University of New Hampshire

Wildfires are an increasingly important factor in boreal forest biome. The fire cycle have significant effects on the cycling of nutrients within and through an ecosystem. Past research shows that major elements, nutrients, and organic matter in stream water can be altered for decades after a wildfire. Here we examine how stream chemistry might be used to characterize biogeochemical effects of fire across the continuous permafrost taiga of the Central Siberia. By comparing the results of laboratory combustion of organic horizons, soil solution chemistry in burned and unburned watersheds, and stream chemistry in a chronosequence of watersheds with a well-described fire history, we assess possible proxies in stream water chemistry for wildfire severity and timing in this landscape. Our results suggest that the time since last wildfire can be estimated by sulfates (SO 4 2− ) and nitrates (NO 3 − ) concentrations, and that the soil active layer thickness (ALT, the soil depth at which soil thaws annually) increase by wildfires is reflected in bicarbonates (HCO 3 − ) concentrations. Phosphate (PO 4 3− ), although it is released from organic matter by combustion, is unchanged in stream water following fire. Chloride (Cl − ) produces a useful marker for hydrologic conditions at the time of sampling, allowing a relatively small number of stream water samples to be used to characterize past fire regime. Concentrations of SO 4 2− , NO 3 − and HCO 3 − in stream runoff can thus be used as a specific fingerprint of fire history in the northern taiga larch and birch forests of the Central Siberia, since an increase in their concentrations in stream runoff reflects fire occurrence in the catchment area. • Wildfires increase concentrations of major ions in pyrogenic organic layers, topsoil and streams. • Phosphorus is liberated by organic matter combustion, but retained in subsoil. • Wildfires affect stream HCO 3 − , SO 4 2− , Cl − and NO 3 − concentrations at decadal scales. • Stream bicarbonate can serve as a proxy for the active layer depth and wildfire timing • Sulfate in stream water is the most reliable indicator of time since fire disturbance in the catchments.

Stormwater runoff is a significant contributor of phosphorus (P) loading to waterbodies around the world. Green stormwater infrastructure (GSI) that uses filtration media, such as bioretention, can effectively retain suspended solids and associated particulate P, but is commonly less effective for soluble P retention. The addition of aluminum-based drinking water treatment residuals (DWTRs) may increase P-sorbing capacity of GSI media, though guidance is needed for material selection and to reduce risk of potential contamination. This study examined the P removal capacities of DWTRs (n=11) from drinking water treatment plants in the New England region (northeastern USA). DWTRs were compared for P-sorption potential using batch isotherm and column experiments and characterized for several material properties as well as arsenic leaching and per and polyfluoroalkyl substances (PFAS) content. Results indicate that P retention capacity of DWTRs is generally high (>1,000 mg P kg-1) but varies by approximately one order of magnitude. Lower DWTR bulk density and greater oxalate-extractable Al + Fe were correlated with greater P retention in column experiments. Our findings also indicate that the potential for significant arsenic leaching is low. PFAS were detected in 36% of DWTRs, often at low levels near the method detection limit, with three DWTRs having higher levels of certain PFAS. The addition of DWTRs to GSI is promising for enhanced soluble P removal on a decadal scale (10-90 years), but additional research on As, PFAS, and other contaminants should be pursued prior to use, especially in areas with known or suspected source water contamination. Achieving effective long-term P removal requires selecting DWTRs with favorable material properties (e.g., drier, lower bulk density, greater oxalate-extractable Al + Fe), and mixture with sand at up to 10% DWTR by volume and potentially higher if proven to not impede hydraulic conductivity. Field monitoring of DWTR-enhanced infrastructure at multiple time points postinstallation (e.g., years 1, 5, 10, 20, and 30) is needed to confirm P removal longevity over expected infrastructure lifespans.

Salt marshes in the northeastern United States support several specialized breeding bird species that are threatened by sea level rise (SLR) and coastal development, processes that drive habitat change and fragmentation. There have been rapid, widespread declines in some species, but mechanisms driving population change and whether declines continue remain unclear. We examined the influence of phenomena expected to modify salt marshes, including SLR, sediment delivery rates, and land use, on the population trajectories of saltmarsh breeding birds. We modeled population trajectories of 5 species with spatially extensive point count surveys conducted from Maine to Virginia from 2011 to 2022. We used Bayesian hierarchical abundance models and model selection to identify phenomena that had the strongest effect on population change. Clapper rails (Rallus crepitans) continued their long-term decline (-4.1%/year). Willets (Tringa semipalmata semipalmata) (2.6%/year) and saltmarsh sparrows (Ammospiza caudacuta) (4.1%/year) increased, and seaside (Ammospiza maritima) and Nelson's (Ammospiza nelsoni subvirgatus) sparrows exhibited no clear change in abundance. The estimated increase for saltmarsh sparrow was not consistent with trends over the previous 25years but aligned with prior demographic modeling, which predicted a short-term stabilization during the study years before an expected return to a long-term decline. Road density and other tidal restrictions near marshes were generally good predictors of abundance over the study period, as was marsh habitat composition. Local rates of SLR and sediment delivery were not as good predictors. During periods of relatively low rates of realized SLR, local-scale drivers of population trends had relatively stronger effects than global drivers on the persistence of several saltmarsh breeding birds. Conservation practitioners, however, should be attentive to global drivers, especially as rates of SLR accelerate in the future.

The Arctic is one of the fastest-warming marine regions in the world, which is changing the timing of seasonal sea-ice dynamics. The annual summer breakup of sea-ice coincides with resource pulses, which provide critical food sources for consumers to exploit. Marine organisms respond behaviourally to exploit these resources, with some migrating to presumably maximize feeding opportunities, whereas others remain resident, providing an ideal model to assess potential variability in fish movements and feeding. To assess variability in how migratory and resident fishes exploit increases in resource availability associated with ice-off, we collected stomach contents from anadromous Arctic char (Salvelinus alpinus; n = 91) and resident sculpins (Myoxocephalus spp.; n = 190) in Tremblay Sound, Nunavut, Canada, during the ice-free seasons of 2017-2019. Despite eating larger prey, Arctic char experienced lower relative consumption [mean ± standard deviation (SD); 1.92% body mass ± 1.38%] than sculpins (2.88% ± 2.93%). Arctic char also had fewer empty stomachs (n = 1; 1.96%) than sculpins (n = 11; 14.7%). Of identified prey categories, 52.6% (n = 10 categories) were shared by both consumers, but notable exceptions occurred. Non-metric multidimensional scaling (NMDS) ordination revealed dietary distinctions primarily driven by Arctic char's higher consumption of fishes and copepods, whereas sculpins fed heavily on amphipods. Our findings are consistent with sedentary and benthic-oriented resident sculpins intermittently consuming small, benthic prey at high levels, whereas mobile, semipelagic, migratory Arctic char consume pelagic prey at consistent levels that likely do not impede aerobic activity. Ultimately, diets are reflective of consumer physiology but are also influenced by migratory versus resident movement strategies and likely interannual variation in prey abundance, providing insight into strategies used by fishes in the extremely seasonal Arctic, which may become increasingly consequential with climate change.

Physiological signals are increasingly used to study stress, engagement, and user experience. Yet collecting and interpreting these signals remains difficult for students and novice researchers, who must navigate complex device setups, scattered software tools, and technical analysis workflows. This demo presents Sensei, an intelligent browser-based platform that streamlines the entire process of running small physiological studies—from connecting sensors and defining protocols to visualizing data and generating interpretations. In this demo, attendees will run a brief recording session and explore Sensei’s AI-assisted analysis tools, illustrating how intelligent support can make physiological computing more approachable for learning and early-stage research.

Short wind-wave growth is central to estimating sea-surface drag and air-sea momentum transfer, as it increases surface roughness and facilitates directional wave breaking. Therefore, field observations that resolve the full wind-sea scale are essential for parameterizing air-sea fluxes and validating numerical weather prediction models.In these efforts, we developed a measurement system with a polarimetric camera integrated into a UAV platform, leveraging RTK-enabled aircraft positioning and an inertial measurement unit for high-precision georeferencing. With varying altitudes, we resolve ocean waves ranging from centimeters to decameters, extending the polarimetric camera’s capabilities to those of wave buoys.Field measurements were conducted from May to July 2025 on the coast of Rye, New Hampshire, under various conditions, including gusty winds, limited/unlimited fetch, and misaligned wind-swell and current. The observations yield 3D directional wave spectra, resolving wavelengths from 20 m to 6 cm and frequencies from 0.3 to 5 Hz. The directional spreading, current shear, and bimodal peaks are plotted against the mean current direction and wind speed, which were measured by a nearby buoy. With these measurements we aim to explore the dynamics of locally generated surface waves by linking the gravity capillary scales to larger wind-sea.

Magnetic reconnection at the near-Sun heliospheric current sheet (HCS) dissipates the Parker spiral and converts magnetic energy into kinetic energy of the plasma constituents. Observations at a radial distance of ~16.25 Rs by Parker Solar Probe associated with the encounter 14 (E14) HCS crossing have shown that reconnection-driven particle acceleration mechanisms, likely facilitated by the merging of large-scale flux tubes, are able to accelerate protons up to ~400 keV, which is ≈1000 times greater than the available magnetic energy per particle during this crossing (Desai et al. 2025; Phan et al. 2024). In this paper, we present a detailed analysis of the pitch-angle distributions, differential energy spectra, and maximum energies and spectra of protons and heavy ions (He, O, and Fe) in conjunction with observations of local wave activity during the E14 HCS crossing. Our results show the following: 1) First direct observations of the energization of protons and heavy ions during reconnection. 2) First direct observations that the power-law spectral slopes of heavy ions differ from that of protons, which contradicts previous simulation results where the spectral indices of all ion species are essentially identical. 3) First demonstration that the anisotropies and beams of ions produced during reconnection drive waves in the ion cyclotron range of frequencies. 4) First evidence that the pitch angle scattering of protons is stronger than that of the other ion species and that this might be responsible for the harder spectral slopes of the heavy ions compared with protons. In summary, PSP observations during the E14 HCS crossing provide strong evidence for in-situ reconnection-driven acceleration of protons and heavy ions at the near-Sun HCS that will need to be fully accounted for by contemporary reconnection-driven energization models.