In:
Biogeosciences, Copernicus GmbH, Vol. 16, No. 9 ( 2019-05-15), p. 2003-2031
Abstract:
Abstract. The reactive trace gases nitric oxide (NO) and nitrous acid (HONO) are
crucial for chemical processes in the atmosphere, including the formation of
ozone and OH radicals, oxidation of pollutants, and atmospheric
self-cleaning. Recently, empirical studies have shown that biological soil
crusts are able to emit large amounts of NO and HONO, and they may therefore
play an important role in the global budget of these trace gases. However,
the upscaling of local estimates to the global scale is subject to large
uncertainties, due to unknown spatial distribution of crust types and their
dynamic metabolic activity. Here, we perform an alternative estimate of
global NO and HONO emissions by biological soil crusts, using a process-based
modelling approach to these organisms, combined with global data
sets of climate and land cover. We thereby consider that NO and HONO are
emitted in strongly different proportions, depending on the type of crust and
their dynamic activity, and we provide a first estimate of the global
distribution of four different crust types. Based on this, we estimate global
total values of 1.04 Tg yr−1 NO–N and 0.69 Tg yr−1 HONO–N
released by biological soil crusts. This corresponds to around 20 % of
global emissions of these trace gases from natural ecosystems. Due to the low
number of observations on NO and HONO emissions suitable to validate the
model, our estimates are still relatively uncertain. However, they are
consistent with the amount estimated by the empirical approach, which
confirms that biological soil crusts are likely to have a strong impact on
global atmospheric chemistry via emissions of NO and HONO.
Type of Medium:
Online Resource
ISSN:
1726-4189
DOI:
10.5194/bg-16-2003-2019
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2158181-2
