Upcoming events

  • The 111th ICREA Colloquium ‘Stable isotopes in plants: reconstructing climate and human impacts on the environment’


    Speakers: ICREA Research Professors Laia Andreu Hayles, from the Centre de Recerca Ecològica i Aplicacions Forestals (CREAF) and Carla Lancelotti, from the Universitat Pompeu Fabra (UPF)


    When: 28th of May 2024, 18:00h


    Where: Auditorium FCRI, Passeig de Lluís Companys, 23, 08010 Barcelona


    Understanding the coupling between human and natural systems is paramount in the current context of climate change. The application of stable isotopic analysis in plant emerges as a robust methodological tool for elucidating the intricate complexities of environmental history, enabling the reconstruction of both climatic shifts and human influences on ecosystems.


    Stable isotopes provide insights into the underlying physiological and biochemical processes within plant organisms as response to environmental changes. By analysing variations in isotopic compositions in paleo archives such as tree rings, we can decipher past climate conditions, such as temperature and precipitation variability, providing a unique long-term perspective of environmental dynamics. Moreover, the integration of stable isotopes in archaeobotanical remains such as seeds, pollen or charcoal, among others, offers a unique lens through which to trace the interplay between human activities and nature. Whether detecting shifts in agricultural methodologies or changes in land-use patterns, isotopic analysis allows to elucidate the discernible imprint of anthropogenic impacts on ecosystems. This interdisciplinary approach, combining botanical science and environmental history, empowers scientists to construct a detailed narrative of the co-evolution of climate and human-environment interactions over time.


    In this colloquium we will explain how a biologist and an archaeologist can find a common interest in plant stable isotopes and we will show exemplary applications of this technique in our work.

  • The 112th ICREA Colloquium ‘Silicate stardust: from the nanoscale to galactic relevance’


    Speakers: ICREA Research Professors Stephan Bromley from the Universitat de Barcelona (UB) and Ciska Kemper from the Institut de Ciències de l'Espai (ICE-CSIC)


    When: 17th of September 2024, 18:00h


    Where: Auditorium FCRI, Passeig de Lluís Companys, 23, 08010 Barcelona




    Although stars are the most eye-catching component of galaxies, the space between stars inside galaxies is not empty. Instead, this interstellar medium (ISM) is sparsely filled with gas and dust. Denser parts of the ISM – so-called molecular clouds – may form stars from gravitational contraction. Stars, as they age,  produce increasingly heavier atoms (e.g. C, O, Mg, Si) from fusion reactions in their highly compressed interiors. Ultimately, old dying stars shed parts of their outer layers back into the ISM, enriched with the products of these reactions. Indeed, stars are the source of virtually all elements that we see around us today, with the exception of hydrogen and helium, which were formed during the Big Bang.


    While many of these heavier elements are mostly present in the gas phase, many become condensed into solids, often in the form of sub-micron-sized dust grains. These dust particles absorb and emit radiation in the ISM and thus play an important role in the energy balance of a galaxy. As such, at galactic length scales, they can regulate the process of star formation and indeed galaxy evolution itself.  At much smaller nanoscale length scales, dust grains also provide a catalytic surface for essential chemical reactions to take place, potentially including those relevant to the origins of life. Ultimately, these tiny grains also provide the building blocks for forming planets like our own Earth. Thus, even though dust takes up only 1% of the mass of the ISM, and even a smaller fraction of the mass of galaxies as a whole, understanding its nature, formation and evolution is an important quest in understanding the evolution of galaxies, astrochemical processes and the formation of planetary systems.


    With a share of about 75% of the total galactic dust mass, silicates (i.e. solids based on mixtures of Si, O and Mg/Fe) form the main constituent of interstellar dust. We will discuss the life cycle of silicate dust from its production in evolved stars, through processing in the interstellar medium to its demise in star forming regions in our own Milky Way and in other galaxies. To understand the nature of silicate dust at the nanoscale we will highlight how quantum chemical computer modelling can provide otherwise difficult to obtain insights that can be used to interpret experiments and observations. Here, we will focus on the properties and formation of silicate nanograins, and the role of silicate dust in catalysing the  formation of important chemical species. From a larger scale observational perspective we will explore the observational evidence of the presence of silicates in different astrophysical environments, and the different forms in which it may be present.  Here we will particularly highlight new results from the James Webb Space Telescope, which is ideally suited to study the properties of astronomical silicates with unprecedented detail.