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Dataset Title: | [GA01 - Pb Isotopes] - Lead isotope data collected from the R/V Pourquoi pas (GEOVIDE) in the North Atlantic, Labrador Sea (section GA01) during 2014 (Filling Gaps in the Atlantic and Pacific Pb and Pb Isotope Spatial and Temporal Evolution) |
Institution: | BCO-DMO (Dataset ID: bcodmo_dataset_652127) |
Information: | Summary | License | FGDC | ISO 19115 | Metadata | Background | Subset | Files | Make a graph |
Attributes { s { cruise_id { String bcodmo_name "cruise_id"; String description "Cruise identification"; String long_name "Cruise Id"; String units "unitless"; } SECT_ID { String bcodmo_name "cruise_part"; String description "Cruise section identifier"; String long_name "SECT ID"; String units "unitless"; } STNNBR { Byte _FillValue 127; String _Unsigned "false"; Byte actual_range 1, 77; String bcodmo_name "station"; String description "Station number"; String long_name "STNNBR"; String units "unitless"; } BTL_DATE { Int32 _FillValue 2147483647; Int32 actual_range 20140519, 20140625; String bcodmo_name "date"; String description "Date (yyyymmdd) when the bottle was fired according to the bottle file."; String long_name "BTL DATE"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/ADATAA01/"; String units "unitless"; } latitude { String _CoordinateAxisType "Lat"; Float64 _FillValue NaN; Float64 actual_range 40.33325, 59.79927; String axis "Y"; String bcodmo_name "latitude"; String description "Latitude of bottle firing; north is positive."; String ioos_category "Location"; String long_name "BTL LAT"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/LATX/"; String standard_name "latitude"; String units "degrees_north"; } longitude { String _CoordinateAxisType "Lon"; Float64 _FillValue NaN; Float64 actual_range -51.09588, -10.036; String axis "X"; String bcodmo_name "longitude"; String description "Lonitude of bottle firing; east is positive."; String ioos_category "Location"; String long_name "BTL LON"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P09/current/LONX/"; String standard_name "longitude"; String units "degrees_east"; } BTLNBR { Byte _FillValue 127; String _Unsigned "false"; Byte actual_range 1, 24; String bcodmo_name "bottle"; String description "Bottle number; typically 1-24"; String long_name "BTLNBR"; String units "unitless"; } CTDPRS { Float32 _FillValue NaN; Float32 actual_range 11.1, 5436.9; String bcodmo_name "pressure"; String description "CTD pressure"; String long_name "CTDPRS"; String nerc_identifier "https://vocab.nerc.ac.uk/collection/P01/current/PRESPR01/"; String units "decibars"; } SAMPNO { Int16 _FillValue 32767; Int16 actual_range 1, 560; String bcodmo_name "bottle"; String description "Sequential sample number within the cast (usually corresponds to the bottle number)"; String long_name "SAMPNO"; String units "unitless"; } PI_SAMPNO { Int16 _FillValue 32767; Int16 actual_range 10003, 10516; String bcodmo_name "bottle"; String description "PI issued sample number for when a standard SAMPNO was not appropriate."; String long_name "PI SAMPNO"; String units "unitless"; } Pb_206_207_D_RATIO_BOTTLE { Float32 _FillValue NaN; Float32 actual_range 1.1635, 1.2121; String bcodmo_name "unknown"; String description "Dissolved Pb isotope ratios Pb 206/Pb 207 for Pb passing through a 0.2um SARTOBRAN or 0.45um Supor filter."; String long_name "Pb 206 207 D RATIO BOTTLE"; String units "dimensionless"; } Pb_208_207_D_RATIO_BOTTLE { Float32 _FillValue NaN; Float32 actual_range 2.436, 2.4607; String bcodmo_name "unknown"; String description "Dissolved Pb isotope ratios Pb 208/Pb 207 for Pb passing through a 0.2um SARTOBRAN or 0.45um Supor filter."; String long_name "Pb 208 207 D RATIO BOTTLE"; String units "dimensionless"; } Pb_206_204_D_RATIO_BOTTLE { Float32 _FillValue NaN; Float32 actual_range 18.23, 19.05; String bcodmo_name "unknown"; String description "Dissolved Pb isotope ratios Pb 206/Pb 204 for Pb passing through a 0.2um SARTOBRAN or 0.45um Supor filter."; String long_name "Pb 206 204 D RATIO BOTTLE"; String units "dimensionless"; } Pb_206_207_D_RATIO_BOTTLE_FLAG { Byte _FillValue 127; String _Unsigned "false"; Byte actual_range 1, 4; String bcodmo_name "flag"; Float64 colorBarMaximum 150.0; Float64 colorBarMinimum 0.0; String description "Quality flag for parameter Pb_206_207_D_RATIO_BOTTLE; follows the convention: 1 = good; 3 = questionable; 4 = bad"; String long_name "Pb 206 207 D RATIO BOTTLE FLAG"; String units "unitless"; } Pb_208_207_D_RATIO_BOTTLE_FLAG { Byte _FillValue 127; String _Unsigned "false"; Byte actual_range 1, 4; String bcodmo_name "flag"; Float64 colorBarMaximum 150.0; Float64 colorBarMinimum 0.0; String description "Quality flag for parameter Pb_208_207_D_RATIO_BOTTLE; follows the convention: 1 = good; 3 = questionable; 4 = bad"; String long_name "Pb 208 207 D RATIO BOTTLE FLAG"; String units "unitless"; } Pb_206_204_D_RATIO_BOTTLE_FLAG { Byte _FillValue 127; String _Unsigned "false"; Byte actual_range 1, 4; String bcodmo_name "flag"; Float64 colorBarMaximum 150.0; Float64 colorBarMinimum 0.0; String description "Quality flag for parameter Pb_206_204_D_RATIO_BOTTLE; follows the convention: 1 = good; 3 = questionable; 4 = bad"; String long_name "Pb 206 204 D RATIO BOTTLE FLAG"; String units "unitless"; } CASTNO { Byte _FillValue 127; String _Unsigned "false"; Byte actual_range 2, 10; String bcodmo_name "cast"; String description "Cast number"; String long_name "CASTNO"; String units "unitless"; } } NC_GLOBAL { String access_formats ".htmlTable,.csv,.json,.mat,.nc,.tsv,.esriCsv,.geoJson"; String acquisition_description "Sample storage bottle lids and threads were soaked overnight in 2N reagent grade HCl, then filled with 1N reagent grade HCl to be heated in an oven at 60 degrees celcius\\u00a0overnight, inverted, heated for a second day, and rinsed 5X with pure distilled water.\\u00a0 The bottles were then filled with trace metal clean dilute HCl (0.01N HCl) and again heated in the oven for one day on either end.\\u00a0 Clean sample bottles were emptied, and double-bagged prior to rinsing and filling with sample. As stated in the cruise report, trace metal clean seawater samples were collected using the French GEOTRACES clean rosette (General Oceanics Inc. Model 1018 Intelligent Rosette), equipped with twenty-two new 12L GO-FLO bottles (two bottles were leaking and were never deployed during the cruise). The 22 new GO-FLO bottles were initially cleaned in LEMAR laboratory following the GEOTRACES procedures (Cutter and Bruland, 2012). The rosette was deployed on a 6mm Kevlar cable with a dedicated custom designed clean winch. Immediately after recovery, GO-FLO bottles were individually covered at each end with plastic bags to minimize contamination. They were then transferred into a clean container (class-100) for sampling. On each trace metal cast, nutrient and/or salinity samples were taken to check potential leakage of the Go-Flo bottles. Prior to filtration, GO-FLO bottles were mixed manually three times. GO-FLO bottles were pressurized to less than\\u00a08 psi with 0.2-um filtered N2\\u00a0(Air Liquide). For Stations 1, 11, 15, 17, 19, 21, 25, 26, 29, 32 GO-FLO spigots were fitted with an acid-cleaned piece of Bev-a-Line tubing that fed into a 0.2 um capsule filters (SARTOBRAN\\u00a0300, Sartorius). For all other stations (13, 34, 36, 38, 40, 42, 44, 49, 60, 64, 68, 69, 71, 77) seawater was filtered directly through paired filters (Pall Gelman Supor 0.45um polystersulfone, and Millipore mixed ester cellulose MF 5 um) mounted in Swinnex polypropylene filter holders, following the Planquette and Sherrell (2012) method. Filters were cleaned following the protocol described in Planquette and Sherrell (2012) and kept in acid-cleaned 1L LDPE bottles (Nalgene) filled with ultrapure water (Milli-Q, 18.2 megaohm/cm) until use. Subsamples were taken into acid-cleaned (see above) Nalgene HDPE bottles after a triple rinse with the sample. All samples were acidified back in the Boyle laboratory at 2mL per liter seawater (pH 2) with trace metal clean 6N HCl. On this cruise, only the particulate samples were assigned GEOTRACES numbers. In this dataset, the dissolved Pb samples collected at the same depth (sometimes on a different cast) as the particulate samples have been assigned identifiers as \\u201cSAMPNO\\u201d which corresponds to the particulate GEOTRACES number. In cases where there were no corresponding particulate samples, a number was generated as \\u201cPI_SAMPNO\\u201d. Upon examining the data, we observed that the sample taken from rosette position 1 (usually the near-bottom sample) was always higher in [Pb] than the sample taken immediately above that, and that the excess decreased as the cruise proceeded. The Pb isotope ratio of these samples were higher than the comparison bottles as well. A similar situation was seen for the sample taken from rosette positions 5, 20 and 21 when compared to the depth-interpolated [Pb] from the samples immediately above and below. Also, at two stations where our near-bottom sample was taken from rosette position 2, there was no [Pb] excess over the samples immediately above. We believe that this evidence points to sampler-induced contamination that was being slowly washed out during the cruise, but never completely. So we have flagged all of these analyses with a \\u201c3\\u201d indicating that we do not believe that these samples should be trusted as reflecting the true ocean [Pb]. In addition, we observed high [Pb] in the samples at Station 1 and very scattered Pb isotope ratios. The majority of these concentrations were far in excess of those values observed at nearby Station 11, and also the nearby USGT10-01. Discussion among other cruise participants revealed similarly anomalous data for other trace metals (e.g., Hg species). After discussion at the 2016 GEOVIDE Workshop, we came to the conclusion that this is*- evidence of GoFlo bottles not having sufficient time to \\u201cclean up\\u201d prior to use, and that most or all bottles from Station 1 were contaminated. We flagged all Station 1 data with a \\u201c3\\u201d indicating that we do not believe these values reflect the true ocean [Pb]. Samples were analyzed at least 1 month after acidification over 11 mass spectrometry sessions by the method of Reuer et al. (2003) as modified by Boyle et al. (2012) and further slightly modified as noted in the following: Double magnesium hydroxide co-precipitation followed by anion exchange purification: This method is a slight adaptation of the isotope ratio method of Reuer et al., 2003, which was further modified as described by Boyle et al. (2012) and as slightly revised as described below. The method includes low- blank pre-concentration by Mg(OH)2\\u00a0co-precipitation and isotope ratio analysis on a GV/Micromass IsoProbe multicollector ICPMS using a 50 uL/min nebulizer aspirated into an APEX/SPIRO desolvator, using post-desolvator trace N2\\u00a0addition to boost sensitivity. Nalgene polypropylene separatory funnels (1000mL) and Corning 50 ml conical centrifuge vials were cleaned by heated submersion for 2 days at 60 degrees celcius\\u00a0in 1N reagent grade HCl, followed by a bulk rinse and 4X individual rinse of each vial with pure distilled water. Each vial was then filled with trace metal clean dilute HCl (0.01N HCl) and heated in the oven at 60 degrees celcius\\u00a0for one day on either end.\\u00a0 Centrifuge vials were kept filled until just before usage. The separatory funnels were rinsed with distilled water after each use and then filled with high-purity distilled water spiked with high-purity HCl (final concentration 0.01N) between uses. 1000mL polypropylene separatory funnels (Nalgene) were weighed and rinsed one time with seawater sample, then filled with 500ml of sample. Mg(OH)2\\u00a0coprecipitation was induced by minimal addition of high-purity ammonia solution and mixing (typically 8uL ammonia per 1mL seawater sample). The separatory funnels were left to settle overnight, then agitated to move the precipitate down the funnel walls. After complete settling, the precipitate was drawn from the bottom of the funnels into a 50mL conical centrifuge tubes. The solution/precipitate mix was centrifuged and the solution siphoned off, and then the precipitate was dissolved in a minimal amount of high-purity 6N HCl before undergoing another ammonia addition and Mg(OH)2\\u00a0coprecipitation. The mixture was centrifuged and the overlying solution was siphoned. Eichrom AG-1x8 resin was cleaned by three batch rinses with 6N trace metal clean HCl for a 12 hours on a shaker table, followed by multiple washes with distilled water until the pH of the solution was above 4.5. Resin was stored at room temperature in the dark until use. The precipitate was dissolved in 1 ml of high purity 1.1M HBr. The amount of solution was adjusted depending on the Si concentration of the seawater sample; if too little solution is used, the Si precipitates as a gel, impeding the column separation. The resin in the column was first cleaned with 6M HCl, equilibrated with 1.1M HBr, and then sample was loaded onto the column. The column was then washed with 1.1M HBr followed by 2M HCl and then eluted with 6M HCl. The samples in a 5 ml Savillex PTFE vial were then taken to dryness on a hotplate in a recirculating filtered air fume hood, and stored sealed until analysis. Just before analysis, samples were dissolved for several minutes in 10\\u03bcl concentrated ultrapure HNO3. Then, an appropriate volume of ultrapure water was added (typically 400ul) and spiked with an appropriate amount of Tl for mass fractionation correction. IsoProbe multicollector ICPMS Faraday cups were used to collect on 202Hg, 203Tl, 205Tl, 206Pb, 207Pb, and 208Pb. An Isotopx Daly detector with a WARP filter was used to collect on 204Pb+204Hg. This Daly detector is a revised version that eliminates a reflection problem with the electronic circuitry of the previous version. We do not report 206Pb/204Pb data for samples run on the old Daly detector. Because the deadtime of the Daly detector varied from day to day, we calibrated deadtime on each day by running a standard with known 206Pb/204Pb at a high 204 count rate. The counter efficiency drifts during the course of a day, so we established that drift by running a standard with known 206Pb/204Pb (and a 204 count rate comparable to the samples) every five samples. Tailing from one Faraday cup to the next was corrected by the 209Bi half-mass method as described by Thirlwall (2000). On each analytical date, we calibrated the instrument by running NBS981 and normalized measured sample isotope ratios to our measured raw NBS981 isotope ratios to those established by Baker et al. (2004). Using this method for 22 determinations of an in-house standard (\\u201cBAB\\u201d) shows that for samples near the upper range of the Pb signals shown for samples (~1V), 206Pb/207Pb and 208Pb/207Pb can be reproduced to 200ppm. Low-level samples will be worse than that, but generally better than 1000ppm in this data set. Because of the drift uncertainty in the Daly detector, 206Pb/204Pb for samples in the mid-to-upper range of sample concentrations will be at best reproducible to 500ppm. We have intercalibrated Pb isotope analyses with two labs as reported in Boyle et al. (2012). Since that report, two more labs have added intercalibration data. The outcome of that intercalibration suggests that the accuracy of our measurements approaches the analytical reproducibility we note above."; String awards_0_award_nid "651714"; String awards_0_award_number "OCE-1357224"; String awards_0_data_url "http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1357224"; String awards_0_funder_name "NSF Division of Ocean Sciences"; String awards_0_funding_acronym "NSF OCE"; String awards_0_funding_source_nid "355"; String awards_0_program_manager "Henrietta N Edmonds"; String awards_0_program_manager_nid "51517"; String cdm_data_type "Other"; String comment "Pb Isotopes E. Boyle and C. Zubrick, PIs Version 3 October 2017"; String Conventions "COARDS, CF-1.6, ACDD-1.3"; String creator_email "info@bco-dmo.org"; String creator_name "BCO-DMO"; String creator_type "institution"; String creator_url "https://www.bco-dmo.org/"; String data_source "extract_data_as_tsv version 2.3 19 Dec 2019"; String date_created "2016-07-18T13:38:41Z"; String date_modified "2020-03-24T13:50:44Z"; String defaultDataQuery "&time<now"; String doi "10.1575/1912/bco-dmo.652127.1"; Float64 Easternmost_Easting -10.036; Float64 geospatial_lat_max 59.79927; Float64 geospatial_lat_min 40.33325; String geospatial_lat_units "degrees_north"; Float64 geospatial_lon_max -10.036; Float64 geospatial_lon_min -51.09588; String geospatial_lon_units "degrees_east"; String history "2024-11-23T16:44:49Z (local files) 2024-11-23T16:44:49Z https://erddap.bco-dmo.org/erddap/tabledap/bcodmo_dataset_652127.html"; String infoUrl "https://www.bco-dmo.org/dataset/652127"; String institution "BCO-DMO"; String instruments_0_acronym "ICP Mass Spec"; String instruments_0_dataset_instrument_description "Inductively Coupled Plasma Mass Spectrometer"; String instruments_0_dataset_instrument_nid "652137"; String instruments_0_description "An ICP Mass Spec is an instrument that passes nebulized samples into an inductively-coupled gas plasma (8-10000 K) where they are atomized and ionized. Ions of specific mass-to-charge ratios are quantified in a quadrupole mass spectrometer."; String instruments_0_instrument_external_identifier "https://vocab.nerc.ac.uk/collection/L05/current/LAB15/"; String instruments_0_instrument_name "Inductively Coupled Plasma Mass Spectrometer"; String instruments_0_instrument_nid "530"; String instruments_0_supplied_name "ICP-MS"; String instruments_1_acronym "Bottle"; String instruments_1_dataset_instrument_description "The General Oceanics Inc Model 1018 Intelligent Rosette was equipped with 22 new 12L GO-FLO bottles."; String instruments_1_dataset_instrument_nid "652136"; String instruments_1_description "A container, typically made of glass or plastic and with a narrow neck, used for storing drinks or other liquids."; String instruments_1_instrument_name "Bottle"; String instruments_1_instrument_nid "542498"; String instruments_1_supplied_name "12L GO-FLO"; String instruments_2_acronym "HMD"; String instruments_2_dataset_instrument_description "Reduces solvent derived polyatomic interferences in the ICPMS mass spectrum"; String instruments_2_dataset_instrument_nid "652140"; String instruments_2_description "Membrane desolvation module that reduces solvent derived polyatomic interferences in the ICPMS mass spectrum. Both aqueous and organic solutions can be desolvated."; String instruments_2_instrument_name "Heated Membrane Desolvator"; String instruments_2_instrument_nid "652139"; String instruments_2_supplied_name "APEX/SPIRO Desolvator"; String instruments_3_acronym "DD"; String instruments_3_dataset_instrument_description "Revised version that eliminates a reflection problem with the electronic circuitry of the previous version."; String instruments_3_dataset_instrument_nid "652142"; String instruments_3_description "The Daly detector was designed by N.R Daly in the 1960’s. The design uses a conversion dynode to convert incident ions into electrons. It also separates the multiplication electronics away from the ion beam preventing secondary ion production on the multiplication dynodes."; String instruments_3_instrument_name "Daly detector"; String instruments_3_instrument_nid "652141"; String instruments_3_supplied_name "Isotopx Daly detector"; String instruments_4_acronym "FC"; String instruments_4_dataset_instrument_description "Metal (conductive) cup designed to catch charged particles in a vacuum."; String instruments_4_dataset_instrument_nid "652144"; String instruments_4_description "A Faraday cup is a metal (conductive) cup designed to catch charged particles in a vacuum. The resulting current can be measured and used to determine the number of ions or electrons hitting the cup."; String instruments_4_instrument_name "Faraday cup"; String instruments_4_instrument_nid "652143"; String instruments_4_supplied_name "IsoProbe multicollector ICPMS Faraday Cup"; String keywords "bco, bco-dmo, biological, bottle, btl, BTL_DATE, BTL_LAT, BTL_LON, btlnbr, castno, chemical, cruise, cruise_id, ctdprs, data, dataset, date, dmo, erddap, flag, management, oceanography, office, Pb_206_204_D_RATIO_BOTTLE, Pb_206_204_D_RATIO_BOTTLE_FLAG, Pb_206_207_D_RATIO_BOTTLE, Pb_206_207_D_RATIO_BOTTLE_FLAG, Pb_208_207_D_RATIO_BOTTLE, Pb_208_207_D_RATIO_BOTTLE_FLAG, PI_SAMPNO, preliminary, ratio, sampno, sect, SECT_ID, stnnbr"; String license "https://www.bco-dmo.org/dataset/652127/license"; String metadata_source "https://www.bco-dmo.org/api/dataset/652127"; Float64 Northernmost_Northing 59.79927; String param_mapping "{'652127': {'BTL_LON': 'master - longitude', 'BTL_LAT': 'master - latitude'}}"; String parameter_source "https://www.bco-dmo.org/mapserver/dataset/652127/parameters"; String people_0_affiliation "Massachusetts Institute of Technology"; String people_0_affiliation_acronym "MIT-EAPS"; String people_0_person_name "Edward A. Boyle"; String people_0_person_nid "50984"; String people_0_role "Principal Investigator"; String people_0_role_type "originator"; String people_1_affiliation "Massachusetts Institute of Technology"; String people_1_affiliation_acronym "MIT-EAPS"; String people_1_person_name "Cheryl Zurbrick"; String people_1_person_nid "644617"; String people_1_role "Co-Principal Investigator"; String people_1_role_type "originator"; String people_2_affiliation "Massachusetts Institute of Technology"; String people_2_affiliation_acronym "MIT-EAPS"; String people_2_person_name "Cheryl Zurbrick"; String people_2_person_nid "644617"; String people_2_role "Contact"; String people_2_role_type "related"; String people_3_affiliation "Woods Hole Oceanographic Institution"; String people_3_affiliation_acronym "WHOI BCO-DMO"; String people_3_person_name "Hannah Ake"; String people_3_person_nid "650173"; String people_3_role "BCO-DMO Data Manager"; String people_3_role_type "related"; String project "GEOVIDE_Pb"; String projects_0_acronym "GEOVIDE_Pb"; String projects_0_description "Lead is a trace metal that has historically been emitted into the atmosphere through human activities such as coal burning and the use of leaded gasoline followed by deposition into the ocean. Once introduced into the marine environment, lead is dispersed via currents and removed by biota and other sinking particles. This century-scale growth of lead emissions followed by a decline upon the phase-out of leaded gasoline is one of the great global geochemical experiments. In this study, researchers at the Massachusetts Institute of Technology will analyze archived seawater samples to improve our knowledge on the spatial and temporal variability of lead concentrations and lead isotope ratios. This data will yield new insights into the sources and transport of lead and other metals, document the time-evolving human footprint on the ocean, and assist with validating models."; String projects_0_end_date "2017-02"; String projects_0_geolocation "Subpolar North Atlantic; Labrador Sea; Greenland"; String projects_0_name "Filling Gaps in the Atlantic and Pacific Pb and Pb Isotope Spatial and Temporal Evolution"; String projects_0_project_nid "651715"; String projects_0_project_website "http://www.geovide.obs-vlfr.fr/"; String projects_0_start_date "2014-03"; String publisher_name "Biological and Chemical Oceanographic Data Management Office (BCO-DMO)"; String publisher_type "institution"; String sourceUrl "(local files)"; Float64 Southernmost_Northing 40.33325; String standard_name_vocabulary "CF Standard Name Table v55"; String subsetVariables "cruise_id,SECT_ID"; String summary "Lead isotope data collected from the R/V Pourquoi pas (GEOVIDE) in the North Atlantic, Labrador Sea (section GA01) during 2014"; String title "[GA01 - Pb Isotopes] - Lead isotope data collected from the R/V Pourquoi pas (GEOVIDE) in the North Atlantic, Labrador Sea (section GA01) during 2014 (Filling Gaps in the Atlantic and Pacific Pb and Pb Isotope Spatial and Temporal Evolution)"; String version "1"; Float64 Westernmost_Easting -51.09588; String xml_source "osprey2erddap.update_xml() v1.3"; } }
The URL specifies what you want: the dataset, a description of the graph or the subset of the data, and the file type for the response.
Tabledap request URLs must be in the form
https://coastwatch.pfeg.noaa.gov/erddap/tabledap/datasetID.fileType{?query}
For example,
https://coastwatch.pfeg.noaa.gov/erddap/tabledap/pmelTaoDySst.htmlTable?longitude,latitude,time,station,wmo_platform_code,T_25&time>=2015-05-23T12:00:00Z&time<=2015-05-31T12:00:00Z
Thus, the query is often a comma-separated list of desired variable names,
followed by a collection of
constraints (e.g., variable<value),
each preceded by '&' (which is interpreted as "AND").
For details, see the tabledap Documentation.