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Forests are often considered to be able to play a significant role in tackling global warming. To fully understand their potential in mitigating climate change and to develop more accurate ecosystem GHG flux budgets and process-based models of forests, we require more knowledge of methane (CH4) and nitrous oxide (N2O) exchange in forests, their underlying processes, environmental controls and responses to forest management. In recent years, it is becoming evident that not only soils but also the trees themselves may significantly contribute to CH4 and N2O fluxes in forest ecosystems.Our research mainly focussed on greenhouse gas (GHG) exchange in temperate UK forests on both mineral and organic soils. We will primarily concentrate on CH4 fluxes as N2O fluxes were often relatively low in these forests and, by including CO2 fluxes, we will put them into the context of the overall ecosystem GHG exchange. A range of flux methods at different scales were used in our field studies to be able to capture the often high temporal and spatial variability of the GHG exchange between the atmosphere and either soils, tree stems or entire trees aboveground, and to identify potential drivers of the fluxes. The impact of management practices including clear fell, drainage and the resulting micro-topography, and forest-to-bog restoration on CH4 fluxes from organic soils following the first forest rotation will also be described. We regularly used novel automated and chamber approaches and technologies, and the advantages and limitations of the different flux approaches and their use to upscale fluxes to the landscape scale will be evaluated.

Methane (CH4) is the second most important anthropogenic greenhouse gas (GHG) after carbon dioxide (CO2), globally responsible for more than 20% of the additional radiative forcing since 1750. Well-drained forest soils are considered as one of the most important biological CH4 sinks. Net CH4 exchange in forest soils depends on the balance of two contrasting microbial processes, i.e. CH4 production and CH4 oxidation, which are controlled by the population and activity of methanogens and methanotrophs, respectively. Additionally, recent reports have shown that living stems and shoots of trees in forests may produce and emit substantial quantities of CH4, which can offset CH4 consumption by soils; potentially switching the forest from a net CH4 sink to a net source.Tree-emitted CH4 in forests may result from biological production in soils which is subsequently absorbed by roots and then transported in stems and emitted from stems and leaves. However, there is also evidence that CH4 emissions from living tree stems may be biologically produced in situ within tree stems themselves. Long-term and high-frequency measurements of stem CH4 flux in various individuals, tree species and forest ecosystems are needed to unravel the potential underlying mechanisms and pathways of stem CH4 exchange.This research compares CH4 exchange from tree stem fluxes and soil in forest stands of English oak (Quercus robur) and Japanese larch (Larix kaempferi) and tries to understand the underlying mechanism of stem CH4 exchange in temperate forests. High-frequency measurements of tree stem CH4 exchange across various individuals were carried out in 2020 and the results will be presented from this study to help inform forest management and how to promote this globally important forest CH4 sink under climate change.

Growing global demand of water use, and regional changes in precipitation in many regions, has resulted in increasing long-term irrigation of agricultural soils with post-treatment waste water. Overlaying this trend with the rising use of pharmaceuticals has created a new pathway for these pollutants, including biologically active compounds such as antibiotics, to enter the soil environment. We present results from a new interdisciplinary study of the response of an agroecosystem which was repeatedly contaminated with a typical combination of antibiotics at a representative concentration found in waste water effluent. Results from this experimental manipulation, show the impact of different concentrations of antibiotics in the soil and the unexpected repercussions throughout the agroecosystem. This includes effects on soil microbial communities, microbial function (anti-microbial resistance), abiotic soil condition, antibiotic persistence in the soil, ecosystem function (greenhouse gas exchange) and the effect on the arable crop itself. Implications of this study are relevant to fully understanding the impact of this land management technique on the sustainability of food production.This study was funded through the UK’s N8AgriFood Programme.

Existing methods of measuring flow velocities in natural rivers are largely based on series of point measurements. Acquisition of these data can be time consuming and difficult, especially in high flow conditions. This paper introduces the use of GPS drifters (termed GRiFTers) to measure surface flow velocities in a 400 m reach of the River Swale, UK. Over 10 000 measurements were made in a 3 hour period and aggregated over a 2 m grid to generate a genuine distributed representation of flow across the reach. The technique shows great promise to provide new insights into flow patterns over long reaches of rivers, over a range of flow conditions, and may also provide valuable data for numerical model validation. Copyright © 2007 John Wiley & Sons, Ltd.

As text-based authentication has had its critiques, non-textual techniques have been suggested throughout the last two decades. However, it is only lately, with the wide-spread adoption of smartphones and tablet devices that they have found a compelling application. Non-textual authentication may be faster and more secure and it also introduces a new paradigm for the authentication decision. We present a three factor system based on facial recognition, gesture and device ID and we define a fuzzy matching engine to handle authentication. Preliminary results indicate that such an approach can be fast and user-friendly.