School of Geography, Geology and the Environment

Research seminars

Both external and internal speakers are invited to the School of Geography, Geology and the Environment to present the latest results of their research.

Everyone is invited, so please join us!

From Swamp to Sea: the fate of tropical peatland carbon in the coastal ocean

Thursday 9 May 2024, Teams Online, 1.00pm-2.00pm (Geology)

Dr Patrick Martin, Associate Professor, Asian School of the Environment, Nanyang Technological University

Southeast Asia’s tropical peat swamps are a globally significant carbon pool, and their widespread deforestation and drainage are a large source of CO2 to the atmosphere. A less recognised fact is that they also account for about 10% of the global flux of dissolved organic carbon (DOC) from land to sea, which flows out from peatland-draining “blackwater” rivers. In this talk, I will discuss the progress we are making to understand the biogeochemical fate of this DOC in Southeast Asia’s coastal sea. Based on ocean colour remote sensing, we have found evidence that peatland drainage has increased the flux of DOC to the ocean. From long-term observations of carbon concentrations and stable isotope ratios, we have also found that the majority of this DOC is remineralized to CO2 in coastal waters. This production of CO2 at sea has a strong acidifying effect on coastal seawater that will interact with long-term ocean acidification, and thus peatland DOC has emerged as a key biogeochemical driver of coastal carbon cycling in Southeast Asia. I will also show how we are quantifying the rates of photochemical and microbial remineralization of peatland DOC with laboratory experiments that are specially designed to allow both processes to interact realistically, and how we are working towards representing these rates in a regional ocean model.

Patrick obtained a B.Sc. (Hons.) in Biology from the University of York, and a PhD in oceanography from the University of Southampton / National Oceanography Centre, UK. He then worked as a postdoc at Woods Hole Oceanographic Institution, and at Nanyang Technological University, before joining the faculty at NTU in 2016. His research currently focuses on coastal carbon cycling, and includes dissolved organic matter optical properties, satellite remote sensing and coral-core palaeo-reconstructions of coastal dissolved organic matter concentrations, photochemical and microbial degradation processes, and variability in coastal inorganic carbon chemistry. In 2017, he started a monthly biogeochemical time series in Singapore that is still continuing, now as part of Singapore’s Marine Environment Sensing Network.

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The Earliest Years: Loess investigation in the Nineteenth Century

Wednesday 15 May 2024, Lecture Theatre 10, Bennett Building, 1.00pm-2.00pm (Geography)

Honorary Professor Ian Smalley, School of Geography, Geology and the Environment, University of Leicester

In the beginning was the word and the word was Loess. In 1824 Karl Caesar von Leonhard fixed the word to the deposit. Loess in Heidelberg; named, defined and described by von Leonhard in 1824:  Section 89 of vol.3 of his ‘Characteristik der Felsarten’ contains the first account of the sedimentary material which we came to know as Loess.

Charles Lyell published vol.3 of ‘The Principles of Geology’ in 1833. This volume contained a small section on loess, on loess in the Rhine valley - in 1833 loess was essentially confined to the Rhine valley. This book introduced loess to the world at large. It is said that his copy reached Charles Darwin in 1834 in Valparaiso, on his great circumnavigation.

Also in 1833 Leonard Horner gave his paper on the Loess at Bonn to a meeting of the Geological Society in London. This was not published until 1836 but it was probably the first presentation on loess in English.  Horner in particular described loess as an interesting material which presented several novel geological problems.

As a sediment: it was associated with the Rhine, so logically it was deposited by the Rhine, or perhaps from lakes which were formed from Rhine waters. Darwin in the ‘Origin’ in 1859 was happy to have the loess as a Rhine sediment ‘We have evidence in the loess of the Rhine of considerable changes of level in the land.’

In 1877-1885 Ferdinand von Richthofen published ‘China: Ergebnisse einer Reisen und darauf gegrundeter Studien’ in 5 vols. The loess description and discussion in vol.1 were largely responsible for establishing the aeolian theory of deposition and the fame of Richthofen, and showing the importance of Chinese loess.

In 1890 John Hardcastle in Timaru, New Zealand introduced the really key idea into loess research (an idea that drives much of todays research) that loess recorded climate. He claimed loess as a ‘Climate Register’. His observations at the Dashing Rocks section in Timaru on the South Island of New Zealand were truly pioneering observations. He ends the nineteenth century with the key observation made (the direct connection between loess deposits and climate observations) and opens the way for a century of great scientific advance, and the accumulation of much scientific data.

Deep histories of food systems in eastern Africa and current patterns of food insecurity

Thursday 16 May 2024, Lecture Theatre 10, Bennett Building, 1.00pm-2.00pm (Geology)

Dr Matthew Hannaford, Senior Lecturer in Human Geography, University of Lincoln

This seminar examines long-term patterns and drivers of continuity and change in eastern African food systems. It points towards considerable dynamism in place-based and regional trends in the integration of new foodstuffs, agricultural commercialization, resistance and transformations in diets, and diversification and specialisation as livelihood strategies—each of which emerged within imbricated contexts of African agency, transoceanic exchanges and colonial incursions. Such historical data provide important deep-time perspectives for interventions to address modern food insecurity, as demonstrated through examples of agricultural value chains, ‘under-utilised’ crops and major infrastructure projects in southeast Africa.

Matthew Hannaford is a Senior Lecturer in Human Geography at the University of Lincoln, UK. 
His research interests centre around the environmental history and historical climatology of southern and eastern Africa before colonial times, especially human interactions with climate variability and the history of food systems. His research also examines the relevance of historical research for present-day questions of climate adaptation and food security.

Microplastics and rock-like plastic pollution as sedimentary components in coral reef systems

Thursday 23 May 2024, Lecture Theatre 5, Bennett Building, 1.00pm-2.00pm (Geology)

Dr Lars Reuning, Senior Lecturer of Paleontology and Historical Geology, Institute of Geosciences, Kiel University

Microplastic pollution is pervasive in coral reef systems across the tropics, adversely impacting coral health through bleaching, tissue necrosis, and immune system impairment. Simultaneously, unregulated plastic waste disposal contributes to the formation of pyroplastics and plastiglomerates—“rocks” comprised of natural elements and melted plastic. Microplastics and plastiglomerates form from a wider variety of plastic polymers, which determine their unique properties. 

We demonstrated based on work in Indonesia and the Mediterranean, that microplastics and plastiglomerates are becoming a significant component in reef sediments. Microplastics, predominantly secondary and derived from local sources, exhibit similar transport and accumulation behavior as fine siliciclastic grains. Proximity to important plastic debris sources and hydrodynamic processes influences microplastic abundance and distribution. Reef sediments act as a permanent sink for microplastics, with accumulation facilitated by biofouling, interlocking, and compound grain formation. The transport behavior of pyroplastics and plastiglomerates in turn depends on the ratio and type of polymers. Pyroplastics are typically buoyant, while plastiglomerates are not. Plastiglomerates therefore have a high potential to be preserved as a new rock-like component in the fossil record. Rock-like plastics are therefore becoming an integral component of the sedimentation system. Coastal ecosystems worldwide, will be increasingly affected by microplastics and plastiglomerates, transferring organic pollutants to marine organisms and negatively impacting ocean health.

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