Isotopic signals in an agricultural watershed suggest denitrification is locally intensive in riparian areas but extensive in upland soils

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Sigler, W. A., Ewing, S. A., Wankel, S. D., Jones, C. A., Leuthold, S., Brookshire, E. N. J., & Payn, R. A. Isotopic signals in an agricultural watershed suggest denitrification is locally intensive in riparian areas but extensive in upland soils. Biogeochemistry, 158, (2022): 251–268, https://doi.org/10.1007/s10533-022-00898-9.Nitrogen loss from cultivated soils threatens the economic and environmental sustainability of agriculture. Nitrate (NO3−) derived from nitrification of nitrogen fertilizer and ammonified soil organic nitrogen may be lost from soils via denitrification, producing dinitrogen gas (N2) or the greenhouse gas nitrous oxide (N2O). Nitrate that accumulates in soils is also subject to leaching loss, which can degrade water quality and make NO3− available for downstream denitrification. Here we use patterns in the isotopic composition of NO3− observed from 2012 to 2017 to characterize N loss to denitrification within soils, groundwater, and stream riparian corridors of a non-irrigated agroecosystem in the northern Great Plains (Judith River Watershed, Montana, USA). We find evidence for denitrification across these domains, expressed as a positive linear relationship between δ15N and δ18O values of NO3−, as well as increasing δ15N values with decreasing NO3− concentration. In soils, isotopic evidence of denitrification was present during fallow periods (no crop growing), despite net accumulation of NO3− from the nitrification of ammonified soil organic nitrogen. We combine previous results for soil NO3− mass balance with δ15N mass balance to estimate denitrification rates in soil relative to groundwater and streams. Substantial denitrification from soils during fallow periods may be masked by nitrification of ammonified soil organic nitrogen, representing a hidden loss of soil organic nitrogen and an under-quantified flux of N to the atmosphere. Globally, cultivated land spends ca. 50% of time in a fallow condition; denitrification in fallow soils may be an overlooked but globally significant source of agricultural N2O emissions, which must be reduced along-side other emissions to meet Paris Agreement goals for slowing global temperature increase.National Institute of Food and Agriculture, 2011–51130-31121, S. A. Ewing, 2011, S. A. Ewing, 2016–67026-25067, S. A. Ewing, Montana State University Extension, Montana Fertilizer Advisory Committee, Montana Agricultural Experiment Station, Montana State University Vice President of Research, Montana State University College of Agriculture, Montana Institute on Ecosystems, NSF EPSCoR, OIA-1757351, S. A. Ewing, OIA-1443108, S. A. Ewing, EPS-110134, S. A. Ewing

Performance of the LHC Arc Superconducting Quadrupoles Towards the End of their Series Fabrication

The fabrication of the 408 main arc quadrupole magnets and their cold masses will come to an end in summer 2006. A rich collection of measurement and test data has been accumulated and their analysis is presented in this paper. These data cover the fabrication and the efficiency in the use of the main components, the geometrical measurements and the achieved dimensional precision, the warm magnetic measurements in the factory and the performance at cold conditions, especially the training behaviour. The scrap rate of the Nb-Ti/Cu conductor as well as that of other components turned out to be acceptably low and the quench performance measured was in general very good. Most quadrupoles measured so far exceeded the operating field gradient with one or no quench. The multipole content at cold was measured for a limited number of quadrupoles in order to verify the warm-to-cold correlation. From the point of view of field quality, all quadrupoles could be accepted for the machine. The measures taken to overcome the problem of a too high permeability of a batch of collars are discussed

Exploring changes in the spatial distribution of stream baseflow generation during a seasonal recession

[1] Relating watershed structure to streamflow generation is a primary focus of hydrology. However, comparisons of longitudinal variability in stream discharge with adjacent valley structure have been rare, resulting in poor understanding of the distribution of the hydrologic mechanisms that cause variability in streamflow generation along valleys. This study explores detailed surveys of stream base flow across a gauged, 23 km 2 mountain watershed. Research objectives were (1) to relate spatial variability in base flow to fundamental elements of watershed structure, primarily topographic contributing area, and (2) to assess temporal changes in the spatial patterns of those relationships during a seasonal base flow recession. We analyzed spatiotemporal variability in base flow using (1) summer hydrographs at the study watershed outlet and 5 subwatershed outlets and (2) longitudinal series of discharge measurements every $100 m along the streams of the 3 largest subwatersheds (1200 to 2600 m in valley length), repeated 2 to 3 times during base flow recession. Reaches within valley segments of 300 to 1200 m in length tended to demonstrate similar streamflow generation characteristics. Locations of transitions between these segments were consistent throughout the recession, and tended to be collocated with abrupt longitudinal transitions in valley slope or hillslope-riparian characteristics. Both within and among subwatersheds, correlation between the spatial distributions of streamflow and topographic contributing area decreased during the recession, suggesting a general decrease in the influence of topography on stream base flow contributions. As topographic controls on base flow evidently decreased, multiple aspects of subsurface structure were likely to have gained influence

Health promotion: results of focus groups with African-American men

http://dx.doi.org/10.1016/j.jomh.2010.11.00

Adaptive Contact Networks Change Effective Disease Infectiousness and Dynamics

Human societies are organized in complex webs that are constantly reshaped by a social dynamic which is influenced by the information individuals have about others. Similarly, epidemic spreading may be affected by local information that makes individuals aware of the health status of their social contacts, allowing them to avoid contact with those infected and to remain in touch with the healthy. Here we study disease dynamics in finite populations in which infection occurs along the links of a dynamical contact network whose reshaping may be biased based on each individual's health status. We adopt some of the most widely used epidemiological models, investigating the impact of the reshaping of the contact network on the disease dynamics. We derive analytical results in the limit where network reshaping occurs much faster than disease spreading and demonstrate numerically that this limit extends to a much wider range of time scales than one might anticipate. Specifically, we show that from a population-level description, disease propagation in a quickly adapting network can be formulated equivalently as disease spreading on a well-mixed population but with a rescaled infectiousness. We find that for all models studied here – SI, SIS and SIR – the effective infectiousness of a disease depends on the population size, the number of infected in the population, and the capacity of healthy individuals to sever contacts with the infected. Importantly, we indicate how the use of available information hinders disease progression, either by reducing the average time required to eradicate a disease (in case recovery is possible), or by increasing the average time needed for a disease to spread to the entire population (in case recovery or immunity is impossible)

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Forest biodiversity, ecosystem functioning and the provision of ecosystem services

Forests are critical habitats for biodiversity and they are also essential for the provision of a wide range of ecosystem services that are important to human well-being. There is increasing evidence that biodiversity contributes to forest ecosystem functioning and the provision of ecosystem services. Here we provide a review of forest ecosystem services including biomass production, habitat provisioning services, pollination, seed dispersal, resistance to wind storms, fire regulation and mitigation, pest regulation of native and invading insects, carbon sequestration, and cultural ecosystem services, in relation to forest type, structure and diversity. We also consider relationships between forest biodiversity and multifunctionality, and trade-offs among ecosystem services. We compare the concepts of ecosystem processes, functions and services to clarify their definitions. Our review of published studies indicates a lack of empirical studies that establish quantitative and causal relationships between forest biodiversity and many important ecosystem services. The literature is highly skewed; studies on provisioning of nutrition and energy, and on cultural services, delivered by mixed-species forests are under-represented. Planted forests offer ample opportunity for optimising their composition and diversity because replanting after harvesting is a recurring process. Planting mixed-species forests should be given more consideration as they are likely to provide a wider range of ecosystem services within the forest and for adjacent land uses. This review also serves as the introduction to this special issue of Biodiversity and Conservation on various aspects of forest biodiversity and ecosystem services

A Tale of Two Karsts, Bear River Range, Cache National Forest, Utah

The Bear River Range of northern Utah, composed primarily of a thick sequence (several km) of Paleozoic carbonates with lesser amounts of sandstone and shale, contains at least two alpine karst aquifer systems. Higher elevations in the range are marked by significant numbers of sinks, and members of local National Speleological Society grottoes report a multitude of caves. Spangler (2001, 2004) has shown that the karst is the recharge area for several of the numerous springs issuing along the north side of the Logan River. We are investigating the responses of two of those springs: DeWitt Spring, which is the main water source for Logan, Utah, and which flows into the Logan River from the north, and the spring at Spring Hollow, which enters the Logan River from the south. Chemical and flow data suggest that aquifer characteristics are different north and south of the Logan River. Spangler’s (2001, 2004) data show that the northern part of the aquifer is a very well-developed karst drainage system, with estimated flow velocities on the order of a thousand feet per day or greater. Mineral saturation indices (log(IAP/Ksp)) are indicators of the degree to which a water is saturated with respect to particular minerals. A saturation index of 0 indicates saturation or equilibrium, a negative number indicates undersaturation, and a positive number indicates supersaturation. The mean calcite saturation index in water from DeWitt Spring is 0.2 and for quartz 0.1, slightly supersaturated, consistent with a relatively short period of water-rock interaction. However, the mean calcite saturation index in water from the spring at Spring Hollow, south of the Logan River, is 1.2 and for quartz 2.0, an order of magnitude greater. Such a difference suggests a much lower flow velocity, more time for water-rock interaction, and thus implies a less-well-developed karst system