All seminars will take place from 13:00 to 14.00, with coffee and tea at 12:30 in the lobby outside the upstairs entrance G.03 on the first floor of the Williamson Building. These seminars are open to all and are a good opportunity to meet your fellow students and staff.
For details of previous seminars please see our seminar archive.
Title: Pollution of Urban Rivers: A Call for an Inclusive Assessment
Abstract: All European Union Rivers, including urban systems, are expected to achieve “Good Ecological Status” for physical, chemical and benthic macroinvertebrate parameters according to the EU’s Water Framework Directive (EUWFD). Achieving good ecological status focuses on improvements in water quality. However, an alternative hypothesis explains the distribution of benthic macroinvertebrates in urbanised rivers in relation to urban area and resulting changes in the flow regime to due episodic run-off. The study location, River Medlock, Greater Manchester, UK was selected due to its legacy of industrial pollution, the presence of a major wastewater treatment works (WwTW), numerous combined sewer overflows (CSOs) and mixed catchment land use with 37% urban area. Five sample sites were selected upstream and downstream of the WwTW and CSOs over a distance of 17 km. Physical, chemical variables consisting of dissolved oxygen, pH, conductivity, temperature, suspended solids, nutrients, flow and discharge plus the benthic macroinvertebrate community were analysed. Based on the EU WFD, the physical/chemical results indicated little sewage pollution which classified the river as “good” while invertebrate indices indicated “poor” quality and with declining condition downstream. Covariation between the variables, altitude, latitude and slope using PRIMER-6 BIOENV showed the assemblages of benthic macroinvertebrates were strongly associated with these natural variables plus anthropogenically influenced changes in discharge rather than point and diffuse pollution. The results show the EU WFD assessment is insufficient for the classification of urban rivers due to the influence of episodic urban run-off on discharge. The presentation will also discuss the uncertainties of EU WFD post Brexit.
Title: The Light at the End of the Tunnel: New Developments in Synchrotron Methods applied to the Study of Ancient Life
Abstract: For over a decade X-ray imaging and spectroscopy has been developed in a partnership between the University of Manchester and Stanford University in order to resolve and study trace quantities of residual biochemistry in exceptionally preserved fossils. Recently, a large tranche of funding has been secured and applied to upgrade one of the beamlines at the Stanford Synchrotron Radiation Lightsource specifically to improve and extend that beamline for studying such specimens. In tandem, developments of new capabilities have also been pioneered in collaborations with the Diamond Light Source and the Soleil Synchrotron. This presentation will review some of the most recent results in this field and then describe the new capabilities that are now available as a result of collaborative development with these major X-ray facilities. The technique development has relevance not only to the study of residual biochemistry, but also creates opportunities in studying most classes of natural solid phase material, from meteorites to extant plant spores, from nuclear waste pond solids to the pigments in your skin and hair.
Title: Investigating meat-eating in human evolutionary history
Abstract: Despite the popularity of the modern “paleodiet” movement, which usually assumes our ancestors ate large proportions of meat in their diets, only a handful of prehistoric archaeologists are actively engaged in research to determine if and how Early Stone Age humans routinely procured resources from large animals as a part of their overall foraging strategies. In this talk, I’ll outline the different kinds of evidence we can use to investigate this fundamental shift in human evolutionary history with a focus on butchery experiments conducted with stone tools, prey consumption and chewing damage left on bones by captive and free-ranging carnivores, and traces of bone surface modifications left by humans and carnivores on fossil assemblages. I’ll describe the results of studies I have conducted using all three of these approaches, including a study of modern large carnivore prey consumption in central Kenya that supports the idea of a scavenging niche for early humans and a study of bone surface modification on 1.5 million year old fossil assemblages from northern Kenya that documents early access to large animal carcasses by Homo erectus, the first early human species that incorporated substantial amounts of meat into its diet.
Title: Understanding the environmental impacts of large fissure eruptions: Aerosol and gas emissions from the 2014–2015 Holuhraun eruption (Iceland)
Abstract: The 2014–2015 Holuhraun eruption in Iceland, emitted ∼11 Tg of SO2 into the troposphere over 6 months, and caused one of the most intense and widespread volcanogenic air pollution events in centuries. This study provides a number of source terms for characterisation of plumes in large fissure eruptions, in Iceland and elsewhere. We characterised the chemistry of aerosol particle matter (PM) and gas in the Holuhraun plume, and its evolution as the plume dispersed, both via measurements and modelling. The plume was sampled at the eruptive vent, and in two populated areas in Iceland. The plume caused repeated air pollution events, exceeding hourly air quality standards (350 μg/m3) for SO2 on 88 occasions in Reykjahlíð town (100 km distance), and 34 occasions in Reykjavík capital area (250 km distance). Average daily concentration of volcanogenic PM sulphate exceeded 5 μg/m3 on 30 days in Reykjavík capital area, which is the maximum concentration measured during non-eruptive background interval. There are currently no established air quality standards for sulphate. Combining the results from direct sampling and dispersion modelling, we identified two types of plume impacting the downwind populated areas. The first type was characterised by high concentrations of both SO2 and S-bearing PM, with a high Sgas/SPM mass ratio (SO2(g)/View the MathML source(PM) > 10). The second type had a low Sgas/SPM ratio (<10). We suggest that this second type was a mature plume where sulphur had undergone significant gas-to-aerosol conversion in the atmosphere. Both types of plume were rich in fine aerosol (predominantly PM1 and PM2.5), sulphate (on average ∼90% of the PM mass) and various trace species, including heavy metals. The fine size of the volcanic PM mass (75–80% in PM2.5), and the high environmental lability of its chemical components have potential adverse implications for environmental and health impacts. However, only the dispersion of volcanic SO2 was forecast in public warnings and operationally monitored during the eruption. We make a recommendation that sulphur gas-to-aerosol conversion processes, and a sufficiently large model domain to contain the transport of a tropospheric plume on the timescale of days be utilized for public health and environmental impact forecasting in future eruptions in Iceland and elsewhere in the world.
Title: Abiotic chemical cycling on Earth and beyond
Abstract: Chemical communication between planetary interiors and atmospheres both establishes and maintains habitability and drives long-term evolution. Here, we look at oxygen cycling in the solid Earth, using basalt samples to identify the role of subduction in sequestering oxygen into the mantle. We extend this analysis to planets more generally, considering how oxygen drawdown into planetary interiors can detoxify planetary atmospheres.
Title: Life in Earth: Why soil biodiversity matters for ecosystem functioning
Abstract: Life in Earth: Why soil biodiversity matters for ecosystem functioning
Soils are repositories for a huge abundance and vast diversity of organisms that drive processes that sustain all other life on Earth. The last two decades has seen considerable advances in our understanding of the crucial functions played by soil organisms. Soils provide fascinating examples of how evolution has overcome the need for organisms to acquire energy and nutrients, provide protection from natural enemies, to form intimate symbioses with other organisms, and to resist human-driven perturbations. In this lecture, I will provide some examples of the critical roles soil organisms play in regulating life-sustaining ecosystem processes, and illustrate how soil organisms are ideal model systems to test ecological theory. Finally, I will argue that we must better understand Life in Earth if we are to manage ecosystems both to mitigate predicted changes in global climate, and to feed a rapidly increasing human population.
Title: Nannopores to caves: how does porosity evolve in carbonate rocks, and why should we care?
Abstract: Carbonate rocks, principally limestone and dolostone, are an important component of many sedimentary basins. They are scientifically important archives of Earth’s evolution and global climate change through time. They are of huge economic and societal impact as they host large volumes of hydrocarbons and low-temperature (MVT) mineralization and are also critical to the supply of aggregate, building stone and cement. Carbonate rocks are often considered by petroleum geologists to be complex and heterogeneous, despite their simple mineralogy, because they are so chemically reactive. Consequently, their texture, pore system and even their mineralogy can change significantly in space and time so that thei total and effective porosity can change dramatically after deposition. This plays a critical role in their quality as natural resources, making their rock physical properties and flow behaviour difficult to predict.
This seminar will illustrate how we describe porosity in carbonate rocks, and what we know about its evolution as a result of compaction, cementation, dissolution and dolomitization. Since modification of porosity can begin almost immediately after deposition, the importance of mapping diagenetic pathways through time will be shown. How high-resolution petrographical and geochemical data can be used to predict porosity distribution on a regional or even a basin scale will be discussed. Finally, new knowledge pertaining to the shape, size and connectivity of porosity, revealed by high resolution X-ray CT analysis, will be presented. From here, our ability to predict complex fluid migration pathways in aqueous and hydrocarbon systems will be considered.
Title: Straight out of thin air: Online characterisation of dust mineralogy by single particle mass spectrometry
Abstract: Mineral dust represents a large fraction of the atmospheric aerosol burden. The mineralogy of individual dust particles is important for atmospheric processes because it influences their optical properties, their potential to act as ice nucleating particles (INP) and geochemical cycling of elements to land and ocean. Measurement of mineral dust composition is most commonly performed offline by environmental scanning electron microscopy (ESEM) and transition electron microscopy (TEM) on material collected on filters. Online characterisation of single particle mineralogy is highly desirable so that the composition of individual particles can be reported at a temporal resolution that is relevant to atmospheric processes. Single particle mass spectrometry
(SPMS) can identify ambient dust particles online (i.e. in real time) but the differentiation of mineral phase within these particles is hampered by matrix effects that result in a non-quantatative measurement. This presentation will describe the development of new analytical techniques for the online characterisation of dust mineralogy that links properties in the mass spectra to crystal structure in addition to traditional compositional analysis. The technique will be demonstrated with mineralogical signatures in dust derived from the Sahara desert, the world’s largest source of mineral dust aerosol.
Title: Heavy and persistent rainfall in SW England
Abstract: Weather prediction models make assumptions about the physics of in cloud processes via parameterisations; learning about the physical processes occurring in clouds should lead to improved accuracy of the forecasts. An increased warning time of even 10 mins for a flash flood event could result in saving lives. However, is it essential to use a model with resolution of about 100 m that includes detailed calculations of microphysical processes, in order to capture the location, timing and intensity of the precipitation in this region, and hence accurately forecast flash flooding?
Observations were made with three aircraft, a ground-based X-band radar and several other ground-based instruments during the COnvective Precipitation Experiment (COPE) in the southwest peninsula of England during the summer of 2013. Convergence lines form in the region as a result of colliding sea-breeze fronts. Convective clouds often develop along the lines sometimes resulting in flash flooding. The most infamous recent example occurred in Boscastle in August 2004. The flash floods and convergence lines have been studied using models and the UK Met Office (MO) network radars and rain gauges, but observations of the microphysics and dynamics of the systems had never been made until COPE.
Modelling results and observations of a quasi-stationary convective system on 3 August 2013 will be presented in this talk. Heavy precipitation persisted for several hours in a fairly localised region, although a flash flood did not occur. The measurements on this day were made with two research aircraft (University of Wyoming King Air and UK BAe 146), a mobile radar, the MO network of radars and ground-based aerosol instruments. The mobile radar made PPIs with a volume return time of about 5 mins. The WRF model run at 400-m resolution and a detailed microphysics model were used to help interpret the observations. The interplay of the warm rain process, freezing of supercooled raindrops, growth and then melting of graupel particles and cloud-scale dynamics (multiple thermals) appears to be key to the intensity and persistence of the precipitation.