• A personal note on IGBP and the social sciences

    Humans are an integral component of the Earth system as conceptualised by IGBP. João Morais recalls key milestones in IGBP’s engagement with the social sciences and offers some words of advice for Future Earth.
  • IGBP and Earth observation:
    a co-evolution

    The iconic images of Earth beamed back by the earliest spacecraft helped to galvanise interest in our planet’s environment. The subsequent evolution and development of satellites for Earth observation has been intricately linked with that of IGBP and other global-change research programmes, write Jack Kaye and Cat Downy .
Published: November 17, 2015
HONO Emissions from Soil Bacteria as a Major Source of Atmospheric Reactive Nitrogen

Science (2013)

Oswald R, Behrendt T, Ermel M, Wu D, Su H, Cheng Y, Breuninger C, Moravek A, Mougin E, Delon C, Loubet B, Pommerening-Röser A, Sörgel M, Pöschl U, Hoffmann T, Andreae M O, Meixner F X and Trebs I

DOI: 10.1126/science.1242266

Vol 341, Issue 6151, pp 1233-1235


Abiotic release of nitrous acid (HONO) in equilibrium with soil nitrite (NO2–) was suggested as an important contributor to the missing source of atmospheric HONO and hydroxyl radicals (OH). The role of total soil-derived HONO in the biogeochemical and atmospheric nitrogen cycles, however, has remained unknown. In laboratory experiments, we found that for nonacidic soils from arid and arable areas, reactive nitrogen emitted as HONO is comparable with emissions of nitric oxide (NO). We show that ammonia-oxidizing bacteria can directly release HONO in quantities larger than expected from the acid-base and Henry’s law equilibria of the aqueous phase in soil. This component of the nitrogen cycle constitutes an additional loss term for fixed nitrogen in soils and a source for reactive nitrogen in the atmosphere.

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