Publication Date:
2020-02-24
Description:
Recent studies have highlighted the need
to consider geological carbon sources when estimating
the net ecosystem carbon balance (NECB) of terrestrial
ecosystems located in areas potentially affected
by geofluid circulation. We propose a new methodology
using physical parameters of the atmospheric
boundary layer to quantify the CO2 coming from deep
ground origin in a steppe ecosystem located in the SE
of Spain. Then, we compared published NECB
estimates at the site with seasonal patterns of soil
CO2 efflux and biological activity measured by
satellite images over a 2-year period (2007/2008).
The alpha grass ecosystem was a net carbon source
(93.8 and 145.1 g C m-2 year-1, in 2007 and 2008,
respectively), particularly as a result of large amounts
of carbon released over the dry period that were not
related to biological activity. While the highest
ecosystem CO2 emission rates were measured over
the dry period (reaching up to 15 lmol m-2 s-1), soil
CO2 efflux rates (ca. 0.5 lmol m-2 s-1) and plant
productivity were minimal during this period. After
using a linear relationship between NECB and wind
speed for different stability conditions and wind
sectors, we estimated the geological flux FGEO
(217.9 and 244.0 g C m-2 in 2007 and 2008, respectively)
and subtracted it from the NECB to obtain the
biological flux FBIO (-124.0 and -98.9 g C m-2 in
2007 and 2008, respectively). We then partitioned
FBIO into gross primary productivity and ecosystem
respiration and proved that, after removing FGEO,
ecosystem respiration and soil CO2 efflux followed similar seasonal patterns. The annual contribution of
the geological component to NECB was 49.6 and
46.7 % for the year 2007 and 2008, respectively.
Therefore, it is clear that geological carbon sources
should be quantified in those ecosystems located in
areas with potential natural emission of geological
gases to the surface.
Description:
Published
Description:
83-101
Description:
7A. Geofisica di esplorazione
Description:
JCR Journal
Description:
restricted
Keywords:
carbon emission, soil, dry land
;
03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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