CASE STUDIES OF CLIMATE CHANGE EFFECTS ON MICROBIAL COMMUNITIES

INTRODUCTION

In the course of the 19th century, many changes were produced due to environmental factors, all provoked by anthropogenic activity, which affects the biogeochemical cycles that take place in the environment. Some of these factors are temperature, CO₂ concentration and soil humidity. In the case of temperature, for example, it has increased during the last century in order to reach a value of more than 0.5 °C. In such a way, that the temperature of the soil has also increased, which has made to accelerate the routes of the cycles of the carbon in microbial communities, as they can be in the process of the decomposition or the mineralization of nutrients. On the other hand, the humidity of the soil has also been affected by all these processes, and bearing in mind that it regulates the flow of CO₂, produced by the breathing of soil organisms, the concentration of this compost in the soil will also be affected. In the case of microbial colonies, it is possible to see affected because if there is a saturation of CO₂ it will only produce anaerobic conditions, which will decrease the level of microbial activity, such as the reduction of the speed of decomposition. In addition, this condition will reduce the production of new CO₂.
Therefore, it is possible to reach the conclusion that not all organisms will react in the same way to these changes that are produced in the Earth. In this text, it will speak concretely of effects that can produce these changes in microbial communities, dealing with different cases that arrive to produce. These microorganisms highlight the effects produced on the cycles of carbon and nitrogen, from which arise some of the most important gases in the composition of the atmosphere, such as CO₂, CH₄ or N₂O. It should be borne in mind that microbial communities are very complex and specific because of their structure and the functions they provide, for which the climatic change can insert many different ways.
Some examples of cases are explained below.

1.       Cyanobacteria in aquatic environments that have an impact on climate change

Cyanobacteria are a group of bacteria that appropriate energy through the process of photosynthesis, absorb solar energy and convert it into profitable energy.

The worldwide proliferation of cyanobacterial flowers, which are harmful to ecological and animal health, has continued to promote eutrofitzation. Cyanobacteria have a very high growth rate of bloom at high water temperatures; so the earth's poaching provides that these bacteria grow and are dispersed without control. The one that causes this increase of temperature, are different intervals of nutrients on the cyanobacterial flowers that are able to develop, for what it is necessary that the reductions of nutrients for the control of flowering follow more aggressive in response to the climatic changes that are produced to the planet Earth.

2.       Planktonic bacterial communities in the ocean

The planktonic bacterial communities of the marine environment can be considered affected by climate change through a combination of direct and indirect effects. As with direct effects, as has been the case before, take into account the high temperatures and the CO₂ found in the environment. With indirect effects, it produces a large spectrum of impacts ranging from increased stratification of surface water to deoxygenation of water; increased occurrence of extreme weather phenomena and modification of the food chain and nutrient regimens cause a change in bacterioplankton control.

3.       Microbes in aquatic biofilms under the effect of climate change

A biofilm is a complex addition of microorganisms growing on a solid surface. These biofilms, when poached, include changes in the autotrophic community composition and extracellular polymeric substances, stimulation of the heterotrophic community and changes in the microbes. This temperature has consequences on the functioning of the biofilm through direct control of biological activities and the selection of adapted taxon, which provide information on the activities.

On the other hand, desiccation can produce permanent changes in the community microbial composition and in extracellular enzymatic activities, which also depend on the specific sensitivity of the species and biofilm structure.

4.       Microbial communities and the global carbon cycle

Microbial communities, because of climate change, will partially control the equilibrium of soil stockpiling and carbon loss, as these microorganisms are influenced by temperature, water availability, oxygen penetration and carbon supply.

These four different response mechanisms are proposed, which allow a better general understanding of microbial climate responses. There are also subsets of variables that give local microbial responses to climate change, specifically sensitivity to soil moisture, which have a major effect on predictions for carbon stocks and the proliferation of microorganisms in the soil.

Colonies of single microorganisms have an important role in the global carbon cycle by metabolizing organic matter and releasing more than 60 Pg of carbon for year. Since the composition and microbial activities are strongly influenced by environmental changes, the climatic change can exert pressure on the microorganisms in order to accelerate or alleviate the emissions of winter effect gases.

Climate change is one of the most important factors in the loss of microbial diversity. This problem is really serious, since microorganisms make up the largest part of the world's biological diversity, and have essential functions in the biogeochemical processes that make life possible for organisms located at higher levels of the tropic chain.

5.       Microbial processes in relation to climate change and the use of land in the tropics

As it has been said before, the climatic change and the change of the uses of the soil are two factors that influence the composition of this one. The first factor refers to environmental variables, such as temperature or the concentration of CO₂ in the soil, while the second is related to the anthropization process, which has increased exponentially in recent years. All these changes directly affect the diversity of the composition of microbial colonies. These individuals have an important role in biogeochemical cycles, as they perform functions that are essential for the rest of the organisms. Furthermore, it should be borne in mind that these changes are not the same in all ecosystems, so that, for example, the tropics area will have a better effect due to the increase in temperature.

All these impacts explained on this point have not come to be studied in detail in relation to the microbial communities, so there is a need for more research.

CONCLUSION

Climate change is a very important phenomenon for everyone, but today it’s not have enough aware that there are small microorganisms that play a big role in regulating this disaster caused by climate change. For this reason it is important to do a better research, because the bacteria are organisms so small that the people don’t take important mind about him and without them most of the ecosystems or efficient characteristics for the live of other organisms and the correct life cycles of them over the long term would not have been created. Therefore, they play an essential role in the development of ecosystems and make it possible for them to proliferate.

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