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We used ramped pyrolysis/oxidation radiocarbon (RPO-14C) analyses to investigate spatial and temporal variations in the thermochemical stability and relative ages of fluvial particulate organic carbon (POC), soil organic carbon, and rock organic carbon in the Canning River drainage basin in northeastern Alaska. This dataset includes thermogram data (CO2 released from a sample as a function of RPO thermal oxidation temperature), activation energy distribution data, and radiocarbon and stable carbon isotope data for distinct RPO fractions for each sample. Activation energy distributions were calculated from the thermogram data using the RampedPyrox package (Hemingway et al., 2016). References: Hemingway, J. D. (2016). rampedpyrox: open-source tools for thermoanalytical data analysis (Version 0.1.2). Retrieved from http://pypi.python.org/pypi/rampedpyrox 

This dataset describes the chemical composition of water samples collected from the Canning River, Alaska from 2021-2024. Samples were collected from various locations throughout the catchment, spanning the headwaters in the Brooks Range to the coastal plain near the Beaufort Sea. The purpose of these data are to understand the spatial and temporal patterns of water chemistry changes as they are related to chemical weathering, organic carbon mobilization, and permafrost processes. 

The Arctic region is experiencing accelerated temperature increases, which has been driving increased rates of permafrost thaw and causing changes in the physical and chemical dynamics of Arctic landscapes. One such change is in the timing and magnitude of spring river ice breakup and flooding. It is difficult to observe river ice breakup in remote Alaskan rivers, and even more difficult to collect samples of river bedload and suspended load during ice breakup events. Building on a geophysical dataset collected on the Canning River in summer 2023, we deployed three geophones during river ice breakup and continuously recorded the signals generated by river ice breakup and river discharge rise in the Canning River, Alaska during this dynamic period. We deployed three SmartSolo geophones (IGU-16HR 3C Multi Channel Data Loggers) on an elevated floodplain surface at 20, 30, and 40 m from the bank of the Canning River from 28 May through 24 June 2024. Unfortunately, only two nodes were recovered (stations 2 and 3 at 30 and 40 m from the river bank, respectively). Using the recorded geophone data, we will work to translate the seismic signals into river ice movement, bedload sediment transport, and stage height changes. These data will provide key information on the timing and driving mechanisms of river bank erosion, soil carbon loss, and sediment transport rates in changing Arctic river systems. 

Permafrost holds more than twice the amount of carbon currently in the atmosphere, but this large carbon reservoir is vulnerable to thaw and erosion under a rapidly changing Arctic climate. Convective storms are becoming increasingly common during Arctic summers and can amplify runoff and erosion. These extreme events, in concert with active layer deepening, may accelerate carbon loss from the Arctic landscape. However, we lack measurements of carbon fluxes during these events. Rivers are sensitive to physical, chemical, and hydrological perturbations, and thus are excellent systems for studying landscape responses to thunderstorms. We present observations from the Canning River, Alaska, which drains the northern Brooks Range and flows across a continuous permafrost landscape to the Beaufort Sea. During summer 2022 and 2023 field campaigns, we opportunistically monitored river discharge, sediment, and organic carbon fluxes during several thunderstorms. During one notable storm, river discharge nearly doubled from ~130 m3/s to ~240 m3/s, suspended sediment flux increased 70-fold, and the particulate organic carbon (POC) flux increased 90-fold relative to non-storm conditions. Taken together, the river exported ~16 metric tons of POC over one hour of this sustained event, not including the additional flux of woody debris. Furthermore, the dissolved organic carbon (DOC) flux nearly doubled. Although these thunderstorm-driven fluxes are short-lived (hours to days), they play an outsized role in exporting organic carbon from Arctic rivers. Understanding how these extreme events impact river water, sediment, and carbon dynamics will help predict how Arctic climate change will modify the global carbon cycle. 

This dataset contains geochemical and grain size measurements of seabed and suspended sediment samples collected from the Bering Shelf and Yukon prodelta in June 2023. These samples were collected during the 6-12 June 2023 Arctic Chief Scientist Training Cruise, which was a short cruise on the R/V Sikuliaq during its transit from Seward, Alaska to Nome, Alaska. The cruise was sponsored by the University National Oceanographic Laboratory System (UNOLS) Arctic Icebreaker Coordinating Committee and the National Science Foundation. These data were generated as a pilot data set to understand the fate of terrestrial organic carbon in the Yukon River delta and adjacent Bering Sea. Seabed sediment was collected at three locations (MC04, MC06, and MC08) using a multicorer. One seabed sediment sample was collected using a van veen grab sampler. Suspended sediment samples were collected using a hand-deployed niskin bottle and transferred into a clean 10-liter cubitainer for transport and temporary storage. Suspended sediment was filtered on the ship within 24 hours of collection using a Geotech barrel filter with a 0.45 micron Polyethersulfone (PES) membrane filter. Multicores were extruded on deck and subsamples were transferred to sterile whirl-pak sample bags. All sediment samples were frozen and subsequently shipped back to the lab in coolers. Sediment samples were analyzed for grain size, bulk elemental composition via X-ray fluorescence (XRF), and organic carbon and nitrogen concentrations and isotopes via EA-IRMS (elemental analyzer-isotope ratio mass spectrometry). Grain size distributions were measured using a Malvern mastersizer laser diffraction particle size analyzer at the University of Colorado Boulder. Bulk elemental composition was measured on the Rigaku XRF in the Analytical Geochemistry Lab at the University of New Mexico. Total organic carbon (TOC), total nitrogen (TN), and carbon/nitrogen isotopes were measured at the Center for Stable Isotopes at the University of New Mexico. Prior to EA-IRMS analyses, sediment samples were acid-treated to remove inorganic carbon following the method of Galy et al., 2007. References Galy, V., Bouchez, J., & France‐Lanord, C. (2007). Determination of total organic carbon content and δ13C in carbonate‐rich detrital sediments. Geostandards and Geoanalytical research, 31(3), 199-207. 

This dataset contains measurements of river discharge, suspended sediment, and organic carbon fluxes in the Canning River, Alaska during one field campaign from 28 June to 10 July 2022 and a second field campaign from 21 July to 2 August 2023. The purpose of this dataset is to demonstrate the impact of summer convective storms on river suspended sediment and particulate organic carbon fluxes in Arctic Rivers. During the 2022 field campaign, we rafted down the Canning River starting on the upper Canning within the headwaters and ending near the mouth at the Beaufort Sea coast. During this campaign, we selected five locations along the active channel to conduct Acoustic Doppler Current Profiler (ADCP) surveys to measure river discharge and sample the river water for suspended sediment and particulate organic carbon, where T1 is the farthest upstream transect and T5 is the farthest downstream. During the 2023 field campaign, we collected instantaneous river discharge measurements of the Canning River in the headwaters at the Marsh Fork Bench Airstrip, at the Staines Airstrip, and on the Staines branch of the Canning River delta. We observed several thunderstorms during these field campaigns, during which the river water level and suspended load increased dramatically, prompting us to sample river suspended sediment during these events. This dataset includes ADCP measurements of river water discharge, suspended sediment concentrations, particulate and dissolved organic carbon concentrations, woody debris flux measurements, and estimates of instantaneous fluxes. 

Abstract Bank erosion in Arctic rivers helps shape channel geometry, mobilizes carbon from permafrost and influences sediment delivery to the Arctic Ocean. On Alaska's Arctic coastal plain, rivers begin flowing during snowmelt in late spring while extensive river ice persists in channels, such that hydraulics are altered and water is kept cool. The effects of river ice on permafrost bank erosion are poorly understood, primarily due to a dearth of field observations and a lack of river ice in existing models. To address this knowledge gap, we developed a numerical model to simulate the melt of substrate interstitial ice and bank collapse along individual permafrost river banks. We parameterize the model with field observations from riverbanks in three different channels on the Canning River delta, which are disparately impacted by river ice during snowmelt. We explore the bank erosion produced without river ice in the model and with modern river ice model scenarios that we drive with different stages and water temperature boundary conditions. We also compare predicted erosion rates to observations from satellite imagery to validate this approach. In the model, banks are idealized as vertical profiles that rise 1–2 m above the river bed and are comprised of silt‐ to sand‐sized sediment with dense roots in the active layer. Underneath, we generalize bank ice content underneath the active layer to represent ice‐rich permafrost on the river corridor boundaries. The model predicts that these ice‐rich river banks can erode by 2–6 m/yr. Scenarios without ice underpredict erosion in the distributary channels. Scenarios with varying river ice for different deltaic channels produce erosion rates similar to observations. Our results suggest that the prolonged melt of thick river ice in a delta nonlinearly impacts permafrost bank erosion by blocking river discharge to certain branches, heightening stage across the distributary network and locally limiting river water warming. Given expected changes in air temperature and hydrology, future estimates of Arctic river bank erosion could be improved by considering river ice. 

We are interested in borrowing seismic sensors to collect a pilot dataset that captures river bedload transport and river ice breakup in the Canning River on Alaska's North Slope. We have two field campaigns this year in which we would like to deploy these sensors: 1) March 22 - April 2 2023, and 2) July 14 – August 6 2023. River ice will be pervasive in the March-April field campaign, so we want to deploy a geophone and datalogger to record the dynamic movements of river ice, and determine whether there is water flowing beneath the ice. In the July-August field campaing, our goal is to use the geophone to record river bed sediment transport. The Canning River is a gravel bed river and we want to determine how much of this gravel moves during and after river ice breakup. We are looking for a 4.5 Hz 3-channel geophone and datalogger for these field campaigns. 

Silicate weathering and organic carbon (OC) burial in soil regulate atmospheric CO2, but their influence on each other remains unclear. Generally, OC oxidation can generate acids that drive silicate weathering, yet clay minerals that form during weathering can protect OC and limit oxidation. This poses a conundrum where clay formation and OC preservation either compete or cooperate. Debate remains about their relative contributions because quantitative tools to simultaneously probe these processes are lacking while those that exist are often not measured in concert. Here we demonstrate that Li isotope ratios of sediment, commonly used to trace clay formation, can help constrain OC cycling. Measurements of river suspended sediment from two watersheds of varying physiography and analysis of published data from Hawaii soil profiles show negative correlations between solid-phase d7Li values and OC content, indicating the association of clay mineral formation with OC accumulation. Yet, the localities differ in their ranges of d7Li values and OC contents, which we interpret with a model of soil formation. We find that temporal trends of Li isotopes and OC are most sensitive to mineral dissolution/clay formation rates, where higher rates yield greater OC stocks and lower d7Li values. Whereas OC-enhanced dissolution primarily dictates turnover times of OC and silicate minerals, clay protection distinctly modifies soil formation pathways and is likely required to explain the range of observations. These findings underscore clay mineral formation, driven primarily by bedrock chemistry and secondarily by climate, as a principal modulator of weathering fluxes and OC accumulation in soil.