The files in this data release are the DNA sequence files referenced in the journal article by Dawn B. Goldsmith, Zoe A. Pratte, Christina A. Kellogg, Sara E. Snader, and Koty H. Sharp titled 'Stability of temperate coral Astrangia poculata microbiome is reflected across different sequencing methodologies', published in AIMS Microbiology 5(1): 62-76 (doi: 10.3934/microbiol.2019.1.62). They represent a 16S rRNA gene amplicon survey (bacterial and archaeal genes) of the coral's microbiome completed using Sanger sequencing. The sequences associated with this study have also been submitted to the National Center for Biotechnology Information's (NCBI) GenBank repository under accession numbers MK175495 to MK176300 (bacterial sequences) and MH915525 to MH915542 (archaeal sequences). For more information, you may contact Christina Kellogg at the USGS St. Petersburg Coastal and Marine Science Center, 600 4th Street South, St. Petersburg, Florida, USA, 33701; telephone (727) 502-8128; email ckellogg@usgs.gov. The file titled 'Astrangia_bacterial_seqs_GenBank.fasta' contains 806 bacterial sequences. These sequences consist of one representative sequence for each bacterial operational taxonomic unit (OTU) identified from the Astrangia bacterial sequences. The sequences have been modified from the sequences returned by the sequencing vendor as follows. Vector and ends were trimmed from the sequences using Geneious (version 11.1.4; Biomatters Ltd., Auckland, NZ). Using QIIME version 1.9.1, all sequences less than 50 bp were removed. Greengenes (version 13_8) was used through QIIME to perform a chimera check with usearch61 and to classify taxonomy using an open reference algorithm with a 97% similarity threshold. Singletons were retained, while all other default parameters were used. After chimeric, unclassified, chloroplast, and mitochondrial sequences were removed, 996 bacterial OTUs remained. Upon submission of the sequences to NCBI's GenBank, GenBank's implementation of version 10 of usearch (64-bit version) using the uchime2_ref command in high confidence mode uncovered 190 additional chimeras. These sequences were removed, resulting in a dataset of 806 bacterial OTUs. The file titled 'Astrangia_archaeal_seqs_GenBank.fasta' contains 18 archaeal sequences. These sequences consist of one representative sequence for each archaeal OTU identified from the Astrangia archaeal sequences. The sequences were modified from the sequences returned by the sequencing vendor in the same way as described above for the bacterial sequences, except that GenBank's chimera check did not reveal any chimeras to be removed from the dataset. The files labeled 'Astrangia_MIMARKS_metadata_bacteria.xlsx,' 'Astrangia_MIMARKS_metadata_bacteria.txt', 'Astrangia_MIMARKS_metadata_bacteria.csv', 'Astrangia_MIMARKS_metadata_archaea.xlsx', 'Astrangia_MIMARKS_metadata_archaea.txt', and 'Astrangia_MIMARKS_metadata_archaea.csv' are MIMARKS (minimum information about a marker gene) compliant metadata, based on standards developed by the Genomic Standards Consortium for reporting marker gene sequences (Yilmaz and others, 2011, Nature Biotechnology 29:415-420, doi:10.1038/nbt.1823). The column headers in those files are defined as follows: sequence_ID: a unique identifier for each sequence source_mat_id: a unique identifier assigned to the material sample from which the sequence was derived investigation_type: type of investigation that produced the sequence data project_name: name of the project within which the sequencing was organized collection_date: date of sample collection lat_lon: geographical origin of the sample as defined by latitude and longitude geo_loc_name: geographical origin of the sample as defined by the country or sea name followed by specific region name env_biome: descriptor of the broad ecological context of a sample env_feature: geographic environmental features; more local descriptor of environment than biome env_material: material that was displaced by the sample env_package: MIMARKS environmental package samp_store_temp: temperature at which sample was stored depth: vertical distance below local surface; units are meters temp: temperature of sample at time of sampling; units are degrees Celsius samp_collect_device: method or device employed for collecting the sample samp_mat_process: any processing applied to the sample during or after retrieving the sample from environment nucl_acid_ext: nucleic acid extraction; doi is provided for the paper which describes the specific extraction method employed for these samples nucl_acid_amp: nucleic acid amplification; amplification method employed for these samples lib_const_meth: library construction method used for clone libraries lib_reads_seqd: total number of clones sequenced from the library lib_vector: cloning vector used in construction of libraries lib_screen: specific enrichment or screening methods applied before and/or after creating clone libraries target_gene: targeted gene or locus name for marker gene studies pcr_primers: PCR primers that were used to amplify the sequence of the targeted gene, locus or subfragment pcr_cond: description of reaction conditions and components for PCR seq_meth: sequencing method used chimera_check: method(s) used to check sequence data for presence of chimeric sequences