The microbial community within each living organism is essential for its healthy state. Even highly complex matrices like soil, depend on microorganisms to sustain and even improve plant development. Although it is a very robust and well‐equilibrated system, soil microbial populations are prone to changes of abundance caused by environmental changes. These community shifts may result in loss of groups related to biogeochemical cycles or soil structure. This work aimed to compare changes in soil microbial community driven by the amendment with crude oil. We used microcosms of two soils from Rothamsted Research UK agricultural station, being one a bare fallow soil, one a grassland soil and a pristine beach soil (tide line under Cyperus atlanticus growth) from Trindade Island ‐ Brazil. Soils were contaminated with crude oil at a concentration of 5% (w/w) and incubated at 26 °C for 20 days. We monitored CO2 emissions and extracted total DNA and total RNA. The DNA obtained was used for microbial profiling using the protocol suggested by Earth Microbiome Project (http://www.earthmicrobiome.org). The bioinformatics pipeline was executed as recommended by the Brazilian Microbiome Project (http://www.brmicrobiome.org).
 The preliminary results showed that the three environments are highly divergent about its microbial community even when they presented very similar CO2 emissions. The pristine soil presented more archeal individuals and a bigger community shift between the treated and non‐treated state, a sign of fragility. As future research we intent to evaluate the expression of genes related to soil services and related to degradation of crude oil hydrocarbon.We are thankful to Rothamsted Research for the support and to our funding agencies CAPES and CNPq.