Jane Kathryn Willenbring

All Publications

• Late Holocene Cliff Retreat in Del Mar, CA, Revealed From Shore Platform Be-10 Concentrations and Numerical Modeling JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE Clow, T., Willenbring, J. K., Young, A. P., Matsumoto, H., Hidy, A. J., Shadrick, J. R. 2023; 128 (4)

  View details for DOI 10.1029/2022JF006855

  View details for Web of Science ID 000973537700001

• Shaping of topography by topographically-controlled vegetation in tropical montane rainforest. PloS one Brocard, G., Willebring, J. K., Scatena, F. N. 2023; 18 (3): e0281835

  Abstract

  Topography is commonly viewed as a passive backdrop on which vegetation grows. Yet, in certain circumstances, a bidirectional feedback may develop between the control of topography and the spatial distribution of vegetation and landform development, because vegetation modulates the erosion of the land surface. Therefore, if reinforcing feedbacks are established between erosion and land cover distribution over timescales relevant to landform development, then the interactions between vegetation and topography may create distinctive landforms, shaped by vegetation. We expose here a strong correlation between the spatial distribution of vegetation, erosion rates, and topography at a characteristic length scale of 102-103m (mesoscale topography) in the Luquillo Experimental forest (LEF) of Puerto Rico. We use high-resolution LiDAR topography to characterize landforms, satellite images to classify the vegetation into forest types, and in-situ produced cosmogenic 10Be in the quartz extracted from soils and stream sediments to document spatial variations in soil erosion. The data document a strong correlation between forest type and topographic position (hilltop vs. valleys), and a correlation between topographic position and 10Be-derived erosion rates over 103-104 years. Erosion is faster in valleys, which are mostly covered by monocot Palm Forest, and slower on surrounding hills mostly covered by the dicot Palo Colorado Forest. Transition from one forest type to the next occurs across a break-in-slope that separates shallowly convex hilltops from deeply concave valleys (coves). The break-in-slope is the consequence of a longer-lasting erosional imbalance whereby coves erode faster than hills over landscape-shaping timescales. Such a deepening of the coves is usually spurred by external drivers, but such drivers are here absent. This implies that cove erosion is driven by a process originating within the coves themselves. We propose that vegetation is the primary driver of this imbalance, soil erosion being faster under Palm forest than under Palo Colorado forest. Concentration of the Palm forest in the deepening coves is reinforced by the better adaptation of Palm trees to the erosive processes that take place in the coves, once these develop steep slopes. At the current rate of landscape development, we find that the imbalance started within the past 0.1-1.5 My. The initiation of the process could correspond to time of settlement of these mountain slopes by the Palm and Palo Colorado forests.

  View details for DOI 10.1371/journal.pone.0281835

  View details for PubMedID 36893140

• Across-strike asymmetry of the Andes orogen linked to the age and geometry of the Nazca plate br GEOLOGY Val, P., Willenbring, J. K. 2022

  View details for DOI 10.1130/G50545.1

  View details for Web of Science ID 000868425100001

• There is no Neogene denudation conundrum. Proceedings of the National Academy of Sciences of the United States of America von Blanckenburg, F., Bouchez, J., Willenbring, J. K., Ibarra, D. E., Rugenstein, J. K. 2022; 119 (35): e2202387119

  View details for DOI 10.1073/pnas.2202387119

  View details for PubMedID 35939659

• Non-native species change the tune of tundra soils: Novel access to soundscapes of the Arctic earthworm invasion. The Science of the total environment Keen, S. C., Wackett, A. A., Willenbring, J., Yoo, K., Jonsson, H., Clow, T., Klaminder, J. 2022: 155976

  Abstract

  Over the last decade, an increasing number of studies have used soundscapes to address diverse ecological questions. Sound represents one of the few sources of information capable of providing in situ insights into processes occurring within opaque soil matrices. To date, the use of soundscapes for soil macrofauna monitoring has been experimentally tested only in controlled laboratory environments. Here we assess the validity of laboratory predictions and explore the use of soil soundscape proxies for monitoring soil macrofauna (i.e., earthworm) activities in an outdoor context. In a common garden experiment in northern Sweden, we constructed outdoor mesocosm plots (N = 36) containing two different Arctic vegetation types (meadow and heath) and introduced earthworms to half of these plots. Earthworms substantially altered the ambient soil soundscape under both vegetation types, as measured by both traditional soundscape indices and frequency band power levels, although their acoustic impacts were expressed differently in heath versus meadow soils. While these findings support the as-of-yet untapped promise of using belowground soundscape analyses to monitor soil ecosystem health, direct acoustic emissions from earthworm activities appear to be an unlikely proxy for tracking worm activities at daily timescales. Instead, earthworms indirectly altered the soil soundscape by 're-engineering' the soil matrix: an effect that was dependent on vegetation type. Our findings suggest that long-term (i.e., seasonal) earthworm activities in natural soil settings can likely be monitored indirectly via their impacts on soundscape measures and acoustic indices. Analyzing soil soundscapes may enable larger-scale monitoring of high-latitude soils and is directly applicable to the specific case of earthworm invasions within Arctic soils, which has recently been identified as a potential threat to the resilience of high-latitude ecosystems. Soil soundscapes could also offer a novel means to monitor soils and soil-plant-faunal interactions in situ across diverse pedogenic, agronomic, and ecological systems.

  View details for DOI 10.1016/j.scitotenv.2022.155976

  View details for PubMedID 35618134

• Quantifying Rates of Landscape Unzipping JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE Harrison, E. J., McElroy, B., Willenbring, J. K. 2022; 127 (4)

  View details for DOI 10.1029/2021JF006236

  View details for Web of Science ID 000788118500001

• Cosmogenic nuclide techniques NATURE REVIEWS METHODS PRIMERS Schaefer, J. M., Codilean, A. T., Willenbring, J. K., Lu, Z., Keisling, B., Fulop, R., Val, P. 2022; 2 (1)

  View details for DOI 10.1038/s43586-022-00096-9

  View details for Web of Science ID 000888565700005

• Landscape Evolution as a Diversification Driver in Freshwater Fishes FRONTIERS IN ECOLOGY AND EVOLUTION Val, P., Lyons, N. J., Gasparini, N., Willenbring, J. K., Albert, J. S. 2022; 09

  View details for DOI 10.3389/fevo.2021.788328

  View details for Web of Science ID 000748019800001

• Tectonically and climatically driven mountain-hopping erosion in central Guatemala from detrital Be-10 and river profile analysis EARTH SURFACE DYNAMICS Brocard, G., Willenbring, J., Salles, T., Cosca, M., Guttierez-Orrego, A., Cacao Chiquin, N., Moran-Ical, S., Teyssier, C. 2021; 9 (4): 795-822

  View details for DOI 10.5194/esurf-9-795-2021

  View details for Web of Science ID 000679819300001

• Landslides, hurricanes, and sediment sourcing impact basin-scale erosion estimates in Luquillo, Puerto Rico EARTH AND PLANETARY SCIENCE LETTERS Grande, A., Schmidt, A. H., Bierman, P. R., Corbett, L. B., Lopez-Lloreda, C., Willenbring, J., McDowell, W. H., Caffee, M. W. 2021; 562

  View details for DOI 10.1016/j.epsl.2021.116821

  View details for Web of Science ID 000636736200006

• Quaternary record of terrestrial environmental change in response to climatic forcing and anthropogenic perturbations, in Puerto Rico QUATERNARY SCIENCE REVIEWS Harrison, E. J., Willenbring, J. K., Brocard, G. Y. 2021; 253

  View details for DOI 10.1016/j.quascirev.2020.106770

  View details for Web of Science ID 000610835200015

• An actionable anti-racism plan for geoscience organizations. Nature communications Ali, H. N., Sheffield, S. L., Bauer, J. E., Caballero-Gill, R. P., Gasparini, N. M., Libarkin, J., Gonzales, K. K., Willenbring, J., Amir-Lin, E., Cisneros, J., Desai, D., Erwin, M., Gallant, E., Gomez, K. J., Keisling, B. A., Mahon, R., Marín-Spiotta, E., Welcome, L., Schneider, B. 2021; 12 (1): 3794

  Abstract

  Geoscience organizations shape the discipline. They influence attitudes and expectations, set standards, and provide benefits to their members. Today, racism and discrimination limit the participation of, and promote hostility towards, members of minoritized groups within these critical geoscience spaces. This is particularly harmful for Black, Indigenous, and other people of color in geoscience and is further exacerbated along other axes of marginalization, including disability status and gender identity. Here we present a twenty-point anti-racism plan that organizations can implement to build an inclusive, equitable and accessible geoscience community. Enacting it will combat racism, discrimination, and the harassment of all members.

  View details for DOI 10.1038/s41467-021-23936-w

  View details for PubMedID 34158472

• Seepage Erosion in the Luquillo Mountains, Puerto Rico, Relict Landscapes JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE Harrison, E. J., Brocard, G. Y., Gasparini, N. M., Lyons, N. J., Willenbring, J. K. 2020; 125 (6)

  View details for DOI 10.1029/2019JF005341

  View details for Web of Science ID 000555443200004

• Chemical and physical drivers of beryllium retention in two soil endmembers. The Science of the total environment Boschi, V. n., Willenbring, J. K. 2020; 754: 141591

  Abstract

  Meteoric 10Be and 7Be produced in the atmosphere from high-energy spallation reactions are deposited onto the Earth's surface through wet and dry deposition and are sorbed onto the surfaces of particles. On land, the sorbed concentrations scale with the residence time of sediments in a landscape-offset by slow (10Be) and fast (7Be) radioactive decay. Additionally, the amount of native 9Be, leached from minerals, correlates with the chemical weathering of soils. However, previous work has shown that chemical and physical properties of soils and river sediments affects sorption of beryllium. Therefore, the magnitude of sorbed beryllium concentrations may be more representative of the sorption capacity of the system rather than its erosional or weathering history. Although previous work has examined the physical and chemical properties of soil that influence beryllium sorption, these studies either lack consensus or exclude potentially important variables. In this work, we provide a thorough examination of variables previously reported to have influence on beryllium chemistry as well as new variables such as nitrogen, phosphorus and sulfur concentrations in order to determine which factors best predict beryllium sorption. We selected two soil endmembers with differing compositions, separated them into different size fractions, and characterized the surface area, cation exchange capacity (CEC), mineralogy, sulfur, carbon, nitrogen and phosphorus concentrations. We determined that the inverse percent abundance of quartz and the CEC best predict beryllium sorption potential in these soils. By deriving a model that relates these two variables to the percent sorbed beryllium, we were able to predict the sorption capacity of our system and reduced the error in sorbed beryllium amounts due to differences in soil properties by about 42%. From these results, we provide insight as to why there is inconsistency in the literature with regards to the physio-chemical controls on the environmental behavior of beryllium.

  View details for DOI 10.1016/j.scitotenv.2020.141591

  View details for PubMedID 32916480

• Calibrating a long-term meteoric 10Be delivery rate into eroding western US glacial deposits by comparing meteoric and in situ produced 10Be depth profiles Geochronology Clow, T. W., Willenbring, J. K., et al 2020; 2 (2): 411-423

  View details for DOI 10.5194/gchron-2-411-2020

• Meteoric Beryllium-10 as a Tracer of Erosion Due to Postsettlement Land Use in West-Central Minnesota, USA JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE Jelinski, N. A., Campforts, B., Willenbring, J. K., Schumacher, T. E., Li, S., Lobb, D. A., Papiernik, S. K., Yoo, K. 2019; 124 (4): 874–901

  View details for DOI 10.1029/2018JF004720

  View details for Web of Science ID 000467399700001

• Be-10/Be-9 Ratios Reflect Antarctic Ice Sheet Freshwater Discharge During Pliocene Warming PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY Valletta, R. D., Willenbring, J. K., Passchier, S., Elmi, C. 2018; 33 (9): 934–44

  View details for DOI 10.1029/2017PA003283

  View details for Web of Science ID 000447556200002

• Addressing time-scale-dependent erosion rates from measurement methods with censorship GEOLOGICAL SOCIETY OF AMERICA BULLETIN McElroy, B., Willenbring, J., Mohrig, D. 2018; 130 (3-4): 381–95

  View details for DOI 10.1130/B31644.1

  View details for Web of Science ID 000427362500002

• Siderophore-mediated iron removal from chrysotile: Implications for asbestos toxicity reduction and bioremediation. Journal of hazardous materials Mohanty, S. K., Gonneau, C. n., Salamatipour, A. n., Pietrofesa, R. A., Casper, B. n., Christofidou-Solomidou, M. n., Willenbring, J. K. 2018; 341: 290–96

  Abstract

  Asbestos fibers are highly toxic (Group 1 carcinogen) due to their high aspect ratio, durability, and the presence of iron. In nature, plants, fungi, and microorganisms release exudates, which can alter the physical and chemical properties of soil minerals including asbestos minerals. We examined whether exudates from bacteria and fungi at environmentally relevant concentrations can alter chrysotile, the most widely used asbestos mineral, and lower its toxicity. We monitored the release of iron from chrysotile in the presence of organic acid ligands and iron-specific siderophores derived from bacteria and fungi and measured any change in fiber toxicity toward peritoneal macrophages harvested from mice. Both fungal and bacterial siderophores increased the removal of iron from asbestos fibers. In contrast, organic acid ligands at environmentally relevant concentrations neither released iron from fibers nor helped in siderophore-mediated iron removal. Removal of plant-available or exchangeable iron did not diminish iron dissolution by both types of siderophores, which indicates that siderophores can effectively remove structural iron from chrysotile fibers. Removal of iron by siderophore lowered the fiber toxicity; fungal siderophore appears to be more effective than bacterial siderophore in lowering the toxicity. These results indicate that prolonged exposure to siderophores, not organic acids, in the soil environment decreases asbestos fiber toxicity and possibly lowers the health risks. Thus, bioremediation should be explored as a viable strategy to manage asbestos-contaminated sites such as Brownfield sites, which are currently left untreated despite dangers to surrounding communities.

  View details for DOI 10.1016/j.jhazmat.2017.07.033

  View details for PubMedID 28797944

  View details for PubMedCentralID PMC5771417

• "Difference Dating": A novel approach towards dating alpine glacial moraines QUATERNARY GEOCHRONOLOGY Valletta, R. D., Willenbring, J. K., Lewis, A. R. 2017; 41: 1–10

  View details for DOI 10.1016/j.quageo.2017.05.001

  View details for Web of Science ID 000407535300001

• Sediment supply controls equilibrium channel geometry in gravel rivers PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Pfeiffer, A. M., Finnegan, N. J., Willenbring, J. K. 2017; 114 (13): 3346–51

  Abstract

  In many gravel-bedded rivers, floods that fill the channel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D50). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D50 has become a commonly used assumption. However, not all natural gravel channels actually conform to this simple relationship; some channels maintain bankfull stresses far in excess of the critical stress required to initiate sediment transport. We use a database of >300 gravel-bedded rivers and >600 10Be-derived erosion rates from across North America to explore the hypothesis that sediment supply drives the magnitude of bankfull shear stress relative to the critical stress required to mobilize the median bed surface grain size ([Formula: see text]). We find that [Formula: see text] is significantly higher in West Coast river reaches (2.35, n = 96) than in river reaches elsewhere on the continent (1.03, n = 245). This pattern parallels patterns in erosion rates (and hence sediment supplies). Supporting our hypothesis, we find a significant correlation between upstream erosion rate and local [Formula: see text] at sites where this comparison is possible. Our analysis reveals a decrease in bed surface armoring with increasing [Formula: see text], suggesting channels accommodate changes in sediment supply through adjustments in bed surface grain size, as also shown through numerical modeling. Our findings demonstrate that sediment supply is encoded in the bankfull hydraulic geometry of gravel bedded channels through its control on bed surface grain size.

  View details for DOI 10.1073/pnas.1612907114

  View details for Web of Science ID 000397607300051

  View details for PubMedID 28289212

  View details for PubMedCentralID PMC5380060

• Short-lived increase in erosion during the African Humid Period: Evidence from the northern Kenya Rift EARTH AND PLANETARY SCIENCE LETTERS Garcin, Y., Schildgen, T. F., Acosta, V., Melnick, D., Guillemoteau, J., Willenbring, J., Strecker, M. R. 2017; 459: 58-69

  View details for DOI 10.1016/j.epsl.2016.11.017

  View details for Web of Science ID 000393006500006

• Framework for assessment and phytoremediation of asbestos-contaminated sites. Environmental science and pollution research international Gonneau, C. n., Miller, K. n., Mohanty, S. K., Xu, R. n., Hwang, W. T., Willenbring, J. K., Casper, B. B. 2017; 24 (33): 25912–22

  Abstract

  We examine the feasibility of phytoremediation as an alternative strategy to limit the exposure of asbestos in site with asbestos-containing materials. We collected soils from four locations from two sites-one with naturally occurring asbestos, and another, a superfund site, where asbestos-containing materials were disposed over decades-and performed ecotoxicology tests. We also performed two experiments with crop cultivar and two grasses from serpentine ecotype and cultivar to determined best choice for phytoremediation. Asbestos concentrations in different size fractions of soils varied by orders of magnitude. However, different asbestos concentrations had little effect on germination and root growth. Presence of co-contaminants such as heavy metals and lack of nutrients affected plant growth to different extents, indicating that several of these limiting factors should be considered instead of the primary contaminant of concern. Crop cultivar survived on asbestos-contaminated soil. Grasses from serpentine ecotype did not show higher biomass than the cultivar. Overall, these results showed that soil conditions play a critical role in screening different crop species for phytoremediation and that asbestos concentration has limited to no effect on plant growth. Our study provided a framework for phytoremediation of asbestos-contaminated sites to limit long-term asbestos exposure.

  View details for DOI 10.1007/s11356-017-0177-x

  View details for PubMedID 28940054

  View details for PubMedCentralID PMC5769457

• Differential elemental uptake in three pseudo-metallophyte C4 grasses in situ in the eastern USA. Plant and soil Gonneau, C. n., Mohanty, S. K., Dietterich, L. H., Hwang, W. T., Willenbring, J. K., Casper, B. B. 2017; 416 (1-2): 149–63

  Abstract

  Elemental uptake in serpentine floras in eastern North America is largely unknown. The objective of this study was to determine major and trace element concentrations in soil and leaves of three native pseudo-metallophyte C4 grasses in situ at five sites with three very different soil types, including three serpentine sites, in eastern USA.Pseudo-total and extractible concentrations of 15 elements were measured and correlated from the soils and leaves of three species at the five sites.Element concentrations in soils of pseudo-metallophytes varied up to five orders of magnitude. Soils from metalliferous sites exhibited higher concentrations of their characteristic elements than non-metalliferous. In metallicolous populations, elemental concentrations depended on the element. Concentrations of major elements (Ca, Mg, K) in leaves were lower than typical toxicity thresholds, whereas concentrations of Zn were higher.In grasses, species can maintain relatively low metal concentrations in their leaves even when soil concentrations are richer. However, in highly Zn-contaminated soil, we found evidence of a threshold concentration above which Zn uptake increases drastically. Finally, absence of main characteristics of serpentine soil at one site indicated the importance of soil survey and restoration to maintain serpentinophytes communities and avoid soil encroachment.

  View details for DOI 10.1007/s11104-017-3198-9

  View details for PubMedID 28845059

  View details for PubMedCentralID PMC5568086

• Beryllium desorption from minerals and organic ligands over time CHEMICAL GEOLOGY Boschi, V., Willenbring, J. K. 2016; 439: 52–58

  View details for DOI 10.1016/j.chemgeo.2016.06.009

  View details for Web of Science ID 000382345600004

• Abrupt Change in Forest Height along a Tropical Elevation Gradient Detected Using Airborne Lidar REMOTE SENSING Wolf, J., Brocard, G., Willenbring, J., Porder, S., Uriarte, M. 2016; 8 (10)

  View details for DOI 10.3390/rs8100864

  View details for Web of Science ID 000387357300078

• Relict landscape resistance to dissection by upstream migrating knickpoints JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE Brocard, G. Y., Willenbring, J. K., Miller, T. E., Scatena, F. N. 2016; 121 (6): 1182–1203

  View details for DOI 10.1002/2015JF003678

  View details for Web of Science ID 000382580600005

• The null hypothesis: globally steady rates of erosion, weathering fluxes and shelf sediment accumulation during Late Cenozoic mountain uplift and glaciation TERRA NOVA Willenbring, J. K., Jerolmack, D. J. 2016; 28 (1): 11–18

  View details for DOI 10.1111/ter.12185

  View details for Web of Science ID 000368164100003

• Asbestos Fiber Preparation Methods Affect Fiber Toxicity. Environmental science & technology letters Salamatipour, A. n., Mohanty, S. K., Pietrofesa, R. A., Vann, D. R., Christofidou-Solomidou, M. n., Willenbring, J. K. 2016; 3 (7): 270–74

  Abstract

  To measure the toxic potential of asbestos fibers-a known cause of asbestosis, lung cancer, and malignant mesothelioma-asbestos minerals are generally first ground down to small fibers, but it is unknown whether the grinding condition itself changes the fiber toxicity. To evaluate this, we ground chrysotile ore with or without water for 5-30 min and quantified asbestos-induced reactive oxygen species generation in elicited murine peritoneal macrophages as an indicator of fiber toxicity. The toxicity of dry-ground fibers was higher than the toxicity of wet-ground fibers. Grinding with or without water did not materially alter the mineralogical properties. However, dry-ground fibers contained at least 7 times more iron than wet-ground fibers. These results indicate that grinding methods significantly affect the surface concentration of iron, resulting in changes in fiber-induced reactive oxygen species generation or toxicity. Therefore, fiber preparation conditions should be accounted for when comparing the toxicity of asbestos fibers between reported studies.

  View details for DOI 10.1021/acs.estlett.6b00174

  View details for PubMedID 27540559

  View details for PubMedCentralID PMC4985249

• The effect of pH, organic ligand chemistry and mineralogy on the sorption of beryllium over timeL ENVIRONMENTAL CHEMISTRY Boschi, V., Willenbring, J. K. 2016; 13 (4): 711–22

  View details for DOI 10.1071/EN15107

  View details for Web of Science ID 000379973200015

• Stable-isotope and solute-chemistry approaches to flow characterization in a forested tropical watershed, Luquillo Mountains, Puerto Rico APPLIED GEOCHEMISTRY Scholl, M. A., Shanley, J. B., Murphy, S. F., Willenbring, J. K., Occhi, M., Gonzalez, G. 2015; 63: 484–97

  View details for DOI 10.1016/j.apgeochem.2015.03.008

  View details for Web of Science ID 000366219800041

• Sequence and chronology of the Cuerpo de Hombre paleoglacier (Iberian Central System) during the last glacial cycle QUATERNARY SCIENCE REVIEWS Carrasco, R. M., Pedraza, J., Dominguez-Villar, D., Willenbring, J. K., Villa, J. 2015; 129: 163-177

  View details for DOI 10.1016/j.quascirev.2015.09.021

  View details for Web of Science ID 000366232300010

• Effects of a tectonically-triggered wave of incision on riverine exports and soil mineralogy in the Luquillo Mountains of Puerto Rico APPLIED GEOCHEMISTRY Brocard, G. Y., Willenbring, J. K., Scatena, F. N., Johnson, A. H. 2015; 63: 586-598

  View details for DOI 10.1016/j.apgeochem.2015.04.001

  View details for Web of Science ID 000366219800050

• Rain revs the crustal conveyor NATURE GEOSCIENCE Willenbring, J. K. 2015; 8 (6): 424–25

  View details for DOI 10.1038/ngeo2450

  View details for Web of Science ID 000355236500007

• Extreme decay of meteoric beryllium-10 as a proxy for persistent aridity. Scientific reports Valletta, R. D., Willenbring, J. K., Lewis, A. R., Ashworth, A. C., Caffee, M. n. 2015; 5: 17813

  Abstract

  The modern Antarctic Dry Valleys are locked in a hyper-arid, polar climate that enables the East Antarctic Ice Sheet (EAIS) to remain stable, frozen to underlying bedrock. The duration of these dry, cold conditions is a critical prerequisite when modeling the long-term mass balance of the EAIS during past warm climates and is best examined using terrestrial paleoclimatic proxies. Unfortunately, deposits containing such proxies are extremely rare and often difficult to date. Here, we apply a unique dating approach to tundra deposits using concentrations of meteoric beryllium-10 ((10)Be) adhered to paleolake sediments from the Friis Hills, central Dry Valleys. We show that lake sediments were emplaced between 14-17.5 My and have remained untouched by meteoric waters since that time. Our results support the notion that the onset of Dry Valleys aridification occurred ~14 My, precluding the possibility of EAIS collapse during Pliocene warming events. Lake fossils indicate that >14 My ago the Dry Valleys hosted a moist tundra that flourished in elevated atmospheric CO2 (>400 ppm). Thus, Dry Valleys tundra deposits record regional climatic transitions that affect EAIS mass balance, and, in a global paleoclimatic context, these deposits demonstrate how warming induced by 400 ppm CO2 manifests at high latitudes.

  View details for DOI 10.1038/srep17813

  View details for PubMedID 26647733

  View details for PubMedCentralID PMC4673429

• In Situ Liquid Cell Observations of Asbestos Fiber Diffusion in Water. Environmental science & technology Wu, L. n., Ortiz, C. n., Xu, Y. n., Willenbring, J. n., Jerolmack, D. n. 2015; 49 (22): 13340–49

  Abstract

  We present real-time observations of the diffusion of individual asbestos fibers in water. We first scaled up a technique for fluorescent tagging and imaging of chrysotile asbestos fibers and prepared samples with a distribution of fiber lengths ranging from 1 to 20 μm. Experiments were then conducted by placing a 20, 100, or 150 ppm solution of these fibers in a liquid cell mounted on a spinning-disk confocal microscope. Using automated elliptical-particle detection methods, we determined the translation and rotation and two-dimensional (2D) trajectories of thousands of diffusing chrysotile fibers. We find that fiber diffusion is size-dependent and in reasonable agreement with theoretical predictions for the Brownian motion of rods. This agreement is remarkable given that experiments involved non-idealized particles at environmentally relevant concentrations in a confined cell, in which particle-particle and particle-wall interactions might be expected to cause deviations from theory. Experiments also confirmed that highly elongated chrysotile fibers exhibit anisotropic diffusion at short time scales, a predicted effect that may have consequences for aggregate formation and transport of asbestos in confined spaces. The examined fibers vary greatly in their lengths and were prepared from natural chrysotile. Our findings thus indicate that the diffusion rates of a wide range of natural colloidal particles can be predicted from theory, so long as the particle aspect ratio is properly taken into account. This is an important first step for understanding aggregate formation and transport of non-spherical contaminant particles, in the environment and in vivo.

  View details for DOI 10.1021/acs.est.5b03839

  View details for PubMedID 26461183

  View details for PubMedCentralID PMC4747642

• Identifying Sediment Sources and Sinks in the Root River, Southeastern Minnesota ANNALS OF THE ASSOCIATION OF AMERICAN GEOGRAPHERS Stout, J. C., Belmont, P., Schottler, S. P., Willenbring, J. K. 2014; 104 (1): 20–39

  View details for DOI 10.1080/00045608.2013.843434

  View details for Web of Science ID 000328247600002

• What does a mean mean? The temporal evolution of detrital cosmogenic denudation rates in a transient landscape GEOLOGY Willenbring, J. K., Gasparini, N. M., Crosby, B. T., Brocard, G. 2013; 41 (12): 1215–18

  View details for DOI 10.1130/G34746.1

  View details for Web of Science ID 000329786200016

• Supraglacial Debris Supply in the Cuerpo de Hombre paleoglacier (Spanish Central System): Reconstruction and Interpretation of a Rock Avalanche Event GEOGRAFISKA ANNALER SERIES A-PHYSICAL GEOGRAPHY Carrasco, R. M., Pedraza, J., Dominguez-Villar, D., Willenbring, J. K., Villa, J. 2013; 95 (3): 211–26

  View details for DOI 10.1111/geoa.12010

  View details for Web of Science ID 000323725300002

• A cosmic trip: 25 years of cosmogenic nuclides in geology GEOLOGICAL SOCIETY OF AMERICA BULLETIN Granger, D. E., Lifton, N. A., Willenbring, J. K. 2013; 125 (9-10): 1379–1402

  View details for DOI 10.1130/B30774.1

  View details for Web of Science ID 000328506500001

• Meteoric Be-10 concentrations from saprolite and till in northern Sweden: Implications for glacial erosion and age QUATERNARY GEOCHRONOLOGY Ebert, K., Willenbring, J., Norton, K. P., Hall, A., Hattestrand, C. 2012; 12: 11-22

  View details for DOI 10.1016/j.quageo.2012.05.005

  View details for Web of Science ID 000310481900002

• RATE AND PROCESSES OF RIVER NETWORK REARRANGEMENT DURING INCIPIENT FAULTING: THE CASE OF THE CAHABON RIVER, GUATEMALA AMERICAN JOURNAL OF SCIENCE Brocard, G., Willenbring, J., Suski, B., Audra, P., Authemayou, C., Cosenza-Muralles, B., Moran-Ical, S., Demory, F., Rochette, P., Vennemann, T., Holliger, K., Teyssier, C. 2012; 312 (5): 449-507

  View details for DOI 10.2475/05.2012.01

  View details for Web of Science ID 000307623800001

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