Background

Introduction

 I have over 25 years research experience in experimental approaches and techniques which explicitly link microbial biodiversity’s structure to function and geochemical conditions. These approaches and techniques have been applied widely to determine changes in community structure, relative abundance and activities of micro-organisms in response to natural and artificial environmental perturbations. I have applied these techniques to study varied geochemical processes (sulfur cycling, nitrogen cycling, methanogenesis, methane oxidation) in a number of different geochemical environments (soils, freshwater and marine sediments) with the overall objective of understanding how microorganisms influence the geosphere and visa versa.

Background

As a Geomicrobiologist I am fascinated by the interaction of microbes with their geochemical environments. It is clear to me that these interactions have far reaching effects on ecosystems, global processes and human societies. I am often struck by the relevance of microbial communities and their activities (which occur at relatively such small scales) to the larger scale environmental issues e.g. ecosystem damage and regeneration, climate change and its mitigation, soil productivity and health, water quality). This is of course because of the shear diversity and distribution of microbial processes. Compared to plants and animals microbes use a staggering range of metabolic paths to consume inorganic and organic substrates. New metabolisms are still being discovered and it is this richness which allows microbes to directly influence environments stretching from the deep biosphere to the upper atmosphere.

Area of Expertise

Geomicrobiology and biogeochemistry

Qualifications

PhD Chemistry (Cardiff University, 1994)

BSc (hons) Chemistry (Cardiff University, 1989)

Roles and responsibilities

Geoscience PG degree programme director   

Module Leader for CEG8601 Research Methods

Lecturer Introduction to Microbiology CEG8604

Lecturer  Solid Waste Management CEG8105

Lecturer Engineering Biology through Molecular Microbial Ecology CEG8109

CEGs Radiation Protection Supervisor   

Member of the University Radiation committee

Member of CEGs safety committee

Memberships

Member of the Society for General Microbiology

Google Scholar

Research

Research Interests

Microbial diversity and its link to function;
Ecological mechanisms which control microbial diversity and distribution;
The freshwater sedimentary sulfur cycle;
The geomicrobilogy of constructed wetlands;
The effect of soil improvement treatments on microbially mediated geochemical processes (nitrification, denitrification, methanogenesis and methane oxidation;
The use of stable isotopes to determine pathways of carbon mineralization in freshwater, estuarine, and marine environments;
Petroleum degradation in aerobic soils and sediments and in anaerobic near and deep sub-surface environments

Postgraduate Supervision

Current students

Katie Gilmour

Sola Olawuyi

Salisa Suchitwarsan: Potential for growth enhancement by arbuscular mycorrhizal fungi in potato: Dr Julia Cooper, Dr Neil Gray, Dr Ankush Prashar 

Burhan Shamurad: Integrating waste resources for improved production of renewable energy and utilisable digestate: Dr Paul Sallis, Dr Neil Gray 

Alex Mutshow: Effect of Weathering and Biodegradation on Makers used in Oil Fingerprinting: Dr Martin Jones, Dr Neil Gray

Past students

Dr. Pete Leary: Microbial diversity and function in radionuclide impacted soils and sediments: Supervisors Dr Neil Gray, Dr Clare McCann 

Dr. Priscilla Carrillo-Barragan: Development of a microbial consortium for bioprocessing of municipal solid waste for ethanol production: Supervisors: Dr Neil Gray, Jan Dolfing, Dr Paul Sallis

Dr. Tetyana Olegivna Korin: Biogeochemistry and Microbial Ecology of Petroleum Systems: Supervisors: Prof. Ian Head, Dr Casey Hubert, Dr Neil Gray

Dr. Graham Purvis: The characterisation of organic material in geological samples as analogue for life detection on Mars and other bodies in the solar system Supervisors: Dr Neil Gray, Dr Geoff Abbot

Dr Isabel Sierra Garcia (Occasional student): Investigation of crude oil anaerobic biodegradation in microcosms by microbiota from Brazilian oil reservoir samples: Supervisors: Dr Neil Gray, Prof. Ian Head

Dr Emma Bell: Microbial Biogeography and the Deep Biosphere. Supervisors: Dr Casey Hubert, Prof. Ian Head, Dr Neil Gray

Dr Sani Makarfi: The variability, stability and impacts of biochars in soil environments Supervisors: Dr Neil Gray, Prof. David Manning

Dr Obioma Mejeha: A study on the microbial uptake of heavy metals associated with crude oil using hydrocarbon degrading microorganisms: Supervisors: Dr Neil Gray, Prof. Ian Head, Dr Martin Jones

Dr Safiya Mohammed Othoman: A Novel Source of Potassium in Southern Libyan soils Supervisors: Dr Kirsten Brandt, Dr Neil Gray, Prof. David Manning

Dr Kate Osborne Title: Investigating the environmental controls of hopanoid biosynthesis via functional gene analysis Supervisors: Dr Helen Talbot, Angela Sherry, Dr Neil Gray

Dr Lynsay Blake: Methanogenic and methanotrophic processes in temperate and high latitude environments: Supervisors: Dr Neil Gray, Prof. Ian Head

Dr Clare McCann: Mn oxide as a contaminated-land remediation product: Supervisors: Dr Neil Gray, Dr Russell Davenport

Past and Present Funding

Co-Investigator (Newcastle)- NERC Consortium grant NE/P00637X- The Changing Arctic Ocean Seafloor (ChAOS) £402,643 (2017-2020) 

Principle Investigator (Newcastle)- NERC Consortium grant NE/L000326 Long-lived Radionuclides in the Surface Environment (LO-RISE)- Mechanistic Studies of Speciation, Environmental Transport and Transfer £429,767 (2013-2018)

Co-investigator Coal Authority project -Monitoring and optimisation of the Force Crag metal mine water treatment system £301,777 (2015-2018)

Co-investigator EU Knowledge Based Bio Economy Grant. KILL*SPILL Integrated Biotechnological Solutions for Combating Marine Oil Spills £363,436 (2013-2017)

Co-investigator on NERC Small Grant NE/J01446X/1. Impact of methanotrophs, methanogens and geochemical conditions on net methane flux to the atmosphere from Arctic soils. £64,627 (2013)

Co-investigator on NERC Standard Grant NE/J024325/1. OILSPORE Spore-forming hydrocarbon degraders and thermophiles, dispersal from petroleum reservoirs, and a test of the palaeopasteurization hypothesis £445,372 (2012-2015)

Principle scientist - Knowledge Transfer Partnership (KTP) programme No. 7181-Graphite resources Ltd and Newcastle University Development of anaerobic digestion biotechnology to convert autoclaved MSW into biogas (methane). Technology Stragey Board, £202,000 . 2008-2012

Mitigation of pollution from abandoned metal mines Phase II, £101,000, Environment Agency, 2011-2012

Mitigation of pollution from abandoned metal mines Phase I, £166,000, Environment Agency, 2009-2011 

The effect of copper geochemistry on the abundance and activity of methane oxidizing bacteria in the Arctic’ (NERC small grant, 2009-2010)

Role of methanobactin in methane oxidation rates in the presence of mineral copper: Natural Environment Research Council (NERC): £581,763 from Mar 2008 to Feb 2011 

Crude oil oxidation without an electron acceptor; syntrophic hydrocarbon degrading microbes work together to "crack" a tough problem
Prof Ian Head, Dr Neil Gray, Dr Martin Jones
NERC, 2007-2010, £420,379

The use of waste Mn oxides as contaminated land remediation products
The project represents a close collaboration between the University of Durham (Dr Karen Johnson and Dr Fred Worrell) and Newcastle University (Dr Neil Gray and Russell Davenport).
EPSRC 2007-2010

Biological recovery of energy assets (Brea/Methmax)
Prof Steve Larter, Prof Ian Head, Dr Neil Gray
Industrial sponsors Norsk Hydro, 2005-2007, £337,352

NERC consortium Grant (Universities of Southampton, Bristol, British Antarctic Survey and Newcastle. (2008-11) Chemosynthetically-driven Ecosystems in the Southern Ocean (CHESO). Newcastle component (£346,340) co-author with Nicholas Polunnin (MAST) and Helen Talbot.

Academic fellowships (3 x £125K) 2006-211in Earth Systems Science Engineering and Management obtained under the 2006 RCUK fellowships scheme. Co-authorship with Russell Davenport and Matt King

Leverhulme Trust (Grants to Institutions) Competition, niche adaptation and biogeography in uncultured sulfur bacteria. (£118,559) 20003. Co-authorship with Ian Head.

Esteem Indicators

Invited author Chapter 406: Family Achromatiaceae. In: Rosenberg, E; DeLong, EF; Lory, S; Stackebrandt, E; Thompson, F, eds. The Prokaryotes (4^th Edition), Springer.

Member of the Natural Environment Research Council, Peer Review College (2006-2009)

Member of the editorial board of the Journal of Microbiological Methods

Regular reviewer for ISME journal, Journal of Microbiological Methods, FEMS Microbial Ecology, Microbial Ecology, Organic Geochemistry amongst others

Invited article for the Encyclopedia of Ecology to be published by Elsevier in 2008 (written in collaboration with Ian Head)

Paper (Gray et al. ISME J 2007 Nov 1(7):596-605) selected for the Faculty of 1000 Biology www.f1000biology.com/article/id/1103375. Faculty of 1000 Biology is an online service that highlights and evaluates the most interesting papers published in the biological sciences, based on the recommendations of over 2000 of the world's top researchers.

Co-convener of the 12th Molecular Microbial Ecology Group meeting (MMEG12) held at Newcastle 24th-25th July 2006. MMEG is an annual gathering of UK molecular microbial ecologists held on a rotational basis at different institutions throughout the UK.

Invited author for a new book series entitled Microbiology Monographs, The unique role of intracellular calcification in the genus Achromatium. Microbiology Monographs. Vol. 1 Inclusions in Prokaryotes, edited by Jessup Shively, Springer-Verlag, Berlin, 299-309

Invited paper and presentation (Minerals, mats, pearls and veils: themes and variations in giant sulfur bacteria) for the Society for General Microbiology's symposium on Microorganisms and Earth Systems: Advances in Geomicrobiology, Keele University, UK. 12-15 September 2005

Research on niche differentiation in Bacteria from the genus Achromatium highlighted in an article entitled-Living together, Nature-microbiology reviews, July 2004

Invited author of a mini-review for the Journal Environmental Microbiology: Linking genetic identity and function in uncultured bacteria (2001. See publications.

Invited author for a special issue of the Journal Hydrobiologia: Molecular Ecology of Aquatic Communities.
(eds), J.P. Zehr & M.A. Voytek (1999). See publications.

Teaching

Undergraduate teaching 

Module Leader for Research Methods in Environmental pollution CEG2609

Postgraduate Teaching

Degree programme director (DPD) for Environmental Consultancy and Environmental and Petroleum Geochemistry MSc courses 

Module Leader for Research Methods CEG8601

Module Leader for Aqueous Geochemistry CEG8605

Module leader for Energy from the Earth SPG8025

Lecturer Groundwater assessment  CEG8511

Lecturer Professional Development in Environmental Engineering CEG8110 

Lecturer Sources, Fates and Control of pollutants CEG8606

Lecturer Engineering Biology through Molecular Microbial Ecology CEG8109

Lecturer Petroleum in the Environment CEG8626

Lecturer (occasional) Introduction to Microbiology CEG8604

Publications

• Articles

  • Gandy CJ, Gray ND, Mejeha OK, Sherry A, Jarvis AP. Use of propionic acid additions to enhance zinc removal from mine drainage in short residence time, flow-through sulfate-reducing bioreactors. Journal of Environmental Management 2023, 327, 116862.
  • Gilmour KA, Davie CT, Gray N. Survival and activity of an indigenous iron-reducing microbial community from MX80 bentonite in high temperature / low water environments with relevance to a proposed method of nuclear waste disposal. Science of the Total Environment 2022, 814, 152660.
  • Gilmour K, Davie C, Gray N. Microbial community of MX80 bentonite and their interaction with iron. Access Microbiology 2022, 4(5).
  • Wang S, Sun P, Zhang G, Gray N, Dolfing J, Esquivel-Elizondo S, Peñuelas J, Wu Y. Contribution of periphytic biofilm of paddy soils to carbon dioxide fixation and methane emissions. The Innovation 2022, 3(1), 100192.
  • Marz C, Freitas F, Faust J, Godbold J, Henley S, Tessin A, Abbott GD, Arndt S, Barnes D, Grange L, Gray N, Head I, Hendry K, Hilton R, Reed A, Rhul S, Souster T, Solan M, Stevenson M, Tait K, Widdicombe S. Biogeochemical consequences of a changing Arctic shelf seafloor ecosystem. Ambio 2022, 51, 370-382.
  • Baptista JdeC, Gray ND, Tarumoto MB, Singleton I, McCann CM, Manning DAC. Bacterial communities in soils as indicators of the potential of syenite as an agromineral. Pesquisa Agropecuária Brasileira (Brazilian Journal of Agricultural Research) 2022, 57, e01414.
  • Johnson KL, Gray ND, Stone W, Kelly BFJ, Fitzimons M, Clarke C, Blake L, Chivasa S, Mtambanengwe F, Mapfumo P, Baker A, Beckmann S, Dominelli L, Neal AL, Gwandu T. A nation that rebuilds its soils rebuild itself- an engineer’s perspective. Soil Security 2022, 7, 100060.
  • Carrillo-Barragan P, Dolfing J, Sallis P, Gray N. The stability of ethanol production from organic waste by a mixed culture depends on inoculum transfer time. Biochemical Engineering Journal 2021, 166, 107875.
  • Gilmour KA, Davie CT, Gray N. An indigenous iron-reducing microbial community from MX80 bentonite - A study in the framework of nuclear waste disposal. Applied Clay Science 2021, 205, 106039.
  • Purvis G, Sano N, van der Land C, Barlow A, Cumpson P, Gray N, Lopez-Capel E. A comparison of the molecular composition of plant and fungal structuralbiopolymer standards with the organic material in early cretaceous OntongJava Plateau Tuff. Chemical Geology 2021, 565, 120078.
  • Stevenson MA, Faust JC, Andrade LL, Freitas FS, Gray ND, Tait K, Hendry KR, Hilton RG, Henley SF, Tessin A, Leary P, Papadaki S, Ford A, März C, Abbott GD. Transformation of organic matter in a Barents Sea sediment profile: coupled geochemical and microbiological processes. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 2020, 378(2181), 20200223.
  • Shamurad B, Sallis P, Petropoulos E, Tabraiz S, Ospina C, Leary P, Dolfing J, Gray N. Stable biogas production from single-stage anaerobic digestion of food waste. Applied Energy 2020, 263, 114609.
  • Shamurad B, Gray N, Petropoulos E, Tabraiz S, Membere E, Sallis P. Predicting the effects of integrating mineral wastes in anaerobic digestion of OFMSW using first-order and Gompertz models from biomethane potential assays. Renewable Energy 2020, 152, 308-319.
  • Fuller AJ, Leary P, Gray ND, Davies HS, Mosselmans JFW, Cox F, Robinson CH, Pittman JK, McCann CM, Muir M, Graham MC, Utsunomiya S, Bower WR, Morris K, Shaw S, Bots P, Livens FR, Law GTW. Organic complexation of U(VI) in reducing soils at a natural analogue site: Implications for uranium transport. Chemosphere 2020, 254, 126859.
  • Sherry S, Grant RJ, Aitken CM, Jones M, Bowler BFJ, Larter SR, Head IM, Gray ND. Methanogenic crude oil-degrading microbial consortia are not universally abundant in anoxic environments. International Biodeterioration & Biodegradation 2020, 155, 105085.
  • Shamurad B, Gray N, Petropoulos E, Dolfing J, Quintela-Baluja M, Bashiri R, Tabraiz S, Sallis P. Low Temperature Pre-treatment of Organic Feedstocks with Selected Mineral Wastes Sustains Anaerobic Digestion Stability through Trace Metal Release. Environmental Science and Technology 2020, 54(14), 9095-9105.
  • Sierra-Garcia IN, Belgini DRB, Torres-Ballesteros A, Paez-Espino D, Capilla R, Santos Neto EV, Gray N, de Oliveira VM. In depth metagenomic analysis in contrasting oil wells reveals syntrophic bacterial and archaeal associations for oil biodegradation in petroleum reservoirs. Science of The Total Environment 2020, 715, 136646.
  • Shamurad B, Gray N, Petropoulos E, Tabraiz S, Sallis P. Improving the methane productivity of anaerobic digestion using aqueous extracts from municipal solid waste incinerator ash. Journal of Environmental Management 2020, 260, 110160.
  • Ray D, Leary P, Livens F, Gray N, Morris K, Law KA, Fuller AJ, Abrahamsen-Mills L, Howe J, Tierney K, Muir G, Law GTW. Controls on anthropogenic radionuclide distribution in the Sellafield-impacted Eastern Irish Sea. Science of The Total Environment 2020, 743, 140765.
  • Blake LI, Sherry A, Mejeha OK, Leary P, Coombs H, Stone W, Head IM, Gray ND. An Unexpectedly Broad Thermal and Salinity-Tolerant Estuarine Methanogen Community. Microorganisms 2020, 8(10), 1467.
  • McCann CM, Christgen B, Roberts JA, Su J, Arnold KE, Gray ND, Zhu Y, Graham DW. Understanding drivers of antibiotic resistance genes in High Arctic soil ecosystems. Environment International 2019, 125, 497-504.
  • Purvis G, van der Land C, Sano N, Cockell C, Barlow A, Cumpson P, Lopez-Capel E, Gray N. The organic stratigraphy of Ontong Java Plateau Tuff correlated with the depth‐related presence and absence of putative microbial alteration structures. Geobiology 2019, 17(3), 281-293.
  • Carrillo-Barragan P, Bowler B, Dolfing J, Sallis P, Gray ND. Enrichment and characterisation of a mixed-source ethanologenic community degrading the organic fraction of municipal solid waste under minimal environmental control. Frontiers in Microbiology 2019, 10, 722.
  • Shamurad B, Gray N, Petropoulos E, Tabraiz S, Acharya K, Quintela-Baluja M, Sallis P. Data of metal and microbial analyses from anaerobic co-digestion of organic and mineral wastes. Data in Brief 2019, 24, 103934.
  • Purvis G, Sano N, van der Land C, Barlow A, Lopez-Capel E, Cumpson P, Hood J, Sheriff J, Gray N. Combining thermal hydrolysis and methylation-gas chromatography/mass spectrometry with X-ray photoelectron spectroscopy to characterise complex organic assemblages in geological material. MethodsX 2019, 6, 2646-2655.
  • Shamurad B, Gray N, Petropoulos E, Tabraiz S, Acharya K, Quintela-Baluja M, Sallis P. Co-digestion of organic and mineral wastes for enhanced biogas production: Reactor performance and evolution of microbial community and function. Waste Management 2019, 87, 313-325.
  • Mejeha OK, Head IM, Sherry A, McCann CM, Leary P, Jones DM, Gray ND. Beyond N and P: The impact of Ni on crude oil biodegradation. Chemosphere 2019, 237, 124545.
  • McCann CM, Peacock CL, Hudson-Edwards KA, Shrimpton T, Gray ND, Johnson KL. In situ arsenic oxidation and sorption by a Fe-Mn binary oxide waste in soil. Journal of Hazardous Materials 2018, 342, 724-731.
  • Statham JME, Blake L, Gray N, Dix JCH. Technical feasibility and experimental development of sand recycling options for dairy cattle bedding. Cattle Practice 2017, 25, 303.
  • Sierra-Garcia IN, Dellagnezze BM, Santos VP, De-Barros-Chaves MR, Capilla R, Santos-Neto EV, Gray N, Oliveira VM. Microbial diversity in degraded and non degraded petroleum samples and comparison across oil reservoirs at local and global scales. Extremophiles 2017, 21(1), 211-229.
  • Osborne KA, Gray ND, Sherry A, Leary P, Mejeha O, Bischoff J, Rush D, Sidgwick FR, Birgel D, Kalyuzhnaya MG, Talbot HM. Methanotroph-derived bacteriohopanepolyol (BHP) signatures as a function of temperature related growth, survival, cell death and preservation in the geological record. Environmental Microbiology Reports 2017, 9(5), 492–500.
  • Blake LI, Halim FA, Gray C, Mair R, Manning DA, Sallis P, Hutchinson H, Gray ND. Evaluating an anaerobic digestion (AD) feedstock derived from a novel non-source segregated municipal solid waste (MSW) product. Waste Management 2017, 59, 149-159.
  • Purvis G, Gray N, Sano N, Barlow A, Cockell C, Abbott GD, van der Land C, Cumpson P. Decontamination of geological samples by gas cluster ion beam etching or ultra violet/ozone. Chemical Geology 2017, 466, 256-262.
  • McCann CM, Wade MJ, Gray ND, Roberts JA, Hubert CRJ, Graham DW. Microbial Communities in a High Arctic polar desert landscape. Frontiers in Microbiology 2016, 7, 419.
  • Head IM, Gray ND. Microbial Biotechnology 2020; microbiology of fossil fuel resources. Microbial Biotechnology 2016, 9(5), 626-634.
  • Sano N, Purvis GWH, Barlow AJ, Abbott GD, Gray NND, Cumpson PJ. Gas cluster ion beam for the characterization of organic materials in submarine basalts as Mars analogs. Journal of Vacuum Science and Technology 2016, 34(4), 041405.
  • Sherry A, Osborne KA, Sidgwick FR, Gray ND, Talbot HM. A temperate river estuary is a sink for methanotrophs adapted to extremes of pH, temperature and salinity. Environmental Microbiology Reports 2016, 8(1), 122-131.
  • Johnson KL, Purvis G, Lopez-Capel E, Peacock CL, Gray ND, Wagner T, März C, Bowen L, Ojeda J, Finlay NC, Robertson SR, Worrall F, Greenwell C. Towards a mechanistic understanding of carbon stabilization in manganese oxides. Nature Communications 2015, 6, 7628.
  • Blake LI, Tveit A, Øvreås L, Head IM, Gray ND. Response of methanogens in Arctic sediments to temperature and methanogenic substrate availability. PLoS One 2015, 10(6), e0129733.
  • McCann CM, Gray ND, Tourney J, Davenport RJ, Wade MJ, Finlay N, Hudson-Edwards KA, Johnson KL. Remediation of a historically Pb contaminated soil using a model natural Mn oxide waste. Chemosphere 2015, 138, 211-217.
  • Sherry A, Grant RJ, Aitken CM, Jones M, Head IM, Gray ND. Volatile hydrocarbons inhibit methanogenic crude oil degradation. Frontiers in Microbiology 2014, 5, 131.
  • Gray ND, McCann CM, Christgen B, Ahammad SZ, Roberts JA, Graham DW. Soil geochemistry confines microbial abundances across an Arctic landscape; Implications for net carbon exchange with the atmosphere. Biogeochemistry 2014, 120(1-3), 307-317.
  • Jarvis AP, Davis JE, Gray ND, Orme PHA, Gandy CJ. Mitigation of pollution from abandoned metal mines: Investigation of passive compost bioreactor systems for treatment of abandoned metal mine discharges. Environment Agency Science Report SC090024/R3 2014, 1-98.
  • Head IM, Gray ND, Larter SR. Life in the slow lane; biogeochemistry of biodegraded petroleum containing reservoirs and implications for energy recovery and carbon management. Frontiers in Microbiology 2014, 5, 566.
  • Singh AK, Sherry A, Gray ND, Jones DM, Bowler BFJ, Head IM. Kinetic parameters for nutrient enhanced crude oil biodegradation in intertidal marine sediments. Frontiers in Microbiology 2014, 5, 160.
  • Mohammed SMO, Brandt K, Gray ND, White ML, Manning DAC. Comparison of silicate minerals as sources of potassium for plant nutrition in sandy soil. European Journal of Soil Science 2014, 65(5), 653-662.
  • Bennett B, Adams JJ, Gray ND, Sherry A, Oldenburg TBP, Huang H, Larter SR, Head IM. The controls on the composition of biodegraded oils in the deep subsurface - Part 3. The impact of microorganism distribution on petroleum geochemical gradients in biodegraded petroleum reservoirs. Organic Geochemistry 2013, 56, 94-105.
  • Zegeye A, Yahaya S, Fialips CI, White ML, Gray ND, Manning DAC. Refinement of industrial kaolin by microbial removal of iron-bearing impurities. Applied Clay Science 2013, 86, 47-53.
  • Callbeck CM, Sherry A, Hubert CRJ, Gray ND, Voordouw G, Head IM. Improving PCR efficiency for accurate quantification of 16S rRNA genes. Journal of Microbiological Methods 2013, 93(2), 148-152.
  • Aitken CM, Jones DM, Maguire MJ, Gray ND, Sherry A, Bowler BFJ, Ditchfield AK, Larter SR, Head IM. Evidence that crude oil alkane activation proceeds by different mechanisms under sulfate-reducing and methanogenic conditions. Geochimica et Cosmochimica Acta 2013, 109, 162-174.
  • Guermouche MA, Bensalah F, Gray N. Application of molecular methods as a biomarker in bioremediation studies. International Journal of Biotechnology Applications 2013, 5(1), 147-154.
  • Sherry A, Gray ND, Ditchfield AK, Aitken CM, Jones DM, Röling WFM, Hallmann C, Larter SR, Bowler BFJ, Head IM. Anaerobic biodegradation of crude oil under sulphate-reducing conditions leads to only modest enrichment of recognized sulphate-reducing taxa. International Biodeterioration & Biodegradation 2013, 81, 105-113.
  • Hubert CRJ, Oldenburg TBP, Fustic M, Gray ND, Larter SR, Penn K, Rowan AK, Seshadri R, Sherry A, Swainsbury R, Voordouw G, Voordouw JK, Head IM. Massive dominance of Epsilonproteobacteria in formation waters from a Canadian oil sands reservoir containing severely biodegraded oil. Environmental Microbiology 2012, 14(2), 387-404.
  • Gray ND, Sherry A, Grant RJ, Rowan AK, Hubert CRJ, Callbeck CM, Aitken CM, Jones DM, Adams JJ, Larter SR, Head IM. The quantitative significance of Syntrophaceae and syntrophic partnerships in methanogenic degradation of crude oil alkanes. Environmental Microbiology 2011, 13(11), 2957-2975.
  • Westerholm M, Dolfing J, Sherry A, Gray ND, Head IM, Schnürer A. Quantification of syntrophic acetate-oxidizing microbial communities in biogas processes. Environmental Microbiology Reports 2011, 3(4), 500-505.
  • Chi Fru E, Gray ND, McCann C, Baptista JDC, Christgen B, Talbot HM, El Ghazouani A, Dennison C, Graham DW. Effects of copper mineralogy and methanobactin on cell growth and sMMO activity in Methylosinus trichosporium OB3b. Biogeosciences 2011, 8, 2887-2894.
  • Fialips CI, Cooper NGA, Jones DM, White ML, Gray ND. Reductive Degradation of p,p'-DDT by Fe(II) in Nontronite NAu-2. Clays and Clay Minerals 2010, 58(6), 821-836.
  • Gray ND, Sherry A, Hubert C, Dolfing J, Head IM. Methanogenic degradation of petroleum hydrocarbons in subsurface environments: remediation, heavy oil formation, and energy recovery. Advances in Applied Microbiology 2010, 72, 137-161.
  • Dolfing J, Xu A, Gray ND, Larter SR, Head IM. The thermodynamic landscape of methanogenic PAH degradation. Microbial Biotechnology 2009, 2(5), 566-574.
  • Gray ND, Sherry A, Larter SR, Erdmann M, Leyris J, Liengen T, Beeder J, Head IM. Biogenic methane production in formation waters from a large gas field in the North Sea. Extremophiles 2009, 13(3), 511-519.
  • Tourney J, Dowding C, Worrall F, McCann C, Gray N, Davenport R, Johnson K. Mn oxide as a contaminated-land remediation product. Mineralogical Magazine 2008, 72(1), 513-513(1).
  • Jones DM, Head IM, Gray ND, Adams JJ, Rowan AK, Aitken CM, Bennett B, Huang H, Brown A, Bowler BFJ, Oldenburg T, Erdmann M, Larter SR. Crude-oil biodegradation via methanogenesis in subsurface petroleum reservoirs. Nature 2008, 451(7175), 176-180.
  • Gray ND, Brown A, Nelson DR, Pickup RW, Rowan AK, Head IM. The biogeographical distribution of closely related freshwater sediment bacteria is determined by environmental selection. The ISME Journal: multidisciplinary journal of microbial ecology 2007, 1(7), 596–605.
  • Kitidis V, Tizzard L, Uher G, Judd A, Upstill-Goddard RC, Head IM, Gray ND, Taylor G, Duran R, Diez R, Iglesias J, Garcia-Gil S. The biogeochemical cycling of methane in Ria de Vigo, NW Spain: Sediment processing and sea-air exchange. Journal of Marine Systems 2007, 66(1-4), 258-271.
  • Gray ND, Matthews JNS, Head IM. A stable isotope titration method to determine the contribution of acetate disproportionation and carbon dioxide reduction to methanogenesis. Journal of Microbiological Methods 2006, 65(1), 180-186.
  • Sheppard SK, McCarthy AJ, Loughnane JP, Gray ND, Head IM, Lloyd D. The impact of sludge amendment on methanogen community structure in an upland soil. Applied Soil Ecology 2005, 28(2), 147-162.
  • Sheppard SK, Gray N, Head IM, Lloyd D. The impact of sludge amendment on gas dynamics in an upland soil: Monitored by membrane inlet mass spectrometry. Bioresource Technology 2005, 96(10), 1103-1115.
  • Kitidis V, Tizzard LH, Uher G, Judd AG, Upstill-Goddard RC, Head IM, Gray ND, Durán R, Diez R, Iglesias J, Garcia-Gil S. Methane cycling in the Ria de Vigo. SOLAS News 2005, 2, 10-10.
  • Logan BE, Murano C, Scott K, Gray ND, Head IM. Electricity generation from cysteine in a microbial fuel cell. Water Research 2005, 39(5), 942-952.
  • Gray ND, Comaskey D, Miskin IP, Pickup RW, Suzuki K, Head IM. Adaptation of sympatric Achromatium spp. to different redox conditions as a mechanism for coexistence of functionally similar sulphur bacteria. Environmental Microbiology 2004, 6(7), 669-677.
  • Gray ND, Hastings RC, Sheppard SK, Loughnane P, Lloyd D, McCarthy AJ, Head IM. Effects of soil improvement treatments on bacterial community structure and soil processes in an upland grassland soil. FEMS Microbiology Ecology 2003, 46(1), 11-22.
  • Gray ND, Miskin IP, Kornilova O, Curtis TP, Head IM. Occurrence and activity of Archaea in aerated activated sludge wastewater treatment plants. Environmental Microbiology 2002, 4(3), 158-168.
  • Gray ND, Howarth R, Pickup RW, Jones JG, Head IM. Use of combined microautoradiography and fluorescence in situ hybridization to determine carbon metabolism in mixed natural communities of uncultured bacteria from the genus Achromatium. Applied and Environmental Microbiology 2000, 66(10), 4518-4522.
  • Head IM, Gray ND, Babenzien H-D, Oliver Glockner F. Uncultured giant sulfur bacteria of the genus Achromatium. FEMS Microbiology Ecology 2000, 33(3), 171-180.
  • Head IM, Gray ND, Howarth R, Pickup RW, Clarke KJ, Jones JG. Achromatium oxaliferum: Understanding the unmistakable. Advances in Microbial Ecology 2000, 16(1), 1-40.
  • Gray ND, Howarth R, Pickup RW, Jones JG, Head IM. Substrate uptake by uncultured bacteria from the genus Achromatium determined by microautoradiography. Applied and Environmental Microbiology 1999, 65(11), 5100-5106.
  • Gray ND, Head IM. New insights on old bacteria: bacterial diversity and function in aquatic ecosystems. Hydrobiologia 1999, 401, 97-112.
  • Gray ND, Howarth R, Rowan A, Pickup RW, Jones JG, Head IM. Natural communities of Achromatium oxaliferum comprise genetically, morphologically, and ecologically distinct subpopulations. Applied and Environmental Microbiology 1999, 65(11), 5089-5099.
  • Elvy SB, Gray ND, McAndrew J, Williams PA, French DR. Unnamed Palladium Telluride Minerals from Broken Hill, New South Wales. Journal and Proceedings of The Royal Society of New South Wales 1998, 131(3-4), 85-93.
  • Elvy SB, Gray ND, McAndrew J, Williams PA, French DR. Platinum group minerals from the Broken Hill District, New South Wales. Australian Journal of Mineralogy 1998, 4(1), 33-39.
  • Gray ND, Pickup RW, Jones JG, Head IM. Ecophysiological evidence that Achromatium oxaliferum is responsible for the oxidation of reduced sulfur species to sulfate in a freshwater sediment. Applied and Environmental Microbiology 1997, 63(5), 1905-1910.
  • Head IM, Gray ND, Clarke KJ, Pickup RW, Jones JG. The phylogenetic position and ultrastructure of the uncultured bacterium Achromatium oxaliferum. Microbiology 1996, 142(9), 2341-2354.

• Book Chapters

  • Gray ND, Head IM. Family Achromatiaceae. In: Rosenberg, E; DeLong, EF; Lory, S; Stackebrandt, E; Thompson, F, ed. The Prokaryotes: Gammaprotobacteria. New York, USA: Springer, 2014, pp.1-14.
  • Sherry A, Gray ND, Aitken CM, Dolfing J. Microbial oil degradation under methanogenic conditions. In: Timmis, K.N, ed. Handbook of Hydrocarbon and Lipid Microbiology. Heidelberg, Germany: Springer, 2010, pp.3906-3917.
  • Head IM, Larter SR, Gray ND, Sherry A, Adams JJ, Aitken CM, Jones DM, Rowan AK, Huang H, Röling WFM. Hydrocarbon Degradation in Petroleum Reservoirs. In: Timmis, K.N. ed. in chief, McGenity, T., van der Meer, J.R., de Lorenzo, V, ed. Handbook of Hydrocarbon and Lipid Microbiology. Heidelberg, Germany: Springer, 2010, pp.3097-3109 (chapter 54).
  • Singh AK, Sherry A, Gray ND, Jones MD, Roeling WFM, Head IM. How Specific Microbial Communities Benefit the Oil Industry: Dynamics of Alcanivorax spp. in Oil Contaminated Intertidal Beach Sediments Undergoing Bioremediation. In: Whitby, C; Skovhus TL, ed. Applied Microbiology and Molecular Biology in Oilfield Systems: Proceedings from the International Symposium on Applied Microbiology and Molecular Biology in Oil Systems 2009. United Kingdom: Springer, 2009, pp.199-210.
  • Gray ND, Head IM. Microbial Ecology. In: Jorgensen, SE; Fath, B, ed. Encyclopedia of Ecology. London: Elsevier, 2008, pp.3120.
  • Gray ND. The unique role of intracellular calcification in the genus Achromatium. In: Shively JM, ed. Inclusions in Prokaryotes. Berlin: Springer-Verlag, 2006, pp.299-309.
  • McCarthy AJ, Gray ND, Curtis TP, Head IM. Response of the Soil Bacterial Community to Perturbation. In: Bardgett, RD; Usher, MB; Hopkins DW, ed. Biological Diversity and Function in Soils. Cambridge; New York: Cambridge University Press, 2005, pp.273-294.
  • Gray ND, Head IM. Minerals, mats, pearls and veils: themes and variations in giant sulfur bacteria. In: Gadd, GM; Semple, Lappin-Scott, HM, ed. Micro-organisms and Earth Systems: advances in geomicrobiology. Cambridge: Cambridge University Press, 2005, pp.35-70.
  • Head IM, Gray ND, Howarth R, Pickup RW. Achromatium oxaliferum: understanding the unmistakable. In: Schink,Bernhard, ed. Advances in Microbial Ecology. New York: Springer, 2000, pp.1-40.

• Conference Proceedings (inc. Abstracts)

  • Dolfing J, Xu A, Gray ND, Larter SR, Head IM. Thermodynamic constraints on methanogenic PAH degradation. In: 19th Annual V.M. Goldschmidt Conference. 2009, Davos, Switzerland: Geochimica et Cosmochimica Acta: Pergamon.
  • Zegeye A, Fialips CI, White M, Manning DAC, Gray N. Refinement of kaolin and silica sand by microbial removal of iron impurities. In: Geochimica et Cosmochimica Acta: 18th Annual V M Goldschmidt Conference. 2008, Vancouver, Canada: Pergamon.

• Note

  • Gray ND, Head IM. Linking genetic identity and function in communities of uncultured bacteria. Environmental Microbiology 2001, 3(8), 481-492.

• Reports

  • Gray ND, Gandy CJ, Jarvis AP. Mitigation of pollution from abandoned metal mines Part 2: Review of resource recovery options from the passive remediation of metal-rich mine waters. Bristol: Environment Agency, 2012. Environment Agency Science Report SC090024/R2.
  • Jarvis AP, Gandy CJ, Gray ND. Mitigation of pollution from abandoned metal mines Part 1: Review of passive treatment technologies for metal mine drainage remediation. Bristol: Environment Agency, 2012. Environment Agency Science Report SC090024/R1.

• Review

  • Sherry A, Andrade L, Velenturf A, Christgen B, Gray ND, Head IM. How to access and exploit natural resources sustainably: petroleum biotechnology. Microbial Biotechnology 2017, 10(5), 1206–1211.