Professor of Biogeochemistry
Biogeochemistry, Anammox, Methane cycling, Nitrogen cycling, Microbial ecology, Climate warming
Publications of specific relevance to the Centre for Biodiversity and Sustainability
Nitrous oxide sources, mechanisms and mitigationProglacial methane emissions driven by meltwater and groundwater flushing in a high-Arctic glacial catchmentWarming reduces trophic diversity in high‐latitude food websNitrogen and phosphorus interactions at a 21 nitrogen:1 phosphorus Redfield‐like ratio impact growth and seed yield in wheat (Triticum aestivum L.)Suspended particles are hotspots of microbial remineralization in the ocean's twilight zoneDirect biological fixation provides a freshwater sink for N2OGroundwater springs formed during glacial retreat are a large source of methane in the high ArcticGlacial retreat driving enhanced methane emissions in the high ArcticA rationale for higher ratios of CH4 to CO2 production in warmer anoxic freshwater sediments and soilsSeparating natural from human enhanced methane emissions in headwater streamsHydrological properties predict the composition of microbial communities cycling methane and nitrogen in riversContrasting biophysical controls on carbon dioxide and methane outgassing from streamsDiversity of dimethylsulfide‐degrading methanogens and sulfate‐reducing bacteria in anoxic sediments along the Medway Estuary, UKSpatial and temporal dynamics of nitrogen exchange in an upwelling reach of a groundwater‐fed river and potential response to perturbations changing rainfall patterns under UK climate change scenariosWarming impairs trophic transfer efficiency in a long-term field experimentCoupled nitrification and N2 gas production as a cryptic process in oxic riverbedsDisproportionate increase in freshwater methane emissions induced by experimental warmingMineralization and nitrification: Archaea dominate ammonia-oxidising communities in grassland soilsInteractions between plant genome size, nutrients and herbivory by rabbits, molluscs and insects on a temperate grasslandSpatial separation of anaerobic ammonium oxidation and nitrite‐dependent anaerobic methane oxidation in permeable riverbedsGeographically widespread 13C‐depletion of grazing caddis larvae: A third way of fuelling stream food webs?Drought intensification alters the composition, body size, and trophic structure of invertebrate assemblages in a stream mesocosm experimentExtreme drought pushes stream invertebrate communities over functional thresholdsActive pathways of anaerobic methane oxidation across contrasting riverbedsHeadwater gas exchange quantified from O2 mass balances at the reach scaleAlternative Particle Formation Pathways in the Eastern Tropical North Pacific's Biological Carbon PumpEnhanced hyporheic exchange flow around woody debris does not increase nitrate reduction in a sandy streambedThe Temperature Dependence of Phytoplankton Stoichiometry: Investigating the Roles of Species Sorting and Local AdaptationHydrological controls on DOC : nitrate resource stoichiometry in a lowland, agricultural catchment, southern UKImpacts of Nitrogen and Phosphorus: From Genomes to Natural Ecosystems and AgricultureReach‐scale river metabolism across contrasting sub‐catchment geologies: Effect of light and hydrologyBringing methanotrophy in rivers out of the shadowsErratum: Riverbed methanotrophy sustained by high carbon conversion efficiencyRemineralization of particulate organic carbon in an ocean oxygen minimum zoneAdaptation of phytoplankton to a decade of experimental warming linked to increased photosynthesisOrigin and fate of methane in the Eastern Tropical North Pacific oxygen minimum zoneLong-term warming amplifies shifts in the carbon cycle of experimental pondsNitrous oxide as a function of oxygen and archaeal gene abundance in the North PacificControls over Ocean Mesopelagic Interior Carbon Storage (COMICS): Fieldwork, Synthesis, and Modeling EffortsDeforestation for oil palm alters the fundamental balance of the soil N cycleImportance and controls of anaerobic ammonium oxidation influenced by riverbed geologyModelling flow and inorganic nitrogen dynamics on the Hampshire Avon: Linking upstream processes to downstream water quality.Genome size and ploidy influence angiosperm species' biomass under nitrogen and phosphorus limitationINSTREAM WOOD AS A DRIVER OF NUTRIENT ATTENUATION IN A LOWLAND SANDY STREAMFive Years of Experimental Warming Increases the Biodiversity and Productivity of PhytoplanktonGene‐to‐ecosystem impacts of a catastrophic pesticide spill: testing a multilevel bioassessment approach in a river ecosystemRiverbed methanotrophy sustained by high carbon conversion efficiencyThe interplay between transport and reaction rates as controls on nitrate attenuation in permeable, streambed sedimentsTemperature and the biogeography of algal stoichiometryDiffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large-scale nitrate transformation in a groundwater-fed riverTemperature and the biogeography of algal stoichiometryHigher biodiversity is required to sustain multiple ecosystem processes across temperature regimes.Microbial methane cycling in the bed of a chalk river: Oxidation has the potential to match methanogenesis enhanced by warmingMicrobial methane cycling in the bed of a chalk river: oxidation has the potential to match methanogenesis enhanced by warmingControl of river stage on the reactive chemistry of the hyporheic zoneDiffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large‐scale nitrate transformation in a groundwater‐fed riverImpact of genomic diversity in river ecosystems.Widespread methanotrophic primary production in lowland chalk rivers.Fine-scale in situ measurement of riverbed nitrate production and consumption in an armored permeable riverbed.The potential of large woody debris to alter biogeochemical processes and ecosystem services in lowland riversInfluence of emergent vegetation on nitrate cycling in sediments of a groundwater-fed riverInterpreting spatial patterns in redox and coupled water-nitrogen fluxes in the streambed of a gaining river reachStark contrast in denitrification and anammox across the deep Norwegian trench in the Skagerrak.Biogeochemical Nitrogen Cycling in Wetland Ecosystems: Nitrogen‐15 Isotope TechniquesThe potential effect of sustained hypoxia on nitrogen cycling in sediment from the southern North Sea: a mesocosm experimentRevealing the spatial variability of water fluxes at the groundwater-surface water interfaceMesocosm Experiments as a Tool for Ecological Climate-Change ResearchControl of river stage on the reactive chemistry of the hyporheic zonePASSIVE PORE WATER SAMPLING PROVIDES EVIDENCE OF SUPPRESSION OF HYPORHEIC EXCHANGE AND NITRATE TRANSFORMATION IN A GROUNDWATER-FED RIVERChapter Two Mesocosm Experiments as a Tool for Ecological Climate-Change ResearchRiver bed carbon and nitrogen cycling: state of play and some new directions.River bed carbon and nitrogen cycling: State of play and some new directionsEvidence for the direct oxidation of organic nitrogen to N2 gas in the Arabian Sea.Warming alters community size structure and ecosystem functioning.Reconciling the temperature dependence of respiration across timescales and ecosystem types.Reconciling the temperature dependence of respiration across timescales and ecosystem typesThe depth-specific significance and relative abundance of anaerobic ammonium-oxidizing bacteria in estuarine sediments (Medway Estuary, UK).Consistent temperature dependence of respiration across ecosystems contrasting in thermal historyConsistent temperature dependence of respiration across ecosystems contrasting in thermal historyCharacterization of the key pathways of dissimilatory nitrate reduction and their response to complex organic substrates in hyporheic sedimentsIn situ measurement of redox sensitive solutes at high spatial resolution in a riverbed using Diffusive Equilibrium in Thin Films (DET)Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) in a temperate re-connected floodplain.Distribution, Activity, and Ecology of Anammox Bacteria in Aquatic EnvironmentsWarming alters the size spectrum and shifts the distribution of biomass in freshwater ecosystemsShort-term hypoxia alters the balance of the nitrogen cycle in coastal sedimentsWarming increases the proportion of primary production emitted as methane from freshwater mesocosmsBiomonitoring of Human Impacts in Freshwater Ecosystems: The Good, the Bad and the UglyDistribution, activity, and ecology of anammox bacteria in aquatic environmentsSystems biology for ecology. From molecules to ecosystemsWarming alters the metabolic balance of ecosystems.Potential carbon fixation via methane oxidation in well-oxygenated riverbed gravelsSystems Biology for Ecology: From Molecules to EcosystemsThe Temperature Dependence of the Carbon Cycle in Aquatic EcosystemsChapter 3 Systems Biology for Ecology From Molecules to EcosystemsEvidence for the role of methane-derived carbon in a free-flowing, lowland river food webModelling the distribution and growth of 'problem' green seaweed in the Medway estuary, UKCarbon and nitrogen cycling in a vegetated lowland chalk river impacted by sedimentComparison of ladderane phospholipid and core lipids as indicators for anaerobic ammonium oxidation (anammox) in marine sedimentsProduction of nitrogen gas via anammox and denitrification in intact sediment cores along a continental shelf to slope transect in the North AtlanticCarbon and nitrogen cycling in a vegetated lowland chalk river impacted by sedimentWidespread occurrence of the anammox reaction in estuarine sedimentsA single channel for nitrate uptake, nitrite export and nitrite uptake by Escherichia coli NarU and a role for NirC in nitrite export and uptake.Modelling the distribution and growth of ‘problem’ green seaweed in the Medway estuary, UKSedimentary and water column processes in the Oyster Grounds: A potentially hypoxic region of the North SeaEmission of methane from chalk streams has potential implications for agricultural practicesHigh-resolution profiles and nitrogen isotope tracing reveal a dominant source of nitrous oxide and multiple pathways of nitrogen gas formation in the central Arabian SeaNutrient dynamics in relation to surface-subsurface hydrological exchange in a groundwater fed chalk streamMacrophytes and suspension-feeding invertebrates modify flows and fine sediments in the Frome and Piddle catchments, Dorset (UK)In situ application of the (NO3-)-N-15 isotope pairing technique to measure denitrification in sediments at the surface water-groundwater interfaceDirect measurement of anaerobic ammonium oxidation (anammox) and denitrification in intact sediment coresBiphasic behavior of anammox regulated by nitrite and nitrate in an estuarine sediment.Impact of long-term benthic trawl disturbance on sediment sorting and biogeochemistry in the southern North SeaAnaerobic ammonium oxidation measured in sediments along the Thames estuary, United Kingdom.Changes in sediment processes across the western Irish Sea FrontInvestigation of factors controlling the presence of macroalgae in some estuaries of the Southern Water Region.Preliminary report on the effect of disturbance on sediment biogeochemistry.Nutrient Conditions for Different Levels of Ecological Status and Biological Quality in Surface Waters (Phase I).A diagenetic model discriminating denitrification and dissimilatory nitrate reduction to ammonium in a temperate estuarine sedimentProduction and its fate in two coastal regions of the Irish Sea: the influence of anthropogenic nutrientsProcess measurement and phylogenetic analysis of the sulfate reducing bacterial communities of two contrasting benthic sites in the upper estuary of the Great Ouse, Norfolk, UKNitrate availability modulates the temperature effect on N2O and N2 production from denitrificationNitrate availability modulates the temperature sensitivity of N₂O and N₂ production from denitrificationHydrological controls on DOC : nitrate resource stoichiometry in a lowland, agricultural catchment, southern UKProglacial methane emissions driven by meltwater and groundwater flushing in a high Arctic glacial catchmentGrants of specific relevance to the Centre for Biodiversity and SustainabilityMicrobial link from organosulfur compounds to methane in anoxic sedimentsProbing the cryptic nitrogen cycleFlocculation in cyanobacteria: from mechanism to ecologyTemperature and nitrogen modulated nitrous oxide fixationPhosphorus in Riverbed Nitrogen CyclingIn this year's university-wide climate action week, the Centre for Biodiversity and Sustainability (CBS) represented the Faculty of Science and Engineering through the exhibition From London to the White Continent: Cooperation, Science and Climate Action in the Graduate Centre Foyer. The exhibition featured posters of CBS science highlights, various items ... [more]
