grass. Total removal of all macronutrients in 2016 was higher in reed canary grass and tall fescue than in timothy. For nitrogen (N), reed canary grass removed a total of 173 kg N ha(-1) yr(-1), tall fescue 169 kg ha(-1) yr(-1) and timothy 121 kg ha(-1) yr(-1), while the fertilisation rate was only 50 kg N ha(-1). There were no differences in trafficability, measured as penetration resistance. Measurements of greenhouse gas emissions in the snow-free season in 2016 and 2017 using manual dark chambers (CO2, N2O and CH4) and in 2016 automatic dark chambers (CO2) revealed only small differences in CO2 emissions between the treatments. The N2O emissions were also low and CH4 emissions were very low and in general negative. The estimated carbon capture efficiency (ratio of C in aboveground biomass plus roots to emitted CO2-C measured by the automatic chambers) for the growing season (May-October) in 2016 was lowest for timothy (0.61) and higher for reed canary grass and tall fescue (0.70 and 0.70, respectively). Reed canary grass and tall fescue are thus promising alternatives to timothy on peat soils regarding yield, nutrient removal and carbon capture efficiency.
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33.
  • Cannone, N., et al. (author)
  • Effects of active layer seasonal dynamics and plant phenology on CO2 land-atmosphere fluxes at polygonal tundra in the High Arctic, Svalbard
  • 2019
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 174, s. 142-153
  • Journal article (peer-reviewed)abstract
    • Terrestrial Arctic ecosystems play a key role in the global carbon (C) cycle, as they store a large amount of organic matter in permafrost. Among regions with continuous permafrost, Svalbard has one of the warmest permafrost and may provide a template of the environmental responses of Arctic regions to future climate change. We analyze the CO2 fluxes at a polygonal tundra site in Adventdalen (Svalbard) during one full growing season across a vegetation and environmental gradient to understand how the interaction of different abiotic (thaw depth, ground surface temperature (GST), soil moisture, photosynthetic active radiation - PAR) and biotic (leaf area index (LAI), and plant phenology) factors affect the CO2 fluxes and identify the drivers of Net Ecosystem Exchange (NEE) and Ecosystem Respiration (ER). Three distinct periods (early, peak, and late) characterized the growing season based on plant phenology and the main environmental conditions. Comparing early, peak and late season, both NEE and ER exhibited specific patterns: ER shown high values since the early season, only slightly increased at peak, and then decreased drastically in the late season, with GST being the most important driver of ER. The drivers of NEE changed during the season: thaw depth, PAR and GST during the early season, LAI at peak, and PAR during the late season. These data allow to highlight that the thawing and freezing of the upper part of the active layer during the early and late season controls ER, possibly due to the response of microbial respiration in the upper part of the soil. Especially during the late season, despite the fully developed active layer (reaching its highest thawing depth), the freezing of the uppermost 2 cm of soil induced the drastic decrease of the respiratory efflux. In addition, the seasonal C balance of our plots indicated a seasonal source at our plots, in apparent contrast with previous eddy covariance (EC) measurements from a wetter area nearby. This difference implies that drier ecosystems act as sources while wetter ecosystems are sinks, suggesting that a drying trend in polygonal tundra could switch these ecosystems from CO2 sinks to sources in a feedback to future climate change.
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34.
  • Chen, Peng, et al. (author)
  • Tendency of soil erosion dynamics by coupling radioisotopes and RUSLE model on the Southeastern Tibetan Plateau in response to climate warming and human activity
  • 2023
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 223
  • Journal article (peer-reviewed)abstract
    • Soil erosion has created landscape problems in many parts of the world and in particular in cold regions where the sensitive permafrost conditions have changed due to climate warming. Such a case occurred in the Tibetan Plateau (TP), which has been strongly affected by global warming and human activities. Monitoring technologies, like remote sensing and field surveys were used to explore soil erosion rates in the TP, but they were limited by the resolution and meteorological disturbance factors or the spatial and time scales. Here, we present for the first time 210Pbex (excess lead-210) and 137Cs (caesium-137) data of soils from the southeastern TP (SETP) covering an area of 640,000 km2. In the permafrost-dominant areas, the results show mean soil-erosion rates in the last 56–100 years that were relatively higher (1891 t·km−2·a-1) based on 210Pbex than those based on 137Cs (1623 t·km−2·a-1). Modelling results from the Revised Universal Soil Loss Equation (RUSLE) indicate relatively high mean soil erosion rates of 4363 and 4394 t·km−2·a-1 using a period covering the last 40 or 10 years respectively. Our data suggest accelerating erosion rates on the SETP that are linked to permafrost degradation, and glacier and snow melting due to accelerating global climate warming. The increase in ground surface temperature of ∼2 °C in the last four decades has further shifted the regional hydrology, affecting the degeneration of vegetation cover and a further increase in soil-erosion rates. However, our radionuclides data also expose low erosion rates in the seasonally frozen ground at some sampling sites which indicates the complex nature of erosion trends in cold regions that require careful adaptation of soil management.
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35.
  • Collentine, Dennis (author)
  • Land-use change in a Nordic future towards bioeconomy: A methodological framework to compare and merge stakeholder and expert opinions on qualitative scenarios
  • 2023
  • In: CATENA. - 0341-8162. ; 228
  • Journal article (peer-reviewed)abstract
    • Future development of bioeconomy is expected to change land use in the Nordic countries in agriculture and forestry. The changes are likely to affect water quality due to changes in nutrient run-off. To explore possible future land-use changes and their environmental impact, stakeholders and experts from four Nordic countries (Denmark, Finland, Norway and Sweden) were consulted. The methodological framework for the consultation was to identify a set of relevant land-use attributes for agriculture and forestry, e.g. tillage conservation effort, fertiliser use, animal husbandry, biogas production from manure, forestry management options, and implementation of mitigation measures, including protection of sensitive areas. The stakeholders and experts provided their opinions on how these attributes might change in terms of their environmental impacts on water quality given five Nordic bioeconomic scenarios (sustainability, business as usual, self-sufficiency, cities first and maximizing economic growth). A compilation methodology was developed to allow comparing and merging the stakeholder and expert opinions for each attribute and scenario. The compiled opinions for agriculture and forestry suggest that the business-as-usual scenario may slightly decrease the current environmental impact for most attributes due to new technologies, but that the sustainability scenario would be the only option to achieve a clear environmental improvement. In contrast, for the self-sufficiency scenario, as well as the maximum growth scenario, a deterioration of the environment and water quality was expected for most of the attributes. The results from the stakeholder consultations are used as inputs to models for estimating the impact of the land-use attributes and scenarios on nutrient run-off from catchments in the Nordic countries (as reported in other papers in this special issue). Furthermore, these results will facilitate policy level discussions concerning how to facilitate the shift to bioeconomy with increasing biomass exploitation without deteriorating water quality and ecological status in Nordic rivers and lakes.
  •  
36.
  • Collentine, Dennis (author)
  • The value of change: A scenario assessment of the effects of bioeconomy driven land use change on ecosystem service provision
  • 2023
  • In: CATENA. - : Elsevier BV. - 0341-8162. ; 223
  • Journal article (peer-reviewed)abstract
    • Policy makers in Nordic countries envisage a developing bioeconomy as an important element in the transition towards a fossil-energy-free future. However, although the shape of such a bioeconomy is unclear, impacts on land use and land management are likely. To analyse the possible impact on ecosystem services value of this transition, we used five scenarios that describe possible socio-economic environments in the four Nordic countries in the year 2050. These five Nordic Bioeconomy Pathways (NBPs) have been labelled in brief as: 'sustainability first', 'conventional first', 'self-sufficiency first', 'city first' and 'growth first'. In this paper, we adapted an existing integrating framework of ecosystem service delivery to accommodate these NBPs and esti-mated economic value of all services for six study catchments across the Nordic countries: Odense (DK), Simojoki (FI), Haldenvassdraget (NO), Orrevassdraget (NO), Sa center dot vjaan (SE) and Vindela center dot lven (SE). We articulated the sce-nario storylines to a set of numerical attributes per NBP using input from secondary data sources and interviews with stakeholder representatives and local experts. We made land use change spatially explicit based on the catchment's physical characteristics and used links between catchment attributes and ecosystem services flow to estimate annual ecosystem services generation in biophysical and monetary units. Outcomes suggest: the value of active recreation increases more in 'sustainability first' and 'growth first' than in other scenarios; variations in total value are largest among catchments under 'city first'; the overall rank order of ecosystem services value within catchments largely remains unchanged under all NBPs. We conclude that outdoor recreation contributes a high benefit to society that is likely not adequately considered relative to provisioning services in current de-cision making, and that these benefits appear sensitive to how a bioeconomy will develop. Overall, the estimated summed value delivered in these catchments is highest under the 'sustainability first' and 'growth first' scenarios.
  •  
37.
  • Du, Jie, et al. (author)
  • Effects of rainfall intensity and slope on interception and precipitation partitioning by forest litter layer
  • 2019
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 172, s. 711-718
  • Journal article (peer-reviewed)abstract
    • Rainfall interception and other hydrologic processes affected by the forest litter layer are usually related to litter characteristics and rainfall conditions, with limited studies that consider the influence of slope. To simulate the hydrological functions of the litter layer at different slope gradients, artificial rainfall experiments were conducted at four rainfall intensities (from 30 to 120 mm hr−1) in horizontal and inclined trays (with the slope of 0° 10° 20° and 30°) with litter of Pinus tabuliformis or Quercus variabilis. The results indicated that (1) the dynamic process of litter interception had 3 phases: a rapid intercepted phase within the first 5 min, a moderate intercepted phase and a post-rainfall drainage phase; (2) the maximum interception storage (Cmax) and the minimum interception storage (Cmin) of Q. variabilis were larger than those of P. tabuliformis; (3) Cmax and Cmin were correlated with slope for both types of litter, whereas only Cmax was correlated with rainfall intensity; and (4) lateral flow amount significantly increased with both slope gradient and rainfall intensity only for Quercus variabilis, whereas drainage volume showed significant correlation with rainfall intensity. Moreover, the ratio of lateral runoff and drainage was affected by slope gradient whereas percentage of litter interception had a good relationship with rainfall intensity, rather than slope, with litter interception and drainage contributing the smallest and the largest proportions, respectively. Overall, the results demonstrate the effect of rainfall and slope factors on hydrological processes in the forest litter layer.
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38.
  •  
39.
  • Futter, Martyn, et al. (author)
  • Influence of forest management changes and reuse of peat production areas on water quality in a northern river
  • 2023
  • In: CATENA. - : Elsevier BV. - 0341-8162. ; 226
  • Journal article (peer-reviewed)abstract
    • In Northern Finland, the most significant land use challenges are related to bioenergy production from peat extraction and forest biomass. Increasing societal demand for bioenergy may increase production rates. However, environmental impacts of peat extraction are of increasing concern, which has led to a decline in production, thereby freeing up these areas for other uses. Using storylines for different societal futures and process-based models (PERSiST and INCA), we simulated the effect of simultaneous land use change and climate change on water quality (phosphorus, nitrogen and suspended sediments concentration). Conversion of peat extraction areas to arable land, together with climate change, may pose a risk for deterioration of ecological status. On the other hand, continuous forestry may have positive impacts on water quality. Suspended sediment concentrations in the river do not exceed water quality requirements for salmonids, but nitrogen concentrations may exceed threshold values especially during high flows. A storyline emphasizing sustainable development in energy pro-duction led to the best outcome in terms of water protection.
  •  
40.
  • He, Haoran, et al. (author)
  • Linking soil depth to aridity effects on soil microbial community composition, diversity and resource limitation
  • 2023
  • In: Catena. - 0341-8162. ; 232
  • Journal article (peer-reviewed)abstract
    • With ongoing climate change, aridity is increasing worldwide, affecting biodiversity and ecosystem function in drylands. However, how the depth-profile microbial community structure and metabolic limitations change along aridity gradients are still poorly explored. Here, 16S rRNA and ITS amplicon sequencing and ecoenzymatic stoichiometry analysis were used to investigate both bacterial and fungal diversities and resource limitations in 1 m depth profiles across a wide aridity gradient (0.51–0.78) in a semiarid region. Results showed a sharp decrease in microbial diversity with soil depth, accompanied by an increase in microbial phosphorus (P) vs. N (nitrogen) limitation and a decrease in microbial carbon (C) vs. nutrient limitation. Aridity led to a strong shift in microbial community composition, but aridity has a threshold effect on microbial resource limitation through impacts on soil pH and C/P or N/P. When the aridity threshold (1-precipitation/evapotranspiration) exceeds 0.65, relationship between aridity and microbial resource demand was decoupled; but at aridity threshold = 0.65, microbial relative C limitation and C-acquiring enzyme activity dropped. These results suggest that aridity might have a stronger influence on microbial community composition, than on diversity, shaped by inherent soil biotic factors (i.e., MBC:MBP or MBN:MBP). These findings suggest that soil microbial diversity or enzymatic stoichiometry may be not necessary to mirror changes in water availability in the drylands, while aridity would be well explained by microbial community composition.
  •  
41.
  • Hu, Guojie, et al. (author)
  • Water and heat coupling processes and its simulation in frozen soils : Current status and future research directions
  • 2023
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 222
  • Research review (peer-reviewed)abstract
    • To date, most studies on coupled-water-and-heat processes in frozen soils haves focused on the mechanism of changes in frozen soil and the contribution of climate change, hydrological processes, and ecosystems in cold regions. Several studies have demonstrated considerable improvements in the accuracy of simulating water and heat transfer processes in cold regions. However, substantial differences remain among the different models and parameterizations because of the lack of observations and in-depth understanding of the water and heat transfer processes. Hence, it is necessary to summarize recent advances in the simulation of water-and-heat-coupling processes and challenges for further research. Therefore, we present a theory-focused summary of progress in this field considering the aspects of water flow and coupled-water-and-heat transfer. The simulation progress is discussed in terms of physical process models; one type of model only considers the heat conduction transfer processes without water flow, and the other considers coupled-water-and-heat transfer processes. Aspects of model deficiencies related to non-conductive heat transfer and soil water transfer processes in the frozen soil are also summarized. Moreover, the major parameterizations are reviewed, including phase changes, freeze–thaw fronts, thermal conductivity, hydraulic conductivity, snow processes, surface parameterization schemes, ground ice, and lower boundary conditions. While models and parameterizations can suitably capture local-scale water and heat transfer processes in frozen soil, their applications are spatiotemporally constrained, requiring further improvement. We provide a theoretical basis for further studying water and heat transfer processes in frozen soil and suggest that future research should enhance the accuracy of frozen soil parameterization and improve the understanding of the coupling of water and heat transfer processes based on improved observation techniques and high-resolution data.
  •  
42.
  • Kristensen, Jeppe Aagaard, et al. (author)
  • The combined effect of termite bioturbation and water erosion on soil nutrient stocks along a tropical forest catena in Ghana
  • 2019
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 178, s. 307-312
  • Journal article (peer-reviewed)abstract
    • In the tropical moist semi-deciduous forests of West Africa, soil catenas with extremely gravel-rich soil horizons at the summits and upper slopes and largely gravel-free profiles at the lower slope are common. Previous investigations have suggested that these gravel layers are the result of macro-invertebrates mining of fine-grained soil material from the subsoil leaving behind the gravel, to build galleries at the surface subsequently exposing it to water erosion transport downslope. We examined the indirect effect of this process on the distribution along a soil catena of crucial base cations (Ca 2+ , Mg 2+ , K + ) and plant available phosphorous (P), which is often growth-limiting in these tropical ecosystems. We found that the export of fine-grained soil material at the top of the catena reduces the soil stocks (to 1 m) of these elements by up to 60%, while the soil fertility downslope did not change significantly. This important long-term (100–1000 yr scale) reduction in soil fertility at the top of slopes resulting from bioturbation and water erosion is overlooked in contemporary literature, which primarily focus on the beneficial impact termites and ants have on ecosystem functioning in more level savannah landscapes. As the type of catena studied is widespread across tropical environments, this effect is likely ecologically substantial. Future research should aim at understanding such long-term consequences of bioturbation on landscape ecology as well as soil heterogeneity and fertility, so we do not overlook potential negative ecosystem effects.
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43.
  • Kyllmar, Katarina, et al. (author)
  • Nitrogen and phosphorus losses in Nordic and Baltic agricultural monitoring catchments-Spatial and temporal variations in relation to natural conditions and mitigation programmes
  • 2023
  • In: CATENA. - 0341-8162. ; 230
  • Journal article (peer-reviewed)abstract
    • Nitrogen (N) and phosphorus (P) losses via agricultural drainage water have negative impacts on receiving water bodies and large-scale programmes to reduce nutrient losses have been established in the Nordic and Baltic countries, together with agricultural catchment monitoring programmes. This study evaluated time series (9-40 years) of data from 34 selected Nordic-Baltic catchments for spatial and temporal variations in area-specific water discharge (mm) and in concentrations and transport of total nitrogen (TN) and total phosphorus (TP).Water discharge from the catchments varied from 125 mm (Denmark) to > 1000 mm (Norway). Catchments with low TN concentrations (& LE;3 mg L-1) were dominated by clay or grass leys or were undrained with reduction of nitrate (NO3) in shallow groundwater. Catchments with high TN concentrations (& GE;10 mg L-1) had loams and cereal crops. TP concentrations were highest (& GE;0.45 mg L-1) in catchments with erosive soils, relatively high water discharge and cereal crops, and lowest (& LE;0.07 mg L-1) in catchments with permeable soils.Generalised additive mixed model (GAMM) analysis of time series of transport and flow-weighted concen-trations of TN and TP for temporal patterns revealed decreases in TN concentrations in seven catchments and increases in eight, while four had periods with opposing trends. TN concentrations decreased in Denmark and Sweden in 1990-2010, following introduction of mitigation programmes. TP concentrations decreased in eight catchments and increased in six, while one showed opposing trends. Decreases in TP coincided with improved P balance in catchments with sand and loam. To further reduce N and P losses, a tailored set of mitigation measures is needed for each combination of soil, climate, geohydrology and agricultural production. Intensive monitoring of small catchments can reveal how N and P losses relate to natural conditions and to changes in agricultural production.
  •  
44.
  • Kyllmar, Katarina (author)
  • Projecting the impacts of the bioeconomy on Nordic land use and freshwater quality and quantity-An overview
  • 2023
  • In: CATENA. - 0341-8162. ; 228
  • Journal article (peer-reviewed)abstract
    • This paper synthesizes a five-year project (BIOWATER) that assessed the effects of a developing bioeconomy on Nordic freshwaters. We used a catchment perspective and combined several approaches: comparative analyses of long-term data sets from well-monitored catchments (agricultural, with forestry, and near pristine) across Fennoscandia, catchment biogeochemical modelling and ecosystem services assessment for integration. Various mitigation measures were also studied. Benchmark Shared Socio-economic Pathways were downscaled and articulated in dialogue with national stakeholder representatives leading to five Nordic Bioeconomy Pathways (NBPs) describing plausible but different trajectories of societal development towards 2050.These were then used for catchment modelling and ecosystem service assessment. Key findings from the work synthesized here are: (a) The monitoring results from 69 catchments demonstrate that agricultural lands exported an order of magnitude more nutrients than natural catchments (medians 44 vs 4 kg P km-2 y-1 and 1450 vs 139 kg N km-2 y-1) whilst forests were intermediate (7 kg P km-2 y-1 and 200 kg N km-2 y-1). (b) Our contrasting scenarios led to substantial differences in land use patterns, which affected river flow as well as nutrient loads in two of the four modelled catchments (Danish Odense angstrom and Norwegian Skuterud), but not in two others (Swedish catchment C6 and Finnish Simojoki). (c) Strongly contrasting scenarios (NBP1 maximizing resource circularity versus NBP5 maximizing short-term profit) were found to lead to similar monetary estimates of total societal benefits, though for different underlying reasons - a pattern similar across the six studied Nordic catchments. (d) The ecological status of small to medium sized rivers in agricultural landscapes benefitted greatly from an increase in riparian forest cover from 10 % to 60 %. Riparian buffer strips, constructed wetlands, rewetting of ditched peatlands, and similar nature-based solutions optimize natural biogeochemical processes and thus can help in mitigating negative impacts of intensified biomass removal on water quality.
  •  
45.
  • Larsbo, Mats (author)
  • Quantifying the impact of a succession of freezing-thawing cycles on the pore network of a silty clay loam and a loamy sand topsoil using X-ray tomography
  • 2017
  • In: CATENA. - : Elsevier BV. - 0341-8162. ; 156, s. 365-374
  • Journal article (peer-reviewed)abstract
    • In the Nordic countries, changes in pore structure during winter can affect e.g. water transport capacity in soils after winter. A reduction in pore space can cause an increase in runoff volume due to snowmelt and rain, resulting in flooding and soil erosion. This study quantified the effect of freezing-thawing cycles (FTCs) on the macropore structure of a silt and a sandy soil. Six consecutive FTCs were applied to intact soil samples, which were scanned after 0, 1, 2, 4 and 6 FTCs with an industrial X-ray scanner. Using state-of-the-art image processing and analysis techniques, changes in soil macropore network characteristics were quantified. The results showed that freezing-thawing affected the looser sandy soil more than the silt with its more cohesive structure. However, in both soils freezing-thawing had a negative effect on properties of macropore networks (e.g. reduction in macroporosity, thickness and specific surface area of macropores). These findings can help improve understanding of how undisturbed soils react to different winter conditions, which can be beneficial in the development of models for predicting flooding and soil erosion.
  •  
46.
  • Li, Xiaojuan, et al. (author)
  • Latitudinal patterns of light and heavy organic matter fractions in arid and semi-arid soils
  • 2022
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 215
  • Journal article (peer-reviewed)abstract
    • Semi-arid and arid ecosystems are important for the global C cycle. Despite this, it remains unclear how organic matter fractions vary across latitudinal gradients, and what drives this variation, in dry ecosystems. In this study, we sampled soils from 100 sites across a latitudinal gradient in the dry valleys of southwestern China to explore the latitudinal patterns of light fraction organic matter (LFOM) and heavy fraction organic matter (HFOM) at two soil depths (0–10 cm and 10–20 cm). Across the studied gradient, HFOM accounted for a larger fraction of soil organic matter than LFOM. LFOM increased exponentially with increasing latitude at both 0–10 cm and 10–20 cm depths. Heavy fraction organic C increased linearly with increasing latitude at both depths, while heavy fraction organic N only increased with latitude in soils from 10 to 20 cm depth. Latitudinal patterns of LFOM were mainly explained by climate, with the most important driver being mean annual temperature, followed by mean annual precipitation. Soil physicochemical factors – in particular cation exchange capacity and silt content – explained the most variation in HFOM. Total microbial biomass was also important in explaining variation in HFOM, especially in the 10–20 cm soil layer. Overall, our results shed light on the spatial distribution of organic matter fractions in arid and semi-arid regions. We also identify candidate drivers of the variation in LFOM and HFOM in arid and semi-arid regions, finding that climate primarily explains variation in LFOM while soil physiochemistry primarily explains variation in HFOM.
  •  
47.
  • Mårtensson, Kristina, et al. (author)
  • Estimated nutrient leakage from arable land in different bioeconomy scenarios for two areas in central Sweden, determined using a leaching coefficient method
  • 2023
  • In: CATENA. - : Elsevier BV. - 0341-8162. ; 226
  • Journal article (peer-reviewed)abstract
    • Knowledge of future developments in agriculture and how these will affect nutrient leakage from arable land is important in efforts to achieve good ecological status of surface waters. This study assessed the impact of five scenarios for a bioresource-based economy, involving use of renewable biological resources from land and sea, on nitrogen (N) and phosphorus (P) leakage from arable land to surface-waters and groundwater. The scenarios (developed in an earlier study) were applied to two areas in central Sweden, leaching region LR-6 (5350 km2) and catchment C6 (19 km2). Using the NLeCCS calculation system to produce leakage coefficients, we evaluated the changes in total N and total P leakage from arable soil. The leakage coefficients described agricultural management practices and climate conditions representing the leaching region LR-6 in Sweden and the baseline year was 2016. The scenarios varied from a baseline in terms of crop combination (relative area of different crops) and extent of mitigation measures (e.g. delayed tillage date, buffer zone width and relative area, and catch crop). Expected consumption of meat varied in the scenarios, with lower consumption meaning fewer cattle and consequently less grass ley. The scenarios was supplemented with calculations of introducing mitigation mea-sures up to their maximum potential. In leaching region LR-6, calculated baseline leakages was 10.5 kg N ha-1 year-1 and 0.87 kg P ha-1 year-1, values that varied in the scenarios by-4% to 5% (N) and-6% to 19% (P). In catchment C6 calculated baseline leakages was 7.1 kg N ha-1 year-1 and 1.11 kg P ha-1 year-1, and the values in the scenarios varied by-15% to 2% (N) and-5% to 5% (P). Assuming maximum potential of the mitigation measures decreased leakage further, by up to-19%. Crop combination had a major impact on total N and P leakage in the scenarios. Leakage increased when the amount of grass ley in the rotation decreased, but remained relatively unchanged when the crop combination change only involved annual crops. Frequency of the mitigation measures increased in all scenarios, with associated decreases in N and P leakage that counteracted the increased leakage caused by changes in crop combination. The most effective mitigation measure was catch crop for N leakage and delayed soil tillage for P leakage.
  •  
48.
  • Olszak, Janusz, et al. (author)
  • Luminescence and radiocarbon dates from alluvial sediments, Podhale, Central Europe — A methods comparison
  • 2023
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 221
  • Journal article (peer-reviewed)abstract
    • Optically stimulated luminescence (OSL) and radiocarbon (14C) techniques were employed to investigate the absolute ages of alluvial sediments in Podhale in the West Carpathians, southern Poland. This is an approach to (i) testing the credibility of the above dating methods by their reciprocal age control and (ii) further implications to regional geochronology and to dating campaigns of alluvial sequences elsewhere. Nine geological sections comprised of mineral and organic material were selected for the study. Our age determinations range from 26.9 to 2.27 ka, and are in good geochronological order. OSL age estimates show good agreement with independent ages from radiocarbon dating. However, in three alluvial successions the discrepancy between the resulting ages is considerable. We attribute the difference to the partial bleaching, and organic material redeposition. We also report on an age reversal of sediments in a single geological section. This might have been resulted from the alluviation-erosion scheme of meandering rivers over a millennial time-scale, i.e. the dominance of channel migration, point bar deposition (lateral accretion), and crosswise erosion. Finally, new geochronological data are provided abolishing sediment age assumptions based on uncertain chronostratigraphical approaches.
  •  
49.
  • Rizinjirabake, Fabien, et al. (author)
  • Sources of soil dissolved organic carbon in a mixed agricultural and forested watershed in Rwanda
  • 2019
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 181
  • Journal article (peer-reviewed)abstract
    • Dissolved organic carbon (DOC) plays a key role in linking terrestrial and aquatic carbon cycles. Most of the work on soil and water DOC has been conducted in temperate watersheds. There is still a gap in knowledge on DOC dynamics within the tropics. This study assesses water extractable organic carbon (WEOC) in topsoils and describes the relationship between WEOC and land use/land cover (LULC), slope position, curvature and soil properties using linear regression in the Rukarara River Watershed (RRW) in Rwanda. The study analyzes DOC concentration in soil percolation water (pDOC) and describes its relationship with antecedent precipitation index (API) and mean antecedent temperature (MAT) within the watershed using quadratic regression. Generalized linear model (GLM) and linear mixed effect model (LME) with site and/or LULC random effects are used to predict WEOC within the watershed. WEOC concentrations range from 124 to 855 mgC/L in the study area. The highest WEOC concentrations were observed in natural forest, followed by tree plantations, tea plantations and croplands. t-test results did not reveal a significant difference between concentrations of WEOC in valleys, upper slopes, ridges, flat, concave and convex areas in the Rukarara River Watershed (RRW). Considering the relationship between WEOC and soil properties, significant positive correlation coefficients were 0.60, 0.53, 0.50, and 0.36 respectively for the total organic carbon (TOC), the total nitrogen (TN), the cation exchange capacity (CEC), and the aluminum (Al). The best predictor WEOC as a function of soil properties was the generalized linear model (GLM) and indicated soil TOC as the overarching soil factor of WEOC in the RRW by 71%. The pDOC concentration ranges between 0.34 and 10.03 mgC/L and its relationship with both API and MAT was concave upward. APIs explained 12 to 17% of the pDOC variation in the RRW whereas MATs explained 8 to 25%, the natural forest site showing the highest values and the cropland site the lowest values. This result means that a conversion from forest to cropland within the RRW could decrease DOC in both soils and in percolation water. Also, an increase of precipitation and temperature up to respective optima in the RRW, could increase DOC in percolation water and consequently in streams. This increase of instream DOC can impact the water quality of the Rukarara River and its streams, with implications for their ecological function. Strategies of land management and water resources should be enhanced to preserve soil and water quality in the RRW.
  •  
50.
  • Ronchi, Benedicta, et al. (author)
  • Factors controlling Si export from soils: A soil column approach
  • 2015
  • In: Catena. - : Elsevier BV. - 0341-8162. ; 133, s. 85-96
  • Journal article (peer-reviewed)abstract
    • The release of dissolved silicon (DSi) from A and B horizons was investigated with leaching tests on unsaturated columns. As forest A horizons have larger biogenic Si (BSi) pools than arable lands, we compared the Si release from a forest and a cropland from the same geographical region developed on a Luvisol in Belgium and a Cambisol in Sweden. The A horizons released a quickly dissolving Si fraction in contrast to the B horizons, which did contain no or only little amounts of BSi and released lower Si concentrations. Our experiments show that Si export from forest soils is high because of the presence of a large reservoir of soluble BSi as well as due to the acidity of the soil (pH<4). Leaching at two different water fluxes revealed that export in forest soils was transport controlled while cropland soils were in equilibrium. (C) 2015 Elsevier B.V. All rights reserved.
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