Changing conditions and reducing resources will lead to promoting adaptation
strategies that allow the production of enzymes with a minimum of carbon and
nutrient costs for the cell but still obtaining maximum benefits. In this sense, the
enzymatic activity will be a result of the efficiency achieved by microorganisms, in
terms of spending resources to produce enzymes versus the benefit of increasing the
availability of assimilable mineral nutrients, energy sources and low molecular
weight organic compounds. While in a climate change scenario, microbial cells face
the need to reduce the energy they use to produce enzymes, they must, on the other
hand, maintain a sufficiently high concentration of the reaction products to ensure
the maintenance of cell function and maintain viability of their populations. The
products necessary to guarantee the microbiological functions in the soil and the
balance of nutrient cycles, are C and the nutrients (especially nitrogen and phosphorus) necessary to ensure the existence of energy (i.e. ATP) and the synthesis and
secretion of enzymes (proteins). Therefore, N is a crucial element to maintain soil
functions as well as microbial and plants survival.
Because of climate change, soil temperature is increasing, soil wetting and
drying cycles are more frequent and carbon dioxide and other greenhouse gases are
increasing in the atmosphere [25]. These abiotic phenomena will have marked
effects in the microbial community composition and may increase biomass and
enzyme activities, which can occur as a direct effect or as a result of plant growth,
increases in litter deposition and root exudation. So, any attempt to mitigate the
impacts of global warming in plant production and soil quality must take into
account the microbial responses, including soil enzyme activity dynamics.
A good SOM turnover and balanced nutrient cycles greatly depend on enzymatic
activity which in turn is dependent on soil conditions such as temperature and water
content but are also influenced by enzyme pool size [19]. The rate of enzymes
production by soil microbial populations versus the rate of degradation in the
environment, determine pool size. Both production and turnover are affected by soil
conditions that vary seasonally but are also affected by climate change, that produces temperature, moisture and atmosphere composition alterations. Enzyme
production by microbes requires energy and nutrients, and an adequate stoichiometry of their biomass targeting specific C, N or P rich compounds [19].
Besides the mere maintenance of the enzymatic pool, temperature and moisture can
affect both the global rate of enzyme production and the relative rate of production
of the different enzymes present in soils. This is due to climatic effects on substrate
availability for microbes, microbial efficiency and finally on enzyme efficiency.
Therefore, whether climate changes affect environmental conditions locally and
regardless of the duration and timing of the impacts, it is certain that this will affect
enzyme pool sizes and will have an effect on N-footprint of plant production.
Whenever the enzymatic activity increases as a consequence of higher soil temperature, in the presence of available substrate for microbes, enzyme production
may be reduced if microbial biomass remains unchanged [77]. Different enzymes
are differentially affected by temperature thus, climate change is enzyme-specific.
Reference [78] observed that N-degrading enzymes have lower temperature sensitivity compared to C-degrading enzymes, which will lead to a higher production
146
C. M. d. S. Cordovil et al.
strategies that allow the production of enzymes with a minimum of carbon and
nutrient costs for the cell but still obtaining maximum benefits. In this sense, the
enzymatic activity will be a result of the efficiency achieved by microorganisms, in
terms of spending resources to produce enzymes versus the benefit of increasing the
availability of assimilable mineral nutrients, energy sources and low molecular
weight organic compounds. While in a climate change scenario, microbial cells face
the need to reduce the energy they use to produce enzymes, they must, on the other
hand, maintain a sufficiently high concentration of the reaction products to ensure
the maintenance of cell function and maintain viability of their populations. The
products necessary to guarantee the microbiological functions in the soil and the
balance of nutrient cycles, are C and the nutrients (especially nitrogen and phosphorus) necessary to ensure the existence of energy (i.e. ATP) and the synthesis and
secretion of enzymes (proteins). Therefore, N is a crucial element to maintain soil
functions as well as microbial and plants survival.
Because of climate change, soil temperature is increasing, soil wetting and
drying cycles are more frequent and carbon dioxide and other greenhouse gases are
increasing in the atmosphere [25]. These abiotic phenomena will have marked
effects in the microbial community composition and may increase biomass and
enzyme activities, which can occur as a direct effect or as a result of plant growth,
increases in litter deposition and root exudation. So, any attempt to mitigate the
impacts of global warming in plant production and soil quality must take into
account the microbial responses, including soil enzyme activity dynamics.
A good SOM turnover and balanced nutrient cycles greatly depend on enzymatic
activity which in turn is dependent on soil conditions such as temperature and water
content but are also influenced by enzyme pool size [19]. The rate of enzymes
production by soil microbial populations versus the rate of degradation in the
environment, determine pool size. Both production and turnover are affected by soil
conditions that vary seasonally but are also affected by climate change, that produces temperature, moisture and atmosphere composition alterations. Enzyme
production by microbes requires energy and nutrients, and an adequate stoichiometry of their biomass targeting specific C, N or P rich compounds [19].
Besides the mere maintenance of the enzymatic pool, temperature and moisture can
affect both the global rate of enzyme production and the relative rate of production
of the different enzymes present in soils. This is due to climatic effects on substrate
availability for microbes, microbial efficiency and finally on enzyme efficiency.
Therefore, whether climate changes affect environmental conditions locally and
regardless of the duration and timing of the impacts, it is certain that this will affect
enzyme pool sizes and will have an effect on N-footprint of plant production.
Whenever the enzymatic activity increases as a consequence of higher soil temperature, in the presence of available substrate for microbes, enzyme production
may be reduced if microbial biomass remains unchanged [77]. Different enzymes
are differentially affected by temperature thus, climate change is enzyme-specific.
Reference [78] observed that N-degrading enzymes have lower temperature sensitivity compared to C-degrading enzymes, which will lead to a higher production
146
C. M. d. S. Cordovil et al.