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Received 12th May 2021. Accepted 17th May 2021. Published online 28th May 2021. Issue published 1st August 2021.

Background Children and young people (CYP) are increasingly attending acute paediatric services due to mental health difficulties. 50% of all mental health problems are established by 14 years of age and 75% by 24 years. Underinvestment in mental health has been a longstanding concern, amplified by the COVID-19 pandemic through extra stress caused by prolonged school closures, social isolation and a lack of access to usual support services. In 2020, the Royal College of Paediatrics and Child Health highlighted that suicide is now the leading cause of death in England and Wales for children aged 5-19 years, emphasising the need to prioritise and improve mental health. Paediatricians must develop the knowledge and skills to identify, support and make appropriate referrals for common mental health problems. HEEADSSS is a well-known psychosocial screening tool with eight domains, used to identify potential or actual harm. Objectives Establish whether CYP within the West Midlands, UK are receiving adequate psychosocial assessments on hospital admission and whether healthcare professionals are signposting to relevant services. The primary outcome was the percentage of CYP with documented evidence of being offered a HEEADSSS assessment. Methods A regional prospective audit across nine hospitals was performed for three days per week from 4st -31st January 2021. A standardised proforma was used to gather information from medical records of all CYP aged >12 years admitted to paediatric wards. Pooled data were analysed using Microsoft Excel. Results 231 patients were included. The median age was 14 years old (range 12-17 years). 163(71%) were female. 202 (87%) had no known communication difficulties. 53(23%) were known to CAMHS and 43(19%) to social care. 78/231 (34%) were admitted with mental health as the presenting complaint. 35/231(15%) were documented to be given the opportunity to be spoken to alone;29(82%) accepted. No department had a psychosocial screening tool embedded in the admission document. 158/231(69%) had less than half of the eight domains completed. The median was 1.5 (range 0-8). Home and education/ employment were most frequently asked (37-42%). Eating/exercise, drugs, safety, sexual activity and other activities were the least frequently asked (14-27%). The proportion of those with a concern identified when asked ranged from 18%-39%. However, in self-harm, depression and suicide, only 85/231 (37%) were asked, with concern identified in 87%. 78 patients were admitted for mental health;28(39%) had less than half the domains completed (median 5, range 0-8). Drug use 46/78(59%), safety and sexual activity (both 38/78 (49%)) were inconsistently documented in this group, with concerns identified in 20-26% of those asked. 90/231(39%) were referred to CAMHS, social care, counselling, online or other support services. 16/77(21%) patients with a concern documented in at least one domain were not referred onwards. Conclusions This study demonstrates poor implementation of the HEEADSSS tool on admission, across a wide geographical area. Increased utilisation of a psychosocial screening tool would provide more opportunities to CYP to discuss their psychosocial health and receive appropriate support, in line with national guidance standards. Further work is underway addressing barriers to using HEEADSSS, considering electronic or embedded tools and signposting to relevant services.

This investigation was conducted to examine middle school students’ use of formative assessment technologies in informal science learning contexts. Specifically, this study focused on students’ overall preferences when using a game-based student response system (GSRS; Wang, 2015) as a formative assessment. Data sources included students’ (n = 42) self-reported preferences for competitive versus non-competitive GSRS, teachers’ reflective journals, and external observations focused on student engagement. Data analysis examined the degree to which students preferred competitive or noncompetitive types of games. The study also uncovered some of the challenges associated with implementation. Results illuminate potential trade-offs and suggest that while students ultimately prefer competitive-style games, the competitive nature of those games sometimes proved to be a hindrance with undesirable characteristics. More research is needed to better understand this discrepancy, and to better determine how the competitive characteristics might influence students’ perceptions of the tools.

Aim The 2012 RCPCH position statement described vitamin D deficiency as a significant health risk1. The 2016 Scientific Advisory Committee on Nutrition (SACN) report now recommends starting vitamin D supplements at birth until 5 years of age in all children living in the UK. A citywide intervention in 2013 reduced the incidence of symptomatic vitamin D deficiency2. A regional survey aimed to explore parental awareness of Vitamin D supplementation in children and their mothers, and to compare a large urban area with other parts of the region. Methods A regional multicentre, qualitative study using a 19point questionnaire was distributed to parents of all children below 5 years of age. The questionnaire was distributed at the point of paediatric contact, in secondary care, assessment units, wards or outpatients. Written information was provided with the survey to educate parents about the study and the importance of Vitamin D. Results There have been 62 responses to date, from 3 centres across the region. 13 children (22%) were receiving an appropriate form of vitamin supplementation. Two children were supplemented but >5 years old, therefore excluded from the numbers. 55% (n=34) of respondents had heard of the ‘Healthy Start’ Programme, with 19% (n=12) having received information about vitamin D from their Health Visitor. 8 (13%) of the children surveyed had a chronic disease, none of which was directly related to bone health or vitamin D deficiency. Conclusion We have provided evidence that despite ongoing efforts by government, the public are largely unaware of the importance of normal vitamin D levels and also of the need for vitamin supplementation. We propose that further progress could be made starting with postnatal wards, as the culture of starting supplements in neonates could be the trigger to wider uptake of vitamin D. Food fortification is still an area of review, as is the availability of free vitamins in specific geographical areas.

Prehistoric farmers in arid and semiarid ecosystems commonly used rock alignments to concentrate water and sediments on their fields. Previous research has emphasized the importance of runoff from organic matter-rich uplands as a mechanism for soil nutrient replenishment. However, eolian inputs to these dryland ecosystems might also contribute substantially to mineral-derived nutrient pools. We explored the relative importance of eolian deposition, prehistoric agriculture, and the presence of rock alignments on soil properties in a semiarid grassland in Arizona. Subsurface soils behind natural rock alignments are finer in texture than soils unbound by rock alignments, while subsurface soils behind agricultural rock alignments coarsen relative to unbound soils. Neither rock alignments nor estimated crop yields had detectable effects on mineral-derived nutrient pools. In contrast, eolian deposition is an important source of soil mass and nutrients to modern soils. While dust deposition likely reduced soil heterogeneity across this landscape, it could have also contributed to the sustainability of prehistoric agriculture.

Soil fertility is one of the major drivers of ecological processes and is therefore frequently investigated in ecological research. Although often referred to in studies, soil fertility is not well quantified. Consequently some studies have resorted to classifying site soil fertility according to the potential fertility associated with underlying geology, ignoring the soil nutrient status of the rootzone. A common protocol is for ecologists to sample the upper soil layers only (

A catena is a series of distinct but co-evolving soils arrayed along a slope. On low-slope, slowly eroding catenas the redistribution of mass occurs predominantly as plasma, the dissolved and suspended constituents in soil water. We applied mass balance methods to track how redistribution via plasma contributed to physical and geochemical differentiation of nine slowly eroding (~ 5 mm ky − 1 ) granitic catenas. The catenas were arrayed in a 3 × 3 climate by relief matrix and located in Kruger National Park, South Africa. Most of the catenas contained at least one illuviated soil profile that had undergone more volumetric expansion and less mass loss, and these soils were located in the lower halves of the slopes. By comparison, the majority of slope positions were eluviated. Soils from the wetter climates (550 and 730 mm precipitation yr − 1 ) generally had undergone greater collapse and lost more mass, while soils in the drier climate (470 mm yr − 1 ) had undergone expansion and lost less mass. Effects of differences in catena relief were less clear. Within each climate zone, soil horizon mass loss and strain were correlated, as were losses of most major elements, illustrating the predominant influence of primary mineral weathering. Nevertheless, mass loss and volumetric collapse did not become extreme because of the skeleton of resistant primary mineral grains inherited from the granite. Colloidal clay redistribution, as traced by the ratio of Ti to Zr in soil, suggested clay losses via suspension from catena eluvial zones. Thus illuviation of colloidal clays into downslope soils may be crucial to catena development by restricting subsurface flow there. Our analysis provides quantitative support for the conceptual understanding of catenas in cratonic landscapes and provides an endmember reference point in understanding the development of slowly eroding soil landscapes.

A number of scientists have named our age the Anthropocene because humanity is globally affecting Earth systems, including the soil. Global soil change raises important questions about the future of soil, the environment, and human society. Although many soil scientists strive to understand human forcings as integral to soil genesis, there remains an explicit need for a science of anthropedology to detail how humanity is a fully fledged soil-forming factor and to understand how soil change affects human well being. The development and maturation of anthropedology is critical to achieving land-use sustainability and needs to be nurtured by all soil disciplines, with inputs from allied sciences and the humanities,. The Soil Science Society of America (SSSA) has recently approved a cross-divisional Working Group on Soil Change, which aims to advance the basic and applied science of anthropedology, to facilitate networks of scientists, long-term soil field studies, and regional databases and modeling, and to engage in new modes of communications about human–soil relations. We challenge all interested parties, especially young scientists and students, to contribute to these activities and help grow soil science in the Anthropocene.

Soil catenas integrate and amplify gravity transfer and differentiation processes of eluviation and illuviation in soil profiles. We quantified differences in these redistribution processes along granitic catenas across an arid to sub-humid climate gradient in Kruger National Park, South Africa. We measured soil properties in nine catenas sampled from three areas receiving annual rainfall of 470 mm (arid zone), 550 mm (semi-arid zone) and 730 mm (sub-humid zone). As rainfall increased, kaolinite replaced smectite as the dominant clay mineral in all landscape positions across the catenas. Toeslopes showed the strongest evidence of this transition with an excess of smectite in the arid catenas but complete prevalence of kaolinite in toeslopes of sub-humid catenas. The concentration and distribution of clay along the catenas were dependent on landscape position as well — soil profiles at and near the crests were clay depleted (as low as 1%) while those at the toeslopes had much more clay (up to 60%). Clay redistribution along catenas was sensitive to climate with the least amount of redistribution occurring in the dry sites and the most occurring in the wet sites. As a consequence, the sub-humid catenas had clay accumulation only in a small part of the toeslopes while the bulk of their length was represented by highly leached soils. In contrast, arid zone catenas showed little clay redistribution and semi-arid sites displayed the greatest within-catena clay redistribution and preservation. Clay movement and storage conditioned other soil properties such as CEC, base cation distribution, base saturation and pH.

The efficacy of higher plants at mining Si from primary and secondary minerals in terrestrial ecosystems is now recognized as an important weathering mechanism. Grassland ecosystems are a particularly large reservoir of biogenic silica and are thus likely to be a key regulator of Si mobilization. Herein, we examine the effects of parent material (basaltic and granitic rocks) on the range and variability of biogenic silica pools in grass-dominated ecosystems along two precipitation gradients of Kruger National Park, South Africa. Four soil pedons and adjacent dominant plant species were characterized for biogenic silica content. Our results indicate that although soils derived from basalt had less total Si and dissolved Si than soils derived from granite, a greater proportion of the total Si was made up of biogenically derived silica. In general, plants and soils overlying basaltic versus granitic parent material stored greater quantities of biogenic silica and had longer turnover times of the biogenic silica pool in soils. Additionally, the relative abundance of biogenic silica was greater at the drier sites along the precipitation gradient regardless of parent material. These results suggest that the biogeochemical cycling of Si is strongly influenced by parent material and the hydrologic controls parent material imparts on soils. While soils derived from both basalt and granite are strongly regulated by biologic uptake, the former is a “tighter” system with less loss of Si than the latter which, although more dependent on biogenic silica dissolution, has greater losses of total Si. Lithologic discontinuities span beyond grasslands and are predicted to also influence biogenic silica cycling in other ecosystems.

Studies of weathering and pedogenesis have long used calculations based upon low solubility index elements to determine mass gains and losses in open systems. One of the questions currently unanswered in these settings is the degree to which mass is transferred in solution (solutes) versus suspension (colloids). Here we show that differential mobility of the low solubility, high field strength (HFS) elements Ti and Zr can trace colloidal redistribution, and we present a model for distinguishing between mass transfer in suspension and solution. The model is tested on a well-differentiated granitic catena located in Kruger National Park, South Africa. Ti and Zr ratios from parent material, soil and colloidal material are substituted into a mixing equation to quantify colloidal movement. The results show zones of both colloid removal and augmentation along the catena. Colloidal losses of 110 kg m −2 (− 5% relative to parent material) are calculated for one eluviated soil profile. A downslope illuviated profile has gained 169 kg m −2 (10%) colloidal material. Elemental losses by mobilization in true solution are ubiquitous across the catena, even in zones of colloidal accumulation, and range from 1418 kg m −2 (− 46%) for an eluviated profile to 195 kg m −2 (− 23%) at the bottom of the catena. Quantification of simultaneous mass transfers in solution and suspension provide greater specificity on processes within soils and across hillslopes. Additionally, because colloids include both HFS and other elements, the ability to quantify their redistribution has implications for standard calculations of soil mass balances using such index elements.

Intensive agricultural systems interact strongly and reciprocally with features of the lands they occupy, and with features of the societies that they support. We modeled the distribution of two forms of pre-European contact intensive agriculture – irrigated pondfields and rain-fed dryland systems – across the Hawaiian archipelago using a GIS approach based on climate, hydrology, topography, substrate age, and soil fertility. Model results closely match the archaeological evidence in defined locations. On a broader scale, we calculate that the youngest island, Hawai'i, could have supported 572 km2 of intensive agriculture, 97% as rain-fed dryland field systems, while Kaua'i, the oldest island, could have supported 58 km2, all as irrigated wetland systems. Irrigated systems have higher, more reliable yields and lower labor requirements than rain-fed dryland systems, so the total potential yield from Kaua'i (∼49k metric tons) was almost half that of Hawai'i (∼97k metric tons), although Kaua'i systems required only ∼0.05 of the agricultural labor (∼8400 workers, versus ∼165,000 on Hawai'i) to produce the crops. We conclude that environmental constraints to intensive agriculture across the archipelago created asymmetric production efficiencies, and therefore varying potentials for agricultural surplus. The implications both for the emergence of complex sociopolitical formations and for anthropogenic transformation of Hawaiian ecosystems are substantial.

Savannas are shaped by drought, herbivory, nutrient limitation, and fire. We assessed the interactions between two of these factors—nutrient limitation and fire—across a savanna landscape in Kruger National Park, South Africa, by quantifying increases in plant-available forms of soil phosphorus (P) following experimental or simulated burns. Plant-available pools of P were defined for granitic surface soils subjected to four experimental fire regimes (no fire, triennial fire in the wet season, triennial fire in the dry season, and annual fire in the dry season). To provide context for these results, we also fractionated surface soils from a granitic catena after simulating burning of these soils in a furnace. Burned soils showed comparable pyromineralization rates, with the experimental burn plot soils averaging 0.49 ± 0.04 g labile P m− 2 y− 1 and catena soils averaging 0.63 ± 0.12 g labile P m− 2 y− 1. Only soils from subplots burned triennially during the wet summer season with moderate fire intensities (∼ 1.1 MW m− 1) showed significant increases in labile P relative to control soils. Soils from other burned subplots with greater fire intensities showed smaller gains in labile P, suggesting pyromineralization rates may peak at intermediate fire intensities. We estimated ash contributed up to 33% of pyromineralized P. For catena soils, simulated burning led to significant increases in pyromineralized P for the relatively P-rich footslope soils and smaller increases for sandy crest and midslope soils. These pyromineralization P fluxes are of the same order of magnitude as plant P demand estimated using foliar P levels, and about one-half microbial mineralization rates. In P-limited ecosystems where chemical weathering rates are slow, moderate-intensity fires could play a critical biogeochemical role in the supply of labile P.

Creosote-bush [Larrea tridentata (Sesse & Moc. ex DC.) Coville] shrubs in California's Mojave Desert support well-developed soil resource islands, where individual shrubs define areas of elevated soil nutrients, water-holding capacity, and microbial activity. To better understand the spatial variability of microbial communities and potential impacts on nutrient cycling in shrub ecosystems, we examined microbial communities using polar lipid fatty acids (PLFA) and several soil properties including δ 15 N, DNA, C and N contents under mature shrubs and as a function of horizontal distance (0-3 m) away from the base of the shrubs. Shrub-base soils (0 m) contained more C and N, were slightly more acidic, and supported significantly larger microbial populations than soils between shrubs. The PLFA fingerprints also suggested that microbial communities, particularly at the shrub base, had a different composition than soils between shrubs, including a higher proportion of actinomycetes containing the biomarker 10me17:0. Soil respiration was generally highest at 0 m, corresponding with larger microbial biomass and larger C and N pools, but was highly variable, probably due to contributions from grasses and forbs. Average δ 15 N values resembled plant material at the shrub base (4%o) and were significantly isotopically enriched away from the shrubs (7%o), suggesting that fractionating losses of soil N occurred between shrubs. The elevated nutrient status of resource islands supported soil microbial communities that were larger, were different in character, respired more actively, and cycled N more tightly than those found in open spaces between shrubs. These open spaces "leak" isotopically light N from the soil.

Wind erosion is a major problem for modern farmers, a key variable affecting nutrient levels in ecosystems, and a potentially major force impacting archaeological site formation; however, it has received scant consideration in geoarchaeological studies of agricultural development compared with more easily quantifiable environmental costs, such as vegetation change or fluvial erosion. In this study, soil nutrient analysis is used in the Kalaupapa field system, Moloka’i Island, Hawai’i, to detect an increase in wind erosion attributable to intensive agriculture following the burning of endemic forest. This practice began on a small scale in the 13th century A.D., expanded around cal A.D. 1450–1550, and continued until the near total abandonment of the fields after European contact in the 18th century. Nutrients that naturally occur in high amounts in coastal windward areas due to the long-term, cumulative effect of sea spray were especially impacted. However, thanks to the unique landform of the Kalaupapa Peninsula, nutrient depletion in windward areas was offset by downwind enrichment and likely contributed to the long-term sustainability of the system as a whole. Future research on tropical and arid agriculture should consider the cumulative environmental cost of increased eolian erosion attributable to anthropogenic landscape modification. © 2007 Wiley Periodicals, Inc.

We investigated the fate of soil nutrients after centuries of indigenous dryland agriculture in Hawai‘i using a coupled geochemical and archaeological approach. Beginning ≈500 years ago, farmers began growing dryland taro and sweet potato on the leeward slopes of East Maui. Their digging sticks pierced a subsurface layer of cinders, enhancing crop access to the soil water stored below the intact cinders. Cultivation also catalyzed nutrient losses, directly by facilitating leaching of mobile nutrients after disturbing a stratigraphic barrier to vertical water movement, and indirectly by increasing mineral weathering and subsequent uptake and harvest. As a result, centuries of cultivation lowered volumetric total calcium, magnesium, sodium, potassium, and phosphorus content by 49%, 28%, 75%, 37%, and 32%, respectively. In the absence of written records, we used the difference in soil phosphorus to estimate that prehistoric yields were sufficient to meet local demand over very long time frames, but the associated acceleration of nutrient losses could have compromised subsequent yields.

Polynesians settled and farmed the leeward, relatively arid slopes of Haleakala Volcano beginning about ad 1400. Archaeological investigations at two sites revealed dense concentrations of conical impressions in a subsurface 20cm cinder layer that was previously undisturbed, interpreted as resulting from cultivation practices involving digging sticks. Ethnographic accounts of Hawaiian sweet potato and dryland taro cultivation techniques provide details on the use of such digging sticks. By puncturing this cinder layer, farmers created a loamy mixture of ash and cinder suited to root crop development. Archaeobotanical analyses suggest an intensive, short-fallow regime: macroscopic wood charcoal was absent (therefore no fallow sufficient for secondary re-growth of dryland forest) and evidence of disturbance-tolerant, weedy species is abundant. Geochemical analyses relying on stratigraphic relationships show that cultivation depleted nutrient levels in the digging-stick impressions, through harvest and leach...

Before European contact, Hawai`i supported large human populations in complex societies that were based on multiple pathways of intensive agriculture. We show that soils within a long-abandoned 60-square-kilometer dryland agricultural complex are substantially richer in bases and phosphorus than are those just outside it, and that this enrichment predated the establishment of intensive agriculture. Climate and soil fertility combined to constrain large dryland agricultural systems and the societies they supported to well-defined portions of just the younger islands within the Hawaiian archipelago; societies on the older islands were based on irrigated wetland agriculture. Similar processes may have influenced the dynamics of agricultural intensification across the tropics.

High-latitude warming could cause northern peatlands to become C sources. Where peatlands border boreal forests, strong differences in ecosystem C balances reflect drainage differences. Because local drainage conditions could be influenced by alterations in temperature and precipitation regimes, peatland-forest ecotones represent useful locations for monitoring potential impacts of global warming. We characterized the soils, hydrology, and forest structure along transects bracketing a peatland-forest ecotone in southeastern Alaska. We expected to find soil properties and processes at the peatland-forest edge that were intermediate between those from peatland and forest. Instead, we found that above- and belowground features of the ecotone did not coincide. Conifers grew on mineral soils, but also grew on Cryofibrists and Cryohemists, soils with high soil organic C (SOC) contents to 100 cm (57 kg m -2 ) that are significantly greater than the SOC contents of adjacent forested, non-Histosol pedons. Soil respiration rates (SRR) at peatland-forest edges (0.08 g CO 2 -C m -2 h -1 ), by contrast, were threefold lower than forest rates and did not differ significantly from peatland rates. Respiration rates were strongly influenced by water table height. Peatland and edge water tables were both significantly shallower than forest water tables. Our conceptual model suggests that if additional forest expansion and warmer summers enhance drainage of these edge soils and stimulate SRR to forest-like levels, 23 kg C m -2 could ultimately be mineralized from these extensive peatland-forest boundaries. Afforestation of peatland margins under this scenario could represent a transient positive feedback to rising atmospheric CO 2 levels.

Three ground datasets were used to simulate the canopy height characteristics of tropical forests in Costa Rica for the purposes of forest biomass estimation. The canopy height models (CHMs) were used in conjunction with airborne laser data. Gross biomass estimation errors on the order of 50-90% arose in two of the three analyses. The characteristics of the datasets and the biomass estimation procedure are reviewed to identify sources of error. In one dataset, the width of the fixed-area ground plots were small enough (5 m) that significant portions of the overstory canopy above the plots were not accounted for in the ground samples. The use of mapped stand data from thin ground plots resulted in inaccurate CHMs, which in turn lead to gross overestimates of forest biomass (about 90% larger than the ground reference value). CHMs generated using mensuration data collected on thin, fixed-area plots may significantly underestimate the average canopy height and crown closure actually found on that plot. This u...

Tropical forest ecosystems are of global importance because of their great biodiversity and the many ecosystem services they provide. Their protection in national parks and equivalent reserves is a high priority for international organizations, national agencies, and local communities. Yet the destruction of tropical forests destroys ecosystem services and is a significant source of CO 2 and other greenhouse gases accumulating in the Earth's atmosphere.

Unless sustainable development becomes much more prevalent in tropical forests, appreciable areas of unprotected tropical forests will not survive far into the twenty-first century. Sustainable tropical forestry must integrate forest conservation and economic development. Key ecological factors discussed here include: reproduction, natural regeneration, growth, ecosystem functions, and biodiversity conservation. Four models of sustainable tropical forestry are described: 1) Industrial timber production based on the PORTICO company in Costa Rica that owns and manages its production forests and makes a substantive investment in research. 2) Community-based timber production using the Yanesha Forestry Cooperative in the Peruvian Amazon as an example of local empowerment over the protection and use of forests. This Coop has a local processing facility that enables most of the timber to be marketed, and it uses an innovative strip-cut management system that promotes excellent natural regeneration of native tree species. 3) Community-based production of nontimber forest products depends on local rights of access or tenure to tropical forests. However, more information is needed on harvestable levels and management techniques as local preferences move from subsistence uses to commercial production. 4) Locally controlled nature tourism is touted as the most benign use of tropical forests, but local communities receive minimal economic returns and have little say in prioritizing development objectives.

An index of canopy closure was used to estimate closure above the crowns of all trees ≥ 10 cm dbh in 11.11 ha of undisturbed lowland tropical forest at La Selva, Costa Rica. To correct for the efFects of tree size on canopy closure, we used the residual of the regression of the canopy closure index on tree size. Analyses were carried out for the 104 species which had ≥ individuals; a total of 3224 trees were included. Nine species were found to have their crowns in significantly more open conditions than expected by chance and five species were found to have their crowns in significantly more closed conditions than expected by chance (P < 0.05). The remaining 90 species (86.5% of the assemblage) were distributed at random with respect to canopy closure, occupying the available light conditions indiscriminately. Species occurring under higher light levels did not show a narrower range of tolerance than did other species. Most species were found to occur over a substantial proportion of the canopy closure continuum present in the stand; overlap among the great majority of species in the assemblage is extensive. The results support the view that tropical forests comprise assemblages of generalist tree species, and raise questions about the classic notions of gap-phase dynamics.

Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby controlling the location and extent of biological weathering. (2) Biological stoichiometry drives changes in mineral stoichiometry and distribution through weathering. (3) On landscapes experiencing little erosion, biology drives weathering during initial succession, whereas weathering drives biology over the long term. (4) In eroding landscapes, weathering-front advance at depth is coupled to surface denudation via biotic processes. (5) Biology shapes the topography of the Critical Zone. (6) The impact of climate forcing on denudation rates in natural systems can be predicted from models incorporating biogeochemical reaction rates and geomorphological transport laws. (7) Rising global temperatures will increase carbon losses from the Critical Zone. (8) Rising atmospheric P(CO2) will increase rates and extents of mineral weathering in soils. (9) Riverine solute fluxes will respond to changes in climate primarily due to changes in water fluxes and secondarily through changes in biologically mediated weathering. (10) Land use change will impact Critical Zone processes and exports more than climate change. (11) In many severely altered settings, restoration of hydrological processes is possible in decades or less, whereas restoration of biodiversity and biogeochemical processes requires longer timescales. (12) Biogeochemical properties impart thresholds or tipping points beyond which rapid and irreversible losses of ecosystem health, function, and services can occur.

Global vegetation models predict the spread of woody vegetation in African savannas and grasslands under future climate scenarios, but they operate too broadly to consider hillslope-scale variations in tree-grass distribution. Topographically linked hydrology-soil-vegetation sequences, or catenas, underpin a variety of ecological processes in savannas, including responses to climate change. In this study, we explore the three-dimensional structure of hillslopes and vegetation, using high-resolution airborne LiDAR (Light Detection And Ranging), to understand the long-term effects of mean annual precipitation (MAP) on catena pattern. Our results reveal that the presence and position of hillslope hydrological boundaries, or seeplines, vary as a function of MAP through its long-term influence on clay redistribution. We suggest that changes in climate will differentially alter the structure of savannas through hydrological changes to the seasonally saturated grasslands downslope of seeplines. The mechanisms underlying future woody encroachment are not simply physiological responses to elevated temperatures and CO(2) levels but also involve hydrogeomorphological processes at the hillslope scale.

What controls the chemical weathering of soils in actively eroding landscapes? In this study, we explore the tectonic signature on soil weathering in the San Gabriel Mountains (SGM) of California, where propagating waves of incision triggered by increasing rock uplift have resulted in distinctly different hillslope morphologies and erosion rates across the range. We quantify downslope patterns of soil weathering across this landscape using sites that bracket low-gradient hillslopes of the stable upland plateau and hillslopes near the margins of the incising landscape. We use elemental mass balances in rock and soil to index the weathered extent of soils, and couple these extents with previously measured 10Be-derived soil production rates to calculate rates of soil weathering and erosion. Across all sites, Tau-Si—the fractional loss or gain of Si from parent material—averages -0.32±0.04, and the weathered extent of soils generally increases with increasing distance from the hillcrest. However, weathering intensities decrease as hillslope gradients steepen beyond 30°. Chemical weathering extents on slopes < 30° averaged 0.35±0.04, 50% more than steeper slopes (0.23±0.05). Similarly, the relationships between soil weathering and erosion rates show distinct patterns on high and low gradient slopes. Erosion and weathering rates are positively correlated on low gradient hillslopes, and negatively correlated on high gradient hillslopes, likely due to the role of erosion rates in controlling mineral supply and residence time. These patterns are consistent with previously published predictive models for denudation-weathering relationships based on mineral weathering kinetics. Variable weathering extents in soils indicate that soil weathering in the SGM is largely kinetically limited. This work provides a field-based quantification of the complex relationship between soil erosion and chemical weathering, and together our data suggest that tectonic forcing strongly influences soil weathering rates and extents through its control on erosion rates, transport processes and soil thickness.

Aims In the context of trauma, plain facial X-rays do not represent the gold standard imaging modality, as many patients with equivocal findings will require further imaging with facial CT views. The aim of this project was to review the use of facial X-rays of patients seen in a paediatric ED following trauma, to ascertain the degree of correlation between clinical signs and radiological findings. Methods Retrospective review. All facial X-rays performed within the ED over a 1 year period (09/2012–09/2013) were identified from the hospital PACS system. Clinical details were obtained from the ED notes and compared with the X-ray report from a consultant radiologist. Results See Figure 1 below. Conclusions The vast majority of facial X-rays performed in our ED showed no evidence of fracture. A negative X-ray may be falsely reassuring as, in some cases, clinical suspicion of bony injury was high, but no further investigation/referral was made. In other cases, a facial CT was performed despite a negative facial X-ray. Therefore, in general, facial X-rays and their interpretation by ED clinicians do not appear to make a significant difference to the subsequent clinical management of patients. If suspicion of fracture is high then CT would be a better imaging modality, as where suspicion remains high an equivocal plain X-ray result would not confidently exclude facial bone fracture. On the basis of this we have developed a new clinical guideline which stratifies patients into 3 management paths according to clinical signs and symptoms: Our intention is to reduce the number of unnecessary facial X-rays, and practice will be re-audited one year post- implementation.

We examined the ectomycorrhizal (ECM) fungal community across a bog-forest ecotone in southeastern Alaska. The bog and edge were both characterized by poorly drained Histosols and a continuous layer of Sphagnum species, ericaceous shrubs, Carex species, and shore pine [Pinus contorta Dougl. ex Loud. var. contorta]. The forest had better-drained Inceptisols and Spodosols, a tree community comprised of western hemlock [Tsuga heterophylla (Raf.) Sarg.], yellow cedar (Thuja plicata Donn ex D. Don.), Sitka spruce [Picea sitchensis (Bong.) Carr.] and shore pine, and an understorey of ericaceous shrubs and herbs. ECM root tip density (tips cm(-3) soil) was significantly greater in the forest than the edge or bog and ECM colonization was significantly different in all three plant communities. The below ground ECM fungal taxa were analyzed using molecular techniques (PCR-RFLP and DNA sequencing). Three ECM fungal taxa, Suillus tomentosus (Kauffman) Singer, Cenococcum geophilum Fr.:Fr, and a Russula species, differed in relative frequency, yet were among the four most frequent in all three plant communities. Although differences in ECM fungal richness were observed across plant communities, unequal sampling of ECM roots due to root density and colonization differences confounded richness comparisons. Using resampling procedures for creating taxon-accumulation curves as a function of sampled ECM roots revealed similarities in cumulative ECM fungal taxa richness across the ecotone.

By July 26, 1994, employers with 15 or more employees must comply with the Americans with Disabilities Act. By understanding the ADA regulations, you can recruit qualified, dedicated employees from a virtually untapped segment of the population.

The effects of the El NiA±o-Southern Oscillation on weather are well documented, but ENSO also influences flowering and fruiting of trees in tropical forests. In a Perspective, Hartshorn and Bynum describe new findings ( Curran et al .) showing that mass seed production by dipterocarp canopy trees in the Bornean rainforest is dependent on ENSO. They further discuss the negative synergy between logging and dipterocarp recruitment both in and outside of protected areas.