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    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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    We will mail you new results for this query: q=Román-Sánchez
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Bioturbation and erosion rates along the soil-hillslope conveyor belt, part 1: Insights from single-grain feldspar luminescence
Román-Sánchez, Andrea ; Reimann, Tony ; Wallinga, Jakob ; Vanwalleghem, Tom - \ 2019
Earth Surface Processes and Landforms 44 (2019)10. - ISSN 0197-9337 - p. 2051 - 2065.
bioturbation - Critical Zone - erosion - feldspar luminescence - soil formation

The interplay of bioturbation, soil production and long-term erosion–deposition in soil and landscape co-evolution is poorly understood. Single-grain post-infrared infrared stimulated luminescence (post-IR IRSL) measurements on sand-sized grains of feldspar from the soil matrix can provide direct information on all three processes. To explore the potential of this novel method, we propose a conceptual model of how post-IR IRSL-derived burial age and fraction of surface-visiting grains change with soil depth and along a hillslope catena. We then tested this conceptual model by comparison with post-IR IRSL results for 15 samples taken at different depths within four soil profiles along a hillslope catena in the Santa Clotilde Critical Zone Observatory (southern Spain). In our work, we observed clear differences in apparent post-IR IRSL burial age distributions with depth along the catena, with younger ages and more linear age–depth structure for the hill-base profile, indicating the influence of lateral deposition processes. We noted shallower soils and truncated burial age–depth functions for the two erosional mid-slope profiles, and an exponential decline of burial age with depth for the hill-top profile. We suggest that the downslope increase in the fraction of surface-visiting grains at intermediate depths (20 cm) indicates creep to be the dominant erosion process. Our study demonstrates that single-grain feldspar luminescence signature-depth profiles provide a new way of tracing vertical and lateral soil mixing and transport processes. In addition, we propose a new objective luminescence-based criterion for mapping the soil-bedrock boundary, thus producing soil depths in better agreement with geomorphological process considerations. Our work highlights the possibilities of feldspar single grain techniques to provide quantitative insights into soil production, bioturbation and erosion–deposition.

Bioturbation and erosion rates along the soil-hillslope conveyor belt, part 2: Quantification using an analytical solution of the diffusion–advection equation
Román-Sánchez, Andrea ; Laguna, Ana ; Reimann, Tony ; Giráldez, Juan Vicente ; Peña, Adolfo ; Vanwalleghem, Tom - \ 2019
Earth Surface Processes and Landforms 44 (2019)10. - ISSN 0197-9337 - p. 2066 - 2080.
bioturbation - critical zone - deposition - diffusivity - erosion - feldspar luminescence dating - sensitivity and uncertainty - soil formation

Particles on soil-mantled hillslopes are subject to downslope transport by erosion processes and vertical mixing by bioturbation. Both are key processes for understanding landscape evolution and soil formation, and affect the functioning of the critical zone. We show here how the depth–age information, derived from feldspar-based single grain post-infrared infrared stimulated luminescence (pIRIR), can be used to simultaneously quantify erosion and bioturbation processes along a hillslope. In this study, we propose, for the first time, an analytical solution for the diffusion–advection equation to calculate the diffusivity constant and erosion–deposition rates. We have fitted this model to age–depth data derived from 15 soil samples from four soil profiles along a catena located under natural grassland in the Santa Clotilde Critical Zone Observatory, in the south of Spain. A global sensitivity analysis was used to assess the relative importance of each model parameter in the output. Finally, the posterior probability density functions were calculated to evaluate the uncertainty in the model parameter estimates. The results show that the diffusivity constant at the surface varies from 11.4 to 81.9 mm2 a-1 for the hilltop and hill-base profile, respectively, and between 7.4 and 64.8 mm2 a-1 at 50 cm depth. The uncertainty in the estimation of the erosion–deposition rates was found to be too high to make a reliable estimate, probably because erosion–deposition processes are much slower than bioturbation processes in this environment. This is confirmed by a global sensitivity analysis that shows how the most important parameters controlling the age–depth structure in this environment are the diffusivity constant and regolith depth. Finally, we have found a good agreement between the soil reworking rates proposed by earlier studies, considering only particle age and depth, and the estimated diffusivity constants. The soil reworking rates are effective rates, corrected for the proportion of particles actually participating in the process.

Species-specific alterations in Anopheles mosquito olfactory responses caused by Plasmodium infection
Stanczyk, N.M. ; Brugman, V.A. ; Austin, V. ; Sanchez-Roman Teran, F. ; Gezan, S.A. ; Emery, M. ; Visser, T.M. ; Dessens, J.T. ; Stevens, W. ; Smallegange, R.C. ; Takken, W. ; Hurd, H. ; Caulfield, John ; Birkett, M. ; Pickett, J. ; Logan, J.G. - \ 2019
Scientific Reports 9 (2019)1. - ISSN 2045-2322

Mosquitoes infected with malaria parasites have demonstrated altered behaviour that may increase the probability of parasite transmission. Here, we examine the responses of the olfactory system in Plasmodium falciparum infected Anopheles gambiae, Plasmodium berghei infected Anopheles stephensi, and P. berghei infected An. gambiae. Infected and uninfected mosquitoes showed differential responses to compounds in human odour using electroantennography coupled with gas chromatography (GC-EAG), with 16 peaks triggering responses only in malaria-infected mosquitoes (at oocyst, sporozoite or both stages). A selection of key compounds were examined with EAG, and responses showed differences in the detection thresholds of infected and uninfected mosquitoes to compounds including lactic acid, tetradecanoic acid and benzothiazole, suggesting that the changes in sensitivity may be the reason for differential attraction and biting at the oocyst and sporozoite stages. Importantly, the different cross-species comparisons showed varying sensitivities to compounds, with P. falciparum infected An. gambiae differing from P. berghei infected An. stephensi, and P. berghei infected An. gambiae more similar to the P. berghei infected An. stephensi. These differences in sensitivity may reflect long-standing evolutionary relationships between specific Plasmodium and Anopheles species combinations. This highlights the importance of examining different species interactions in depth to fully understand the impact of malaria infection on mosquito olfactory behaviour.

Getting a grip on soil reworking – Single-grain feldspar luminescence as a novel tool to quantify soil reworking rates
Reimann, Tony ; Román-Sánchez, Andrea ; Vanwalleghem, Tom ; Wallinga, Jakob - \ 2017
Quaternary Geochronology 42 (2017). - ISSN 1871-1014 - p. 1 - 14.
Bioturbation - Creep - Feldspar single-grains - Post-IR IRSL feldspar - Soil mixing
Soil reworking, e.g. due to bioturbation, is an important aspect of soil and landscape evolution. Yet, rates of soil mixing are poorly constrained, especially on pedological and geomorphological relevant time scales of decades to millennia. This study presents a novel method to reconstruct soil reworking rates on such timescales by utilising luminescence signals from individual sand-sized feldspar grains as soil reworking tracers. We propose a post-IR IRSL procedure to harvest two luminescence signals from individual feldspar grains. We applied this method to four soil samples from a single soil profile in Spain, and compared our results to those derived through a more conventional approach based on single-grain quartz luminescence analysis. We also propose novel ways of deriving effective soil reworking rates from luminescence data, using not only apparent burial ages of mineral grains but also the proportion of mineral grains that never reached the soil surface. Our results confirm the general suitability of feldspar post-IR IRSL as soil reworking tracer in terms of measurement performance, luminescence signal resetting and eventually the determination of soil reworking rate. We furthermore demonstrate that the feldspar based method is more time and labour efficient than quartz based methods, and we expect it to be more widely applicable. Most importantly, the method provides a reliable measures of the soil reworking intensity, which was not possible with quartz based methods. We conclude that feldspar single-grain luminescence analysis has the potential to become the method of choice for investigating soil reworking rates.
Out of the dark - inverse modelling to make sense of luminescence properties of soils
Temme, A.J.A.M. ; Langston, A. ; Reimann, T. ; Vanwalleghem, T. ; Roman Sanchez, A. - \ 2015
Novel single-grain luminescence measurements of quartz and feldspar grains offer exciting ways forward to characterize rates and mechanisms of soil bioturbation. However, to fulfil this potential, the attribution problem must be solved – we must know which bioturbation mechanisms can lead to the observed outcome. Inverse modelling is a well-known solution for such problems. We present a new stochastic model of the evolution of grain properties such as apparent age and intrinsic brightness of quartz and feldspar grains in a bioturbated soil column. The model can rapidly simulate the depth profiles of these grain properties due to various bioturbation mechanisms over long periods of time. These can then be compared with the observed profiles.We illustrate the inverse model process for a case study site near Cordoba in Spain, where apparent ages and intrinsic brightness were determined for single quartz grains and single feldspar grains (with a 50 degree and a 175 degree protocol). Results indicate that several hypothesized bioturbation mechanisms can indeed be excluded by inverse modelling. The model can easily be extended to include hillslope processes.
On the quantification of soil bioturbation and soil relocation in a mountainous area in S Spain – testing the potential of single-grain OSL techniques
Román Sánchez, A. ; Reimann, T. ; Vanwalleghem, T. ; Temme, A.J.A.M. ; Giráldez, J.V. - \ 2015
Soil formation depends on bedrock, climate, relief, vegetation and time. Bioturbation and colluvial soil re-location are important and significant processes that affect the mechanisms and rate of bedrock weathering. The estimation of the relative fraction of bedrock grains which has been mixed in the soil and transported either vertically or laterally to different depths gives an indication of the degree to which bedrock weathering is controlled by the latter processes. However, despite the great effort dedicated to the analysis of these processes, little is known about the quantitative relationship between geomorphological changes and soil formation, especially for long timescales. This study presents reconstruction of soil processes by single grain optically stimulated luminescence techniques (OSL) in several profiles sampled along a hillslope. The OSL analyses provide a direct measurement of soil forming processes (e.g. bioturbation, colluviation) and with them a more precise formulation of soil formation models at longer timescales. Single-grain OSL techniques have been applied to quartz and feldspar minerals which were extracted from different soil horizons from a hillslope catena located in Sierra Morena, Córdoba, in the south of Spain. Four profiles were explored extracting twelve samples in order to study vertical and lateral mixing (e.g. soil creep, colluvial processes) of soils. The suitability of three different OSL single grain approaches, quartz OSL, IRSL (infrared stimulated luminescence) and pIRIR (post-IRSL) feldspar, was tested on four samples. From this analysis parameters from single-grain OSL age distributions (e.g. number of zeroed grains, scatter and shape of the distribution) were deduced to be used as indicators for bioturbation and/or soil-relocation. The most suitable approach was the applied to the several samples from hillslope catena. This study reveals the potential of OSL single-grain techniques in order to shed light on bioturbation and pedoturbation processes within soil formation and their interrelationship with geomorphological processes.
Palaeofloods and ancient fishing weirs in NW Iberian rivers
Viveen, W. ; Sanjurjo-Sanchez, J. ; Goy-Dizc, A. ; Veldkamp, A. ; Schoorl, J.M. - \ 2014
Quaternary Research 82 (2014)1. - ISSN 0033-5894 - p. 56 - 65.
regenerative-dose protocol - north-atlantic oscillation - quartz - luminescence - climate - single - australia - peninsula - sediments - records
A 15-m-thick, fluvial sedimentary record of the NW Iberian lower Miño River was studied. Grain-size analyses were performed and twelve samples were dated using optically stimulated luminescence dating techniques, documenting a 1300-yr-old reconstructed fluvial record that does not match with known climate fluctuations in the area, but is linked instead to the construction of a series of ancient fishing weirs (pesqueiras). The sedimentation phases are in agreement with known episodes of increased population density, which suggests active use of the pesqueiras. A number of sedimentation hiatuses in the fluvial record point towards damage to the pesqueiras during large-scale flooding in the Miño River basin, and a sudden drop in population probably due to the arrival of the plague in the 13th century AD. The oldest sedimentation phases started just after 700 AD, and we infer that the first pesqueiras were constructed around this time. This timing coincides with the transition of the NW Iberian landscape towards a more intensively used agricultural landscape, as evidenced from other geo-archeological investigations. The results demonstrate that the pesqueiras are several hundreds of years older than known from historical records, but not so old as to date back to the Roman occupation.
Holocene climate dynamics and construction of the pesqueiras in the NW Iberian Lower Miño River: an OSL approach
Viveen, W. ; Sanjurjo-Sanchez, J. ; Schoorl, J.M. ; Veldkamp, A. - \ 2012
In: Proceedings of the 7th on the Atlantic Iberian Margin, 16-20 december 2012, Lisboa, Portugal. - - p. 166 - 166.
Abstract In the Lower Miño River basin a 15-m thick sandy fluvial sequence is found at the town of Chan de Vide, some 55 km upstream from the Atlantic Ocean. The deposit is exceptional because it is the only known sandy deposit in the upstream reaches of the Lower Miño area, which is dominated by coarse gravel deposits. The deposit is probably preserved because of its location in a structurally-controlled bend of the Miño River, shielding the deposit from the high-energy, erosive currents of the Miño River. A total of 8 samples were OSL-dated in the upper 9 m of the deposit. The oldest age obtained at the base of the deposit centres around 3.1 ka ago and the youngest sample 2 m under the top around 200 years ago. A linear sedimentation rate is observed from 3.1 ka until 1.0 ka ago, but from 1.0 ka onwards the sedimentation rate increases significantly. The deposit could be the result of increasing sea level during the Holocene, but the lower part of the deposit needs to be dated to confirm the onset of sedimentation. The most important result is that the increase in sedimentation rate around 1.0 ka is probably the result of the construction of a series of dams (pesqueiras) used for fishing purposes, just downstream of the studied deposit, which were first described around the 12th century. It is a strong indication that the pesqueiras indeed originate from the Middle Ages and not from Roman times, as postulated by some authors. Keywords Minho, sea-level changes, damming, sediment, OSL-dating
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