Hydrocarbon concentration, gas chromatography-mass spectrometry characterization, mass-to-charge ratio and monoisotopic intensity, short-lived radioisotope, benthic infauna, sediment texture and composition data collected aboard R/V Justo Sierra cruise JS-0815 in the southern Gulf of Mexico from 2015-07-31 to 2015-08-08 (NCEI Accession 0226973)

Supplemental information - data parameters and units:

1. GRIIDC dataset R4.x267.179:0006; Mass-to-charge ratio (m/z) and monoisotopic intensity data: All excel files are from the same sediment core (IXW500, 19.44415 N and 93.88871 W) collected on 2015-08-06 at 1010m water depth. Each file represents a section of the sediment core and the file name contain the depth interval in millimeters. Expt m/z (experimentally derived mass-to-charge ratio) is a dimensionless quantity formed by dividing the mass number of detected ions by its charge number. Monoisotopic intensity (Mono Inty) is the peak height of the most abundant isotopolog. The Excel spreadsheet includes all the instrument metadata. There was no overflow from the experiment, therefore the spreadsheet labelled “overflow” is empty. Columns X and all subsequent columns (both in “details” and “failed groups” tabs) are the various instances of different isotopes evaluation, with the repeating series of columns denoting: Isotope Name Mass Peak Intensity Expected Intensity Isotope Score. The term “Recalibration” in the Details spreadsheet (Row 4-10) is the polynomial equations used for the calibration of the FTMS spectra. DBE means Double Bond Equivalent. Empty cells mean no data is available.

2. GRIIDC dataset R4.x267.179:0024; Hydrocarbon concentration data: Concentration of 2-ring PAHs and biomarkers in units of ng g-1. Site names include the core name (location) and the depth interval for the sediment core. Target compounds are 2-ring PAHs: Naphthalene (N) and alkylated homologues (N C1-C4); 3-ring: Acenaphthylene (ACL), Acenaphthene (ACE), Fluorene (F) and alkylated homologues (F1,F2), Dibenzothiophene (D), Phenanthrene (P), Anthracene (AN), and their alkylated homologues (P/AN C1-C4, D C1-C2), 4-ring: Fluoranthene (FL), Pyrene (PY), Benz[a]anthracene (BAA), Chrysene (C), and their alkylated homologues (FL/PY C1-C4, BAA/C C1-C4), 5-ring: Benzo[b]fluoranthene (BBF), Benzo[k]fluoranthene (BKF), Benzo[a]pyr- ene (BAP), Dibenz[a,h]anthracene (DA), and alkylated homologues (BP/PER C1-C4), and 6-ring: Indeno[1,2,3-cd]pyrene (ID), Benzo[ghi]perylene (BGP). Target biomarkers: Steranes (C27-C29), Hopanes (C23-C32), Hopanes (C33-C35), n-alkane (C12), n-alkane (C13), n-alkane (C14), n-alkane (C15), n-alkane (C16), pristine, n-alkane (C17), n-alkane (C18), phytane, n-alkane (C19), n-alkane (C20), n-alkane (C21), n-alkane (C22), n-alkane (C23), n-alkane (C24), n-alkane (C25), n-alkane (C26), n-alkane (C27), n-alkane (C28), n-alkane (C29), n-alkane (C30), n-alkane (C31), n-alkane (C32), n-alkane (C33), n-alkane (C34), n-alkane (C35), n-alkane (C36), n-alkane (C37). Site information worksheet includes - cruise date (Month, Year), core ID, collection date (mm/dd/yyyy), latitude and longitude (degree minutes; decimal degrees), water depth (m).

3. GRIIDC dataset R4.x267.000:0083; GC-MS Characterization data: File “sampling sites”: sampling station id, sediment core collection date (mm/dd/yyyy), latitude and longitude (degrees minutes), water depth (m).
File “Characterization of marine cores from the southern Gulf of Mexico using GC-MS.xlsx”: Sample id (station id label and depth intervals (in mm) within each core), organic compounds ration acronyms, biomarker ratios. The following organic compounds were included in this analysis and in parenthesis the acronym and the mass-to-charge ratio (m/z): 4-methyl dibenzothiophene (4MDBT, 198); 1-methyl dibenzothiophene (1MDBT, 198); 2+3-methyl dibenzothiophene (2,3MDBT, 198); dibenzothiophene (DBT, 184); methylphenantrene index (MPI-1, 192; calculated as 1.5*(2-methyl phenanthrene+3-methyl phenanthrene)/(phenanthrene+1-methyl phenanthrene+9-methyl phenanthrene)); 18a(H)-22,29,30-trisnorneohopane (Ts, 191); 17a(H)-22,29,30-trisnorneohopane (Tm, 191); C29 17a(H),21 b(H) hopane (29H, 191); C30 17a(H),21 b(H) hopane (30H, 191); 18-a(H)-30-norneohopane (29Ts, 191); C21 Tricyclic terpane (21TT, 191); C23 Tricyclic terpane (23TT, 191); C24 Tricyclic terpane (24TT, 191); C30-moretane (30M/30H, 191); C29 5a(H), 14a(H), 17a(H) 20S sterane (29aaaS, 217); C29 5a(H), 14a(H), 17a(H) 20R sterane (29aaaR, 217); C29 5a(H),14b(H),17b(H) 20S sterane+C29 5a(H),14b(H),17b(H) 20R sterane (29abb(S+R), 217); C27 5a(H), 14b(H), 17b(H) 20S sterane+C27 5a(H), 14b(H), 17b(H) 20R sterane (27abb(S+R), 218); C28 5a(H), 14b(H), 17b(H) 20S sterane+C28 5a(H), 14b(H), 17b(H) 20R sterane (28abb(S+R), 218); Pristane (Pr, 85); Phytane (Ph, 85); C17-normal alkane (C17, 85); C18-normal alkane (C17, 85).

4. GRIIDC dataset R4.x267.000:0114; Benthic foraminifera distribution data: Site name (core ID), date collected (August 2015), depth increment relative to sediment surface (cm), species name, total number of individuals identified (count) per species, number taxa.
Please note that the station location information (latitude, longitude, depth, collection date) for three different sites (IXW250, IXW500, and IXW750) are not included in the data file and are provided in the GRIIDC metadata which are as follows: IXW250 19° 25.8410N, 93° 05.6985W, Depth:583 m, Collection date: 2015-08-06; IXW500 19° 26.6488N, 93° 53.3226W, Depth:1010 m, Collection date: 2015-08-06; IXW750 19° 27.5979N, 94° 35.0968W, Depth:1440 m, Collection date: 2015-08-05.

5. GRIIDC dataset R4.x267.000:0116; Benthic infauna data: Station Name, latitude (decimal degrees), longitude (decimal degrees), core collection depth (m), sampling date (dd-mon-yyyy), CTD depth (m), dissolved oxygen (DO, mg/L), temperature (degrees C), salinity (psu), station name, sediment core section depth (section, cm), section id (sec), replicate number (Rep), total PAH (ng/g), macrofauna abundance (Mac_nm2, n/m^2), macrofauna richness (Mac_S, n of taxa/sample), macrofauna diversity (Mac_Hprime, Shannon H'), macrofauna diversity (Mac_N1, Hill's N1), macrofauna evenness (Mac_Jprime, Pielou J'), meiofauna abundance (Mei_nm2, n/m^2), meiofauna richness (Mei_S, n of taxa/sample), meiofauna diversity (Mei_Hprime, Shannon H'), Meiofauna Diversity (Mei_N1, Hill's N1), Meiofauna Evenness (Mei_Jprime, Pielou J'), Total number of all Copepoda (n/m²), Total number of all Nematoda (n/m²), Total number of all Dorvilleidae (n/m²), Nematode / Copepod ratio (unitless), meiofauna and macrofaunal taxa abundance (n/m²). Please see the metadata sheet inside the dataset to find all the information regarding the taxa.

6. GRIIDC dataset R4.x267.000:0124; Short-lived radioisotope (SLRad) data: Water depth of core site (m), core collection date (mm/dd/yyyy), site identification (ID), sediment core identification (ID), top depth of interval (mm), bottom depth of interval (mm), average depth of interval (mm), 210Pb (Lead) total (dpm/g), 210Pb (Lead) total error (dpm/g), 234Th (Thorium) Total (dpm/g), 234Th (Thorium) error (dpm/g), re-Analysis of 234Th (Thorium) activity (dpm/g) represent 234ThSup (“supported” Thorium), re-Analysis of 234Th (Thorium) activity error (dpm/g) represent 234ThSup (“supported” Thorium), 137Cs (Caesium) activity (dpm/g), 137Cs (Caesium) activity error (dpm/g), 7Be (Beryllium) activity (dpm/g), 7Be (Beryllium) activity error (dpm/g), 214Pb (Lead, 295 keV) activity (dpm/g), 214Pb (Lead, 295 keV) actvity error (dpm/g), 214Pb (Lead, 351 keV) activity (dpm/g), 214Pb (Lead, 351 keV) actvity error (dpm/g), 214Bi (Bismuth) activity (dpm/g), 214Bi (Bismuth) activity error (dpm/g), 210PbSup (“supported” Lead) activity (dpm/g), 210PbSup (“supported” Lead) activity error (dpm/g), 210Pbxs (Excess Lead) activity (dpm/g), 210Pbxs (Excess Lead) activity error (dpm/g), decay corrected 210Pbxs (Excess Lead) activity (dpm/g), decay corrected 210Pbxs (Excess Lead) activity error (dpm/g), 234Thxs (Excess Thorium) activity (dpm/g), 234Thxs (Excess Thorium) activity error (dpm/g), decay corrected 234Thxs (Excess Thorium) activity (dpm/g), decay corrected 234Thxs (Excess Thorium) activity error (dpm/g), laboratory/ facility analysis was performed at: Eckerd College, St. Petersburg FL. Blank cell denotes no analysis performed.

7. GRIIDC dataset R4.x267.000:0140; Sediment texture and composition data: Sediment core collection latitude and longitude (decimal degrees), water depth (m), core collection date (mm/dd/yyyy), site identification (ID), core identification (ID), top depth of interval (mm), bottom depth of interval (mm), average depth of interval (average of top and bottom depths, mm), percent gravel (by dry weight), percent sand (by dry weight), percent silt (by dry weight), percent clay (by dry weight), percent mud (calculated by adding percent silt and clay, by dry weight), percent carbonate (by dry weight), percent total organic matter (TOM) by loss on ignition (LOI) (by dry weight), percent other (non-carbonate, non-organic; by dry weight), laboratory/facility where analysis was performed.