Geoscience Reference
In-Depth Information
managed systems to promote the growth of sulphate reducers at
the expense of methanogens (Neue, 2007). To reduce methane
emissions from ruminant livestock, strategies include improv-
ing feed quality and directly inhibiting methanogen commu-
nities in the rumen using antibiotics, vaccines and alternative
electron acceptors (Smith et al., 2008).
Reducing N
2
O
emissions by
microbial
communities
A major source of anthropogenic N
2
O emission is the use of
nitrogen fertilisers in agriculture. As a substantial proportion of
applied fertilisers are emitted in the form of N
2
O, better-targeted
fertiliser applications, which reduce the availability of nitrogen
to microorganisms, can substantially decrease N
2
O emissions.
Schimel and Gulledge (1998) showed potential strategies that
include reducing the amount of fertiliser and applying it at an
appropriate time (when crop demand for nitrogen is high and
leaching-loss rates are low), using slow-release fertilisers, and
avoiding nitrogen forms that are likely to produce large emis-
sions or leaching losses (such as nitrate in wet soil). Similarly,
improved land drainage and better management practices to
limit anaerobic conditions in soils (e.g. land compaction and
excessive wetness) could reduce denitrification rates and, thus,
N
2
O emissions. Finally, for the mitigation of N
2
O fluxes from
agriculture, the use of nitrification inhibitors in fertilisers to
limit nitrate production and subsequent leaching or denitrifi-
cation losses is now a well-established strategy (Smith et al.,
2008). These and similar microorganism-mediated strategies
have great potential to reduce greenhouse gas emissions from
the land use and agricultural sectors.
Soil-borne
pathogens and
climate change
As per the IPCC (2007) report, climate change will alter pat-
terns of infectious disease outbreaks in humans and animals.
Soil pathogens are no exception: case studies support the claim
that climate change is already changing patterns of infec-
tious diseases caused by soil pathogens. For example, over
the last 20 years, 67% of the 110 species of harlequin frogs
(
Atelopus
) native to tropical regions in Latin America have
gone extinct from chytridiomycosisthe, a lethal disease spread
by the pathogenic chrytid fungus (
Batrachochytrium dendro-
batidis
) (Willey et al., 2009). Research suggests that mid- to
high elevations provide ideal temperatures for
B. dendrobatidis
.
However, as global warming progresses,
B. dendrobatidis
is
able to expand its range due to increasing moisture and warmer
temperatures at higher elevations (Muths et al., 2008). This
expansion exposes more amphibian communities in previously
unaffected or minimally affected areas, specifically at higher
