Understanding past climatic and hydrological variability in the Mediterranean from Lake Prespa sediment isotope and geochemical record over the Last Glacial cycle

Here we present stable isotope and geochemical data from Lake Prespa (Macedonia/Albania border) over the Last Glacial cycle (Marine Isotope Stages 5–1) and discuss past lake hydrology and climate (TIC, oxygen and carbon isotopes), as well as responses to climate of terrestrial and aquatic vegetation (TOC, Rock Eval pyrolysis, carbon isotopes, pollen). The Lake Prespa sediments broadly fall into 5 zones based on their sedimentology, geochemistry, palynology and the existing chronology. The Glacial sediments suggest low supply of carbon to the lake, but high summer productivity; intermittent siderite layers suggest that although the lake was likely to have mixed regularly leading to enhanced oxidation of organic matter, there must have been within sediment reducing conditions and methanogenesis. MIS 5 and 1 sediments suggest much more productivity, higher rates of organic material preservation possibly due to more limited mixing with longer periods of oxygen-depleted bottom waters. We also calculated lakewater δ18O from siderite (authigenic/Glacial) and calcite (endogenic/Holocene) and show much lower lakewater δ18O values in the Glacial when compared to the Holocene, suggesting the lake was less evaporative in the Glacial, probably as a consequence of cooler summers and longer winter ice cover. In the Holocene the oxygen isotope data suggests general humidity, with just 2 marked arid phases, features observed in other Eastern and Central Mediterranean lakes

The Future of Geography Field Course Pedagogy in UK Higher Education

Field courses are widely regarded as integral to geography degree programmes, providing students with opportunities for experiential learning, often in unfamiliar international environments. Yet, this key area of pedagogy appears increasingly unsustainable and complex for Higher Education Institutions (HEIs) within the context of the urgent need for decarbonisation, increasing financial costs, and the institutional challenges of comprehensively embedding necessary Equality, Diversity and Inclusion (EDI) considerations into these activities. Here, we report on a national-level workshop (April 2024) that brought together a wide range of HE practitioners to discuss the future of UK field course pedagogy,using the fieldwork principles adopted by the Royal Geographical Society (with the Institute of British Geographers) (RGS-IBG) in 2020 as a basis for framing future discourse. Using a Three Horizons approach to guide our conversations, we critically explored the (un)sustainability of current academic and institutional practices, alongside future directions and ‘disrupting’ (innovative) practices for promoting transformative change in this area of education. Here, we argue for two sector-wide discussions that require collaborative engagement with practitioners, institutions, and students. Firstly, we highlight the urgent need for transparent and critical reflection on the challenges and hypocrisy of aeromobility in academia and the need for more widespread adoption of low carbon (‘slower’) modes of travel. Secondly, we call for the immediate reconceptualization of field course pedagogy to place EDI considerations at the core of field course design and practice, aiding a transition towards Universal Design for Learning (UDL). As such, we call on the geography community in higher education to engage in critical reflection on how we take meaningful and urgent action to address the disconnect between our stated educational values around environmental sustainability and EDI, and our actual educational practices.<br/

Deglaciation and catchment ontogeny in south-west Greenland : implications for terrestrial and aquatic carbon cycling

Here we present Holocene organic carbon, nitrogen, sulphur, carbon isotope ratio and macrofossil data from a small freshwater lake near Sisimiut in south-west Greenland. The lake was formed c. 11 cal ka BP following retreat of the ice sheet margin and is located above the marine limit in this area. The elemental and isotope data suggest a complex deglaciation history of interactions between the lake and its catchment, reflecting glacial retreat and post-glacial hydrological flushing probably due to periodic melting of local remnant glacial ice and firn areas between 11 and 8.5 cal ka BP. After 8.5 cal ka BP, soil development and associated vegetation processes began to exert a greater control on terrestrial–aquatic carbon cycling. By 5.5 cal ka BP, in the early Neoglacial cooling, the sediment record indicates a change in catchment–lake interactions with consistent δ13C while C/N exhibits greater variability. The period after 5.5 cal ka BP is also characterized by higher organic C accumulation in the lake. These changes (total organic carbon, C/N, δ13C) are most likely the result of increasing contribution (and burial) of terrestrial organic matter as a result of enhanced soil instability, as indicated by an increase in Cenococcum remains, but also Sphagnum and Empetrum. The impact of glacial retreat and relatively subdued mid- to late Holocene climate variation at the coast is in marked contrast to the greater environmental variability seen in inland lakes closer to the present-day ice sheet margin

High-temperature pyrolysis/gas chromatography/isotope ratio mass spectrometry : simultaneous measurement of the stable isotopes of oxygen and carbon in cellulose

Stable isotope analysis of cellulose is an increasingly important aspect of ecological and palaeoenvironmental research. Since these techniques are very costly, any methodological development which can provide simultaneous measurement of stable carbon and oxygen isotope ratios in cellulose deserves further exploration. A large number (3074) of tree-ring α-cellulose samples are used to compare the stable carbon isotope ratios (δ13C) produced by high-temperature (1400°C) pyrolysis/gas chromatography (GC)/isotope ratio mass spectrometry (IRMS) with those produced by combustion GC/IRMS. Although the two data sets are very strongly correlated, the pyrolysis results display reduced variance and are strongly biased towards the mean. The low carbon isotope ratios of tree-ring cellulose during the last century, reflecting anthropogenic disturbance of atmospheric carbon dioxide, are thus overestimated. The likely explanation is that a proportion of the oxygen atoms are bonding with residual carbon in the reaction chamber to form carbon monoxide. The 'pyrolysis adjustment', proposed here, is based on combusting a stratified sub-sample of the pyrolysis results, across the full range of carbon isotope ratios, and using the paired results to define a regression equation that can be used to adjust all the pyrolysis measurements. In this study, subsamples of 30 combustion measurements produced adjusted chronologies statistically indistinguishable from those produced by combusting every sample. This methodology allows simultaneous measurement of the stable isotopes of carbon and oxygen using high-temperature pyrolysis, reducing the amount of sample required and the analytical costs of measuring them separately

Mariposa '74

Item consists of the 49 page Mariposa Folk Festival program for 1974, held on the Toronto Islands, Toronto, Ontario from 21-23 June, 1974. The program was designed and edited by the festival's Programme Book Committee, consisting of Joe Lewis, Enoch Kent, Paul Hornbeck, Marna Snitman, Shelley Spiegel, Ray Woodley, Eileen Keleher and Stew Cameron. Includes a schedule of evening and day concerts and workshops, a list of performer biographies, and ... Also includes several articles, including "Bluegrass Music" by Shelley Posen, "Notes on Accompaniment" by Peggy Seeger and Ewan MacColl (reprinted from "The Singing Island"), "Crafts at Mariposa" by Skye Morisson and short anonymous articles from Mariposa In The Schools and the festival's Ethnic Committee.We acknowledge the financial support of the Department of Canadian Heritage through the Canadian Culture Online Program. | Nous tenons à souligner le soutien financier du ministère du Patrimoine canadien par le biais du Programme de culture canadienne en ligne

The Future of Geography Field Course Pedagogy in UK Higher Education

Field courses are widely regarded as integral to geography degree programmes, providing students with opportunities for experiential learning, often in unfamiliar international environments. Yet, this key area of pedagogy appears increasingly unsustainable and complex for Higher Education Institutions (HEIs) within the context of the urgent need for decarbonisation, increasing financial costs, and the institutional challenges of comprehensively embedding necessary Equality, Diversity and Inclusion (EDI) considerations into these activities. Here, we report on a national-level workshop (April 2024) that brought together a wide range of HE practitioners to discuss the future of UK field course pedagogy, using the fieldwork principles adopted by the Royal Geographical Society (with the Institute of British Geographers) (RGS-IBG) in 2020 as a basis for framing future discourse. Using a Three Horizons approach to guide our conversations, we critically explored the (un)sustainability of current academic and institutional practices, alongside future directions and ‘disrupting’ (innovative) practices for promoting transformative change in this area of education. Here, we argue for two sector-wide discussions that require collaborative engagement with practitioners, institutions, and students. Firstly, we highlight the urgent need for transparent and critical reflection on the challenges and hypocrisy of aeromobility in academia and the need for more widespread adoption of low carbon (‘slower’) modes of travel. Secondly, we call for the immediate reconceptualization of field course pedagogy to place EDI considerations at the core of field course design and practice, aiding a transition towards Universal Design for Learning (UDL). As such, we call on the geography community in higher education to engage in critical reflection on how we take meaningful and urgent action to address the disconnect between our stated educational values around environmental sustainability and EDI, and our actual educational practices.<br/

Spatial variability and temporal trends in water-use efficiency of European forests

The increasing carbon dioxide (CO2) concentration in the atmosphere in combination with climatic changes throughout the last century are likely to have had a profound effect on the physiology of trees: altering the carbon and water fluxes passing through the stomatal pores. However, the magnitude and spatial patterns of such changes in natural forests remain highly uncertain. Here, stable carbon isotope ratios from a network of 35 tree-ring sites located across Europe are investigated to determine the intrinsic water-use efficiency (iWUE), the ratio of photosynthesis to stomatal conductance from 19012000. The results were compared with simulations of a dynamic vegetation model (LPX-Bern 1.0) that integrates numerous ecosystem and landatmosphere exchange processes in a theoretical framework. The spatial pattern of tree-ring derived iWUE of the investigated coniferous and deciduous species and the model results agreed significantly with a clear south-to-north gradient, as well as a general increase in iWUE over the 20th century. The magnitude of the iWUE increase was not spatially uniform, with the strongest increase observed and modelled for temperate forests in Central Europe, a region where summer soil-water availability decreased over the last century. We were able to demonstrate that the combined effects of increasing CO2 and climate change leading to soil drying have resulted in an accelerated increase of iWUE. These findings will help to reduce uncertainties in the land surface schemes of global climate models, where vegetationclimate feedbacks are currently still poorly constrained by observational data