Dr Kate O Brien

Senior Lecturer

+61 7 336 53534

School of Chemical Engineering
The University of Queensland
St Lucia, 4072



  • 2003 PhD The University of Western Australia  The effects of turbulent mixing on the vertical distribution of phytoplankton populations”  Supervisors Greg Ivey, David Hamilton, Anya Waite
  • 1994 Bachelor of Chemical Engineering, Honours I, The University of Queensland, Australia
  • 1994 Bachelor of Science (Mathematics) The University of Queensland, Australia



I undertake research in environmental systems modelling, analysis and synthesis.  This involves working in interdisciplinary teams with ecologists, engineers, economists, remote sensing and field scientists to develop and apply models to address important environmental questions, and to use systems analysis and resilience thinking to identify key controlling variables.  A key question driving my research is, how can scientific knowledge in complex systems be synthesized to inform management actions and promote sustainability?  Student internship and PhD projects available.

Modelling seagrass dynamics for effective management

Seagrass  health is a key ecological indicator in coastal systems, providing essential ecosystem services.  My team is analysing how interactions between natural and anthropogenic processes across different spatial and temporal scales affect seagrass resilience.  Student internship and PhD projects available. 

Nutrient and sediment retention in reservoirs:  costs and implications for land fertility, eutrophication and global phosphorus availability

The loss of soil, nitrogen and phosphorus from terrestrial systems to aquatic systems has increased substantially over the past half-century due to accelerated land-use change, vegetation clearing and fertilizer application.  However impoundment of waterways has reduced the load of sediment and nutrient delivered to the ocean from many river systems.  The result has been the accumulation of nutrient and sediment material in reservoirs.   This study aims to quantify the magnitude, uncertainty and dynamics of phosphorus, nitrogen and sediment retained by a number of Australian reservoirs, and assess the implications for economics, land fertility, eutrophication and global P availability.  Student internship and PhD projects available. 

Planetary quotas: addressing the tragedy of the commons on a global scale

(Rockstrom et al. 2009) defined "planetary boundaries" for 9 earth systems processes, within which we can expect to maintain a "safe operating space" for humanity.  A number of these thresholds have already been exceeded, and we are accelerating towards others.  The fundamental challenge humanity faces can be characterized as the “tragedy of the commons”: whereby we benefit individually and immediately from actions which lead to long-term consequences shared across a wider population.  For example, the greenhouse gas emissions generated from a flight to Sydney for the weekend: we benefit immediately from the trip, but the consequences are deferred and shared amongst the global population. Many studies have quantified footrprint of individuals, organisations and nations in various forms, and concluded that we are indeed living beyond our means , e.g.(Wackernagel et al. 2002; MEA 2005).  However individuals lack quantitative guidelines for sustainable consumption: how many GHG emissions per capita globally would keep temperature rise to less than 2 oC, and what does this translate to in terms of personal energy usage, transport and air travel? The purpose of this project is to quantify individual "quotas" which would enable people to make informed choices about how they can consume a sustainable share of the world's resources, and so directly address the tragedy of the commons.  Student internship and PhD projects available. 

Minimising greenhouse gas emissions from the concrete industry: identifying the right incentives, mechanisms and metrics

The concrete industry is major contributor to global greenhouse gas (GHG) emissions, and the largest consumer of resources globally.  The production of Portland cement, a key ingredient in concrete, accounts for approximately 80 % of GHG emissions associated with concrete.  The main pathway to reduce GHG emissions is to replace Portland cement with “supplementary cementitious materials” (SCM), which are waste by-products from other industries (O’Brien et al. 2009).  Common SCM include fly ash from coal-fired power stations, and blast furnace slag from the steel production (O'Moore and O'Brien 2009).  Policies implemented to reduce GHG emissions from the concrete industry have sometimes produced perverse outcomes, either due to use of incorrect metric (e.g. SCM usage, rather than the reduction in Portland cement or GHG emissions), or providing incentives to source cement offshore (e.g. carbon tax on local but not imported Portland cement). The purpose of this project is to use analysis and modelling to identify strategies for GHG gas reductions from the concrete industry. Student internship and PhD projects available. 


Modelling challenges and opportunities in workforce diversity

The number of women studying engineering, maths and science has increased enormously in recent decades. Women leave science and engineering fields at a greater rate than men.  This phenomenon is called “the leaky pipe”, and is attributed to a range of factors, including but not limited to the competing demands of family responsibilities and a competitive workplace.  While women have high representation and performance in undergraduate and postgraduate studies, women perform worse than men in their research careers, according to most common measures.  For example, all 37 scientists shortlisted for Australian Academy of Science fellowships in 2013 were male, even though women have accounted for 30-60 % of PhD graduates in science and mathematics in Australia since 1997 (Hilton 2013).   This is part of the larger challenge of increasing workforce diversity, which can be characterized as a wicked problem.   Diversity to improve team performance, but there are many barriers to increasing diversity within institutions and disciplines: e.g. optimizing the performance of individuals rather than teams, and unconscious bias.   The purpose of this project is to mathematically model the causes and evaluate the effectives of potential solutions to the “leaking pipeline” problem of poor female retention in science and engineering, using a combination of mathematical model and data collection.  The results will be applied more broadly, to identify barriers and solutions to creating diverse teams in different fields worldwide.  Student internship and PhD projects available

Teaching and Learning: 

2012 - present Developed and co-ordinated Introduction to environmental systems engineering CHEE2501

2011- present BE/ME chemical-environmental program leader

2006-present Lecturer and course coordinator in Heat and mass transfer CHEE3002

2003-2008 Lecturer in Engineering analysis of environmental systems in Introduction to Professional Engineering ENGG1000

Teaching awards: Nominated for UQ Excellence in Teaching Award 2010-2012, Awarded EAIT Faculty Excellence in Teaching Award 2009, Awarded School of Engineering Excellence in Teaching Award 2008, received more than 30 Dean’s Commendations for effective teaching 2006-2012.




    Project title

    Granting Agency

    Chief Investigators


    Seagrass growth and diversity: attributes of a resilient GBR (Phase II)


    Great Barrier Reef Foundation

    Collier, van Dijk, Adams, O’Brien, Waycott, McKenzie, Uthicke, Phinn, Roelfsema


    Seagrass connectivity, community composition and growth: attributes of a resilient Great Barrier Reef (Phase I)

    Great Barrier Reef Foundation

    Collier, van Dijk, O’Brien, Waycott, McKenzie, Uthicke, Liddy, Phinn


    Assessment of carbon partitioning and storage in seagrass ecosystems using mathematical models validated across multiple latitudes and species

    UWA-UQ Bilateral Research Collaboration Award (BRCA) Scheme

    O’Brien, Kendrick, Adams, Hovey, Hipsey, Bruce, Lowe


    Modelling resilience and critical thresholds in seagrass systems

    EAIT strategic grant



    Seagrass as an ecological indicator: resolving challenges of scale and complexity

    UQ Collaboration and Industry Engagement Fund

    O’Brien, Mumby, Callaghan, Roelfsema, Grinham


    Sources of phosphorus promoting cyanobacteria in subtropical reservoirs

    ARC linkage

    Burford, O’Brien, Hamilton, Lemckert


  • Matthew Prentice, PhD in progress, The role of phosphorus in promoting cyanobacteria blooms in subtropical reservoirs
  • Emily Saeck, PhD 2012, Nutrient dynamics of coastal phytoplankton: the role of episodic flow events and chronic sewage discharges
  • Michael Kehoe, PhD 2010, Modelling of physical and physiological processes controlling primary production and growth in cyanobacteria
  • Dana Burfeind, PhD 2009, Caulerpa taxifolia growth dynamics in invasive and native populations


Key Publications: 
  • Saunders, M.I., Leon, J.P., Phinn, S.R., Callaghan, D.P.,  O’Brien, K.R.,  Roelfsema, C.M.,  Lovelock, C. E., Lyons, M.B.  and  Mumby, P. J. (2013) Coastal retreat and improved water quality mitigate losses of seagrass from sea level rise. Global Change Biology, in press
  • Saeck , E.A., O’Brien, K.R., Weber, T.R and Burford M.A. (2013) Changes to chronic nitrogen loading from sewage discharges modify standing stocks of coastal phytoplankton.  Marine Pollution Bulletin, in press.
  • Burfeind, D.D., O'Brien, K.R. and Udy, J.W. (2013) Water temperature and benthic light levels drive horizontal expansion of Caulerpa taxifolia in native and invasive locations. Marine Ecology Progress Series, 472 : 61-72.
  • Brookes, J.D.,  O’Brien, K.R.,  Burford, M.A., Bruesewitz, D.A., Hodges, B.R. McBride, C. , and Hamilton, D.P. (2013) Effects of diurnal vertical mixing and stratification on
  • phytoplankton productivity in geothermal Lake Rotowhero, New Zealand. Inland Waters 3, 369-376.
  • Saeck, E.A., Hadwen, W.D., Rissik, D.A., O’Brien, K.R. and Burford, M.A. (2013) Flow events drive patterns of phytoplankton distribution along a river-estuary-bay continuum. Marine & Freshwater Research, in press.
  • Kehoe, M., O'Brien, K.R., Grinham, A., Rissik, D., Ahern, K. S. and Maxwell, P. (2012) Random forest algorithm yields accurate quantitative prediction models of benthic light at intertidal sites affected by toxic Lyngbya majuscula blooms. Harmful Algae, 19 : 46-52. 
  • Burford, M.A., Green, S.A., Cook, A.J., Johnson, S.A., Kerr, J.G., O’Brien, K.R. 2012. Sources and fate of nutrients in a subtropical reservoir. Aquatic Sciences, 74 1: 179-190.
  • O'Brien, K.R., Hapgood, K.P. 2012 The academic jungle: Ecosystem modelling reveals why women are driven out of research. Oikos, 121 7: 999-1004.
  • O'Brien, K., Hapgood, K. 2011 Part-time balance. Nature, 479 : 257-258.
  • Hamilton, D.P., O’Brien, K.R., Burford, M.A., Brookes, J.D., McBride, C.G. 2010. Vertical distributions of chlorophyll in deep, warm monomictic lakes. Aquatic Sciences 72: 295-307.
  • O’Brien, K.R., M.A. Burford and J.D Brookes. 2009. Effects of light history on primary productivity in a phytoplankton community dominated by the toxic cyanobacterium Cylindrospermopsis raciborskii. Freshwater Biology: 54 2: 272-282.
  • O’Brien, K.R., J. Menache, L.M. O’Moore 2009 Impact of fly ash content and fly ash transportation distance on embodied greenhouse gas emissions and water consumption in concrete. Int. J. Life Cycle Assessment, 14: 621-629.
  • O'Brien, K.R., A.M. Waite, B.L. Alexander, K.A. Perry and L.E. Neumann. 2006. Particle-tracking in a salinity gradient: a method for measuring sinking rate of individual phytoplankton in the laboratory Limnology and Oceanography: Methods, 4:329-335.
  • O’Brien, K.R., D.L. Meyer, A.M. Waite, G.N. Ivey, and D.P. Hamilton. 2004. Disaggregation of Microcystis aeruginosa colonies under turbulent mixing: laboratory experiments in a grid-stirred tank. Hydrobiologia 519: 143-152.
  • O'Brien, K, G.N. Ivey, D.P. Hamilton, A.M. Waite and P.M. Visser. 2003. Simple criteria for the growth of negatively buoyant phytoplankton. Limnology and Oceanography 48: 1326-1337.