Practical Guide to Measuring Wetland Carbon Pools and Fluxes.

Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions. Supplementary Information: The online version contains supplementary material available at 10.1007/s13157-023-01722-2.

Shower thoughts: why scientists should spend more time in the rain.

Stormwater is a vital resource and dynamic driver of terrestrial ecosystem processes. However, processes controlling interactions during and shortly after storms are often poorly seen and poorly sensed when direct observations are substituted with technological ones. We discuss how human observations complement technological ones and the benefits of scientists spending more time in the storm. Human observation can reveal ephemeral storm-related phenomena such as biogeochemical hot moments, organismal responses, and sedimentary processes that can then be explored in greater resolution using sensors and virtual experiments. Storm-related phenomena trigger lasting, oversized impacts on hydrologic and biogeochemical processes, organismal traits or functions, and ecosystem services at all scales. We provide examples of phenomena in forests, across disciplines and scales, that have been overlooked in past research to inspire mindful, holistic observation of ecosystems during storms. We conclude that technological observations alone are insufficient to trace the process complexity and unpredictability of fleeting biogeochemical or ecological events without the shower thoughts produced by scientists' human sensory and cognitive systems during storms.

Incidence of Loss of Reduction After Open Reduction Internal Fixation of Metacarpal Shaft Fractures.

BACKGROUND: This study compared the incidence of loss of reduction (LOR) between metacarpal fractures fixed with screws alone and those fixed with plates and screws. Secondary aims included identifying patient or fracture characteristics associated with increased risk of LOR. METHODS: We retrospectively reviewed 138 metacarpal fractures in 106 patients treated with open reduction internal fixation with screws (60 fractures) or plates and screws (78 fractures) with a mean radiographic follow-up of 50 days for evidence of LOR. We compared the incidence of LOR between the screw and plate groups using a χ2 test. We performed logistic regression analysis to determine whether patient age, sex, metacarpal location (index, long, ring, small), the presence of multiple metacarpal fractures, or fracture pattern were associated with increased incidence of LOR. RESULTS: Loss of reduction occurred in 19 (13.8%) of 138 fractures, with no statistically significant difference between lag screw (7 of 60, 11.6%) and plate fixation (12 of 78, 15.4%). Neither fracture pattern nor the presence of multiple metacarpal fractures was associated with an increased incidence of LOR, but patients experienced a 7% increase in the risk of LOR for each additional year of age. Loss of reduction occurred most frequently in index metacarpal fractures (4 of 12, 33%), although this did not reach statistical significance. CONCLUSIONS: We found no difference in LOR incidence between lag screw fixation and plate fixation. The overall incidence of LOR was higher in this study than previously reported and increased with increasing patient age.

The extent to which soil hydraulics can explain ecohydrological separation.

Field measurements of hydrologic tracers indicate varying magnitudes of geochemical separation between subsurface pore waters. The potential for conventional soil physics alone to explain isotopic differences between preferential flow and tightly-bound water remains unclear. Here, we explore physical drivers of isotopic separations using 650 different model configurations of soil, climate, and mobile/immobile soil-water domain characteristics, without confounding fractionation or plant uptake effects. We find simulations with coarser soils and less precipitation led to reduced separation between pore spaces and drainage. Amplified separations are found with larger immobile domains and, to a lesser extent, higher mobile-immobile transfer rates. Nonetheless, isotopic separations remained small (<4‰ for δ2H) across simulations, indicating that contrasting transport dynamics generate limited geochemical differences. Therefore, conventional soil physics alone are unlikely to explain large ecohydrological separations observed elsewhere, and further efforts aimed at reducing methodological artifacts, refining understanding of fractionation processes, and investigating new physiochemical mechanisms are needed.

The NEON Daily Isotopic Composition of Environmental Exchanges Dataset.

The National Ecological Observatory Network (NEON) provides open-access measurements of stable isotope ratios in atmospheric water vapor (δ2H, δ18O) and carbon dioxide (δ13C) at different tower heights, as well as aggregated biweekly precipitation samples (δ2H, δ18O) across the United States. These measurements were used to create the NEON Daily Isotopic Composition of Environmental Exchanges (NEON-DICEE) dataset estimating precipitation (P; δ2H, δ18O), evapotranspiration (ET; δ2H, δ18O), and net ecosystem exchange (NEE; δ13C) isotope ratios. Statistically downscaled precipitation datasets were generated to be consistent with the estimated covariance between isotope ratios and precipitation amounts at daily time scales. Isotope ratios in ET and NEE fluxes were estimated using a mixing-model approach with calibrated NEON tower measurements. NEON-DICEE is publicly available on HydroShare and can be reproduced or modified to fit user specific applications or include additional NEON data records as they become available. The NEON-DICEE dataset can facilitate understanding of terrestrial ecosystem processes through their incorporation into environmental investigations that require daily δ2H, δ18O, and δ13C flux data.

A 3-D groundwater isoscape of the contiguous USA for forensic and water resource science.

A wide range of hydrological, ecological, environmental, and forensic science applications rely on predictive "isoscape" maps to provide estimates of the hydrogen or oxygen isotopic compositions of environmental water sources. Many water isoscapes have been developed, but few studies have produced isoscapes specifically representing groundwaters. None of these have represented distinct subsurface layers and isotopic variations across them. Here we compiled >6 million well completion records and >27,000 groundwater isotope datapoints to develop a space- and depth-explicit water isoscape for the contiguous United States. This 3-dimensional model shows that vertical isotopic heterogeneity in the subsurface is substantial in some parts of the country and that groundwater isotope delta values often differ from those of coincident precipitation or surface water resources; many of these patterns can be explained by established hydrological and hydrogeological mechanisms. We validate the groundwater isoscape against an independent data set of tap water values and show that the model accurately predicts tap water values in communities known to use groundwater resources. This new approach represents a foundation for further developments and the resulting isoscape should provide improved predictions of water isotope values in systems where groundwater is a known or potential water source.

Comparison of Volar and Dorsal Approach for PIP Arthroplasty.

Background: No consensus exists about whether a volar approach (VA) or dorsal approach (DA) for proximal interphalangeal (PIP) arthroplasty yields better results. Previously reported range of motion (ROM) and complications vary from study to study. This retrospective review compared the ROM and complication rates of VA and DA approaches to PIP arthroplasty. Methods: The study included 66 adults (88 digits) who underwent PIP arthroplasty from 2000 to 2015, with minimum 30-day follow-up. Demographic data, surgical approach, pre- and post-operative ROM, duration of immobilization, timing and duration of hand therapy (occupational therapy [OT]), and major and minor complications were recorded. We compared mean change in ROM, postoperative ROM, and complication rates, and examined the association of duration of immobilization and time to OT initiation with postoperative ROM. Results: While there was no difference in postoperative ROM between volar and dorsal groups (56° and 54°, respectively, P > .05), there was a greater gain in ROM in the DA group (25° vs 2.7°, P = .017). There was no statistically significant difference in overall incidence of complications (VA: 37.8%, DA: 30.3%; P > .05) or revision surgery (VA: 15.6%, DA: 17.1%; P > .05). There were no differences in duration of immobilization, time to OT initiation, or number of OT sessions between the two groups, and none of these correlated with postoperative ROM. Conclusions: We identified no statistical difference in mean postoperative ROM, incidence of complications or revision surgery between volar and dorsal approaches for PIP arthroplasty.

The role of stable isotopes in understanding rainfall interception processes: A review.

The isotopic composition of water transmitted by the canopy as throughfall or stemflow reflects a suite of processes modifying rainfall. Factors that affect isotopic composition of canopy water include fractionation, exchange between liquid and vapor, and selective transmittance of temporally varying rainfall along varying canopy flowpaths. Despite frequent attribution of canopy effects on isotopic composition of throughfall to evaporative fractionation, data suggest exchange and selection are more likely the dominant factors. Temporal variability in canopy effects is generally consistent with either exchange or selection, but spatial variability is generally more consistent with selection. However, most investigations to date have not collected data sufficient to unambiguously identify controlling processes. Using isotopic data for improved understanding of physical processes and water routing in the canopy requires recognizing how these factors and processes lead to patterns of isotopic variability, and then applying this understanding towards focused data collection and analysis.