strategies will result in loss of diversity, altered species interactions, shifted community structure, and often reduced ecosystem functions, all of which are observed
in almost all studies concerning the biological consequences of climate change.
As we saw in the previous section, microbes contribute to climate change as
contributors by producing an excessive amount of greenhouse gases with the help of
human activities. At the same time, microbes are recipients at the forefront of the
impacts of climate change due to their prevalence and tremendous contributions to
our ecosystems’ functions and services. There has been active research to better
understand and predict the biological consequences of climate change in the future.
Perhaps the most innovative experimental setting for such studies is variants of Free
Atmospheric Carbon dioxide Exchange (FACE) for carbon dioxide manipulation.
The FACE facilities implement pipes connected to carbon dioxide sources that
surround vegetation of interest to maintain a local environment with desired carbon
dioxide concentration. This makes it so that there can be a proper investigation into
the responses of vegetation and associated microbes to elevated carbon dioxide
concentrations that represent potential future time points. Our group studied soil
microbial communities from a FACE facility called BioCON (Biodiversity, Carbon
diOxide, and Nitrogen) in Cedar Creek Ecosystem Science Reserve in Minnesota.
After 10 years of continuous carbon dioxide concentration at 560 ppm, we discovered that soil microbial communities responded very clearly: they showed increased
biomass and shifted community structures. Moreover, the abundance of microbial
functional genes responsible for nitrogen fixation (nifH gene) and labile carbon
degradation (e.g., amylase, pullulanase, cellobiase, endoglucanase genes, etc.) was
significantly increased in the plots with elevated carbon dioxide levels as compared
to the plots with ambient carbon dioxide concentrations (control plots). This study
suggested possible positive feedback responses in soil carbon and nitrogen cycles,
with elevating the carbon dioxide levels resulting in more available carbon and a
greater carbon-to-nitrogen ratio (C/N ratio).
Harmful algal blooms (HAB) represent another problem linked with climate
change due to increased environmental temperature, surface stratification, atmospheric carbon dioxide concentration, reduced calcification from ocean acidification,
altered hydrologic patterns, and more. Harmful algal blooms are usually local or
regional problems. However, they are also global problems since they occur in many
coastal regions and freshwater ecosystems around the world. There have been
numerous studies on specific harmful algal blooming organisms including dinoflagellates (e.g., Karenia and Cochlodinium), diatoms (e.g., Pseudo-nitzschia), and
cyanobacteria (e.g., Microcystis and Cylindrospermopsis) for their genetics, physiology, and ecology. Many studies have shown the shifting of local aquatic microbial
communities by harmful algal bloom-causing organisms migrating and proliferating
in response to changing local environmental conditions often related to climate
change. Although most researchers agree that climate change and responsible
anthropogenic activities (e.g., nutrient pollution) must be associated with the increasing frequency and intensifying harmful algal bloom events, specific causal mechanisms are still mostly elusive. This is understandable as the systems that need to be
studied are very complex and dynamic, so appropriate research efforts require truly
190
S. Kang
in almost all studies concerning the biological consequences of climate change.
As we saw in the previous section, microbes contribute to climate change as
contributors by producing an excessive amount of greenhouse gases with the help of
human activities. At the same time, microbes are recipients at the forefront of the
impacts of climate change due to their prevalence and tremendous contributions to
our ecosystems’ functions and services. There has been active research to better
understand and predict the biological consequences of climate change in the future.
Perhaps the most innovative experimental setting for such studies is variants of Free
Atmospheric Carbon dioxide Exchange (FACE) for carbon dioxide manipulation.
The FACE facilities implement pipes connected to carbon dioxide sources that
surround vegetation of interest to maintain a local environment with desired carbon
dioxide concentration. This makes it so that there can be a proper investigation into
the responses of vegetation and associated microbes to elevated carbon dioxide
concentrations that represent potential future time points. Our group studied soil
microbial communities from a FACE facility called BioCON (Biodiversity, Carbon
diOxide, and Nitrogen) in Cedar Creek Ecosystem Science Reserve in Minnesota.
After 10 years of continuous carbon dioxide concentration at 560 ppm, we discovered that soil microbial communities responded very clearly: they showed increased
biomass and shifted community structures. Moreover, the abundance of microbial
functional genes responsible for nitrogen fixation (nifH gene) and labile carbon
degradation (e.g., amylase, pullulanase, cellobiase, endoglucanase genes, etc.) was
significantly increased in the plots with elevated carbon dioxide levels as compared
to the plots with ambient carbon dioxide concentrations (control plots). This study
suggested possible positive feedback responses in soil carbon and nitrogen cycles,
with elevating the carbon dioxide levels resulting in more available carbon and a
greater carbon-to-nitrogen ratio (C/N ratio).
Harmful algal blooms (HAB) represent another problem linked with climate
change due to increased environmental temperature, surface stratification, atmospheric carbon dioxide concentration, reduced calcification from ocean acidification,
altered hydrologic patterns, and more. Harmful algal blooms are usually local or
regional problems. However, they are also global problems since they occur in many
coastal regions and freshwater ecosystems around the world. There have been
numerous studies on specific harmful algal blooming organisms including dinoflagellates (e.g., Karenia and Cochlodinium), diatoms (e.g., Pseudo-nitzschia), and
cyanobacteria (e.g., Microcystis and Cylindrospermopsis) for their genetics, physiology, and ecology. Many studies have shown the shifting of local aquatic microbial
communities by harmful algal bloom-causing organisms migrating and proliferating
in response to changing local environmental conditions often related to climate
change. Although most researchers agree that climate change and responsible
anthropogenic activities (e.g., nutrient pollution) must be associated with the increasing frequency and intensifying harmful algal bloom events, specific causal mechanisms are still mostly elusive. This is understandable as the systems that need to be
studied are very complex and dynamic, so appropriate research efforts require truly
190
S. Kang