There has been a new cultivar of rice developed with low root exudation rates, which
would reduce methane emission as well. Cutting down meat consumption would
also help reduce methane production from those ruminants. Improved agricultural
practices that increase yields and generate higher inputs of residue carbon into the
soil can lead to increased soil carbon storage. These practices include using
improved crop varieties, extending crop rotation, and converting to reduced tillage
or no-tillage. Reduced or no-tillage practice can also reduce carbon emission by
reducing the use of heavy agricultural machinery.
11.5 A Model System in Research
As mentioned previously, the accurate prediction of climate change consequences is
critical for consorted mitigation efforts. But accurate predictions are not easy to
obtain even with innovative research facilities like FACE. Perhaps the most difficult
aspect of climate simulation facilities is the realistic treatment of climate parameters,
such as carbon dioxide concentration and temperature. For example, most FACE
facility settings are based on elevated carbon dioxide concentrations being pumped
into biological systems constantly for some designated period of time, but the real
carbon dioxide concentration has been and will be increasing gradually with daily
and seasonal fluctuations. However, it is very difficult to set up an experimental
system with gradually changing climate parameters for the scales appropriate to most
biological systems. Studies on microbial systems offer an exception because
microbes have relatively short generation times and large population sizes. Several
small-scale lab studies are available to compare abrupt versus gradually increasing
schemes and all show in general rather distinctive responses. Our previous work with
samples collected from a local lake showed a rather similar abundance but quite
distinctive community structure patterns during a 90-day incubation for both carbon
dioxide concentration and temperature. This pattern would have been due to the
different responses of microbial communities to two treatment schemes. Abruptly
increasing carbon dioxide concentration and temperature would exert more selective
pressure, while gradually increasing those parameter values would provide more
acclimation opportunities to the existing microbial communities. This was observed
in an ordination plot (non-metric multidimensional scaling) with a significantly
different degree of dispersion; samples from gradual increasing treatment were
tightly clustered, while samples from abrupt treatment were scattered around the
ordination space. Results available from several studies all indicated that under
gradual treatments, less drastic effects on microbial responses were observed for
such assessments as community structure, richness, and evolutionary adaptation.
These suggest that the general trend of significant consequences of climate change
observed from research at FACE-like facilities may be an overestimation. There
have not been enough large-scale research data available as of yet, which is needed
to provide a more conclusive understanding of how microbial responses to climate
change may be different from the existing knowledge.
192
S. Kang
would reduce methane emission as well. Cutting down meat consumption would
also help reduce methane production from those ruminants. Improved agricultural
practices that increase yields and generate higher inputs of residue carbon into the
soil can lead to increased soil carbon storage. These practices include using
improved crop varieties, extending crop rotation, and converting to reduced tillage
or no-tillage. Reduced or no-tillage practice can also reduce carbon emission by
reducing the use of heavy agricultural machinery.
11.5 A Model System in Research
As mentioned previously, the accurate prediction of climate change consequences is
critical for consorted mitigation efforts. But accurate predictions are not easy to
obtain even with innovative research facilities like FACE. Perhaps the most difficult
aspect of climate simulation facilities is the realistic treatment of climate parameters,
such as carbon dioxide concentration and temperature. For example, most FACE
facility settings are based on elevated carbon dioxide concentrations being pumped
into biological systems constantly for some designated period of time, but the real
carbon dioxide concentration has been and will be increasing gradually with daily
and seasonal fluctuations. However, it is very difficult to set up an experimental
system with gradually changing climate parameters for the scales appropriate to most
biological systems. Studies on microbial systems offer an exception because
microbes have relatively short generation times and large population sizes. Several
small-scale lab studies are available to compare abrupt versus gradually increasing
schemes and all show in general rather distinctive responses. Our previous work with
samples collected from a local lake showed a rather similar abundance but quite
distinctive community structure patterns during a 90-day incubation for both carbon
dioxide concentration and temperature. This pattern would have been due to the
different responses of microbial communities to two treatment schemes. Abruptly
increasing carbon dioxide concentration and temperature would exert more selective
pressure, while gradually increasing those parameter values would provide more
acclimation opportunities to the existing microbial communities. This was observed
in an ordination plot (non-metric multidimensional scaling) with a significantly
different degree of dispersion; samples from gradual increasing treatment were
tightly clustered, while samples from abrupt treatment were scattered around the
ordination space. Results available from several studies all indicated that under
gradual treatments, less drastic effects on microbial responses were observed for
such assessments as community structure, richness, and evolutionary adaptation.
These suggest that the general trend of significant consequences of climate change
observed from research at FACE-like facilities may be an overestimation. There
have not been enough large-scale research data available as of yet, which is needed
to provide a more conclusive understanding of how microbial responses to climate
change may be different from the existing knowledge.
192
S. Kang