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Dr Heather Buss

Dr Heather Buss

Dr Heather Buss
BS(Penn.State), PhD(Penn.State)

Associate Professor in Biogeochemical Weathering

Area of research

Mineral weathering and biogeochemical processes in the Critical Zone

Office IC4.04
Wills Memorial Building,
Queens Road, Clifton BS8 1RJ
(See a map)

+44 (0) 1173314751


The rates and mechanisms of weathering processes are important to understanding a variety of environmentally and economically important issues including the (bio)geochemical cycling of mineral nutrients, the evolution of landforms, and the long-term drawdown of atmospheric CO2. Most weathering occurs within the “critical zone”, which is the external layer of the terrestrial Earth from the vegetation canopy to fractured bedrock. This zone sustains most terrestrial life on the planet, yet natural and human-related processes perturb and threaten the critical zone worldwide. Undoubtedly, the most significant aspect of weathering is the breakdown of rocks to form soils, a process that creates the critical zone and makes life possible on the surface of the Earth. The overarching goal of “critical zone research” is to understand how the outer envelope of the terrestrial earth functions as a whole, how it is formed and maintained on the landscape, what will happen to it in the face of environmental changes, and how its processes impact (bio)geochemical cycles and fluxes on local and global scales.

My expertise is in low-temperature geochemistry and biogeochemistry with a focus on weathering and mineral nutrient cycling in soils. Specific research goals include resolving rates of mineral weathering and soil formation and quantifying feedbacks between weathering, erosion, and biology in the critical zone. In addition, the extreme complexity of the critical zone gives rise to the need to identify how spatial and temporal heterogeneity in physical, geochemical and biological properties impacts critical zone mineral nutrient cycles. Finally, the ability to make full use of emerging isotopic proxies for paleoclimate studies and reconstructions of past nutrient fluxes requires an understanding of the (bio)geochemical fractionation mechanisms that affect the isotopic signatures in the critical zone. Thus a primary research focus is the identification and quantification of the processes that establish the isotopic signatures that are exported from watersheds.


I am an Associate Professor (Reader) in Biogeochemical Weathering. I joined the University of Bristol School of Earth Sciences in 2011 so I could work with undergraduate and postgraduate students, as a teacher, research collaborator, and as a mentor.  In my research, I seek to understand the fate of mineral nutrients as rocks undergo chemical, biological and physical weathering and transform into soil. I am especially interested in the feedbacks between geochemical reactions and biological processes (microbial activities and plant uptake).

I use my research activity and interests to inform my teaching, which includes the following units: Soils and the Critical Zone, Geomicrobiology, Environmental Geoscience Field Skills (in Tenerife, Spain), and undgraduate/postgraduate research projects. I hold several other roles in the School of Earth Sciences, including Director of the Marine and Terrestrial Environments (MATES) research group, Head of the Biogeochemistry Laboratory, Chair of the Student Staff Liaison Committee (SSLC), Teaching Quality Officer, and Staff Advisor to the Bristol University Geology and Geoscience Society (BUGGS).

In my previous position, I was a Research Geochemist with the US Geological Survey (USGS) in Menlo Park, California. In that position, I was the lead USGS scientist for a tropical Critical Zone Observatory in Puerto Rico. Prior to that, I completed a US National Research Council postdoctoral fellowship at the USGS after completing my PhD in Geosciences in 2006 at Penn State University with Professor Susan Brantley. 


Year 2 Soils and The Critical Zone: This is a core unit for Environmental Geoscience students (and an option for Palaeontology and Evolution) and provides an introduction to the biology, mineralogy, chemistry and physics of soils, including how soils form and evolve, methods of soil classification, the global distribution of soil types, the diversity and role of macro- and micro-organisms in soils, and how moisture and heat move within soils. The unit takes a modern approach by placing soils in the integrated framework of critical zone science, wherein the entire portion of the terrestrial Earth that supports life (the critical zone) is viewed from a holistic perspective where compartments (such as soils) and their processes and interfaces are part of the whole system. Key aims of the unit will be to learn the basics of soil science as listed above as well as the feedbacks between soil processes and other parts of the critical zone and the implications of these feedbacks for soil sustainability and functions, regional and global biogeochemical cycles, and climate feedbacks.

The unit is comprised of 3 hours of lectures and 3 hours of practical work each week, for 5 weeks. The practicals consist of laboratory analyses of soil samples collected in a local field trip taken in the first week. Coursework entails producing a scientific report based on the data collected during practicals and the field trip and interpreting these results in the context of soil formation and land use. This report helps to prepare students to write their research dissertations in Year 3. 

Year 2 Environmental Geoscience Field Skills: This is a core unit for Environmental Geoscience students and is conducted as a one-week residential field class in Tenerife, Spain. Tenerife provides an ideal environment for the field study of soil development and plant ecology in the context of geology, topography, and climate. There are numerous soil types, microclimates, topographic and geological variations, and vegetation types over a very small land area. The students study soil formation in the context of local geloogy, climate, topography, and vegetation; practice collecting and recording detailed and useful field notes; gain experience describing, identfiying and interpreting soils; learn how to identify plants and relate them to environmental variables; and produce a website as part of a group effort that records observations and experiences during the field class. It is also a lot of fun!

Year 3 Geomicrobiology: This is an optional unit for students in the School of Earth Sciences and provides an overview of concepts, techniques, and issues in geomicrobiology as they relate to environmental geosciences. Aims: to learn about and examine microbial properties, metabolisms, diversity and abundance in the natural environment; to appreciate the coupling of biological with chemical and physical processes in the natural environment; to examine specific ways in which microorganisms create or contribute to normal geological processes, environmental problems, and remediation of environmental problems; and to summarise current techniques for assessing microbial influences on the environment.

The unit is comprised of 3 hours of lectures and 3 hours of practical work each week, for 5 weeks. The practicals consist of problem sets and an experiment in which students cultivate different types of microorganisms from water samples collected from around Bristol. The students produce a short report based on the experimental results assessing the implications for water quality in the context of the water's usage. 

Year 3 Environmental Geoscience Research Projects (Dissertations): This is a core unit for Environmental Geoscience students and represents a capstone project for those on the BSc programme. In this unit students undertake and experience the process of conducting an independent research investigation integrating field, laboratory and computational methods. Each year, 4 or more projects are offered; each project is supervised by one or two members of staff and can be done by 4 to 5 students. Although some aspects of the project work may be conducted as a group (e.g. data gathering during fieldwork), each student completes their own literature review, laboratory experiments, synthesis of data, computational work and write-up. Prior to undertaking project-specific field work, all students participate in a 5 day non-residential group field trip in the local area in which they develop hypotheses, design sampling and analysis strategies, and collect and analyse data in the field.

Supervisor for Year 4 MSci projects and PhD projects

Personal tutoring Years 1-4: The overall role of the Personal Tutor is to act as a first point of contact within the University from whom the individual tutee can obtain academic and pastoral support. Tutors effectively support student learning by: (i) helping the tutee to develop effective study skills and habits, (ii) reviewing overall academic progress and providing feedback and advice, (iii) helping the tutee to understand relevant University rules and regulations, (iv) helping and advising the tutee, where appropriate, in University processes affecting him/her.


  • geochemistry
  • weathering processes
  • weathering rates
  • critical zone
  • soils
  • biogeochemistry
  • isotope geochemistry
  • geomicrobiology

Selected publications

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View complete publications list in the University of Bristol publications system


Dr Buss currently teaches 4 courses:

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