Temporal hydrologic and chemical records from the Ox Bel Ha cave network within the coastal aquifer of the Yucatan Peninsula, from January 2015 to January 2016

The year-long records were obtained during two deployment periods at two locations. The first deployment was from January-15-2015 to June-15-2015 and the second deployment was from June-15-2015 to January-23-2016. Meteorological parameters (i.e., precipitation, barometric pressure and air temperature) were acquired at a meteorological station installed on the roof of Speleotech facility, located approximately 3.5 km from the Cenote Bang cave entrance. OsmoSamplers (to obtain chemical records) and data-loggers (to monitor water level, flow, water temperature) were deployed in the cave environment accessed through Cenote Bang by scuba divers who followed protocols established by the American Academy of Underwater Sciences and the National Speleological Society Cave Diving Section.
Full details related to the processing of the samples, storage, analysis, and attribute accuracy are provided in the Methods section of Brankovits and others, 2018. Processing took place after each deployment period in 2015 and 2016.
Source cited: Brankovits, D., Pohlman, J.W., Ganju, N.K., Iliffe, T.M., Lowell, N., Roth, E., Sylva, S.P., Emmert, J.A., and Lapham, L.L., 2018, Hydrologic controls of methane dynamics in karst subterranean estuaries: Global Biogeochemical Cycles, https://doi.org/10.1029/2018GB006026. (see Cross Reference 2)

I. Passive measurements made at the meteorological station using sensor-based data loggers:
Precipitation was measured with a rain gauge (Onset RG-3, calibration accuracy of ± 1.0%, up to 2 centimeter per hour (cm h−1); 0.2 mm resolution; time accuracy ± 1 minute per month) and is presented as daily total precipitation in millimeter per day (mm d−1). For resulting data, see data sheet 'precipitation' in data file 'CenoteBangTemporalRecords_2015-2016.xlsx'.
Barometric pressure was monitored at 15-min time intervals alongside the rain gauge with an Onset U20 data logger (less than 0.02 kPa resolution and a ± 0.3% FS or 0.62 kPa accuracy as the maximum error) that also measured air temperature (0.1 degC resolution, ± 0.44 degC accuracy). For resulting data, see data sheet 'barometer' in data file 'CenoteBangTemporalRecords_2015-2016.xlsx'.
II. Passive measurements within the flooded cave environment using sensor-based data loggers:
Within the cave, groundwater flow velocity, water level, and water temperature were monitored at 17 m water depth in the brackish water (BW) and at 22 m water depth in the saline groundwater (SG). Velocity was measured as current speed and direction with a TCM-1 (Lowell Instruments, LLC) tilt current meter (TCM; ± 2 centimeter per second (cm s−1) ± 3% of reading accuracy and 0.1 centimeter per second (cm s−1) resolution; bearing ± 5 degree accuracy for speed greater than 5 centimeter per second (cm s−1) with a 0.1 degree resolution) at 1-minute intervals. For resulting data, see data sheets 'flow_BW' and 'flow_SG' in data file 'CenoteBangTemporalRecords_2015-2016.xlsx'.
Water level, measured with an Onset U20 logger (± 0.21 cm with an error less than ± 1.0 cm at 15-min intervals), is reported as absolute depth and departure from the mean value after compensating for barometric pressure changes measured at the meteorological station. This logger also measured water temperature (0.1 degC resolution, ± 0.44 degC accuracy). For resulting data, see data sheets 'water_level_BW' and 'water_level_SG' in data file 'CenoteBangTemporalRecords_2015-2016.xlsx'.
III. Chemical analyses of water samples collected with the OsmoSamplers in the cave environment:
Analysis of the samples was performed at the Woods Hole Oceanographic Institution (WHOI) and U.S. Geological Survey (USGS) in Woods Hole MA, USA. Sulfate and chloride concentrations were determined using a Metrohm 881 Compact Plus ion chromatograph (IC) equipped with a Metrosep A Supp 5-250 anion column. Chloride concentrations in millimolar (mM) were converted to milligrams per liter (mg l-1) and multiplied by 0.0018066 to determine salinity (psu - practical salinity unit). The analytical error for chloride and sulfate was +/- 3.5% of the IAPSO (International Association for the Physical Sciences of the Oceans) standard sulfate and chloride values.
Headspace methane concentrations were determined using a Shimadzu GC-14-B gas chromatograph (GC) equipped with a flame ionization detector (FID). Headspace concentrations were converted to dissolved concentrations using the method of Magen and others, 2014 and are reported with an relative standard deviation of 2%.
The stable carbon isotope composition of methane from the headspace of the serum vials was determined using a Thermo-Finnigan DELTAPlus XL isotope ratio mass spectrometer (IRMS) coupled to an Agilent 6890 Gas Chromatograph (GC) via a Finnigan GCCIII combustion interface with 1-sigma deviation of 1.6 per mil.
For resulting data, see data sheets 'osmosampler_FW' and 'osmosampler_BW' in data file 'CenoteBangTemporalRecords_2015-2016.xlsx'.
Full details related to the processing of the samples, storage, analysis, and attribute accuracy are provided in the Methods section of Brankovits and others, 2018. Processing took place after each deployment period in 2015 and 2016.
Sources cited: Brankovits, D., Pohlman, J.W., Ganju, N.K., Iliffe, T.M., Lowell, N., Roth, E., Sylva, S.P., Emmert, J.A., and Lapham, L.L., 2018, Hydrologic controls of methane dynamics in karst subterranean estuaries: Global Biogeochemical Cycles, https://doi.org/10.1029/2018GB006026. (see Cross Reference 2)
Magen, C., Lapham, L.L., Pohlman, J.W., Marshall, K., Bosman, S., Casso, M., and Chanton, J.P., 2014, A simple headspace equilibration method for measuring dissolved methane: Limnology and Oceanography Methods, vol. 12, issue 9, https://doi.org/10.4319/lom.2014.12.637 (see Cross Reference 1)

The obtained data are organized in an Excel spreadsheet (CenoteBangTemporalRecords_2015-2016.xlsx) that has eight separate sheets containing data. Each sheet was used to generate a CSV file using Excel Professional Plus 2016. The eight sheets correspond to the eight CSV files as follows:
Sheet barometer corresponds to file barometer.csv; Sheet precipitation corresponds to file precipitation.csv; Sheet water_level_BW corresponds file water_level_BW.csv; Sheet water_level_SG corresponds to file water_level_SG.csv; Sheet flow_BW corresponds to file flow_BW.csv; Sheet flow_SG corresponds to file flow_SG.csv; Sheet osmosampler_FW corresponds to file osmosampler_FW.csv; Sheet osmosampler_BW corresponds to file osmosampler_BW.csv.

Added keywords section with USGS persistent identifier as theme keyword.