• Research Interests
• Brief Biography
• Teaching and Learning
• Publications
• Studentships
• Research Income
• Conference Presentations

Research Interests

My research is geared towards advancing knowledge on the characterisation and cycling of organic nitrogen in estuaries, including abundance, bioavailability and reactivity. Globally, nitrogen (N) loadings to rivers and estuaries are predicted to further increase as a result of changes in climate, transport, agriculture and urbanisation. The estuarine supply of N to coastal waters is a critical component of fisheries production and water quality, including eutrophication. Thus, predictions of the behaviour of N species, coupled with accurate estimates of their fluxes, are of vital strategic, scientific and social importance.

In natural waters, nitrogen is partitioned between the dissolved and particulate phases. More than 50% of the annual global riverine flux of N is likely to be in the form of particulate N, which is almost entirely organic, while dissolved organic N may also constitute a significant fraction of this total. The importance of land-derived particulate N to coastal zone productivity has been inferred from the effects of river damming, and from comparisons between concentrations of N on particles in rivers and their adjacent coastal sediments. However, the speciation and reactivity of organic N in rivers and estuaries are generally poorly quantified, which gives rise to major uncertainties regarding the factors controlling the flux of N from estuaries to coastal seas. The key to reducing these uncertainties lies in understanding the particle-water interactions of organic N and, in particular, the role of estuarine master variables (e.g. salinity, dissolved organic carbon, bacteria, particle morphology) in modifying N partitioning and reactivity.

Studies on the reactivity of the total organic N fraction are valuable, but provide little information on the most biogeochemically reactive components. Complementary research on the bioavailability of organic matter at the compound or molecular level has been undertaken, but has focussed largely on carbon (C). The few studies undertaken on DON have revealed that it is preferentially utilised relative to C. The organic N pool comprises the particulate and dissolved phases and is a complex, heterogeneous mixture of compounds, where the low molecular weight fraction is quantitatively important. This fraction (<1 kDa) includes free and combined amino acids, urea, glycine betaine, amines, amino sugars, nucleosides and nucleotides, all of which are important bacterial substrates. Some peptides, proteins and labile polymers, including amino acids bound in or to humic materials, also appear to be bioavailable. In contrast, some organic N compounds appear not to be bioavailable, perhaps because of earlier bacterial processing  or sorptive preservation. The occurrence, speciation and bioavailability of individual DON compounds originating from anthropogenic sources (e.g. combustion, waste effluents) is barely understood. Their bioavailability may be primarily related to oxidation state, the C/N ratio of the organic matter, or the bacterial assemblage present.

The major obstacle to the study of organic nitrogen cycling, in both particulate and dissolved form, has been a paucity of methods for both bulk and molecular analyses. My PhD was a study of a group of low molecular organic nitrogen compounds, the methylamines, in freshwater and inter- and sub-tidal sediments from a variety of locations around the UK. The methylamines are chemical analogues of ammonia and exist mainly in protonated form (e.g. CH₃NH₃⁺) at natural water pH, which allows them to compete with other dissolved cations for particle exchange sites Early studies with co-workers led to development of a sensitive method for the analysis of these compounds (Abdul-Rashid et al., 1991), facilitating studies on their quantification in pristine and impacted estuarine sediments (Fitzsimons et al., 1997; 2001).

Sediments are now recognised as a significant source of nitrogen. Field and laboratory measurements of the effects of sediment resuspension in the Thames Estuary, UK, showed that the resulting benthic organic N flux can significantly augment water column dissolved organic N concentrations (Fitzsimons et al., 2006). The role of mariculture in N cycling was investigated through analyses of sediments populated by the clam Ruditapes decussatus L. in the Ria Formosa, Portugal, where a substantial flux of benthic dissolved organic N was measured (Fitzsimons et al., 2005), consistent with reports of increased concentrations of dissolved N within this lagoon system. I am co-investigator of a follow up study "Organic Nitrogen cycling pathways in intertidal sediments of contrasting permeability of the Ria Formosa coastal lagoon" led by Dr Carlos Rocha, University of the Algarve, funded by the Portuguese Ministry of Science and Technology.

I have received Leverhulme Trust funding to measure the reactivity of organic N with estuarine suspended particulate matter and results show that microbes play a critical role in the sorption behaviour of ON (Tappin et al., 2007; 2010). Molecular characterization of organic N is now possible using electrospray ionisation (ESI), and we have developed a method for the pre-concentration, separation and detection of low molecular weight peptides using LC-ESI-MS through a NERC studentship (Curtis-Jackson et al., 2009). The development of ESI for determination of macromolecules led to the awarding of the Nobel Prize in Chemistry in 2002 to J.B. Fenn and K. Tanaka "for their development of soft desorption ionisation methods for mass spectrometric analyses of biological macromolecules". ESI allows the transfer of intact molecules to the gas phase allowing structural information to be obtained from molecular or pseudomolecular ions by mass spectrometric detection. It is a relatively new technique for studying polar, non-volatile compounds and, as such, is ideal for molecular characterisation of organic N in dissolved form.

Other research on water quality includes analytical development for the determination of sewage indicator compounds in aqueous systems (e.g. purge and trap), the application of nuclear magnetic resonance spectroscopy to environmental studies, and the effects of water pollutants on the distribution of tropical coral ecosystems. I was President of the Association of Chemistry and the Environment and I am currently Secretary of the Estuarine and Coastal Sciences Association. I am an Associate Editor of the journal Environmental Chemistry Letters, and review for a number of journals, including Limnology & Oceanography, Marine Chemistry, Organic Geochemistry, Chemosphere and Marine Environmental Research. I am a member of the NERC Peer Review College (2009-2012).

• Use of spectroscopic techniques to trace degradation pathways of chemicals in the environment
• Reactivity of organic nitrogen with particles in aqueous systems (NEPTUNE)
• Biogeochemical cycling of nitrogen in recent sediments and salt marshes
• The use of biochemical indicators of sewage contamination and pathogenic organisms in aquatic systems

Brief Biography

I grew up by the Irish Sea and greatly enjoyed Chemistry at school, which led me to search for a university degree programme that could combine my love of both. I graduated in BSc (Hons) in Chemistry with Oceanography from the University of Liverpool, U.K., and remained there to continue my PhD research under the supervision of Professor George Wolff (thesis title: 'The Geochemistry of the Methylamines in Recent Marine and Lacustrine Sediments') in the Environmental Organic Chemistry and Geochemistry Group, Department of Earth and Ocean Sciences. I moved on to the Marine Biological Association of the United Kingdom and worked with Professor Paul Dando on a pan-European project studying the biogeochemistry of hydrothermal, geothermal and cold seep ecosystems. In 1995, I joined Middlesex University as a Lecturer in Environmental Chemistry and renewed my interest in the biogeochemistry of organic nitrogen. I taught Environmental Organic Chemistry at undergraduate and masters level and was Programme Leader for MSc Water Pollution Control. Other pedagogic activities included writing a distance learning module on physico-chemistry and water quality modelling for an MSc Integrated Pollution Control, and developing a transferable skills module for first year undergraduates.

I joined the University of Plymouth in 2001. I teach organic chemistry and analytical chemistry on the BSc (Hons) Chemistry and also manage the programme.

I have continued to pursue my research interests in the marine organic nitrogen cycle, with projects funded by the NERC, the Leverhulme Trust and the EU (see research interests).

Other Information

• Member of Council of the Estuarine and Coastal Sciences Association
• Fellow of the Royal Society of Chemistry (FRSC)
• Chartered Chemist (CChem)
• Member of the Institute of Soil Science (M I Soil Sci)
• External examiner at the Universities of Liverpool, Essex, UHI Millenium Institute (all U.K.) and Dublin City University (PhD)
• External consultant for validation of undergraduate and postgraduate programmes and Scottish Association for Marine Science (SAMS) and Environmental Research Institute (ERI), Scotland, U.K.

Teaching and Learning

I teach on the BSc Analytical Chemistry and BSc Chemistry Programmes in the following areas: organic chemistry (molecular rearrangements; carbonyl chemistry), analytical chemistry (gas chromatography; high performance liquid chromatography), marine chemistry and professional and scientific skills (scientific writing; research project preparation and management).

Recent Publications

My refereed publications are listed below (reverse chronological) and my 'My Citations' page from Google Scholar provides additional bibliographic metrics:

In Press, Submitted or In Preparation

• Tappin A.D., McCarthy A.J., Loughnane P. and Fitzsimons M.F. Unexpected removal of the most neutral cationic pharmaceutical in river waters. Environmental Chemistry Letters (In press). [doi: 10.1007/s10311-016-0582-2].

Published

• Dall'Osto, M., Ovadnevaite, J., Paglione, M., Beddows, D.S.C., Ceburnis, D., Cree, C., Cortés, P., Zamanillo, M., Nunes, S.O., Pérez, G.L., Ortega-Retuerta, E., Emelianov, M., Vaqué, D., Marrasé, C., Estrada, M., Sala, M.M., Vidal, M., Fitzsimons, M.F., Beale, R., Airs, R., Rinaldi, M., Decesari, S., Facchini, M.C., Harrison, R.M., O'Dowd, C. and Simó, R. (2017) Antarctic sea ice region as a source of biogenic organic nitrogen in aerosols. Scientific Reports 7:6047, 1-10. [doi: 10.1038/s41598-017-06188-x].
• Lees, K., Fitzsimons, M., Snape, J., Tappin, A. and Comber, S. (2016) Pharmaceuticals in soils of lower income countries: Physico-chemical fate and risks from wastewater irrigation. Environment International 94, pp.712-723. [doi: 10.1016/j.envint.2016.06.018].
• Tappin A.D., Loughnane J.P., McCarthy A.J. and Fitzsimons, M.F. (2014) Bacterio-plankton transformation of diazepam and 2-amino-5-chlorobenzophenone in river waters. Environmental Science: Processes & Impacts 16, 2227-2236. [doi: 10.1039/C4EM00306C].
• Tappin, A.D., Loughnane, J.P., McCarthy, A.J. and Fitzsimons, M.F. (2012) Removal of atrazine from river waters by indigenous microorganisms. Environmental Chemistry Letters 10, 89-96. [doi: 10.1007/s10311-011-0332-4].
• Fitzsimons, M.F., Lohan, M., Millward, G.E. and Tappin, A.D. (2012) The role of suspended particles in estuarine and coastal biogeochemistry. In: Treatise on Estuarine and Coastal Science, Volume 4, Geochemistry of Estuaries and Coasts, (Shimmield, G., ed.), Elsevier. pp. 71-114. [ISBN: 978-0-08-087885-0 ] [doi: 10.1016/B978-0-12-374711-2.00404-6].
• Ussher, S.J., Manning, A.D., Tappin, A.D. and Fitzsimons, M.F. (2011) Observed dissolved and particulate nitrogen concentrations in a mini flume. Hydrobiologia 672, 69-77. [doi: 10.1007/s10750-011-0759-4].
• Tappin, A.D., Millward, G.E. and Fitzsimons, M.F. (2010) Particle-water interactions of organic nitrogen in turbid estuaries. Marine Chemistry 122, 28-38. [doi: 10.1016/j.marchem.2010.08.006].
• Curtis-Jackson, P.K., Massé, G., Gledhill, M., Fitzsimons, M.F. (2009) Characterisation of low molecular weight dissolved organic nitrogen by liquid chromatography-electrospray ionisation-mass spectrometry. Limnology and Oceanography: Methods 7, 52-63.
• Leakey C.D.B., Attrill M.J., Jennings S. and Fitzsimons M.F. (2009) Multi-element otolith chemistry of juvenile sole (Solea solea), whiting (Merlangius merlangus) and European seabass (Dicentrarchus labrax) in the Thames Estuary and adjacent coastal regions. Journal of Sea Research 61, 268-274. [doi: 10.1016/j.seares.2008.12.002].
• Rees A.P., Hope S.B., Widdicombe C.E., Dixon J.L., Fitzsimons M.F. and Woodward E.M.S. (2009) Alkaline phosphatase activity in the western English Channel: Elevations induced by high summertime rainfall. Estuarine Coastal and Shelf Science 81, 569-574. [doi: 10.1016/j.ecss.2008.12.005].
• Leakey, C.D.B., Attrill, M.J., Jennings, S. and Fitzsimons, M.F. (2008) Stable isotopes in juvenile marine fishes and their invertebrate prey from the Thames Estuary, UK, and adjacent coastal regions. Estuarine, Coastal and Shelf Science 77, 513-522. [doi: 10.1016/j.ecss.2007.10.007].
• Leakey C.D.B., Attrill M.J., Jennings S. and Fitzsimons M.F. (2008) Retrospective quantification of estuarine feeding activity by coastally caught marine fishes. Journal of Sea Research 60, 210-214. [doi: 10.1016/j.seares.2008.05.002].
• Worsfold P.J., McKelvie I.D., Fitzsimons M.F., Monbet P., Stiles D.A. and Tappin A.D. (2008) Characterisation and quantification of organic phosphorus and organic nitrogen components in aquatic systems: A Review. Analytica Chimica Acta 624, 37-58. [doi: 10.1016/j.aca.2008.06.016].
• Tappin, A.D., Millward G.E. and Fitzsimons, M.F. (2007) Distributions, cycling and recovery of amino acids in estuarine waters and sediments. Environmental Chemistry Letters 5, 161-167. [doi: 10.1007/s10311-007-0099-9].
• Tappin A.D., Millward G.E. and Fitzsimons M.F. (2007) Natural estuarine particles and their uptake of nitrogen in estuaries. Geochimica et Cosmochimica Acta 71, A1005-A1005.
• Haley, S.M., Tappin, A.D., Bond, P.R. and Fitzsimons, M.F. (2006) A comparison of SEM-EDS with ICP-AES for the quantitative elemental determination of estuarine particles. Environmental Chemistry Letters 4, 235-238. [doi: 10.1007/s10311-006-0054-1].
• Fitzsimons, M.F., Millward, G.E., Revitt, D.M. and Dawit, M.D. (2006) Desorption kinetics of ammonium and methylamines from estuarine sediments: Consequences for the cycling of nitrogen. Marine Chemistry 101, 12-26. [doi: 10.1016/j.marchem.2005.12.006].
• Fitzsimons, M.F. and Belt, S.T. (2005) Dynamic behaviour of 1-aminopropan-2-one in sewage: a preliminary synthetic and spectroscopic study. Environmental Chemistry Letters 3, 70-73. [doi: 10.1007/s10311-005-0005-2].
• Fitzsimons, M.F., Dawit, M., Revitt, D.M. and Rocha, C.S. (2005) Effects of early tidal inundation on the cycling of methylamines in inter-tidal sediments. Marine Ecology Progress Series 294, 51-61. [doi: 10.3354/meps294051].
• Abdullah A.H., Yasin Z., Ismail W.R., Shutes, B. and Fitzsimons, M.F. (2002) The effect of early coastal development on the fringing coral reefs of Langkawi: a study in small-scale changes. Malaysian Journal of Remote Sensing & GIS 3, 1-10.
• Dawitt, M., Williams, I.D. and Fitzsimons, M.F. (2001) Determination of 1-aminopropan-2-one, a dissolved sewage component, in water samples. Water Research 35, 1151-1156.
• Fitzsimons, M.F., Kamhi-Danon, B. and Dawitt, M. (2001) Distributions and adsorption of the methylamines in the inter-tidal sediments of an East Anglian estuary. Environmental and Experimental Botany 46, 225-236.
• Mattison R.G., Abbiati M., Dando P.R., Fitzsimons, M.F., Pratt, S.M., Southward, A.J. and Southward, E.C. (1998) Chemoautotrophic microbial mats in submarine caves with hydrothermal sulphidic springs at Cape Palinuro, Italy. Microbial Ecology 35, 58-71.
• Fitzsimons, M.F., Jemmett, A.W.L. and Wolff, G.A. (1997) Distributions of the methylamines in a heterogeneous salt marsh through a tidal cycle. Organic Geochemistry 27, 15-24.
• Fitzsimons, M.F., Dando, P.R., Hughes, J.A., Thiermann, F., Akoumianaki, I. and Pratt, S.M. (1997) Submarine hydrothermal brine seeps off Milos, Greece: observations and geochemistry. Marine Chemistry 57, 325-340.
• Fitzsimons, M.F., Abdul-Rashid, M.K., Riley, J.P. and Wolff, G.A. (1995) Aminopropanone as a marker for raw sewage in natural waters. Marine Pollution Bulletin 30, 306-312.
• Abdul-Rashid M.K., Riley J.P., Fitzsimons, M.F. and Wolff, G.A. (1991) A simple method for the determination of volatile amines in sediment and water samples. Analytica Chimica Acta 252, 223-226.

Studentships

Studentships since 1996:

Research Income

Income since 1996:

International & National Conference and Meeting Presentations

• 17^th International Biodeterioration & Biodegradation Symposium, Manchester Metropolitan University, U.K., 6-8 September 2017 (keynote oral).
• 6^th International Symposium on the Biological and Environmental Chemistry of DMS(P) and Related Compounds, Barcelona, Spain, 26-30 May 2014 (poster, colleague).
• British Soil Science Society Annual Meeting 2013: Soil Science and Biogeochemistry: A Journey Through Space and Time, Lancaster, U.K., 3-5 September 2013 (poster, colleague).
• 24^th Annual Meeting of the British Organic Geochemical Society, Plymouth, U.K., 10-11 July 2013 (poster, colleage).
• 23^rd Annual Meeting of the British Organic Geochemical Society, Leeds, U.K., 4-5 July 2012 (oral, colleague).
• ASLO Aquatic Sciences Meeting, Nice, France, 26-30 January, 2009 (poster).
• 8^th European Meeting on Environmental Chemistry, Inverness, U.K., 4-7 December 2007 (oral).
• 7^th European Meeting on Environmental Chemistry, Brno, Czech Republic, 6-9 December 2006 (oral; poster).
• 41^st ECSA International Conference, Venice, Italy, 15-20 October 2006 (plenary).
• 6^th European Meeting on Environmental Chemistry, Belgrade, Serbia and Montenegro, 6-10 December 2005 (oral, colleague; poster).
• 17^th Annual Meeting of the British Organic Geochemical Society, Liverpool, U.K., 14-15 July 2005 (oral, colleague).
• 5^th European Meeting on Environmental Chemistry, Bari, Italy, 15-18 December 2004 (keynote presentation).
• 15^th Annual Meeting of the British Organic Geochemical Society, Plymouth, U.K., 8-9 July 2003 (poster).
• 3^rd European Meeting on Environmental Chemistry, Geneva, Switzerland, 11-14 December 2002 (poster).
• 14^th Annual Meeting of the British Organic Geochemical Society, Newcastle-upon-Tyne, U.K., 2-3 July 2002 (poster).
• 2^nd European Meeting on Environmental Chemistry, Dijon, France, 12-15 December 2001 (poster).
• Millennium Wetland Conference, Quebec, Canada, August 2000 (invited paper).
• 5^th Symposium on the Biogeochemistry of Wetlands, London, U.K., September 1997.
• ECSA/ERF Joint Symposium, Middleburg, The Netherlands, September 1996.
• 15^th Meeting of the European Association of Organic Geochemists, Manchester, U.K., 16-20 September 1991.