terra preta  soils were likely formed between 500 and 2500  years ago by pre - columbian populations .
these soils are found in the amazonian region distinguished by the presence of ceramic artifacts , animal bones and high amounts of charred organic materials , which are commonly referred as black carbon ( bc ) .
ade soils are considered as model soils because their high chemical fertility ( high content levels of organic c , p , ca , mg , zn , and mn ) and stable organic matter .
also , ade soils are characterized by their distinct microbial communities , with a higher diversity and richness when compared to the surrounding soils .
the aim of this study was to investigate the taxonomic and functional diversity of two ade sites based on metagenomic approach .
soils were collected in the hatahara site located in the municipality of iranduba ( 0316494s 6012340w ) , in the amazonas state , brazil .
dna extraction from 250  mg of soil was carried out using powersoil dna isolation kit ( mobio laboratories , carlsbad , ca , usa ) , according to the manufacturer 's protocol .
dna quality and concentration were measured by agarose gel electrophoresis and nanodrop 1000 spectrophotometer ( thermo scientific , waltham , ma , usa ) .
soil dna samples were used to prepare paired - end libraries ( 2    300  bp ) using the miseq reagent kit v.2 ( 500  cycles ; illumina , san diego , ca , usa ) , for further shotgun metagenomic sequencing in a miseq personal sequencing system ( illumina , san diego , ca , usa ) .
a total of 3,716,966 paired - end and non - paired forward sequences ( average length of 241  bp ) were joined using the pear software .
metagenomic sequences were annotated using the mg - rast automatic annotation server ( . ) .
exploratory data analysis was conducted in stamp software . the most abundant phyla detected were proteobacteria ( 40    2% ) , actinobacteria ( 18    1% ) , firmicutes ( 5    0.3% ) and acidobacteria ( 4    0.5% ) .
others phyla detected were planctomycetes ( 3.5 0.4% ) , chloroflexi ( 2.5    0.3% ) , cyanobacteria ( 2.5    0.1% ) , bacteroidetes ( 2    0.2% ) and verrucomicrobia ( 2    0.2% ) . the archaea diversity was represented by the phyla crenarchaeota , euryarchaeota , korarchaeota , nanoarchaeota and thaumarchaeota , with approximately 1.5    0.5% of total abundance .
protein annotations were grouped into functional categories and the most abundant functions were related to carbohydrates ( 15    0.5% ) , clustering - based subsystems ( 14    0.2% ) , aminoacids ( 11    0.16% ) , miscellaneous ( 7    0.03% ) and protein metabolism ( 6    0.16% ) . the most abundant category level 3 is associated with serine - glyoxylate cycle ( 1.8    0.5% ) .
we hypothesize that these functions are related to methylotrophs and methane reducing on ade soils , but further studies are necessary to validate this inference .
our dataset reveals a great taxonomic and functional microbial potential to be explored by bioprospecting of new enzymes or identifying unknown microorganisms .
terra preta  soils were likely formed between 500 and 2500  years ago by pre - columbian populations .
these soils are found in the amazonian region distinguished by the presence of ceramic artifacts , animal bones and high amounts of charred organic materials , which are commonly referred as black carbon ( bc ) .
ade soils are considered as model soils because their high chemical fertility ( high content levels of organic c , p , ca , mg , zn , and mn ) and stable organic matter .
also , ade soils are characterized by their distinct microbial communities , with a higher diversity and richness when compared to the surrounding soils .
the aim of this study was to investigate the taxonomic and functional diversity of two ade sites based on metagenomic approach .
soils were collected in the hatahara site located in the municipality of iranduba ( 0316494s 6012340w ) , in the amazonas state , brazil .
dna extraction from 250  mg of soil was carried out using powersoil dna isolation kit ( mobio laboratories , carlsbad , ca , usa ) , according to the manufacturer 's protocol .
dna quality and concentration were measured by agarose gel electrophoresis and nanodrop 1000 spectrophotometer ( thermo scientific , waltham , ma , usa ) .
soil dna samples were used to prepare paired - end libraries ( 2    300  bp ) using the miseq reagent kit v.2 ( 500  cycles ; illumina , san diego , ca , usa ) , for further shotgun metagenomic sequencing in a miseq personal sequencing system ( illumina , san diego , ca , usa ) .
a total of 3,716,966 paired - end and non - paired forward sequences ( average length of 241  bp ) were joined using the pear software .
metagenomic sequences were annotated using the mg - rast automatic annotation server ( . ) .
exploratory data analysis was conducted in stamp software . the most abundant phyla detected were proteobacteria ( 40    2% ) , actinobacteria ( 18    1% ) , firmicutes ( 5    0.3% ) and acidobacteria ( 4    0.5% ) .
others phyla detected were planctomycetes ( 3.5 0.4% ) , chloroflexi ( 2.5    0.3% ) , cyanobacteria ( 2.5    0.1% ) , bacteroidetes ( 2    0.2% ) and verrucomicrobia ( 2    0.2% ) . the archaea diversity was represented by the phyla crenarchaeota , euryarchaeota , korarchaeota , nanoarchaeota and thaumarchaeota , with approximately 1.5    0.5% of total abundance .
protein annotations were grouped into functional categories and the most abundant functions were related to carbohydrates ( 15    0.5% ) , clustering - based subsystems ( 14    0.2% ) , aminoacids ( 11    0.16% ) , miscellaneous ( 7    0.03% ) and protein metabolism ( 6    0.16% ) .
the most abundant category level 3 is associated with serine - glyoxylate cycle ( 1.8    0.5% ) .
we hypothesize that these functions are related to methylotrophs and methane reducing on ade soils , but further studies are necessary to validate this inference .
our dataset reveals a great taxonomic and functional microbial potential to be explored by bioprospecting of new enzymes or identifying unknown microorganisms .
 the anthropogenic amazon dark earth soil is considered one of the world 's most fertile soils . 
 these soils differs from conventional amazon soils because its higher organic content concentration . here 
 we describe the metagenome sequencing of microbial communities of two sites of anthropogenic amazon dark earth soils from amazon rainforest , brazil . 
 the raw sequence data are stored under short read accession number : prjna344917 . 
Direct link to deposited data
Experimental design, materials and methods
Amazon dark earth (ADE) soils
Sampling, DNA extraction and sequencing
Metagenomic data