Do UK grasslands have the ability to sequester more carbon? Assessment of stability and resilience to changing climate and management

Soil organic matter (SOM) is the largest terrestrial pool of organic carbon (C). Carbon can persist in the soil due to several mechanisms, i) inherent chemical recalcitrance, ii) association with minerals in the soil and iii) limitations to microbial decomposition due to inaccessibility within aggregates, or conditions which limit microbial decomposition. However, C within mineral associated organic matter (MAOM-C), is often considered to be the most persistent, and consequently efforts to increase SOC largely focus on this long-lived SOC pool. The careful management of agricultural soils can contribute to climate mitigation by increasing C within MAOM, with co-benefits for ecosystem services and contributes to food security by increasing soil fertility. However, uncertainty remains with respect to the maximum sequestration potential, and the response of MAOM-C to changes in climate and management. This thesis aims to determine the carbon sequestration potential of agricultural grasslands, and to examine the effect of climate and management on MAOM-C formation within the United Kingdom. Estimating the C sequestration potential of soils is essential in determining their potential contribution to climate mitigation policies. However, the myriad of processes that contribute to the formation, and persistence of soil C makes this difficult. Consequently, a balance must be struck between the accuracy of estimates and resource inputs. In this thesis a relatively simple, but widely used linear regression equation, developed by Hassink (1997), to estimate maximum C was examined in conjunction with boundary line and quantile regression analysis – both suggested as options to overcome the shortcomings of linear regression. The quantile regression estimate of maximum soil organic C was almost double that of the linear regression and boundary line analysis (0.89 ± 0.074, 0.43 ± 0.017 and 0.57 ± 0.052 g C per kg soil, respectively). Additionally, the linear regression generated from the selected UK grasslands, was significantly different to that of Hassink (1997), demonstrating the importance of estimation methods which account for in situ context, such as management and climatic factors which play a role in C accrual. To date, much of the focus on stability and resilience of persistent soil C has focused on its mineralisation and losses due to climatic and management changes. However relatively less focus has been paid to the influence of these factors on the formation of persistent soil C. This thesis examines the influence of management factors relevant to agricultural grasslands, and climatic change on the formation of MAOM-C. Nitrogen fertilisers are frequently used to enhance plant productivity, increasing plant C inputs to the soil. Additionally, nitrogen is thought to play an important role in the formation of organo-mineral associations. Therefore, the effect of the addition of ammonium nitrate and the quantity of C substrate on MAOM-C formation was examined. It was anticipated that greater C inputs would result in greater absolute retention of substrate within MAOM-C, but less proportionally, due to changes in microbial C use efficiency (the amount incorporated into biomass versus respired as carbon dioxide). It was found that absolute substrate C retention increased with higher C addition rates, with no apparent effect on proportional retention within MAOM-C. The results also suggest that the role of nitrogen in the retention of labile substrate C, such as glucose, may be a function of C addition rate. Looking to the future it is necessary to understand how warming will influence the formation of MAOM-C. This was examined in conjunction with the effect of substrate type, to improve the understanding of the effects of substrate type and temperature on MAOM-C formation. There was no effect of temperature or substrate type (glucose versus acetic acid) on substrate C recovered in MAOM-C. However, substrate C recovery was significantly affected by substrate and temperature in the bulk SOC. The substrate C recovered in bulk SOC was significantly higher for glucose than acetic acid at 10 and 15°C, but not at 20 and 25°C. Suggesting that MAOM-C formation was independent of substrate type and temperature, but that substrate type and temperature have an influence on retention of fresh labile C inputs within the bulk soil, possibly within dissolved organic C or microbial biomass. An important aspect of agricultural land management is the maintenance of soil pH. Changes to soil pH can influence the retention of C within the soil by altering the bonds between organic matter and minerals in the soil. In acidic conditions C may be lost due to disruption of organo-mineral associations and reduced microbial activity. Whilst, in alkaline conditions additional C may be preserved due to cation bridging. Soils from a long-term pH trial were used to examine the effect of soil pH, grass ley duration and depth on MAOM-C. Ley duration had no effect on total SOC or MAOM-C, and as expected both declined with depth. In the topsoil, both SOC and MAOM-C increased with soil pH, possibly due to additional abiotic cation stabilisation, due to the presence of calcium, magnesium and manganese associated with lime application in pH management. The findings of this thesis contribute to the understanding of the current C status of a selection of UK grasslands, and how typical management and climatic factors influence the formation and persistence of MAOM-C. There is likely to be potential for additional C sequestration within persistent C pools within agricultural grasslands in the UK. However, further work is required to improve the understanding of the formation and persistence of MAOM-C in response to typical land managements. This would help to guide land management policies which enhance and limit losses of existing SOC

Inorganic nitrogen and glucose additions alter the short-term formation efficiency of mineral associated organic matter carbon

Carbon within mineral associated organic matter (MAOM) is an important persistent form of soil organic carbon (SOC). However, processes driving the retention of new labile C in MAOM are not fully understood. We investigated the effects of glucose and ammonium nitrate (AN) addition on the short-term (72 h) retention of applied 13C-glucose within MAOM. We found an interactive effect of AN addition with the glucose addition rate. Higher rates of glucose addition resulted in proportionally less glucose-C retained, indicating lower MAOM-C formation efficiency. Addition of AN only altered the proportional retention of glucose where glucose was applied at the lowest rate. In this instance glucose-13C recovery increased with AN addition. However, after 72 h there was no treatment difference in total MAOM-C, indicating that any changes in formation efficiency as a result of AN and glucose additions, did not result in differences in total MAOM-C in the short-term. Whether and how this affects the medium and longer-term dynamics of MAOM-C requires further investigation

Massive Open Online Courses (MOOCs) as a Window into the Veterinary Profession

Catriona Bell – ORCID: 0000-0001-8501-1697 https://orcid.org/0000-0001-8501-1697Item not available in this repository.Previously deposited in Edinburgh University repository at: https://www.research.ed.ac.uk/en/publications/massive-open-online-courses-moocs-as-a-window-into-the-veterinaryMassive open online courses (MOOCs) are freely available online courses open to anyone who registers and typically are associated with thousands or hundreds of thousands of participants. Using an established online platform, the authors created and delivered a five-week MOOC aimed primarily at prospective veterinary students, but open to anyone with an interest in finding out more about the veterinary profession in general. 11,911 people signed up for the course, and of these, 8137 interacted in some way with the course and 1716 received a certificate of completion. The majority of participants (84 per cent) were female, and there was a wide age range (under 18 to over 65). Most participants were from North America or the UK. 65 per cent of those completing the entry survey were hoping or intending to work in the vet profession in the future, while 33 per cent were not. Qualitative data indicated that the course was helpful in aiding those undecided as to whether they wanted to be a veterinarian or not to decide one way or another whether they want to pursue veterinary medicine as a career. Furthermore, the course was seen as being a useful introduction to the veterinary profession even for those who had no intention of working in the field.https://doi.org/10.1136/vr.103979180pubpub

Fast pixelated detectors in scanning transmission electron microscopy. Part II: post acquisition data processing, visualisation, and structural characterisation

Fast pixelated detectors incorporating direct electron detection (DED) technology are increasingly being regarded as universal detectors for scanning transmission electron microscopy (STEM), capable of imaging under multiple modes of operation. However, several issues remain around the post acquisition processing and visualisation of the often very large multidimensional STEM datasets produced by them. We discuss these issues and present open source software libraries to enable efficient processing and visualisation of such datasets. Throughout, we provide examples of the analysis methodologies presented, utilising data from a 256×256 pixel Medipix3 hybrid DED detector, with a particular focus on the STEM characterisation of the structural properties of materials. These include the techniques of virtual detector imaging; higher order Laue zone analysis; nanobeam electron diffraction; and scanning precession electron diffraction. In the latter, we demonstrate nanoscale lattice parameter mapping with a fractional precision ≤6×10−4 (0.06%)

Diversity, distribution, and azaspiracids of Amphidomataceae (Dinophyceae) along the Norwegian coast

Azaspiracids (AZA) are a group of lipophilic polyether compounds which have been implicated in shellfish poisoning incidents around Europe. They are produced by a few species of the dinophycean genera Azadinium and Amphidoma (Amphidomataceae). The presence of AZA toxins in Norway is well documented, but knowledge of the distribution and diversity of Azadinium and other Amphidomataceae along the Norwegian coast is rather limited and poorly documented. On a research survey along the Norwegian coast in 2015 from the Skagerrak in the South to Trondheimsfjorden in the North, plankton samples from 67 stations were analysed for the presence of Azadinium and Amphidoma and their respective AZA by on-board live microscopy, real-time PCR assays specific for Amphidomataceae, and liquid chromatography-tandem mass spectrometry (LC–MS/MS). Microscopy using live samples and positive real-time PCR assays using a general family probe and two species specific probes revealed the presence of Amphidomataceae distributed throughout the sampling area. Overall abundance was low, however, and was in agreement with a lack of detectable AZA in plankton samples. Single cell isolation and morphological and molecular characterisation of established strains revealed the presence of 7 amphidomatacean species (Azadiniun spinosum, Az. poporum, Az. obesum, Az. dalianense, Az. trinitatum, Az. polongum, Amphidoma languida) in the area. Azaspiracids were produced by the known AZA producing species Az. spinosum, Az. poporum and Am. languida only. LC–MS/MS analysis further revealed that Norwegian strains produce previously unreported AZA for Norway (AZA-11 by Az. spinosum, AZA-37 by Az. poporum, AZA-38 and AZA-39 by Am. languida), and also four novel compounds (AZA-50, -51 by Az. spinosum, AZA-52, -53 by Am. languida), whose structural properties are described and which now can be included in existing analytical protocols. A maximum likelihood analysis of concatenated rDNA regions (SSU, ITS1-ITS2, partial LSU) showed that the strains of Az. spinosum fell in two well supported clades, where most but not all new Norwegian strains formed the new Ribotype B. Ribotype differentiation was supported by a minor morphological difference with respect to the presence/absence of a rim around the pore plate, and was consistently reflected by different AZA profiles. Strains of Az. spinosum from ribotype A produce AZA-1, -2 and -33, whereas the new strains of ribotype B produce mainly AZA-11 and AZA-51. Significant sequence differences between both Az. spinosum ribotypes underline the need to redesign the currently used qPCR probes in order to detect all AZA producing Az. spinosum. The results generally underline the conclusion that for the Norwegian coast area it is important that amphidomatacean species are taken into account in future studies and monitoring programs

The ALLEGRO trial : a placebo controlled randomised trial of intravenous lidocaine in accelerating gastrointestinal recovery after colorectal surgery

Acknowledgements The authors wish to acknowledge the following persons who have helped deliver the ALLEGRO trial: the programming team based in the Centre for Healthcare Randomised Trials, for their work in developing the study web portal; Sharon Wren and Zoe Batham for their administrative support; ACCORD in Edinburgh; the Perioperative Medicine Clinical Trials Network (POMCTN) for adopting the trial for promotion; and the local recruiting teams and participants. We are also indebted to the late Professor Kenneth Fearon, University of Edinburgh, for protocol development and study design. The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the Health Technology Assessment Programme, National Institute for Health Research (NIHR), NHS or the Department of Health. Funding The trial is funded by the NIHR Health and Technology Assessment programme, project number 15/130/95. The funding body had no role in the design of the study, collection of data or the writing of this paper, nor will the funding body have a role in analysis, interpretation of data or in writing future manuscripts. The co-sponsors are University of Edinburgh & Lothian Health Board (AC- CORD), The Queen’s Medical Research Institute, 47 Little France Crescent, Ed- inburgh EH16 4TJ.Peer reviewedPublisher PD

Fast pixelated detectors in scanning transmission electron microscopy. Part I: data acquisition, live processing and storage

The use of fast pixelated detectors and direct electron detection technology is revolutionising many aspects of scanning transmission electron microscopy (STEM). The widespread adoption of these new technologies is impeded by the technical challenges associated them. These include issues related to hardware control, and the acquisition, real-time processing and visualisation, and storage of data from such detectors. We discuss these problems and present software solutions for them, with a view to making the benefits of new detectors in the context of STEM more accessible. Throughout, we provide examples of the application of the technologies presented, using data from a Medipix3 direct electron detector. Most of our software is available under an open source licence, permitting transparency of the implemented algorithms, and allowing the community to freely use and further improve upon them

Estimating maximum fine-fraction organic carbon in UK grasslands

Publication history: Accepted - 24 November 2021; Published - 27 January 2021.Soil organic carbon (SOC) sequestration across agroecosystems worldwide can contribute to mitigate the effects of climate change by reducing levels of atmospheric CO2. Stabilisation of organic carbon (OC) in the fine soil fraction (<20 μm) is considered an important long-term store of SOC, and the saturation deficit (difference between measured OC and estimated maximum OC in the fine fraction) is frequently used to assess SOC sequestration potential following the linear regression equation developed by Hassink (1997). However, this approach is often taken without any assessment of the fit of the equation to the soils being studied. The statistical limitations of linear regression have previously been noted, giving rise to the proposed use of boundary line (BL) analysis and quantile regression (QR) to provide more robust estimates of maximum SOC stabilisation. The objectives of this work were to assess the suitability of the Hassink (1997) equation to estimate maximum fine-fraction OC in UK grassland soils of varying sward ages and to evaluate the linear regression, boundary line and quantile regression methods to estimate maximum fine-fraction OC. A chronosequence of 10 grasslands was sampled, in order to assess the relationship between sward age (time since the last reseeding event) and the measured and predicted maximum fine-fraction OC. Significantly different regression equations show that the Hassink (1997) equation does not accurately reflect maximum fine-fraction OC in UK grasslands when determined using the proportion of the fine soil fraction (<20 μm, %) and measured finefraction OC (g C per kg soil). The QR estimate of maximum SOC stabilisation was almost double that of the linear regression and BL analysis (0.89 0.074, 0.43 0.017 and 0.57 0.052 gC per kg soil, respectively). Sward age had an inconsistent effect on the measured variables and potential maximum fine-fraction OC. Fine-fraction OC across the grasslands made up 4.5% to 55.9% of total SOC, implying that there may be either high potential for additional C sequestration in the fine fraction of these soils or that protection in aggregates is predominant in these grassland soils. This work highlights the need to ensure that methods used to predict maximum fine-fraction OC reflect the soil in situ, resulting in more accurate assessments of carbon sequestration potential.This research has been supported by SRUC’s postgraduate studentship programme and the Global Academy of Agriculture and Food Security, University of Edinburgh. Funding has also been provided by Business Environment, Industry and Strategy (grant no. TRN1133); Ricardo-AEA; and the Rural & Environment Science & Analytical Services Division of the Scottish government