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School of Biological and Behavioural Sciences

Professor Mark Trimmer


Professor of Biogeochemistry

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 functions 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 these 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 deep oceans. We use natural isotopes of these bio-elements to track their cycling across these diverse aquatic ecosystems and molecular techniques to probe the underlying microbial ecology. We have uncovered new short-circuits in the nitrogen cycle and widespread aerobic and anaerobic methane oxidation supplementing primary production in rivers. We also use a long-term (2005-to present) climate warming experiment (situated in Dorset) to characterise how warming alters the cycling of carbon and nitrogen, recently highlighting disproportionate increases in methane emissions and overall weakening of ecosystem trophic transfer efficiency that could threaten larger animals. This work on warming supplements large-scale research efforts running in the Arctic Circle where, with Imperial Collage, we are taking a ‘genes to ecosystems’ approach to help predict the effects of climate change on key ecosystem services. Other work in the Pacific and Atlantic has helped us understand the dynamics of the powerful greenhouse gases carbon dioxide and nitrous oxide that we are seeking to follow-up on in the near future.

Research department

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PhD supervision

Postdoctoral supervision

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