Pit Samples Research Articles

Provenance of mineral dust deposited on Antarctica over the last sixty years by strontium isotopic analysis of snow from Dome C

The strontium (Sr) concentration and 87Sr/86Sr isotope ratio have been determined in 132 snow pit samples collected at Dome C, on the East Antarctic Plateau, corresponding to the period 1958–2019, and in 12 surface snow samples collected at the same site in 2016–2017. The average Sr concentration was 8.1 ± 5.7 pg g−1 (mean ± SD) in snow pit samples and 10.1 ± 8.0 pg g−1 (mean ± SD) in surface snow, without any significant temporal trend. The 87Sr/86Sr isotope ratio showed small variations (<0.15%), with an average 87Sr/86Sr value of 0.7094 ± 0.0010 (mean ± SD) in snow pit and 0.7103 ± 0.0004 (mean ± SD) in surface snow samples. These results seem to suggest that no change in the source(s) of mineral dust has occurred throughout the period investigated.Comparison of the 87Sr/86Sr isotope ratio of the snow samples with those of potential source areas suggests that the mineral dust reaching the East Antarctic plateau over the last decades is of a mixed origin, with a contribution from Patagonia and one or more other source(s) having a more radiogenic Sr isotopic signature, with a major fraction coming from South Australia.

Behaviour of redox-sensitive elements (Ti, As, V and Fe) in clay pit samples with and without Al normalization

Natural clay minerals, because of their physical and chemical characteristics are good adsorbents of metals. Among metals, heavy metals are often investigated, but redox-sensitive metals are increasingly getting attention. Redox-sensitive elements were measured in clay pit samples from a clay mine in Bosnia and Herzegovina. For the purpose of analysis, a 23 m deep clay pit core sample was taken, and it was randomly subsampled to give 45 clay pit samples from different depths. The pH, electrical conductivity (EC), oxidation–reduction potential (ORP) and redox-sensitive elements contents were measured. Amounts of redox-sensitive metals and aluminium were measured with an inductively coupled plasma optical emission spectrophotometry instrument. For statistical evaluation, maximum, minimum, average, median, Pearson's prior correlation, correlation applying Al normalization and centred log-ratio (clr) transformation were calculated. When justified, principal component analysis (PCA) was also performed. The results show acidic pH and oxidative ORP. EC varied significantly through the sediment. The element concentrations lie in the sequence: Fe &gt; Ti &gt; V &gt; As. There is a significant change in correlations with and without Al normalization. The highest difference was found for Ti and V (coefficient of correlation ( r ) value ranging from −0.553 to 0.835). Correlations and PCA after clr transformation showed mainly strong negative correlations, meaning that redox-sensitive elements behave differently in clay samples. Supplementary material: Graphical abstract is available at https://doi.org/10.6084/m9.figshare.c.7014329

The Fluid–Solid Interaction in the Nonlinear Pressure–Flux Relationship of Bordered Pits in Oriental Arborvitae (Platycladus orientalis)

The nonlinear pressure–flux relationship in the xylem of a conifer is attributed to the fluid–solid interaction within the bordered pits. However, the fluid–solid interactions between the torus–margo structure and the water flow within the pit lack comprehensive understanding. Herein, a fluid–solid interaction model was developed including the deformation of the torus–margo and the flow of water transportation. Nine pit samples were reconstructed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) pictures. Fluid–solid coupling models for pits in the stems of oriental arborvitae (Platycladus orientalis) were developed. The deflection of the torus was roughly proportional to the pressure difference between adjacent tracheids, while the pit resistance exhibited a considerable nonlinear increase. From 250 to 1750 Pa, the pit resistance increased from 4.1466 × 1016 Pa·s/m3 to 8.8344 × 1016 Pa·s/m3. The pit resistance decreased, and the pit’s ability to regulate water flow enhanced when the pit diameter increased. Both the pit resistance and the pit’s ability to regulate water decreased when the pit depth increased. The decrease in Young’s modulus for the margo promoted the nonlinear pressure–flux relationship in bordered pits. The findings provide theoretical evidence for the nonlinear relationship between pressure and flux in bordered pits, as well as for the prevention of gas bubble transit through a bordered pit during tracheid cavitation. The passive hydraulic regulation of bordered pits could increase flow resistance and reduce the water flow rate in the xylem, inhibiting tree transpiration.

Contact Mechanics between Torus and Pit Border for Developing Air-Seeding Seal in Aspirated Bordered Pits

Bordered pits in conifers have been recognized as a significant evolutionary characteristic that served to impede the spread of embolisms between tracheids. Nevertheless, there was a lack of comprehensive understanding regarding the mechanical properties of the torus and the pit border in relation to the formation of contact seals in aspirated pits. A solid mechanics model was developed to study aspirated bordered pits, incorporating the elastic deformation of the torus–margo structure and the contact behavior between the torus and the pit border. Ten pit samples were reconstructed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) pictures in order to develop mechanical models for pits in the stems of Platycladus orientalis. Due to the limited contact area on the torus surface, the contact pressure between the torus and the pit border exceeded the air pressure in aspirated bordered pits. The external force and the duration required to seal pits decreased when the pit diameter increased and the pit depth decreased. The augmentation of the torus and margo mass necessitated a lengthier duration for the closure of cavities. The findings presented in this study offered theoretical support for the capillary-seeding hypothesis. The aspiration in bordered pits mechanically depended on the structural and material characteristics of the torus and margo.

Dust source tracing and their transport mechanisms before monsoon season from three glaciers at the Tibetan Plateau: revelations from REE analysis and an indirect tracing approach.

Understanding the origins of Tibetan Plateau (TP) glacier dust is vital for glacier dynamics and regional climate understanding. In May 2016, snow pit samples were collected from glaciers on the TP: Qiyi (QY) in the north, Yuzhufeng (YZF) in the center, and Xiaodongkemadi (XDK) in the south. Rare earth element (REE) concentrations were analyzed using inductively coupled plasma mass spectrometry (ICP-MS), and near-surface PM10 concentrations were extracted from a dataset of Chinese near-surface PM10. Two tracing approaches were used: direct REE tracing and an indirect approach combining potential source contribution function (PSCF) and concentration-weighted trajectory (CWT). Both methods yielded consistent results. Pre-monsoon, TP surface soils, Taklimakan Desert, and Qaidam Basin contributed to glacier dust. Notably, central and southern glaciers showed Thar Desert influence, unlike the northern ones. Taklimakan and Thar Deserts were major contributors due to their substantial contribution and high dust concentration. Taklimakan dust, influenced by terrain and westerly winds, affected central and southern glaciers more than northern ones. Westerlies carried Thar Desert dust to the TP after it was uplifted by updrafts in northwest India, significantly affecting southern glaciers. Furthermore, comparing the two tracer methods, the indirect approach combining PSCF and CWT proved more effective for short-term dust source tracing.

Pollution revealed by stable lead isotopes in recent snow from the northern and central Tibetan Plateau

Lead (Pb) isotopes are less fractionated than those from different sources, and thus were used to trace the sources of Pb in the environment. To investigate the sources of Pb in the atmosphere of the Tibetan Plateau, stable Pb isotopes (206Pb, 207Pb and 208Pb) in acidified snow pit samples collected from five glaciers (i.e., Qiyi-QY, Meikuang-MK, Yuzhufeng-YZF, Hariqin-HRQ and Xiaodongkemadi-XDKMD) in May 2016 of the northern and central Tibetan Plateau were measured. The results showed narrow ranges of 1.158–1.187 for 206Pb/207Pb and 2.450–2.489 for 208Pb/207Pb respectively. The 206Pb/207Pb ratios in all samples were obviously lower than the environmental background value of 1.196, indicating the primary contributions of anthropogenic sources. At least 60% of Pb was contributed by various human activities, which was supported by the Pb isotopes in the snow pit samples from the QY, MK, YZF, HRQ and XDKMD glaciers. By comparing Pb isotope data, we found that the primary anthropogenic sources are coal combustion, mining and smelting activities in northwestern China and mixed emissions from cities located in western China and close to the glaciers. These sources contributed to the Pb in the northern glaciers (QY and MK) in particular. Coal combustion in India probably contributes to the central glaciers (HRQ and XDKMD). Another potential source could be parts of central Asia (e.g., Kyrgyzstan and Uzbekistan) through long range transport. The above potential source areas of contaminants were traced further by the air mass back-trajectory tracing method.

Monte Alban periphery (Oaxaca, middle Mesoamerica): New evidences on the early occupation trough archaeomagnetic study of pottery kilns

Aimed to obtain absolute chronology data for the early stage of Monte Alban, magnetic mineralogy and archaeomagnetic investigation were carried out of recently discovered pottery kilns. Oriented samples belong to four rectangular kilns, both single and double chambers, and one fire pit at the piedmont peripherical area. Susceptibility vs. temperature curves show market thermal instability while large pseudo-single domain grains seem to carry the major part of remanence for the kiln sample. Fire pit samples, in contrast, seem to be dominated by antiferromagnetic hematite. Alternating field demagnetization allowed to reach primary, characteristic magnetization components with reasonably well-defined mean archaeodirections. Possible archaeomagnetic age intervals were obtained considering currently available global models and local curves. The dates are consistent with the most important periods of occupation at the site, although the results may indicate that there was also a significant cultural presence in the Early Classic Period. Recently discovered kilns indicate constant manufacture of pottery. Although we cannot currently define the intensity of production, we believe that pottery could be a specialized activity in peripherical areas of Monte Alban to exchange ceramics or for its local consumption. Consequently, we propose that the piedmont area was an economically autonomous community whose inhabitants dedicated themselves to various tasks throughout their occupation.

ОСОБЕННОСТИ ФОРМИРОВАНИЯ ХИМИЧЕСКОГО СОСТАВА РЕК ЛЕДНИКОВОГО ПИТАНИЯ КАВКАЗА ПРИ ИНТЕНСИВНОЙ ДЕГРАДАЦИИ ОЛЕДЕНЕНИЯ

The concentration of heavy metals (Cr, Ni, Mo, Mn, Pb, Zn, Ag, Cu, Cd, Co, Al, Fe, V) in one of the most powerful glaciation sites in the Caucasus (Mount Elbrus) since the mid-20th century is investigated. To compare the concentrations of heavy metals in the sources of the Baksan River with those in the Garabashi glacier, a stationary point at a level of 4000 m was chosen, where observations of the glacier mass balance are carried out. The number of pit samples depended on the snow accumulation and varied from 7-8 to 18-20 in accordance with the depth of the seasonal snow layer. The concentrations of heavy metals in the ice, snow, and river water samples were determined during the period from 1978 to 2010 at High-mountain Geophysical Institute by the emission spectral analysis. The analysis of samples from 2018-2021 was performed by the atomic absorption method on an MGA-915 spectrometer. Among all categories of the samples taken on the Elbrus slope, the least impurities were found in pure ice on the tongue of the glacier: it contains three times less impurities of Ag, Ni, Mo, Pb: 0.014, 1.15, 0.18, 0.83 µg/L, respectively. In some samples, the metal content is below the detection limit. The concentrations of heavy metals in the seasonal snow pack and river water in the Elbrus region are one-two orders of magnitude lower than maximum permissible concentrations for sanitary water bodies. For the Baksan River basin and the Elbrus glaciation region, there is a slight decrease in the concentrations of heavy metals from the end of the 20th century until the present, with intensive degradation of glaciers.

Land Use Capability and Suitability Classifications of a Plinthic Alfisol of a Derived Savannah Ecology of Nigeria

Background: In derived savanna ecology, the evaluation of soil characteristics for the current and future capability and suitability for crop production is crucial. Therefore, studies were conducted to evaluate the capability and suitability of plinthic soil of a derived savannah ecology of Nigeria for sustainable crop production. Methods: The methodology was essentially Grid using hand-held GPS to determine the coordinates of sampling points for the collection of soil samples. In all, 18 profile pit samples were collected. The profile pits were described morphologically on the field using the FAO guideline on soil profile description. From the various horizons of these profile pits, soil samples were collected. Results: Land assessment indicates that the soils of the area are very fragile and inherently low in nutrients. Mapping unit A is moderately suitable for arable crop production while Units B and C are fairly suitable. For agricultural activities, mapping unit D is marginal for arable crop production. Stoniness, steep slope, and shallow soil depth are the major limitations. Mapping unit E is the most suitable for lowland rice production. Soil fertility management ought to be integrated (organic and inorganic). The land evaluation shows that the soils of the project site are very fragile and poor in native fertility. Also, the soils are generally defined by the plinthite content. Apart from the traditional crops grown in the area, some other crops like sweet potato and cowpea will do well on the soil of the area. Crop residue has to be well managed and adopted. Crop rotation and intercropping should be encouraged and included in the soil management plan. Also, due to the low level of organic carbon in the soils, the soils will benefit optimally from the application of manure. This will improve the soil aggregation, water, and nutrient-holding capacities as well as improve the pH status of the soil. Conclusion: Soil fertility assessments should be undertaken every two years after continuous cropping. ’High-Intensity Detailed Soil Survey’ of this nature should be carried out every ten years.

New Data on the Storage Pits of the Baraba Culture of the Early Neolithic Era (Ob-Irtysh Forest-Steppe)

Purpose. The Tartas-1 complex of burials, ritual places and settlement takes a special place. Due to the excavation method of full opening of the site area, today the followings are explored and fully studied: an area of more than 36,000 m2 , 802 burials and related structures in the form of ditches, 1745 pits of various orientations, ritual complexes of various eras and cultures, including an early Neolithic settlement. The settlement is represented by two household structures (dwellings) and a complex of storage pits for fish, dated to the 7th millennium BC and attributed to the Baraba culture of the early Neolithic. The purpose of this article is to present the characteristics and dating of the new fish pit studied in the 2021 field season in the context of the known data. Results. The fish pits excavation method, mainly based on the enclosing soil-fill study, is proposed. The stratigraphy characteristic and the parameters of the pit are presented. A feature of the absence of any animal skeleton (dog, hare, fox, wolverine, etc.) placed in the pit as a sacrificial offering is noted. The date of (MAMS 53633) BP 7714 ± 29 Cal BCE 1 σ (Intcal 20) 6588–6502 2σ (Intcal 20) 6636–6469, obtained from an animal horn tool (tur?) found in the pit at the depth of 2.36 m below bedrock, is presented. The analysis was carried out at the Curt-Engelhom-Centre for Archaeometry (Germany). Calibration of the date by 1σ and 2σ demonstrates a complete correlation with the already available dates from the pit samples. The period of the Baraba culture's existence – the 7th millennium BC – is confirmed. Conclusion. The manifestation of economic practice among the bearers of the early Neolithic Baraba culture is a demonstration of innovation. It consists of the improvements on the appropriating economy with the increasing role of water resources, and the transition to a less mobile way of life, found among the ancient Siberian population at the end of the 8th – 6 th millennium BC. Pit no. 1741 also existed in this time period.

Impact of a Regulation Restricting Critical Antimicrobial Usage on Prevalence of Antimicrobial Resistance in Escherichia coli Isolates From Fecal and Manure Pit Samples on Dairy Farms in Québec, Canada.

To tackle antimicrobial resistance (AMR), one of the major health threats of this century, the World Health Organization (WHO) endorsed a global action plan in 2015. This plan calls countries to develop national actions to address AMR. The province of Québec, Canada, adopted a new regulation on the 25th of February 2019, to limit the use in food animals of antimicrobials of very high importance in human medicine. We aimed to establish the impact of this regulation by comparing the AMR situation in dairy cattle in Québec ~2 years before and 2 years after its introduction. We sampled calves, cows, and the manure pit in 87 farms. Generic and putative ESBL/AmpC E. coli were tested for susceptibility to 20 antimicrobials. Logistic regression was used to investigate whether the probability of antimicrobial resistance differed between isolates obtained from the pre and post regulation periods by sample type (calves, cows, manure pit) and in general. To identify AMR genes dissemination mechanisms, we sequenced the whole genome of 15 generic isolates. In the generic collection, at the herd level, the proportion of multidrug resistant (MDR) isolates, decreased significantly from 83 to 71% (p = 0.05). Folate inhibitor and aminoglycoside resistances demonstrated a significant decrease. However, when analyzed by sample type (calves, cows, manure pit), we did not observe a significant AMR decrease in any of these categories. In the ESBL/AmpC collection, we did not detect any significant difference between the two periods. Also, the general resistance gene profile was similar pre and post regulation. We identified both clonal and plasmidic dissemination of resistance genes. In conclusion, as early as 2 years post regulation implementation, we observed a significant decrease in MDR in the dairy industry in Quebec in the generic E. coli collection with folate inhibitor and aminoglycoside resistances showing the most significant decrease. No other significant decreases were yet observed.

Characterization of Tsunami and Palaeo-tsunami deposits in the Neil Island, South Andaman, India

The nature of tsunamigenic and palaeo-tsunamigenic sediments in Neil Island, deposited by the great Indian Ocean in 2004 is documented herein. Pit, trench and core samples were collected from the four beaches, namely, Bharatpur, Ramnagar, Sitapur and Lakshmanpur; which exhibit distinguished anomalies in the sedimentological parameters, viz . skewness, kurtosis and standard deviation at various depths. The palaeontological study shows the simultaneous occurrence of characteristic benthic taxa of near-shore environment and upper part of continental slope along with the open ocean dweller planktic foraminifera- an intermixed foraminiferal assemblage is mainly due to the tsunami wave actions. The multiproxy approach reveals the occurrence of the tsunami and palaeo-tsunami deposits in Neil Island from 9 to 40 cm and below 60 cm depth, respectively.

Trace precious metals in major sulfide minerals from the Federova Tundra platinum group element deposit in the Fedorova-Pana layered intrusion, central Kola Peninsula, Russia

ABSTRACTDrill-core samples from the basal Cu-Ni-platinum-group element mineralization of the Early Proterozoic Fedorova Tundra intrusion in the Fedorova-Pana layered intrusion, central Kola Peninsula, Russia, were studied in two separate projects in Canada and Russia. In Canada, trace precious metal analyses by laser ablation inductively coupled mass spectrometry of 323 base metal sulfide particles [pentlandite (101), pyrrhotite (98), chalcopyrite (25), and pyrite (99)] show that Pd is highly concentrated in pentlandite. Most of the analyses (71%) were done using two master composite samples of comminuted drill core representative of the West Pit and East Pit mineralization, FWMC and FEMC, respectively. Fewer analyses were made of three other comminuted drill core samples from the West Pit referred to as “lithology” samples: OLFW (olivine-bearing rocks), ANFW (leucocratic rocks), and GNFW (gabbronorite). In Russia, 120 polished sections sliced from drill core from the West and East Pits and from four other Fedorova Tundra intrusion deposits (Kievey, Northern Kamennik, Eastern Chuarvy, and Southern Kievey) were studied mineralogically. Platinum group mineral characterization and trace Pd electron probe microanalyses of pentlandite were done using polished sections from all six locations (n = 95). The trace electron probe microanalysis data for Pd in pentlandite from the West (n = 35) and East (n = 19) Pit samples, though at much higher detection levels, are considered to be comparable to the laser ablation inductively coupled mass spectrometry data. The Eastern Chuarvy samples show particularly high Pd concentrations averaging 0.49 wt.% Pd (n = 11) and as high as 1.64 wt.% Pd. The combined data from these studies guides our estimate that pentlandite accounts for 30 to 50% of the Pd in these ores and that Rh solid solution in sulfides may account for &amp;gt;98% of the total Rh.

Applying an isotope-enabled regional climate model over the Greenland ice sheet: effect of spatial resolution on model bias

Abstract. In order to investigate the impact of spatial resolution on the discrepancy between simulated δ18O and observed δ18O in Greenland ice cores, regional climate simulations are performed with the isotope-enabled regional climate model (RCM) COSMO_iso. For this purpose, isotope-enabled general circulation model (GCM) simulations with the ECHAM5-wiso general circulation model (GCM) under present-day conditions and the MPI-ESM-wiso GCM under mid-Holocene conditions are dynamically downscaled with COSMO_iso for the Arctic region. The capability of COSMO_iso to reproduce observed isotopic ratios in Greenland ice cores for these two periods is investigated by comparing the simulation results to measured δ18O ratios from snow pit samples, Global Network of Isotopes in Precipitation (GNIP) stations and ice cores. To our knowledge, this is the first time that a mid-Holocene isotope-enabled RCM simulation is performed for the Arctic region. Under present-day conditions, a dynamical downscaling of ECHAM5-wiso (1.1∘×1.1∘) with COSMO_iso to a spatial resolution of 50 km improves the agreement with the measured δ18O ratios for 14 of 19 observational data sets. A further increase in the spatial resolution to 7 km does not yield substantial improvements except for the coastal areas with its complex terrain. For the mid-Holocene, a fully coupled MPI-ESM-wiso time slice simulation is downscaled with COSMO_iso to a spatial resolution of 50 km. In the mid-Holocene, MPI-ESM-wiso already agrees well with observations in Greenland and a downscaling with COSMO_iso does not further improve the model–data agreement. Despite this lack of improvement in model biases, the study shows that in both periods, observed δ18O values at measurement sites constitute isotope ratios which are mainly within the subgrid-scale variability of the global ECHAM5-wiso and MPI-ESM-wiso simulation results. The correct δ18O ratios are consequently not resolved in the GCM simulation results and need to be extracted by a refinement with an RCM. In this context, the RCM simulations provide a spatial δ18O distribution by which the effects of local uncertainties can be taken into account in the comparison between point measurements and model outputs. Thus, an isotope-enabled GCM–RCM model chain with realistically implemented fractionating processes constitutes a useful supplement to reconstruct regional paleo-climate conditions during the mid-Holocene in Greenland. Such model chains might also be applied to reveal the full potential of GCMs in other regions and climate periods, in which large deviations relative to observed isotope ratios are simulated.

Land capability evaluation and classification of Obosi Land in Anambra State Nigeria

Land capability evaluation and classification of Obosi land was carried out on an approximately total area of 25.58km2 using the map of the area. The aims of the study were to map out the soils of Obosi, classify them for suitability and sustainability for agricultural production and other land use development projects. Auger sample and profile pit samples were collected and examined. Using morphology and topography of the surveyed area, three mapping units; MUI-lowland areas, MUII- upland areas and MUIII-gullied areas were established. The result of the study indicated the textural class of the soils to be sandy loam, except for upland areas in Auger 1 were the textural class were loamy sand. The particle sizes range from 50gkg-1-90gkg-1 clay, 50-90gkg-1 silt, 130-590gkg-1 fine sand and 310-650gkg-1 sand. The pH of the soils varies from slightly acidity to slightly alkaline and was fairly uniform throughout the depths. The exchangeable bases, CEC, TEA, SAR and ESP of the soils were found to be low and below their critical level for crop production the base saturation value of the soils range from 22.28-99.21%. The low land areas and the upland areas were found to be suitable for arable crops. They fall under the suitability class S2 (suitable) and the capability class 11. Their major constraint on agricultural production is low fertility status. The gullied areas MUIII were found within the uplands and low-land areas. They fall under the non-suitability class NS (not suitable) and the capability class vi. The prominent limitation of this unit is erosion hazard. The area cannot be used in their present state without serious reclamation activities. The soils were classified as mixed isothermic kandic argiudult using the USDA soil Taxonomy and correlated as eutric ferralsols by FAO-WAB classification. Generally the soils need to be upgraded in soil nutrients through soil organic matter application and reclamation processes to produce maximally.

Prevalence of Antimicrobial Resistance and Characteristics of Escherichia coli Isolates From Fecal and Manure Pit Samples on Dairy Farms in the Province of Québec, Canada.

Antimicrobial resistance (AMR) is an important burden for public health and veterinary medicine. For Québec (Canada) dairy farms, the prevalence of AMR is mostly described using passive surveillance, which may be misleading. In addition, the presence of extended spectrum β-lactamase (ESBL)/AmpC producing Escherichia coli is unknown. This observational cross-sectional study used random dairy farms (n = 101) to investigate AMR and extended spectrum β-lactamase (ESBL)/AmpC producing Escherichia coli. Twenty antimicrobials were tested on E. coli isolates (n = 593) recovered from fecal samples (n = 599) from calves, cows, and the manure pit. Isolates were mostly susceptible (3% AMR or less) to the highest priority critically important antimicrobials in humans. The highest levels of AMR were to tetracycline (26%), sulfisozaxole (23%) and streptomycin (19%). The resistance genes responsible for these resistances were, respectively: tet(A), tet(B), sul1, sul2, sul3, aph(3”)-Ib (strA), aph(6)-Id (strB), aadA1, aadA2, and aadA5. ESBL analysis revealed two predominant phenotypes: AmpC (51%) and ESBL (46%) where blaCMY−2 and blaCTX−M (blaCTX−M−1, blaCTX−M−15, and blaCTX−M−55) were the genes responsible for these phenotypes, respectively. During this study, 85% of farms had at least one ESBL/AmpC producing E. coli. Isolates from calves were more frequently resistant than those from cows or manure pits. Although prevalence of AMR was low for critically important antimicrobials, there was a high prevalence of ESBL/AmpC-producing E. coli on Quebec dairy farms, particularly in calves. Those data will help determine a baseline for AMR to evaluate impact of initiatives aimed at reducing AMR.

Manure Microbial Communities and Resistance Profiles Reconfigure after Transition to Manure Pits and Differ from Those in Fertilized Field Soil.

ABSTRACTIn agricultural settings, microbes and antimicrobial resistance genes (ARGs) have the potential to be transferred across diverse environments and ecosystems. The consequences of these microbial transfers are unclear and understudied. On dairy farms, the storage of cow manure in manure pits and subsequent application to field soil as a fertilizer may facilitate the spread of the mammalian gut microbiome and its associated ARGs to the environment. To determine the extent of both taxonomic and resistance similarity during these transitions, we collected fresh manure, manure from pits, and field soil across 15 different dairy farms for three consecutive seasons. We used a combination of shotgun metagenomic sequencing and functional metagenomics to quantitatively interrogate taxonomic and ARG compositional variation on farms. We found that as the microbiome transitions from fresh dairy cow manure to manure pits, microbial taxonomic compositions and resistance profiles experience distinct restructuring, including decreases in alpha diversity and shifts in specific ARG abundances that potentially correspond to fresh manure going from a gut-structured community to an environment-structured community. Further, we did not find evidence of shared microbial community or a transfer of ARGs between manure and field soil microbiomes. Our results suggest that fresh manure experiences a compositional change in manure pits during storage and that the storage of manure in manure pits does not result in a depletion of ARGs. We did not find evidence of taxonomic or ARG restructuring of soil microbiota with the application of manure to field soils, as soil communities remained resilient to manure-induced perturbation.

Provenance tracing of dust using rare earth elements in recent snow deposited during the pre-monsoon season from mountain glaciers in the central to northern Tibetan Plateau.

To provide insight into dust sources in snow deposited during the non-monsoon period on the Tibetan Plateau, detailed post-Archean Australian shale (PAAS)-normalized rare earth element (REE) distribution patterns and variations in REE tracers, such as La/Yb, La/Er, and Gd/Yb with depth, as well as the distribution of samples in the plots of REE ratio pairs, such as La/Yb vs. Y/ΣREE, La/Er vs. Gd/Er, and Y/La vs. Nd/Er, were compared in seven potential dust source areas in Asia. Snow samples from five glaciers, i.e., Qiumianleike (QMLK), Meikuang (MK), Yuzhufeng (YZF), Xiaodongkemadi (XDKMD), and Gurenhekou (GRHK), were collected from April 26 to May 13 before the onset of monsoon activity. The results show that dust trapped in snow pits from the studied glaciers, i.e., QMLK, MK, XDKMD, and GRHK, has varying degrees of contribution from the Taklimakan Desert, Qaidam Basin, and the surface soil of the Tibetan Plateau. There are signals of the Tengger and Badain Jaran Desert and Chinese Loess in the MK and XDKMD snow pit samples or in the QMLK and GRHK surface samples from the REE tracers; however, from the point of view of the land location, the three dust sources should not be the major contributors. Signals of dust from the Indian Thar Desert were occasionally detected from the MK, YZF, and XDKMD snow pit samples and GRHK surface snow samples, implying the intrusion of early Indian monsoon activities to the sites. The dust signal from the Thar Desert in India from the YZF glacier is significantly greater than that from the XDKMD and MK glaciers. These findings were also supported by the tracer of dust transmitted to the three snow pits through the air mass backward trajectories. The new finding of this study is that dust from the Indian Desert can even reach the Kunlun Mountains in the northern region of the Tibetan Plateau. The conclusions are helpful in interpreting the sources of dust and the pollutants absorbed by dust particles, as well as the extent of the impact of Indian monsoon activities at the end of the non-monsoon season on the plateau.

Spatial Variability of Glaciochemistry along a Transect from Zhongshan Station to LGB69, Antarctica

The spatial glaciochemical variability of snow samples collected along a transect from Zhongshan Station to Lambert Glacier Basin 69 (LGB69) in Antarctica was investigated. Sea-salt ion concentrations exponentially decreased with increasing distance from the coast and/or altitude. The observed high sea-salt ion concentrations within 20.6 km of the coast may be related to preferential wet or dry deposition of sea-salt aerosols. Methanesulfonic acid (MSA), non-sea-salt sulfate (nssSO42−), and calcium (Ca2+) concentrations decreased along the transect. The mean MSA/nssSO42− value of the surface snow samples (0.34 ± 0.08) indicates that coastal sea areas are their likely source regions. The non-sea-salt Ca2+ (nssCa2+)/Ca2+ percentages of the surface snow and LGB69 snow pit samples reveal that continental dust is the primary Ca2+ source. The δD and δ18O values decreased from the coast inland. The variation of deuterium excess (d-excess) along the transect was stable and d-excess values in the two snow pit samples were low and similar, which indicates that the moisture source region between Zhongshan Station and LGB69 is a coastal sea area. These results reveal the spatial distribution patterns and sources of ions and stable isotopes, as well as factors that influence the deposition of ions and the composition of stable isotopes, which provide important insight for further studies of ice cores drilled in Antarctic coastal regions.

Environmental Conditions and Gas Concentrations in Deep-Pit Finishing Cattle Facilities: A Descriptive Study

HighlightsTemperature and air movement in the naturally ventilated barns correlated to ambient conditions.Manure N-P-K values related to solids distribution in the manure storage.Ammonia and combined sulfur concentrations increased with closer proximity to the manure surface.Influences of manure properties, airflow conditions, barn design, and management were evident for gas concentrations.Abstract. There is a lack of data to describe the range of environmental and air quality conditions in beef cattle confinement buildings with deep-pit manure storage. The objective of this article is to describe the environmental conditions, manure nutrient concentrations, and aerial gas concentrations for three deep-pit manure storage finishing beef cattle facilities and varying weather conditions. Measurements were collected from three barns finishing beef cattle with deep pits in Minnesota on three sampling days per barn in summer, fall, and spring weather conditions. The air temperatures throughout the barns closely mirrored the ambient temperature conditions, although significantly lower temperatures were sometimes evident at the manure surface or in the inlet opening. However, the manure and floor surfaces had 2°C and 5°C temperature increases over ambient temperatures. Air speeds through the barn openings were generally 40% of the ambient wind speed; at animal level, the average air speed was 1 to 3 m s-1. Manure nutrient distributions were not consistent between the surface and agitated (whole pit) samples, and this was likely due in part to solids distribution in the storage. Total nitrogen levels ranged from 4.5 to 6.7 g L-1, and ammonium-N was 50% to 65% of total N in agitated whole-pit samples. Phosphate and potassium oxide levels ranged from 2.8 to 4.2 g L-1 and from 3.7 to 4.5 g L-1, respectively. Aerial ammonia and combined sulfur concentrations varied by location within a barn, pen, and season. Ammonia and combined sulfur increased with proximity to the manure surface. Higher ammonia and combined sulfur concentrations at manure level and floor level for one of the three barns may have related to water quality and/or feed composition and resulting manure nutrients, in addition to warmer temperatures. At floor level, the greatest average ammonia concentration was 8.5 ppm, and 3.9 ppm at nose level. Maximum combined sulfur levels were a maximum of 270 ppb at floor level in summer conditions in one of the barns, while 52 ppb was the maximum average during spring conditions. Carbon dioxide levels also varied by location within a barn, pen, and season and were related in part to the presence of cattle in the pen. This project is the first to quantify air quality in slatted-floor cattle barns and contributes to a body of knowledge that can be used to develop process-based models for estimating air emissions from cattle facilities. Keywords: Airflow, Ammonia, Beef cattle, Confinement, Hydrogenslfide, Manure characteristics, Temperature.