Dr Simon Ussher

Dr Simon Ussher

Associate Professor of Marine and Analytical Chemistry

School of Geography, Earth and Environmental Sciences (Faculty of Science and Engineering)



Lecturer (Chemistry and Environmental Science)
PhD supervisor


MChem Chemistry (University of Wales, Swansea 1995-1999)
PhD Iron biogeochemistry (University of Plymouth, 2000-2005)

Professional membership

MRSC Royal Society of Chemistry
Challenger Society
American Geophysical Union (AGU)
American Society of Limnology and Oceanography (ASLO)

Roles on external bodies

Adjunct Faculty of the Bermuda Institute of Ocean Sciences
Challenger Society Fellow



Research interests

Trace metal biogeochemistry
Coupling biogeochemical models with physical and ecological models
Shipboard analytical methods and trace metal sample processing

Other research

Participant in the Atlantic Meridional Transect (AMT) time series and IRONAGES EU project

Collaboration with the Bermuda Institute of Ocean Science (BIOS), University of Tasmania (UTAS), Florida State University (FSU), Plymouth Marine Laboratory (PML), National Oceanography Centre (NOC)

Grants & contracts

Grant income and submission record      

Co-investigator and named PDRF on the following proposal submissions unless identified:

1. “Redox and colloidal iron biogeochemistry in surface Atlantic waters” NERC Standard Grant, July 2002. Co-investigator and named PDRF, Awarded £ 205,337

2. “Solubility of Aerosol Iron in Open-ocean Seawater” Marie Curie International Outgoing Fellowships (IOF), August 2008, Awarded 245,000

3."The supply of iron from shelf sediments to the ocean" . NERC grant Shelf Seas Biogeochemistry Programme, Co-I with Maeve Lohan, 2013-2017 Awarded £ 304,000

3. “Determining the Impact of Seawater Chemistry on the Solubility of Atmospheric Trace metals (DISCOSAT)” Marie Curie Career Integration Grant, January 2013 Awarded 100,000



Key publications

Key publications are highlighted

Zhu K, Birchill AJ, Milne A, Ussher S, Humphreys MP, Carr N, Mahaffey C, Lohan MC, Achterberg EP & Gledhill M (2021) 'Equilibrium calculations of iron speciation and apparent iron solubility in the Celtic Sea at ambient seawater pH using the NICA-Donnan model' Marine Chemistry , DOI Open access
White C, Ussher SJ, Fitzsimons MF, Atkinson S, Woodward EMS, Yang M & Bell TG (2021) 'Inorganic nitrogen and phosphorus in Western European aerosol and the significance of dry deposition flux into stratified shelf waters' Atmospheric Environment 261, , DOI Open access
Zhi M, Zhang X, Zhang K, Ussher SJ, Lv W, Li J, Gao J, Luo Y & Meng F (2021) 'The characteristics of atmospheric particles and metal elements during winter in Beijing: Size distribution, source analysis, and environmental risk assessment' Ecotoxicology and Environmental Safety 211, , DOI Open access
Leng G, Jin C-F, Bell TG, Ussher SJ, Worsfold PJ & Li W-Y (2020) 'Automated, high frequency, on-line dimethyl sulfide measurements in natural waters using a novel “microslug” gas-liquid segmented flow method with chemiluminescence detection' Talanta 221, 121595-121595 , DOI Open access
Schmidt K, Birchill AJ, Atkinson A, Brewin RJW, Clark JR, Hickman AE, Johns DG, Lohan MC, Milne A & Pardo S (2020) 'Increasing picocyanobacteria success in shelf waters contributes to long-term food web degradation' Global Change Biology , DOI Open access
Sedwick PN, Bowie AR, Church TM, Cullen JT, Johnson RJ, Lohan MC, Marsay CM, McGillicuddy DJ, Sohst BM & Tagliabue A (2020) 'Dissolved iron in the Bermuda region of the subtropical North Atlantic Ocean: Seasonal dynamics, mesoscale variability, and physicochemical speciation' Marine Chemistry 219, 103748-103748 , DOI Open access
Birchill A, Clinton-Bailey G, Hanz R, Mawji E, Cariou T, White C, Ussher SJ, Worsfold P, Achterberg E & Mowlem M (2019) 'Realistic measurement uncertainties for marine macronutrient measurements conducted using gas segmented flow and Lab-on-Chip techniques' Talanta , DOI Open access
Clough R, Lohan MC, Ussher SJ, Nimmo M & Worsfold PJ (2019) 'Uncertainty associated with the leaching of aerosol filters for the determination of metals in aerosol particulate matter using collision/reaction cell ICP-MS detection' Talanta 199, 425-430 , DOI Open access
Birchill AJ, Hartner NT, Kunde K, Siemering B, Daniels C, Gonzalez-Santana D, Milne A, Ussher SJ, Worsfold PJ & Leopold K (2019) 'The eastern extent of seasonal iron limitation in the high latitude North Atlantic Ocean' Scientific Reports 9, Author Site , DOI Open access
Worsfold P, Achterberg E, Birchill A, Clough R, Leito I, Lohan M, Milne A & Ussher S (2019) 'Estimating Uncertainties in Oceanographic Trace Element Measurements' Frontiers in Marine Science , DOI Open access
Shelley RU, Landing WM, Ussher SJ, Planquette H & Sarthou G (2018) 'Regional trends in the fractional solubility of Fe and other metals from North Atlantic aerosols (GEOTRACES cruises GA01 and GA03) following a two-stage leach' Biogeosciences 15, (8) 2271-2288 , DOI Open access
Rusiecka D, Gledhill M, Milne A, Achterberg EP, Annett AL, Atkinson S, Birchill A, Karstensen J, Lohan M & Mariez C (2018) 'Anthropogenic Signatures of Lead in the Northeast Atlantic' Geophysical Research Letters 45, (6) 2734-2743 , DOI Open access
Fishwick MP, Ussher SJ, Sedwick PN, Lohan MC, Worsfold PJ, Buck KN & Church TM (2017) 'Impact of surface ocean conditions and aerosol provenance on the dissolution of aerosol manganese, cobalt, nickel and lead in seawater' Marine Chemistry , DOI Open access
Birchill AJ, Milne A, S. Woodward EM, Harris C, Annett A, Rusiecka D, Achterberg EP, Gledhill M, Ussher SJ & Worsfold PJ (2017) 'Seasonal iron depletion in temperate shelf seas' Geophysical Research Letters , DOI Open access
Floor GH, Clough R, Lohan MC, Ussher SJ, Worsfold PJ & Quetel CR (2015) 'Combined uncertainty estimation for the determination of the dissolved iron amount content in seawater using flow injection with chemiluminescence detection' LIMNOLOGY AND OCEANOGRAPHY-METHODS 13, (12) 673-686 Author Site , DOI Open access
Sedwick PN, Sohst BM, Ussher SJ & Bowie AR (2015) 'A zonal picture of the water column distribution of dissolved iron(II) during the U.S. GEOTRACES North Atlantic transect cruise (GEOTRACES GA03)' Deep Sea Research Part II: Topical Studies in Oceanography 116, 166-175 , DOI
Fishwick MP, Sedwick PN, Lohan MC, Worsfold PJ, Buck KN, Church TM & Ussher SJ (2014) 'The impact of changing surface ocean conditions on the dissolution of aerosol iron' GLOBAL BIOGEOCHEMICAL CYCLES 28, (11) 1235-1250 Author Site , DOI Open access
Worsfold PJ, Lohan MC, Ussher SJ & Bowie AR (2014) 'Determination of dissolved iron in seawater: A historical review' MARINE CHEMISTRY 166, 25-35 Author Site , DOI Open access
Ussher SJ, Achterberg EP, Powell C, Baker AR, Jickells TD, Torres R & Worsfold PJ (2013) 'Impact of atmospheric deposition on the contrasting iron biogeochemistry of the North and South Atlantic Ocean' Global Biogeochemical Cycles 27, (1) , DOI
Weston K, Jickells TD, Carson DS, Clarke A, Meredith MP, Brandon MA, Wallace MI, Ussher SJ & Hendry KR (2013) 'Primary production export flux in Marguerite Bay (Antarctic Peninsula): Linking upper water-column production to sediment trap flux' DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS 75, 52-66 Author Site , DOI
Shelley RU, Sedwick PN, Bibby TS, Cabedo-Sanz P, Church TM, Johnson RJ, Macey AI, Marsay CM, Sholkovitz ER & Ussher SJ (2012) 'Controls on dissolved cobalt in surface waters of the Sargasso Sea: Comparisons with iron and aluminum' GLOBAL BIOGEOCHEMICAL CYCLES 26, Author Site , DOI
Seguret MJM, Kocak M, Theodosi C, Ussher SJ, Worsfold PJ, Herut B, Mihalopoulos N, Kubilay N & Nimmo M (2011) 'Iron solubility in crustal and anthropogenic aerosols: The Eastern Mediterranean as a case study' MARINE CHEMISTRY 126, (1-4) 229-238 Author Site , DOI
Ussher SJ, Manning AJ, Tappin AD & Fitzsimons MF (2011) 'Observed dissolved and particulate nitrogen concentrations in a mini flume' HYDROBIOLOGIA 672, (1) 69-77 Author Site , DOI
Ussher SJ, Achterberg EP, Sarthou G, Laan P, de Baar HJW & Worsfold PJ (2010) 'Distribution of size fractionated dissolved iron in the Canary Basin' Mar Environ Res 70, (1) 46-55 Author Site , DOI
Ussher SJ, Petrov I, Quetel CR & Worsfold PJ (2010) 'Validation of a portable flow injection-chemiluminescence (FI-CL) method for the determination of dissolved iron in Atlantic open ocean and shelf waters by comparison with isotope dilution-inductively coupled plasma mass spectrometry (ID-ICPMS)' ENVIRONMENTAL CHEMISTRY 7, (2) 139-145 Author Site , DOI
Moore CM, Mills MM, Achterberg EP, Geider RJ, LaRoche J, Lucas MI, McDonagh EL, Pan X, Poulton AJ & Rijkenberg MJA (2009) 'Large-scale distribution of Atlantic nitrogen fixation controlled by iron availability' NATURE GEOSCIENCE 2, (12) 867-871 Author Site , DOI
Ussher SJ, Milne A, Landing WM, Attiq-ur-Rehman K, Séguret MJM, Holland T, Achterberg EP, Nabi A & Worsfold PJ (2009) 'Investigation of iron(III) reduction and trace metal interferences in the determination of dissolved iron in seawater using flow injection with luminol chemiluminescence detection' Anal Chim Acta 652, (1-2) 259-265 Author Site , DOI
Mawji E, Gledhill M, Milton JA, Tarran GA, Ussher S, Thompson A, Wolff GA, Worsfold PJ & Achterberg EP (2008) 'Hydroxamate siderophores: occurrence and importance in the Atlantic Ocean' Environ Sci Technol 42, (23) 8675-8680 Author Site , DOI
Séguret MJM, Ussher SJ, Worsfold PJ, Nimmo M & Wood JW (2007) 'Automatic sampler coupled with flow injection-chemiluminescence detection to monitor particle/natural water interactions' Instrumentation Science & Technology 36, 18-31 , DOI
Ussher SJ, Worsfold PJ, Achterberg EP, Laes A, Blain S, Laan P & de Baar HJW (2007) 'Distribution and redox speciation of dissolved iron on the European continental margin' Limnology and Oceanography 52, (6) 2530-2539
Sarthou G, Baker AR, Kramer J, Laan P, Laes A, Ussher S, Achterberg EP, de Baar HJW, Timmermans KR & Blain S (2007) 'Influence of atmospheric inputs on the iron distribution in the subtropical North-East Atlantic Ocean' Marine Chemistry 104, (3-4) 186-202
Bowie AR, Ussher SJ, Landing WM & Worsfold PJ (2007) 'Intercomparison between FI-CL and ICP-MS for the determination of dissolved iron in Atlantic seawater' Environmental Chemistry 4, (1) 1-4
Laes A, Blain S, Laan P, Ussher SJ, Achterberg EP, Treguer P & de Baar HJW (2007) 'Sources and transport of dissolved iron and manganese along the continental margin of the Bay of Biscay' Biogeosciences 4, (2) 181-194
Bowie AR, Achterberg EP, Croot PL, de Baar HJW, Laan P, Moffett JW, Ussher S & Worsfold PJ (2006) 'A community-wide intercomparison exercise for the determination of dissolved iron in seawater' Marine Chemistry 98, (1) 81-99
Ussher SJ, Yaqoob M, Achterberg EP, Nabi A & Worsfold PJ (2005) 'Effect of model ligands on iron redox speciation in natural waters using flow injection with luminol chemiluminescence detection' Analytical Chemistry 77, (7) 1971-1978
Sedwick PN, Church TM, Bowie AR, Marsay CM, Ussher SJ, Achilles KM, Lethaby PJ, Johnson RJ, Sarin MM & McGillicuddy DJ (2005) 'Iron in the Sargasso Sea (Bermuda Atlantic Time-series Study region) during summer: Eolian imprint, spatiotemporal variability, and ecological implications' Global Biogeochemical Cycles 19, (4)
Bowie AR, Achterberg EP, Ussher S & Worsfold PJ (2005) 'Design of an automated flow injection-chemiluminescence instrument incorporating a miniature photomultiplier tube for monitoring picomolar concentrations of iron in seawater' Journal of Automated Methods & Management in Chemistry 2005, (2) 37-43 Open access
Gledhill M, McCormack P, Ussher S, Achterberg EP, Mantoura RFC & Worsfold PJ (2004) 'Production of siderophore type chelates by mixed bacterioplankton populations in nutrient enriched seawater incubations' Marine Chemistry 88, (1-2) 75-83
Ussher SJ, Achterberg EP & Worsfold PJ (2004) 'Marine Biogeochemistry of Iron' ENVIRONMENTAL CHEMISTRY 1, (2) 67-80 Author Site , DOI
Yaqoob M, Ussher SJ, Nabi A, Achterberg EP & Worsfold PJ (2003) 'Direct determination of iron(II) in acidified seawater using a matrix matched flow injection manifold with chemiluminescence detection, ,, , (2003)' Journal of Flow Injection Analysis 20, 183-186
Worsfold PJ, Achterberg E, Bowie A, Gardolinski P, Gledhill M, Hanrahan G, McKelvie I & Ussher S (2003) 'Field-based analytical techniques for aquatic environmental monitoring, , Chiang Mai Journal of Science, , (2003)' Chiang Mai Journal of Science 30, 153-164
Hanrahan G, Ussher S, Gledhill M, Achterberg EP & Worsfold PJ (2002) 'High temporal and spatial resolution environmental monitoring using flow injection with spectroscopic detection' Trac-Trends in Analytical Chemistry 21, (4) 233-239
Bowie AR, Achterberg EP, Sedwick PN, Ussher S & Worsfold PJ (2002) 'Real-time monitoring of picomolar concentrations of iron(II) in marine waters using automated flow injection-chemiluminescence instrumentation' Environmental Science & Technology 36, (21) 4600-4607
Bell TG, Yang M & Ussher SJ (2020) 'Atmospheric Emissions from Ships' Environmental Impact of Ships Cambridge University Press 11-55 , DOI
Conference Papers
Achterberg EP, Ussher S, Gledhill M, Worsfold PJ, Bowie AR, Gehrels WR, Geider R & de Baar HJ (2004) 'Role of iron in marine biogeochemistry' A327-A327
Presentations and posters
Birchill A, Baker C, Wyatt N, Turnbull I, Milne A, Martin A, Moore M & Ussher S Birchill A, Baker C, Wyatt N, Turnbull I, Milne A, Martin A, Moore M & Ussher S '<i>Hydrothermal iron supply to the remote southeast Pacific Ocean</i>' , DOI
Cooper E, Thomas S, Ussher S, Rush D, Cunliffe M & Lengger S Cooper E, Thomas S, Ussher S, Rush D, Cunliffe M & Lengger S 'Marine fungi and the biological carbon pump - a quest for novel biomarkers for key players in the carbon cycle' , DOI Open access


Conferences organised

Co-organiser of the first Marine Institute Conference - “Understanding Marine Systems” (University of Plymouth, December 2007).