Giles H. Brown

Rates of chemical denudation and CO2 drawdown in a glacier-covered alpine catchment

Solute fluxes from a glacier-covered alpine catchment are partitioned into components derived from sea-salt, acid aerosol, dissolution of atmospheric CO2, and crustal weathering. The bulk of solute is crustally derived. Coupled sulfide oxidation and carbonate dissolution (SO-CD) and carbonation of carbonate minerals generate approximately equal amounts of solute. Chemical denudation constitutes <1.5% of solid denudation but is significantly higher than the continental average. CO2 drawdown by weathering reactions varies directly with discharge and suspended-sediment load and inversely with meltwater p(CO2). If it is generally true that flushing rates control CO2 drawdown in glacier-covered catchments, then glacially driven chemical weathering could be a significant factor in carbon cycling and climate change on glacial-interglacial time scales.

Glacier meltwater hydrochemistry

Abstract Glacierised areas present an ideal environment in which to study water-rock interaction, since chemical weathering rates are high and anthropogenic impacts are often minimal. Detailed investigations of meltwater quality variations have suggested the importance of these environments in estimates of terrestrial chemical erosion and global biogeochemical cycles. Most notably, the role of meltwaters in CO2 sequestration during episodes of deglaciation has attracted considerable attention, since this may impact on climate at glacial-interglacial timescales. However, there is still considerable uncertainty surrounding estimates of CO2 drawdown by meltwaters which remains to be resolved. Water flow through glaciers exerts an important control on ice mass dynamics, and influences the quantity and quality of water delivered to environments downstream of glacierised basins. Thus, the study of the configuration and dynamics of subglacial drainage systems is important not only to enhance scientific understanding, but also to allow effective water resource utilisation in glacierised headwater catchments. Bulk meltwater quality characteristics draining terrestrial ice masses also offer the potential to provide unique information on hydrological and hydrochemical processes operating in the inaccessible subglacial environment. Here, significant advances have been made in understanding the controls on chemical weathering reactions, based on the identification of key dissolved indicator species. This has allowed water quality variations to be exploited as a tool for both subglacial hydrochemical and hydrological investigations. As a result, this area of glaciology has received considerable attention in recent years, utilising an increasing range of dissolved ions, and integrating field and laboratory studies. However, uncertainty still surrounds certain areas of meltwater quality science, including the role of microorganisms in a system which to date has largely been viewed as abiotic. A better understanding of the processes and rates of chemical weathering in glacierised environments has the potential to enhance our understanding of the environment, and to facilitate the exploitation of water quality variations for both scientific and applied objectives. In this paper the development and current state of meltwater quality science as a tool for investigating subglacial hydrology and geochemistry is detailed, and problems and future directions identified. This will hopefully stimulate wider interest in an important area of aquatic chemistry with significant applied implications.

Direct effect of ice sheets on terrestrial bicarbonate, sulphate and base cation fluxes during the last glacial cycle: minimal impact on atmospheric CO2 concentrations

Chemical erosion in glacial environments is normally a consequence of chemical weathering reactions dominated by sulphide oxidation linked to carbonate dissolution and the carbonation of carbonates and silicates. Solute fluxes from small valley glaciers are usually a linear function of discharge. Representative glacial solute concentrations can be derived from the linear association of solute flux with discharge. These representative glacial concentrations of the major ions are f25% of those in global river water. A 3-D thermomechanically coupled model of the growth and decay of the Northern Hemisphere ice sheets was used to simulate glacial runoff at 100-year time steps during the last glacial cycle (130 ka to the present). The glacially derived fluxes of major cations, anions and Si over the glaciation were estimated from the product of the glacial runoff and the representative glacial concentration. A second estimate was obtained from the product of the glacial runoff and a realistic upper limit for glacial solute concentrations derived from theoretical considerations. The fluxes over the last glacial cycle are usually less than a few percent of current riverine solute fluxes to the oceans. The glacial fluxes were used to provide input to an oceanic carbon cycling model that also calculates changes in atmospheric CO2. The potential change in atmospheric CO2 concentrations over the last glacial cycle that arise from perturbations in glacial solute fluxes are insignificant, being < 1 ppm. D 2002 Elsevier Science B.V. All rights reserved.

Sustainability in higher education

How HEIs engage with, and respond to, sustainability issues is the topic of Paul Temples paper in this issue of perspectives. Sustainability in HE raises a number of interesting challenges in its ...

Student C&IT skills development and the learning environment: evaluation and module evolution

This paper describes efforts by the Institute of Geography and Earth Sciences at the University of Wales, Aberystwyth, to develop effective strategies with which to develop students’ skills in communications and information technology (C&IT). The strategy adopted was to develop these skills within modules that tackle traditional earth science subjects rather than devise a specific skills development module. Two modules were utilised: Geohazards and the Malta Fieldcourse, which specified the achievement of C&IT skills as key objectives. The results of the first year’s experiment were surprising. Students on the Geohazards module, who received extensive practical instruction in C&IT skills, did not demonstrate appreciable attainment of C&IT skills. In contrast, many students on the Malta Fieldcourse, who received no practical C&IT instruction, created Web pages for assessment. The reasons for these results were evaluated and alterations made to both modules, mainly in respect of the learning environment. Results in 1998 were dramatically improved and demonstrate the importance of creating and maintaining an experiential learning environment to encourage students to develop and demonstrate C&IT skills.

Branding versus branding work, media versus product – HE in the internet age

In the previous issue of perspectives I wrote about SuperBrands (Brown, G. 2011), stimulated by Peter Reader’s paper on public relations, communications and marketing (Reader 2011). In this issue, Paul Temple explores the allied role of branding in HE. He makes the distinction between ‘Branding’ and ‘Branding Work’, with a clear case for the value of the former, based on good management and a well-nurtured academic culture, versus the superficiality of the latter. However, as we move to a more market-like HE ‘economy’ in the UK, we should also not underestimate brand loyalty, ie the commitment to continue to support the brand, either through repurchase or other positive advocacy (Wikipedia 2011a). The importance of an institution’s brand will potentially now resonate over an increasingly longer timescale; lifetime loyalty for an individual alumnus (and implicitly greater fundraising through donations), and potentially inter-generational loyalty as those alumni send their offspring to their alma mater. The lifetime bond to a graduate’s institution is stronger in the USA, and this is likely to become more the case in the UK as more has to be invested financially in obtaining a degree, and the ‘association’ continues through monthly repayment ‘reminders’! This issue also contains another paper in the series solicited to reflect on the AUA’s Golden Jubilee, this time by Barry Taylor. His paper considers the relationship between higher education and the media, which echoes aspects of Temple’s thoughts on branding. Specifically, while the technology may change, and the media’s relationship with HE has moved from deference to varying degrees of criticism, five key verities underpin our success: Leadership, Mission, Authenticity, Realism and Fearlessness. These technologically independent tenets are inherently linked to the ‘products’, namely academic quality and the student experience, and echo Temple’s definition of ‘branding’ (cf branding ‘work’ or media ‘spin’). Taylor’s paper also points to the role of new media, both as a positive (ready dissemination of news, more up-to-date and responsive documentation, evolving FAQs, online applications etc, etc) and less positive (unsubstantiated/unfounded criticism, variable league tables [eg Brown, R. 2006], cyber bullying etc) development. Of course, as we move increasingly from an elite to a mass higher education system the quantity of criticism is likely to increase, since HE impacts on a greater proportion of the population (both as participants and supporters, though I suspect we will have increasing difficulty as time goes by identifying who exactly the ‘customer’ is: the student or their parent/guardian/ funder). The role of the internet is central in both the branding and the media debates. Interestingly, as we become more reliant on (inseparable from?) the web, the challenges it poses for all aspects of HE, from learning, teaching and assessment (eg exciting, innovative, previously unimaginable VLEs, cutand-paste plagiarism versus the technological solutions for plagiarism detection) through to media engagement and information dissemination, becoming increasingly complex. Taylor refers to internet searches employed in the writing of his paper. Yet, even these are becoming shaped not only by our ability to search effectively and efficiently using, for example, Boolean logic, but also by the very search engines used to undertake these enquiries – see Eli Pariser’s new book The Filter Bubble (Pariser 2011a), or if you fancy an online summary (putting the irony aside for a minute) see his TED Talks presentation (Pariser 2011b). Indeed, the Giles H. Brown is School Manager in the Schools of Geographical Sciences and Earth Sciences, University of Bristol. He was previously a lecturer at the University of Wales Aberystwyth and held a NERC Postdoctoral Research Fellowship in Cambridge. He is a member of the AUA Board of Trustees.

Holocene book reviews: Ice core studies of global biogeochemical cycles Edited by R.J. Delmas, NATO ASI Series I, Global Environmental Change, Volume 30, Berlin: Springer-Verlag, 1995, 475 pp., DM298, hardback. ISBN 3-540-59274-1

ate zone in the last 15,000 years’ and forms the latest major output of subproject IGCP 158B which deals with lake and mire environments. The preface of this book by Berglund explains the genesis and development of the project and the aims and rationale for this book, which is the first major publication from the project since Berglund (1986). Broadly, the project intended to provide data from lakes and mires on palaeoecological changes since deglaciation and attempt to establish the causes for these