Conservation at Cambridge

The Australian Antarctic Program Partnership (AAPP) is focused on understanding the nature and impacts of Southern Ocean Change. The Biogeochemistry Project, one of the seven complementary initiatives within the AAPP , combines observations, models and data syntheses to understand changes in the Southern Ocean carbon cycle. This work is undertaken in collaboration with other government agencies, national infrastructure programs, and academic institutions, and highlights the use of essential ocean observations and models to improve understanding and deliver impact. An overview of recent field programs will be presented, along with new work to quantify the uptake and storage of anthropogenic CO2 in the ocean, to validate estimates of ocean carbon export from autonomous platforms, and to improve model representation of air-sea CO2 exchange.

• Speaker: Elizabeth H. Shadwick, CSIRO Environment
• Wednesday 04 June 2025, 13:00-14:00
• Venue: BAS Seminar Room 1.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Abstract: The effects of aerosols on the Earth’s energy balance since pre-industrial times (aerosol radiative forcing) has significantly and repeatedly dominated the uncertainty in reported estimates of global temperature change from the IPCC . The magnitude of aerosol radiative forcing of climate over the industrial period is estimated to lie between about -2 and -0.4 W m-2, compared to a much better understood forcing of 1.6 to 2.0 W m-2 due to CO2 . In this seminar, past efforts to quantify the range of possible aerosol forcings predicted from an aerosol-climate model that are caused by parametric uncertainty, and to constrain that forcing uncertainty through model-observation comparison using extensive aerosol and cloud-based measurements from ships, flight campaigns, satellites and ground stations, will be discussed. We find that despite a very large reduction in plausible parameter space and reasonable constraint on observable properties, the observational constraint based on this comprehensive set of measurements only partially reduces the range of aerosol radiative forcings from our model. In the NERC project ‘Towards Maximum Feasible Reduction in Aerosol Forcing Uncertainty’ (Aerosol-MFR), several key statistical challenges highlighted from this work are being addressed in order to improve the model-observation comparison process for uncertainty constraint. This includes optimising the way observational constraints are applied, designing new approaches for reducing error compensation effects and using the PPE to identify and characterise model structural errors. Preliminary results from the project so far will be outlined, along with further plans to tackle this important problem.

Biography: Dr Jill Johnson is a Lecturer in Statistics in the School of Mathematical and Physical Sciences at the University of Sheffield. Her research interests are in the development and practical application of statistical methods to quantify, assess and then reduce uncertainty in large-scale complex models of real-world systems, with a focus on problems in environmental science. Prior to joining Sheffield in August 2021, Jill worked as an applied statistician / research associate for over 8 years in the aerosol research group at the Institute for Climate and Atmospheric Science, University of Leeds, where her work focussed on the quantification and constraint of key uncertainties in models of the atmosphere and climate. Her current research builds on this work, including the NERC research project ‘Towards Maximum Feasible Reduction in Aerosol Forcing Uncertainty (Aerosol-MFR)’.

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• Speaker: Dr Jill S Johnson; School of Mathematical and Physical Sciences, University of Sheffield, UK
• Tuesday 24 June 2025, 14:00-15:00
• Venue: Chemistry Dept, Unilever Lecture Theatre and Teams.
• Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Yao Ge.

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The Australian Antarctic Program Partnership (AAPP) is focused on understanding the nature and impacts of Southern Ocean Change. The Biogeochemistry Project, one of the seven complementary initiatives within the AAPP , combines observations, models and data syntheses to understand changes in the Southern Ocean carbon cycle. This work is undertaken in collaboration with other government agencies, national infrastructure programs, and academic institutions, and highlights the use of essential ocean observations and models to improve understanding and deliver impact. An overview of recent field programs will be presented, along with new work to quantify the uptake and storage of anthropogenic CO2 in the ocean, to validate estimates of ocean carbon export from autonomous platforms, and to improve model representation of air-sea CO2 exchange.

• Speaker: Elizabeth H. Shadwick, CSIRO Environment
• Wednesday 04 June 2025, 14:00-15:00
• Venue: BAS Seminar Room 1.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Compelling evidence indicates that ocean circulation is undergoing significant changes due to global warming. These changes include reduced ocean ventilation caused by increased stratification and the weakening of the Atlantic Meridional Overturning Circulation (AMOC). Consequently, this will alter carbon, oxygen, heat and nutrient distribution, and will therefore affect primary production and, by extension, the biological carbon pump. Due to the ocean’s huge capacity for carbon storage, it is imperative that we understand the consequences of these changes.

To examine how ocean ventilation influences the biological carbon pump and overall oceanic carbon storage, an idealised box model of ocean carbon and heat uptake is extended to include biological processes and nutrient cycling. The model includes a thermocline with a dynamically controlled thickness and meridional overturning circulation, both of which vary with increasing temperatures, determining the extent of ocean ventilation. This model, previously employed to analyse the ocean’s carbon and thermal response to anthropogenic emissions, is now adapted to explore the effects of changing overturning on the biological carbon pump. A simple nutrient-phytoplankton-zooplankton-detritus (NPZD) biological model is introduced to simulate the role of macronutrient concentrations on phytoplankton and zooplankton growth. Simulations are conducted under scenarios of both constant and changing circulation to investigate the impacts of slower circulation on the biological carbon pump and its contribution to oceanic carbon storage.

• Speaker: Elisavet Baltas, University of Cambridge
• Wednesday 11 June 2025, 14:00-15:00
• Venue: BAS Seminar Room 2.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Yohei Takano.

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Abstract not available

• Speaker: Elisavet Baltas, University of Cambridge
• Wednesday 11 June 2025, 14:00-15:00
• Venue: BAS Seminar Room 2.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Yohei Takano.

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Abstract: Ice-nucleating particles (INPs) have important influences on cirrus clouds and the climate system; however, the understanding of their global impacts is still uncertain. We perform numerical simulations with a global aerosol–climate model to analyse INP -induced cirrus modifications and the resulting climate impacts. We evaluate various sources of uncertainties, e.g. the ice-nucleating ability of INPs and the role of model dynamics, and provide a new estimate for the global INP –cirrus effect.

Biography: Study of Physics (Bachelors and Masters) at Ludwig Maximilian University of Munich (2010-2016) PhD student at the German Aerospace Center (DLR); Institute of Atmospheric Physics, Earth System Modelling Department, Oberpfaffenhofen (2017-2021); Dissertation title: “Global modelling of ice nucleating particles and their effects on cirrus clouds” Postdoc at DLR (since 2021)

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• Speaker: Dr. Christof Beer
• Tuesday 10 June 2025, 11:00-12:00
• Venue: Chemistry Dept, Unilever Lecture Theatre and Teams.
• Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Yao Ge.

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Abstract: Wildfire events have increased in frequency in recent years, especially in regions dominated by elevated temperatures, dry and windy conditions (Donahue et al., 2009; Hodshire et al., 2019). During such events, the generated fire plume contains a mixture of gaseous and particulate species (Figure 1), driving the chemical processing both during the initial and aging stage (Hodshire et al., 2019). Organic aerosols (OA) comprise a large portion of the available chemical species inside a fire plume and their evolution is primarily determined by two competing regimes (Garofalo et al., 2019): (1) oxidation-driven condensation and (2) dilution-driven evaporation. Key components of OA are light-absorbing species (LAS), notably black and brown carbon. Although LAS are not a traditional metric of OA chemical regime identification, their concentrations, together with key gas-phase tracers and water soluble organic carbon, provide crucial insights into the dominant in-plume chemical regime. We evaluated the relationship between fuel type, LAS levels, and fire tracers to assess their connection regime prevalence. Data obtained from the 2019 FIREX -AQ campaign (Warneke et al. 2022) were used to analyse 13 fire plumes across seven flights in late July and early August over the northwestern United States. All flights were conducted at night, restricting the sunlight-driven photochemistry and thus quenching rapid oxidation by hydroxyl radicals. Thus, the fuel composition emerges as the primary driver of LAS and OA regime evolution within the fire plumes.

Biography: Dr. Eleni Dovrou is currently a Postdoctoral Researcher at the Technical University of Crete in the School of Environmental and Chemical Engineering in the Atmospheric Environment and Climate Change Laboratory (Voulgarakis Group). She is an environmental engineer with specialization in atmospheric chemistry and health effects. She obtained her PhD from Harvard University (Keutsch Group), where she focused on molecular level reactions in the troposphere. Upon completion of her PhD, in 2020, she worked as a Postdoctoral Fellow at the Max Planck Institute of Chemistry (Poeschl Group) focusing on laboratory and modeling studies of the effect of atmospheric reactive species on the respiratory and circulatory system. In 2022 she obtained a Postdoc position at the Foundation for Research and Technology Hellas (Pandis Group), where she worked on indoor air quality. She has experimental, field and modeling experience. Her current research focuses on understanding the effect of extreme events, and especially fires, targeting the potential chemical mechanisms that dominate and influence future air quality. Starting this fall, she will be an Assistant Professor in Chemistry at the University of Crete.

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• Speaker: Dr. Eleni Dovrou, Technical University of Crete
• Tuesday 27 May 2025, 11:00-12:00
• Venue: Chemistry Dept, Unilever Lecture Theatre and Teams.
• Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Yao Ge.

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Abstract: Ensembles of simulations from multiple climate models (‘simulators’) underpin much of our understanding of the climate system, and in particular the potential evolution of future climate in response to different scenarios of socioeconomic development and the associated greenhouse gas emissions. No simulator is perfect, however; and ensemble outputs contain structured variation reflecting simulator inter-relationships, as well as shared discrepancies between the simulators and the real climate system. This structure must be accounted for when using ensembles to learn about aspects of the real climate, especially when defensible assessments of uncertainty are needed to support decision-making. This talk will discuss the issues involved, and describe a statistical framework for addressing the problem. A theoretical analysis leads to a mathematical result with major implications for the design and analysis of multimodel ensembles; whilst the practical application of the framework will be demonstrated using future climate projections for the United Kingdom from two contrasting ensembles (UKCP18 and EuroCORDEX). These ensembles have different structures and properties: the approach is shown to reconcile the substantial differences between the original ensemble outputs, in terms of both the real-world climate of the future and the associated uncertainties.

Biography: Richard is a Professor in the Department of Statistical Science at University College London, where he has worked since completing his PhD at UMIST in 1994. He has extensive experience of developing and applying statistical methods for the environmental sciences. Particular interests include the analysis of time series and space-time data, with application areas including hydrology and the impacts of climate change. Other areas of interest include the assessment of uncertainty when interpreting model outputs; the use of mis-specified models; and the use of nonprobability samples to draw population inferences in ecology.

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• Speaker: Prof Richard Chandler, UCL
• Tuesday 13 May 2025, 11:00-12:00
• Venue: Chemistry Dept, Unilever Lecture Theatre and Teams.
• Series: Centre for Atmospheric Science seminars, Chemistry Dept.; organiser: Yao Ge.

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PROGRAMME : https://tinyurl.com/4mnf673f

The Cambridge Centre for Climate Science (in collaboration with the Institute of Computing for Climate Sciences, the British Antarctic Survey and the UK Polar Network) is inviting you to join the CCfCS Polar Symposium 2025. The aim of this event is to connect polar and climate researchers in Cambridge (in both science and humanities) and provide an overview of the work at Cambridge which contributes to understanding and mitigating climate change.

This will be an afternoon of talks from a variety of research institutions and departments in Cambridge, followed by a poster session and workshop aimed at early-career researchers. The event will be a great opportunity to find new collaborators and meet like-minded people interested in polar science and climate change across Cambridge. Early career researchers are particularly encouraged to participate.

Event details:

• When: Monday 12th May 2025 13:00-18:00
• Where: British Antarctic Survey, Conference Theatre
• Registration fee: Free!
• If you wish to attend (presenting or not) please register here: https://forms.gle/kCLv1QWixdfmKb4ZA

If you are interested in presenting a talk or poster, please provide a title and brief abstract in the registration form. The talks should be short (10-15 mins) and accessible to an interdisciplinary audience. In-person attendance is recommended, as the poster session and catering will only be available in-person, however the talks will be also streamed online for anyone unable to attend in-person. We will provide a more detailed schedule once we have collected all the abstracts. The day will include free hot drinks, cake and snacks, and the event will be followed by a social (TBC).

Abstract deadline: Monday 21st April 2025, 17:00

We look forward to seeing you soon! The Organising Committee Polina, Tarkan, Birgit and Sophie

• Speaker: Speaker to be confirmed
• Monday 12 May 2025, 13:00-18:00
• Venue: British Antarctic Survey, Aurora Conference Room.
• Series: Cambridge Centre for Climate Science; organiser: Polina Sevastyanova .

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The dense waters formed on the broad shelf of the western Weddell Sea are a source of Weddell Sea Bottom Water (WSBW), which transports anthropogenic CO2 along the continental slope to the bottom of the ocean. Our updated time series shows a positive trend of carbon in WSBW . To understand the drivers for this pathway for carbon sequestration, we need to understand the processes affecting carbon concentrations in shelf waters at the time of dense water formation, which is predominantly during sea ice formation in winter. Unfortunately, wintertime marine observations are particularly scarce in the western Weddell Sea. We are therefore testing a method that reconstructs the seawater partial pressure of CO2 (pCO2) representative of wintertime conditions in this dense-water formation region, using carbonate chemistry observations made in WSBW in the summer. Results suggest that atmospheric CO2 uptake is the main driver of increasing carbon in WSBW , and thus that equilibration of surface seawater with the atmosphere is possible despite year-round sea ice cover in this region.

• Speaker: Elise Droste (University of East Anglia)
• Wednesday 07 May 2025, 14:00-15:00
• Venue: BAS Seminar Room 1.
• Series: British Antarctic Survey - Polar Oceans seminar series; organiser: Dr Birgit Rogalla.

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Abstract not available

• Speaker: Speakers listed in abstract in due course
• Friday 30 May 2025, 14:00-17:00
• Venue: MR3.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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Abstract not available

• Speaker: Speakers listed in abstract in due course
• Friday 30 May 2025, 14:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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Artificial intelligence (AI) is transforming weather and climate modeling. For example, neural network-based weather models can now outperform physics-based models for up to 15-day forecasts at a fraction of the computing time. However, these AI models have challenges with learning the rarest yet most impactful weather extremes, particularly the gray swans (i.e., physically possible events so rare they have never been seen in the training set). They also poorly learn multi-scale chaotic dynamics. I will discuss some of these challenges, as well as some of the surprising capabilities of these models, e.g., transferring what they learn from one region to another for dynamically similar event. I will present ideas around integrating tools from applied math, climate physics, and AI to address some of these challenges and make progress. In particular, I will discuss the use if rare event sampling algorithms and the Fourier transform and adjoint of the deep neural networks.

• Speaker: Prof Pedram Hassanzedeh, University of Chicago
• Friday 16 May 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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All are invited to the Bradford Hill Seminar:

The SIREN study at five years: Tracking SARS -CoV-2 and respiratory infections in UK healthcare workers since 2020

Speaker: Victoria Hall, Consultant Epidemiologist, Antimicrobial Resistance & Healthcare Associated Infections Division of the UK Health Security Agency (UK HSA )

Register to attend Please note this will be a free hybrid seminar, with the option to attend in-person (Large Seminar Room, East Forvie Building, Forvie Site, Robinson Way, Cambridge CB2 0SR ) or virtually (via Zoom).

No registration is required to attend in person.

Register in advance to attend this seminar online at:

https://cam-ac-uk.zoom.us/meeting/register/CoavXVmNQtWN8j8TOFv-rg#/registration

Abstract The SARS -CoV-2 Immunity and Reinfection Evaluation (SIREN) study is a prospective cohort study of hospital-based healthcare workers across the UK. It was established in 2020 as a pandemic response study, with over 44,000 healthcare workers recruited from 135 NHS trusts/health boards. The study initially investigated SARS -CoV-2 reinfections and the durability of immunity following infection, and subsequently COVID -19 vaccination. It has expanded its scope to evaluate Winter Pressures on the healthcare workforce, and questions related to immunity more broadly.

SIREN has been running since 2024. This has involved collecting data on symptoms and absence from time off work trends in around 5000 participants recruited from the original SIREN cohort. In addition to investigating Winter Pressures, SIREN provides an opportunity to address new research questions of public health importance that impact healthcare workers, including the emergence of multidrug resistant organisms and risk factors for healthcare associated infections.

More details on the study and publications from the study can be found here: https://www.gov.uk/guidance/siren-study

About Victoria Hall Victoria Hall is a Consultant Epidemiologist in the Antimicrobial Resistance & Healthcare Associated Infections Division of the UK Health Security Agency and has been leading the SIREN study team since 2020. She completed public health speciality training in the East of England and the UK Field Epidemiology Training Programme based in South East and London Regional Field Epidemiology Service. She holds a part-time position at the Institute for Health Informatics, UCL working on research on infections and AMR in care homes with the VIVALDI study.

About the Bradford Hill seminars The Bradford Hill seminar series is the principal series of The Cambridge Population Health Sciences Partnership, in collaboration with the PHG Foundation. This comprises the Departments of Public Health & Primary Care, MRC Biostatistics Unit and MRC Epidemiology Unit at the University of Cambridge, bringing together a multi-disciplinary partnership of academics and public health professionals. The Bradford Hill seminar programme of internationally recognised speakers covers topics of broad interest to our public health research community. It aims to transcend as well as connect the activities of our individual partners.

All are welcome at our Bradford Hill seminars.

• Speaker: Victoria Hall, UK Health Security Agency
• Wednesday 07 May 2025, 13:00-14:00
• Venue: Large Seminar Room, East Forvie Building, Forvie Site Robinson Way Cambridge CB2 0SR..
• Series: Bradford Hill Seminars; organiser: Paul Browne.

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All are invited to the Bradford Hill Seminar:

The SIREN study at five years: Tracking SARS -CoV-2 and respiratory infections in UK healthcare workers since 2020

Speaker: Victoria Hall, Consultant Epidemiologist, Antimicrobial Resistance & Healthcare Associated Infections Division of the UK Health Security Agency (UK HSA )

Register to attend Please note this will be a free hybrid seminar, with the option to attend in-person (Large Seminar Room, East Forvie Building, Forvie Site, Robinson Way, Cambridge CB2 0SR ) or virtually (via Zoom).

No registration is required to attend in person.

Register in advance to attend this seminar online at:

https://cam-ac-uk.zoom.us/meeting/register/CoavXVmNQtWN8j8TOFv-rg#/registration

Abstract The SARS -CoV-2 Immunity and Reinfection Evaluation (SIREN) study is a prospective cohort study of hospital-based healthcare workers across the UK. It was established in 2020 as a pandemic response study, with over 44,000 healthcare workers recruited from 135 NHS trusts/health boards. The study initially investigated SARS -CoV-2 reinfections and the durability of immunity following infection, and subsequently COVID -19 vaccination. It has expanded its scope to evaluate Winter Pressures on the healthcare workforce, and questions related to immunity more broadly.

SIREN has been running since 2024. This has involved collecting data on symptoms and absence from time off work trends in around 5000 participants recruited from the original SIREN cohort. In addition to investigating Winter Pressures, SIREN provides an opportunity to address new research questions of public health importance that impact healthcare workers, including the emergence of multidrug resistant organisms and risk factors for healthcare associated infections.

More details on the study and publications from the study can be found here: https://www.gov.uk/guidance/siren-study

About Victoria Hall Victoria Hall is a Consultant Epidemiologist in the Antimicrobial Resistance & Healthcare Associated Infections Division of the UK Health Security Agency and has been leading the SIREN study team since 2020. She completed public health speciality training in the East of England and the UK Field Epidemiology Training Programme based in South East and London Regional Field Epidemiology Service. She holds a part-time position at the Institute for Health Informatics, UCL working on research on infections and AMR in care homes with the VIVALDI study.

About the Bradford Hill seminars The Bradford Hill seminar series is the principal series of The Cambridge Population Health Sciences Partnership, in collaboration with the PHG Foundation. This comprises the Departments of Public Health & Primary Care, MRC Biostatistics Unit and MRC Epidemiology Unit at the University of Cambridge, bringing together a multi-disciplinary partnership of academics and public health professionals. The Bradford Hill seminar programme of internationally recognised speakers covers topics of broad interest to our public health research community. It aims to transcend as well as connect the activities of our individual partners.

All are welcome at our Bradford Hill seminars.

• Speaker: Victoria Hall, UK Health Security Agency
• Wednesday 07 May 2025, 13:00-14:00
• Venue: Large Seminar Room, East Forvie Building, Forvie Site Robinson Way Cambridge CB2 0SR..
• Series: Bradford Hill Seminars; organiser: Paul Browne.

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Abstract not available

• Speaker: Prof Pedram Hassanzedeh, University of Chicago
• Friday 16 May 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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Abstract not available

• Speaker: Speakers listed in abstract in due course
• Friday 30 May 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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Abstract not available

• Speaker: Prof Omar Matar, Imperial College London
• Friday 06 June 2025, 16:00-17:00
• Venue: https://cassyni.com/s/fmws.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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The observation of flocks of birds, schools of fish, and swarms of bees reveals captivating examples of collective behavior in nature. Over the past decade, physicists have unveiled intriguing features in such systems, giving rise to both spectacular phenomena and fundamental questions. In this presentation, we will first explore active wetting phenomena in a suspension of self-propelled Janus colloids near a vertical wall. While classical capillary rise is governed by equilibrium surface tension, active fluids challenge this paradigm. We investigate whether analogous interfacial effects emerge in non-phase-separated active sediments, uncovering how self-propulsion modifies wetting behavior. By studying the interaction between a non-phase-separated active sediment and a wall, we uncover how self-propulsion alters wetting-like behavior, offering insights into the role of activity in interfacial processes. In the second part, we turn to magnetotactic bacteria— microswimmers equipped with intracellular magnetic nanoparticles, enabling directed motion along magnetic fields. These bacteria exhibit dual sensitivity, responding not only to magnetic fields (magnetotaxis) but also to oxygen gradients (aerotaxis), which drives them to form dense, dynamic bands. We demonstrate how the interplay of magnetic steering, chemical gradients, and hydrodynamic interactions leads to rich self-organization.

• Speaker: Prof Cottin-Bizonne, Université Lyon
• Friday 23 May 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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Many real-life fluids are not Newtonian and have to be modelled with something more complex than a single scalar viscosity. In this talk we will look specifically at dilute polymer solutions. We’ll see some simple models that capture the essential features of their behaviour, and then investigate how the properties of these models affect the stability of channel flow.

The story spans my whole research career so far, from an early theoretical prediction which was later observed in experiments, to a more recent realisation that there is still quite a lot we don’t understand. If time permits I will also discuss the latest place the research has taken me, which is neither viscoelastic nor unstable.

• Speaker: Prof Helen Wilson, University College London
• Friday 02 May 2025, 16:00-17:00
• Venue: MR2.
• Series: Fluid Mechanics (DAMTP); organiser: Professor Grae Worster.

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