Stephen Malcolm
Centre for Environment, Fisheries and Aquaculture Science
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Featured researches published by Stephen Malcolm.
AMBIO: A Journal of the Human Environment | 2000
Timothy D. Jickells; Je Andrews; G Samways; Richard Sanders; Stephen Malcolm; D. B. Sivyer; Ruth Parker; David B. Nedwell; John Ridgway
Abstract The geomorphology of the present day and Holocene (3000 years ago) Humber estuary, United Kingdom, are described. More than 90% of the intertidal area and sediment accumulation capacity of the estuary has been lost to reclamation over this period. A similar situation prevails in many other urbanized estuaries. Nutrient budgets for the modern estuary are presented demonstrating little trapping of nutrients, due to the loss of intertidal areas. A speculative budget for the Humber during the Holocene is constructed, which suggests that the estuary was then an efficient sink for nitrogen and phosphorus. A budget is presented describing how nutrient cycling might operate in the Humber with contemporary nutrient loadings, but with the pre-reclamation geography. This suggests that in this form the estuary would significantly attenuate nutrient fluxes to the North Sea. The results are discussed in terms of options for managed realignment of estuaries in response to predicted sea-level rise.
Geochemical Transactions | 2001
Daniel E. Duplisea; Simon Jennings; Stephen Malcolm; Ruth Parker; D. B. Sivyer
Bottom trawling causes physical disturbance to sediments particularly in shelf areas. The disturbance due to trawling is most significant in deeper areas with softer sediments where levels of natural disturbance due to wave and tidal action are low. In heavily fished areas, trawls may impact the same area of seabed more than four times per year. A single pass of a beam trawl, the heaviest gear routinely used in shelf sea fisheries, can kill 5–65% of the resident fauna and mix the top few cm of sediment. We expect that sediment community function, carbon mineralisation and biogeochemical fluxes will be strongly affected by trawling activity because the physical effects of trawling are equivalent to those of an extreme bioturbator, and yet, unlike bioturbating macrofauna, trawling does not directly contribute to community metabolism. We used an existing box-model of a generalised soft sediment system to examine the effects of trawling disturbance on carbon mineralisation and chemical concentrations. We contrasted the effects of a natural scenario, where bioturbation is a function of macrobenthos biomass, with an anthropogenic impact scenario where physical disturbance results from trawling rather than the action of bioturbating macrofauna. Simulation results suggest that the effects of low levels of trawling disturbance will be similar to those of natural bioturbators but that high levels of trawling disturbance prevent the modelled system from reaching equilibrium due to large carbon fluxes between oxic and anoxic carbon compartments. The presence of macrobenthos in the natural disturbance scenario allowed sediment chemical storage and fluxes to reach equilibrium. This is because the macrobenthos are important carbon consumers in the system whose presence reduces the magnitude of available carbon fluxes. In soft sediment systems, where the level physical disturbance due to waves and tides is low, model results suggest that intensive trawling disturbance could cause large fluctuations in benthic chemical fluxes and storage.
Science of The Total Environment | 2014
Tiziana Luisetti; Rk Turner; Timothy D. Jickells; Je Andrews; Michael Elliott; Marije Schaafsma; Nicola Beaumont; Stephen Malcolm; Daryl Burdon; Christopher Adams; W Watts
This research is concerned with the following environmental research questions: socio-ecological system complexity, especially when valuing ecosystem services; ecosystems stock and services flow sustainability and valuation; the incorporation of scale issues when valuing ecosystem services; and the integration of knowledge from diverse disciplines for governance and decision making. In this case study, we focused on ecosystem services that can be jointly supplied but independently valued in economic terms: healthy climate (via carbon sequestration and storage), food (via fisheries production in nursery grounds), and nature recreation (nature watching and enjoyment). We also explored the issue of ecosystem stock and services flow, and we provide recommendations on how to value stock and flows of ecosystem services via accounting and economic values respectively. We considered broadly comparable estuarine systems located on the English North Sea coast: the Blackwater estuary and the Humber estuary. In the past, these two estuaries have undergone major land-claim. Managed realignment is a policy through which previously claimed intertidal habitats are recreated allowing the enhancement of the ecosystem services provided by saltmarshes. In this context, we investigated ecosystem service values, through biophysical estimates and welfare value estimates. Using an optimistic (extended conservation of coastal ecosystems) and a pessimistic (loss of coastal ecosystems because of, for example, European policy reversal) scenario, we find that context dependency, and hence value transfer possibilities, vary among ecosystem services and benefits. As a result, careful consideration in the use and application of value transfer, both in biophysical estimates and welfare value estimates, is advocated to supply reliable information for policy making.
2004 USA-Baltic Internation Symposium | 2004
David K. Mills; Naomi Greenwood; Silke Kröger; Michelle Devlin; D. B. Sivyer; David J. Pearce; S. Cutchey; Stephen Malcolm
Robust assessments of eutrophication are necessary to meet the requirements of a range of international (OSPAR) and EU legislative drivers. To meet these needs EU states have developed marine monitoring programmes designed to allow the application of specified assessment procedures. The UK has reviewed its approach to monitoring eutrophication and has identified a range of future requirements to ensure the evidence base for assessment is robust and the underpinning science is in place. This paper describes the pilot application of in situ monitoring technology (SmartBuoy). Currently, two buoys are deployed in the southern North Sea and a third in Liverpool Bay (Irish Sea). The network of SmartBuoys returns data on physical, chemical and biological variables in near real-time (www.cefas.co.uk/monitoring). The rationale for system and network design will be described. Data from the multi-year time series will be presented and their subsequent use in assessments of eutrophication will be described.
Frontiers in Marine Science | 2017
Tim P. Bean; Naomi Greenwood; Rachel E. Beckett; Lauren Biermann; John P. Bignell; Jan Brant; Gordon H. Copp; Michelle Devlin; Stephen Dye; Stephen W. Feist; Liam Fernand; Dean Foden; Kieran Hyder; Chris Jenkins; Jeroen van der Kooij; Silke Kröger; Sven Kupschus; Clare Leech; Kinson S. Leonard; Christopher P. Lynam; Brett P. Lyons; Thomas Maes; E.E. Manuel Nicolaus; Stephen Malcolm; Paul McIlwaine; Nathan D. Merchant; Lucille Paltriguera; David J. Pearce; Sophie G. Pitois; Paul Stebbing
Marine environmental monitoring is undertaken to provide evidence that environmental management targets are being met. Moreover, monitoring also provides context to marine science and over the last century has allowed development of a critical scientific understanding of the marine environment and the impacts that humans are having on it. The seas around the UK are currently monitored by targeted, impact-driven, programmes (e.g. fishery or pollution based monitoring) often using traditional techniques, many of which have not changed significantly since the early 1900s. The advent of a new wave of automated technology, in combination with changing political and economic circumstances, means that there is currently a strong drive to move towards a more refined, efficient, and effective way of monitoring. We describe the policy and scientific rationale for monitoring our seas, alongside a comprehensive description of the types of equipment and methodology currently used and the technologies that are likely to be used in the future. We contextualise the way new technologies and methodologies may impact monitoring and discuss how whole ecosystems models can give an integrated, comprehensive approach to impact assessment. Furthermore, we discuss how an understanding of the value of each data point is crucial to assess the true costs and benefits to society of a marine monitoring programme.
Archive | 2015
Tiziana Luisetti; Rk Turner; Timothy D. Jickells; Je Andrews; Michael Elliott; Marije Schaafsma; Nicola Beaumont; Stephen Malcolm; Daryl Burdon; Christopher Adams; William Watts
This chapter provides a study of two managed realignment cases in comparable estuarine systems located on the English North Sea coast: the Blackwater estuary and the Humber estuary. Two scenarios of salt marsh expansion and reduction in these estuaries are used to analyse the multiple research challenges that arise, including value transfer and stock and flow issues. The coastal ecosystems are complex and require a thorough natural science understanding of conflicting ecosystem services changes. Moreover, net economic benefits of managed realignment can be demonstrated, but they are context and scale dependent and valuation practices and results should reflect this. The chapter offers some solutions and suggestions for further research on these generic research challenges for coastal ecosystem management.
Archive | 2011
Ronald R. Watson; Steve D. Albon; R. Aspinall; Melanie C. Austen; B. Bardgett; Ian J. Bateman; Pam Berry; W. Bird; Richard S. Bradbury; Claire Brown; J Bulloch; J. Burgess; A. Church; C Christie; Ian Crute; Linda Davies; Gareth Edwards-Jones; B. Emmett; L. G. Firbank; A. H. Fitter; A. Gibson; R. Hails; Roy Haines-Young; A. L. Heathwaite; J. Hopkins; M. Jenkins; Laurence Jones; Georgina M. Mace; Stephen Malcolm; Edward Maltby
Marine Pollution Bulletin | 2007
Suzanne J. Painting; Michelle Devlin; Stephen Malcolm; E.R. Parker; David K. Mills; C. Mills; Paul Tett; A. Wither; J. Burt; R. Jones; K. Winpenny
Marine Ecology Progress Series | 2013
Paul Tett; Richard J. Gowen; Suzanne J. Painting; Michael Elliott; Rodney M. Forster; David K. Mills; Eileen Bresnan; Elisa Capuzzo; Teresa F. Fernandes; Jo Foden; Richard J. Geider; Linda Gilpin; Mark Huxham; Abigail McQuatters-Gollop; Stephen Malcolm; S. Saux-Picart; Trevor Platt; Marie-Fanny Racault; Shubha Sathyendranath; J. van der Molen; M. Wilkinson
Marine Ecology Progress Series | 2000
David B. Nedwell; D. B. Sivyer; Stephen Malcolm