By Jérôme Santolini, DR CEA, Responsable du laboratoire Stress Oxydant et Détoxication à l’Institut de Biologie Intégrative de la Cellule (UMR 9198)
Wednesday, December 4th 2024 at 11am room 1129
Abstract
Nitrogen is a key element in living organisms, due to the essential roles it plays both biologically and ecologically. As a fundamental building block of biomolecules, it is a growth-limiting element for living organisms, yet essential to their proper functioning through reactive nitrogen species such as nitric oxide. Its ecological cycle, based on a rich and complex biochemistry, ensures the dynamic interaction between organisms and ecosystems, and the interconnection of the main planetary cycles. However, the Anthropocene has seen the emergence of another nitrogen history, marked by the industrialization of ammonium nitrate production via the Haber-Bosch process. This process produced tens of millions of tonnes of ammonia every year, introducing almost 10 gigatonnes of reactive nitrogen into the biosphere over the last century, a quantity equivalent to that present in the world’s biomass.
This phenomenon has largely crossed planetary boundaries, redefining ecological and social issues. While this massive production has made it possible to feed an ever-growing world population, it has also led to serious environmental and health problems. Among the most significant consequences are eutrophication of soil and water, global warming, air pollution, loss of biodiversity and the development of numerous chronic diseases.
This situation embodies one of the paradoxes of the Anthropocene: nitrogen is both an indispensable element for human societies and a threat to the sustainability of ecosystems and the habitability of our planet. Reactive nitrogen, the source of numerous negative externalities, is at the heart of this tension. The question then arises: how can we adjust our systems and policies in the face of this Nitrogen Crisis?
This presentation will attempt to describe the chemical and biological properties of the compounds that make up the world of reactive nitrogen, to analyze the history of our relationship with these molecules and the way in which today they disrupt and destabilize our ecological, social, economic and political systems. It will propose new approaches for assessing, modeling and regulating the flows and impact of reactive nitrogen on the biosphere. Through transdisciplinary reflection, it will seek to reinterrogate the place of this knowledge in the development of human policies.