Developing atom probe tomography of phyllosilicates in preparation for extra-terrestrial sample return

Hydrous phyllosilicate minerals, including the serpentine subgroup, are likely to be major constituents of material that will be bought back to Earth by missions to Mars and to primitive asteroids Ryugu and Bennu. Small quantities (< 60 g) of micrometre sized, internally heterogeneous material will be available for study, requiring minimally destructive techniques. Many conventional methods are unsuitable for phyllosilicates as they are typically finely crystalline and electron beam sensitive resulting in amorphisation and dehydration. New tools will be required for nanoscale characterisation of these precious extra‐terrestrial samples. Here we test the effectiveness of atom probe tomography (APT) for this purpose. Using lizardite from the Ronda peridotite, Spain, as a terrestrial analogue, we outline an effective analytical protocol to extract nanoscale chemical and structural measurements of phyllosilicates. The potential of APT is demonstrated by the unexpected finding that the Ronda lizardite contains SiO‐rich nanophases, consistent with opaline silica that formed as a by‐product of the serpentinisation of olivine. Our new APT approach unlocks previously unobservable nanominerals and nanostructures within phyllosilicates owing to resolution limitations of more established imaging techniques. APT will provide unique insights into the processes and products of water/rock interaction on Earth, Mars and primitive asteroids

Botanical benchmarks: application of single assessment site-based vegetation survey data in habitats regulations assessment for regulatory decision-making

Nitrogen has caused, and is continuing to cause, extensive changes in ecosystem functions and the ecological communities these ecosystems support in nutrient-poor habitats in the UK. This project aimed to develop indicators which could be calculated from readily-collected field survey data, and to benchmark those indicators against national datasets, to show the expected impact of additional N deposition from new point or diffuse sources of N. In this study, we considered a wide range of metrics all of which could be derived from botanical survey in the field. To avoid correlation among similar indicators, a subset was selected which were largely uncorrelated with each other, and required varying levels of botanical expertise and investment of time to collect the field data. The selected indicators were: - Graminoid cover as a proportion of total cover - Nitrophile-nitrophobe indicator - Species richness - Mean Ellenberg N Multiple vegetation survey datasets across the UK were collated and analysed in order to assess the response of each indicator against N deposition. The final datasets selected for use included broad (non-targeted) surveys such as Countryside Survey, the Scottish Birse & Robertson re-survey, the Scottish coastal resurvey; and targeted surveys which were primarily designed to detect impacts of N deposition, and which tried to minimise covarying factors such as climate. These included N gradient studies from the Defra-funded Terrestrial Umbrella (TU) consortium, wider acid grassland datasets, and CEH sand dune datasets. Multi-year average N deposition spanning the timeframe of the survey data (2002-2014) and historical S deposition data (1986-1988 average), both derived from the CBED model, and 30-year mean annual temperature and precipitation data (1981-2010) were also collated. 2 Four habitats were selected where surveys provided sufficient data for derivation of indicators. These were: - Acid grassland - Dry heaths - Wet heaths and bogs - Acidic dune grasslands Regression models were produced to explore relationships between the indicators and pollution (N and S) and climate variables. Equations were developed for roughly two thirds of the indicators; equations for the other indicators were not reported due to ambiguous relationships with N deposition. Not all indicators showed significant responses with N deposition in all habitats. In many cases, S deposition was highly correlated with N deposition, meaning that it was not possible to attribute the impacts to one pollutant over another. Statistical uncertainty is high in the parameters of the resulting equations due to variability in the source data unaccounted for in the regression model, which may encompass other drivers of vegetation change. Potential application of the equations was demonstrated using independent data from SEPA biomonitoring programmes, using multiple sites for each habitat. The equations are useful for three main purposes: - They provide an estimate for the effect size, direction and form (e.g. linear) of the relationship between each indicator and N deposition, from which an estimate (prediction) of the indicator can be derived for a typical site at the current level of N deposition, and at given values of temperature, rainfall and historical sulphur deposition. This prediction is benchmarked against the UK-wide dataset used to generate the relationships. - Plotting current values of the indicators using measured data from the field allows comparison of the current status of the site against this UK benchmarked relationship. - The multiple indicators can be used to build up a ‘weight of evidence’ of the eutrophication status of the site. When applying the equations, it should be borne in mind that many factors determine the vegetation of an individual site and not all of these can realistically be included in models of this nature. There is inevitably a high level of uncertainty associated with these predictions. Suggested work to take these findings further includes: - Consideration of additional variables likely to be contributing to within-habitat variation in responses to N, such as soil parameters, current or historical management including grazing by managed livestock and wild grazers such as deer, where appropriate data is available - Benchmarking of additional indicators which include bryophytes and lichens - Application to other habitats not considered in this study, such as woodlands, calcareous grasslands, alpine communities, and additional dune habitats 3 (fixed dune grasslands, semi-fixed and disturbance communities, dune slack wetlands). - Integrating multiple lines of evidence, for example results from experimental manipulation sites - Incorporation of more of these indicators into dynamic process models, to predict the timescales over which change might be expected in response to additional N deposition, and impacts at individual sites. - Evaluation of the number of quadrats at a site required to adequately characterise indicator metrics, for different habitat

The road to recovery: a synthesis of outcomes from ecosystem restoration in tropical and sub-tropical Asian forests

Current policy is driving renewed impetus to restore forests to return ecological function, protect species, sequester carbon and secure livelihoods. Here we assess the contribution of tree planting to ecosystem restoration in tropical and sub-tropical Asia; we synthesize evidence on mortality and growth of planted trees at 176 sites and assess structural and biodiversity recovery of co-located actively restored and naturally regenerating forest plots. Mean mortality of planted trees was 18% 1 year after planting, increasing to 44% after 5 years. Mortality varied strongly by site and was typically ca 20% higher in open areas than degraded forest, with height at planting positively affecting survival. Size-standardized growth rates were negatively related to species-level wood density in degraded forest and plantations enrichment settings. Based on community-level data from 11 landscapes, active restoration resulted in faster accumulation of tree basal area and structural properties were closer to old-growth reference sites, relative to natural regeneration, but tree species richness did not differ. High variability in outcomes across sites indicates that planting for restoration is potentially rewarding but risky and context-dependent. Restoration projects must prepare for and manage commonly occurring challenges and align with efforts to protect and reconnect remaining forest areas

Variação entre-sftios na alometria e densidade da madeira de Goupia glabra Aubl. Na Amazônia

The present study aims to compare the allometry and wood density of Goupia glabra Aubl. (Goupiaceae) in two different terra-firme sites in Amazonian forest. A total of 65 trees ≥ 10 cm DBH was sampled in both sites, with 39 trees in Nova Olinda do Norte (NOlinda, near the Amazon River) and 29 trees in Apui (near the southern edge of the Amazon forest). Except for the relationship between DBH (diameter at breast height) and Ht (total height), allometric relationships for G. glahra differed significantly between sites. Apui had lower intercept and greater slope for log10 (DBH) versus log10 (Hs - stem height), and, conversely, greater intercept and lower slope for log10 (DBH) versus log10 (Ch - crown height). The slope differed significantly between the sites for DBH versus Cd (crown diameter), with greater slope found for NOlinda. Mean basic wood density in Apui was 8.8% lower than in NOlinda. Our findings highlight the variation in adaptive strategy of G. glabra due to environmental differences between sites. This is probably because of different canopy-understory light gradients, which result in differentiation of resource allocation between vertical and horizontal growth, which, in turn, affects mechanical support related to wood density. We also hypothesize that differences in soil fertility and disturbance regimes between sites may act concomitantly with light. © 2016, Instituto Internacional de Ecologia. All rights reserved