How will marine microalgae react to a changing nitrogen balance in the ocean?

Scientific background:

Microalgae are major components of marine ecosystems worldwide, providing essential ecosystem services including using carbon dioxide and producing oxygen. Our research shows that they also produce nitrogencontaining compounds (N-osmolytes) used for alleviating salinity stress and maintaining photosynthesis. These compounds degrade in seawater to produce methylamines, which can move into the atmosphere and take part in chemical reactions, influencing cloud formation and climate. 

Research methodology: 

This is an exciting opportunity to advance understanding of the production of N-osmolytes and methylamines by algae today and in the future. Climate change scenarios predict conditions leading to variable riverine inputs to coastal areas and changes to the balance of nutrient pools. Your challenge is to investigate how these changes might affect production of N-osmolytes and methylamines, which could have important consequences for the climate. 

Objectives 

1. Use liquid chromatography-mass spectrometry and gas chromatography to examine production of N-osmolytes and methylamines by marine algal species. 

2. Experimentally determine how changes in composition of the nitrogen pool influence production of N-osmolytes and methylamines in cultures of key, representative marine algal species (e.g. diatoms, dinoflagellates and coccolithophores). 

3. Undertake seasonal sampling in the Western English Channel to investigate production of N-osmolytes and methylamines under changing natural inputs of organic nitrogen. 

Based at the UoP (Fitzsimons and Ussher) with periods of working at the UEA (Malin) and Plymouth Marine Laboratory (Airs), this studentship will include algal culturing and field sampling in coastal and oceanic waters. We are a strong multidisciplinary team with excellent track records for research on algae and measurement of the compounds to be studied. 

Training: 

You will develop advanced lab and field research skills plus transferable skills to support your future career. The analytical techniques and approach are cutting-edge and will give you an excellent portfolio of skills to launch your future career. 

Person specification: 

This project would suit a self-motivated student, with good experimental skills and practical ingenuity. Relevant analytical skills and an appreciation of marine microalgae would be ideal. You should have/anticipate a minimum 2i (BSc) in the Biological, Chemical or ENV.

Rationale 

Biogenic trace-gases play critical roles in global biogeochemical cycles and climate. Phytoplankton synthesise organic compounds as osmolytes/cryoprotectants, including dimethylsulfoniopropionate and quaternary amines (QAs). The former has received considerable attention, being the main precursor of the climate regulator, dimethylsulfide; however, amines may be equally important. The QA, glycinebetaine, is among the most widely-used compatible solutes in nature; it degrades to produce methylamines (MAs). MAs can diffuse across the sea-air interface and are thought to play a profound role in climate-regulation processes, acting as cloud condensation nuclei. In fact, atmospheric MA concentrations above 65 nmol m-3 could account for observed atmospheric particle-formation rates. 

Climate change scenarios predict variable nutrient inputs to seawater and changes in the balance of the nitrogen pool. Most nutrient studies have focused on dissolved inorganic nitrogen (DIN). However, dissolved organic nitrogen (DON) frequently comprises the largest fraction (60–69%) of dissolved nitrogen in surface waters, and is utilized by phytoplankton even when DIN is available, providing nitrogen to algae at an earlier decomposition stage. This may enable certain species to gain an advantage, particularly if DIN is depleted. We have demonstrated key findings in this area, showing that some marine algae can grow using DON only; and that increased cellular levels of glycine-betaine occurred in the global coccolithophore, Emiliania huxleyi, in cultures where DON was present. Thus, we have an excellent opportunity to make major advances in understanding the production and cycling of marine volatiles; specifically, how predicted changes to the marine nitrogen pool could alter production of QAs and fluxes of climate-active MAs to the atmosphere. 

Few measurements of amines exist so there is little understanding of their role and fate, and the link between QAs and MAs in marine systems. The studentship will benefit from the supervisory team’s excellent combined expertise in studying marine volatiles. It is timely given our recent development of analytical methods for amine analysis, identifying marine microbiota as a source of atmospheric amines. 

Objectives 

Objective 1 focuses on student training in measurement methods. 

Objective 2 will be achieved through participation in the Western Channel Observatory (WCO) sampling programme, focused on Station L4, and is likely to provide the first seasonal data for MAs. Emiliania huxleyi is present in all oceans, except polar oceans. We have observed that cellular levels of the QA, glycine-betaine, increased when DON was available, and this exciting finding will be explored in Objective 3. 

Training 

The student will receive expert training in methylamine and DON analysis (Fitzsimons), N-osmolyte analysis (Airs), microalgal culturing (Malin) and environmental sampling (WCO). Training in scientific, transferable and advanced research skills will include safe working practice, seagoing-research, chemical and biological measurements and data analysis. Fieldwork will develop organizational and interpersonal skills. The student will benefit from seminar series (PML, UoP) and transferable skills courses (UEA, UoP). They will present at national and international conferences, write peer-reviewed publications and a PhD thesis. The research training addresses numerical, statistical, fieldwork and laboratory skills, equipping the student for a career across a range of professions. 

References: 

Manuel Dall’Osto, Ruth L. Airs, Rachael Beale, Charlotte Cree, Mark F. Fitzsimons,David Beddows, Roy M. Harrison, Darius Ceburnis, Colin O’Dowd, Matteo Rinaldi,Marco Paglione, Athanasios Nenes, Stefano Decesari and Rafel Simó. 2019.Simultaneous Detection of Alkylamines in the Surface Ocean and Atmosphere of theAntarctic Sympagic Environment. Earth and Space Chemistry 3, 854-862. 

Birchill A.J., G. Clinton Bailey, R. Hanz, E.Mawji, T. Cariou, C. White, S.J. Ussher,P.J. Worsfold, E.P. Achterberg, M. Mowlem (2019) Realistic measurementuncertainties for marine macronutrient measurements conducted using gassegmented flow and Lab-on-Chip techniques. Talanta 200, 228-235. 

Dall’Osto, M., Ovadnevaite, J., Paglione, M., Beddows, D. C. S., 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., Cristina Facchini, M.,Harrison, R. M., O’Dowd, C. & Simó, R. (2017) Antarctic sea ice region as a sourceof biogenic organic nitrogen in aerosols. Scientific Reports, 7, 6047. 

McKew, B. A., Metodieva, G., Raines, C. A., Metodiev, M. V. & Geider, R. J. (2015)Acclimation of Emiliania huxleyi (1516) to nutrient limitation involves precisemodification of the proteome to scavenge alternative sources of N and P.Environmental Microbiology, 17, 4050. 

Franklin, D.J., Airs, R.L., Fernandes, M., Bell, T.G., Bongaerts, R.J., Berges, J.A.,Malin, G. (2012) Identification of senescence and death in Emiliania huxleyiandThalassiosira pseudonana: Cell staining, chlorophyll alterations, anddimethylsulfoniopropionate (DMSP) metabolism. Limnology & Oceanography 57,305.