Events

This seminar will give an overview of current advances in understanding the persistence and vulnerability of soil organic carbon (SOC). 1) Key mechanisms that govern its stabilisation and destabilisation in soils will be presented. 2) Recent advances using different analytical approaches to understand soil carbon cycling and knowledge are highlighted, including physical and chemical fractionation approaches, using spectroscopic tools such as NMR and NEXAFS. 3) The emerging interest in microbial necromass will be introduced to understand how to improve SOC stability at the molecular level. 4) The presentation will also discuss practical strategies to enhance SOC stocks in agricultural lands, with a focus on improved field management, and biochar applications that support long-term carbon persistence.

Microorganisms are everywhere and they are major contributors to all facets of life on Earth, spanning key metabolic processes to global biogeochemical cycling. Using a combinatorial approach including both culture-dependent and culture-independent techniques, my research career thus far has aimed to answer key questions around the role of bacteria within the environment, and how they interact with macroorganisms. I started by studying how bacteria form symbiotic interactions with marine sponges before pivoting to terrestrial ecosystems, focusing on how metabolically flexible bacteria alter their energy generation strategies across a range of environments and conditions. Since then, my research has shifted to nutrient cycling, with a greater focus on the nitrogen cycle and plant-beneficial microbes as part of the ARC Research Hub for Smart Fertilisers. The ability of microorganisms to utilise hydrogen led me to develop my current research program focused on understanding how the cycling capacity of these soil microorganisms could be affected by agricultural management practices, to characterise how microorganism functioning within nutrient cycles can contribute to the futureproofing of the Australian agricultural industry.

This seminar will discuss physicochemical process affecting the availability of compounds in soil or solution. While the first part of my career was focused on metal contaminants and the second part on fertilizers, the research on these topics shared a lot of common concepts and methodologies. I will present various case studies discussing speciation and transport of inorganic compounds from soil or solution to biotic surfaces such as plant roots. These studies used chemical, spectroscopic and/or isotopic techniques as well as modelling approaches to enhance our understanding of the processes controlling nutrient and contaminant uptake.

From backyard veggie patches to roadside verges, the urban soils we live, work and play on are susceptible to a complex mixture of pollutants. In this presentation to Women in Soil Science Australia, Assoc. Prof. Suzie Reichman will share insights from the SoilTox Lab's research investigating these urban contaminants. Their studies have examined legacy metal contamination in residential areas and associated health risks to urban food producers from home-grown vegetables and chicken foraging. The team has also researched the extent and impacts of vehicle pollution, including metals, platinum group elements, and tire wear particles, on roadside soils and ecosystems. Recommendations will be provided on how to reduce personal contributions to, and exposure from, urban soil pollution. Through this body of work, the SoilTox Lab at the University of Melbourne aims to advance understanding of the fate, behaviour and risks posed by urban soil contaminants to ultimately safeguard environmental and human health.

Zinc deficiency is widespread throughout the world’s agricultural soils. This leads to deficiencies in these essential micronutrients in cereal grains, and ultimately in the humans who rely on cereal-based diets. Arbuscular mycorrhizal fungi (AMF) can take up zinc into cereal crops, so have been proposed as a biofortification tool. This seminar will cover highlights from my research into the physiological and molecular basis for zinc uptake into plants by AMF, and their potential to contribute to crop biofortification. 

Soil erosion is a critical global issue, exacerbating land degradation, reducing agricultural productivity, and threatening both terrestrial and aquatic ecosystems. As climate change intensifies, the frequency and severity of erosion events are expected to increase, posing significant challenges to environmental sustainability and community resilience.

This seminar will share how we use an innovative daily erosivity model to monitor and anticipate erosion risks under climate change. We deliver time-series erosion risk maps at monthly scale. By simulating rainfall patterns and their erosive potential across New South Wales, we identify high-risk erosion areas and predict when these events are likely to occur. This proactive approach enables targeted interventions, such as vegetation buffers, terracing, and improved land management practices, reducing soil loss and enhancing resilience.

If you are interested, there is also openly available erosion data on the SEED portal: https://datasets.seed.nsw.gov.au/dataset/modelled-hillslope-erosion-over-new-south-wales

This seminar will explore the important role of soil science in contaminated land assessment. It will describe how soil science principles are applied in the assessment and remediation of land affected by industrial, agricultural, and urban contaminants, and how contaminated land assessment draws on soil science, hydrogeology and related disciplines to improve site management outcomes.

Feedbacks between soil carbon (C) and the climate system lead to vexing challenges in predicting rates of future climate change, and to developing potential mitigation options based on natural climate solutions. This talk synthesizes results from climate gradients, Free-Air CO2 Enrichment systems, ecosystem warming and drought experiments to reveal areas of uncertainty in mechanistic understanding of soil carbon- climate feedbacks.

 We measure changes in soil C pools in response to rising atmospheric CO2 concentrations in grassland; analyse soil organic matter (SOM) decomposition rates and temperature sensitivity in forest, grassland and wetland ecosystems, at local and continental scales; evaluate the “priming effect” of SOM decomposition; and participate in global synthesis and modelling studies to synthesize mechanistic understanding.

Rising atmospheric CO2 stimulated photosynthesis and C storage in biomass, but at the expense of C storage in soils. This effect appears to be mediated by plant nutrient uptake, and particularly by mycorrhizal associations that differ by ecosystem type. The tradeoff between plant and soil C may neutralize the CO2 fertilization effect to some degree. 

In productive and nutrient-rich forests, soil C may continue being stored if productivity increases and microbes prefer fresh SOM substrates. Soils from cold climates exhibit higher temperature sensitivity than those from warmer regions, potentially worsening the rate of climate change as high latitude areas experience rapid warming. Moreover, temperature sensitivity of SOM decomposition may be higher at depth than at the surface.

Our research has revealed major uncertainties related to the stimulation of SOM decomposition by plant C inputs, temperature sensitivity of soil C, and trade-offs between aboveground and belowground C storage. Future research needs to investigate mechanisms explaining  these critical feedback processes, and then to integrate the mechanisms