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School of Biological and Chemical Sciences

Professor Mark Trimmer


Professor of Biogeochemistry, Director of Research

Telephone: +44 (0)20 7882 3007
Room Number: Room 6.26, Fogg building

Undergraduate Teaching

  • Practical Molecular and Cellular Biology (Tutorials) (BIO190)
  • Practical Biology (Tutorials) (BIO192)
  • Research Methods and Communication (Tutorial) (BIO209)
  • Research Methods and Communication II (Tutorials) (BIO309)

Postgraduate Teaching

Teaching on our Aquatic Ecology by Reserch MScEcology and Evolutionary Biology MSc and Freshwater and Marine Ecology MSc:

  • Ecosystem Structure and Functioning (BIO737P)

Teaching on our Ecology and Evolutionary Biology MSc and Freshwater and Marine Ecology MSc:

  • Science into Policy and Management (BIO739P)


Research Interests:

Bio-element cycling from headwater streams to the deep-ocean

Life on Earth is sustained by the cycling of the key bio-elements – carbon, nitrogen and phosphorus. Humans have altered the balance of these cycles to a truly staggering extent – so much so that we have now entered the Anthropocene. For example, while our doubling of the amount of fixed nitrogen on Earth keeps the population alive today, such large alteration of this key bio-element cycle is putting untold pressures on the world around us, reducing biodiversity and altering the balance of vital ecosystem processes and the services they provide to us. In order to manage these impacts we need to fully understand how these cycles work. Though the basics of cycles are probably familiar to us all from our memories of common school texts, scientific advances are revealing ever greater complexity in the cycling of the bio-elements – including significant contributions from microorganisms that, until recently, were considered as taxonomic curiosities, confined to salt-lakes and bubbling hot muds.

My research is aimed at unravelling the complexities of these life-sustaining cycles, from the pristine chalk streams of England to the tropical oceans. We use natural isotopes of these bio-elements to track their cycling across these diverse aquatic ecosystems and molecular techniques to probe their underlying microbial ecology. I also use the longest running climate warming experiment (situated in Dorset) to characterise how warming alters the cycling of carbon and nitrogen, with a particular interest on how warming alters the ratios of the greenhouse gases CO2, CH4 and N2O emitted. This work on warming is supplementing a large research effort currently running around the Arctic Circle where, with Imperial Collage, we are taking a ‘genes to ecosystems’ approach to help predict the effects of climate change on the key ecosystem service of bio-element cycling. Other work in the tropical north Pacific - where the oxygen deplete waters make large quantities of the potent greenhouse gas nitrous oxide – provided the best insight yet as to how their production of nitrous oxides responds to declining oxygen, work that we will be following up on in the southern Atlantic Ocean in the coming year.

Research department

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PhD supervision

Postdoctoral supervision