More Like this

1. Multi-Dimensional Remote Sensing Analysis Documents Beaver-Induced Permafrost Degradation, Seward Peninsula, Alaska

   https://doi.org/10.3390/rs13234863  

   Jones, Benjamin M.; Tape, Ken D.; Clark, Jason A.; Bondurant, Allen C.; Ward Jones, Melissa K.; Gaglioti, Benjamin V.; Elder, Clayton D.; Witharana, Chandi; Miller, Charles E. (December 2021, Remote Sensing)

   Beavers have established themselves as a key component of low arctic ecosystems over the past several decades. Beavers are widely recognized as ecosystem engineers, but their effects on permafrost-dominated landscapes in the Arctic remain unclear. In this study, we document the occurrence, reconstruct the timing, and highlight the effects of beaver activity on a small creek valley confined by ice-rich permafrost on the Seward Peninsula, Alaska using multi-dimensional remote sensing analysis of satellite (Landsat-8, Sentinel-2, Planet CubeSat, and DigitalGlobe Inc./MAXAR) and unmanned aircraft systems (UAS) imagery. Beaver activity along the study reach of Swan Lake Creek appeared between 2006 and 2011 with the construction of three dams. Between 2011 and 2017, beaver dam numbers increased, with the peak occurring in 2017 (n = 9). Between 2017 and 2019, the number of dams decreased (n = 6), while the average length of the dams increased from 20 to 33 m. Between 4 and 20 August 2019, following a nine-day period of record rainfall (>125 mm), the well-established dam system failed, triggering the formation of a beaver-induced permafrost degradation feature. During the decade of beaver occupation between 2011 and 2021, the creek valley widened from 33 to 180 m (~450% increase) and the length of the stream channel network increased from ~0.6 km to more than 1.9 km (220% increase) as a result of beaver engineering and beaver-induced permafrost degradation. Comparing vegetation (NDVI) and snow (NDSI) derived indices from Sentinel-2 time-series data acquired between 2017 and 2021 for the beaver-induced permafrost degradation feature and a nearby unaffected control site, showed that peak growing season NDVI was lowered by 23% and that it extended the length of the snow-cover period by 19 days following the permafrost disturbance. Our analysis of multi-dimensional remote sensing data highlights several unique aspects of beaver engineering impacts on ice-rich permafrost landscapes. Our detailed reconstruction of the beaver-induced permafrost degradation event may also prove useful for identifying degradation of ice-rich permafrost in optical time-series datasets across regional scales. Future field- and remote sensing-based observations of this site, and others like it, will provide valuable information for the NSF-funded Arctic Beaver Observation Network (A-BON) and the third phase of the NASA Arctic-Boreal Vulnerability Experiment (ABoVE) Field Campaign. 

   more » « less
2. Heterogeneity and nonaffinity of cell-induced matrix displacements

   https://doi.org/10.1103/PhysRevE.98.052410  

   Burkel, Brian; Proestaki, Maria; Tyznik, Stephen; Notbohm, Jacob (November 2018, Physical Review E)
3. Topologically Induced Heterogeneity in Gradient Copolymer Brush Particle Materials

   https://doi.org/10.1021/acs.macromol.2c01131  

   Zhao, Yuqi; Wang, Zongyu; Yu, Chenxi; Wu, Hanshu; Olszewski, Mateusz; Yin, Rongguan; Zhai, Yue; Liu, Tong; Coronado, Amy; Matyjaszewski, Krzysztof; et al (October 2022, Macromolecules)
4. Tapestry Beaver Pond Geochemistry

   https://doi.org/10.4211/hs.8bb8e869e2b9442989163fbaa1d616ea  

   Ledford, Sarah (July 2025, HydroShare)

   Major ion geochemistry and isotopes of nitrate for the Tapestry beaver pond in Atlanta, GA. Samples were collected from the surface from June 2019-March 2020 and from the hyporheic zone from June-August 2019. Logger data (DO and specific conductance at 10 minute intervals) were also collected from June-August 2019. Isotopes of nitrate (d15N and d18O) were measured for a subset of June-August 2019 surface and hyporheic samples. Data were used in the paper "Urban beaver dam shows hyporheic exchange helps mediate high nutrient groundwater and a high productivity pond" 

   more » « less
5. Dynamics and heterogeneity of Erk-induced immediate early gene expression

   https://doi.org/10.1101/2021.04.30.442166  

   Jena, Siddhartha G; Yu, Catherine; Toettcher, Jared E (April 2021, bioRxiv)

   Many canonical signaling pathways exhibit complex time-varying responses, yet how minutes-timescale pulses of signaling interact with the dynamics of transcription and gene expression remains poorly understood. Erk-induced immediate early gene (IEG) expression is a model of this interface, exemplifying both dynamic pathway activity and a rapid, potent transcriptional response. Here, we quantitatively characterize IEG expression downstream of dynamic Erk stimuli in individual cells. We find that IEG expression responds rapidly to acute changes in Erk activity, but only in a sub-population of stimulus-responsive cells. We find that while Erk activity partially predicts IEG expression, a majority of response heterogeneity is independent of Erk and can be rapidly tuned by different mitogenic stimuli and parallel signaling pathways. We extend our findings to an in vivo context, the mouse epidermis, where we observe heterogeneous immediate-early gene accumulation in both fixed tissue and single-cell RNA sequencing data. Our results demonstrate that signaling dynamics can be faithfully transmitted to gene expression and suggest that the signaling-responsive population is an important parameter for interpreting gene expression responses. 

   more » « less