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   set  data   graph     files  public Stable isotopes in reactive silica pools of Mississippi River plume sediments collected
aboard the R/V Pelican in May 2017
   ?     I   M   background (external link) RSS Subscribe BCO-DMO bcodmo_dataset_786508

The Dataset's Variables and Attributes

Row Type Variable Name Attribute Name Data Type Value
attribute NC_GLOBAL access_formats String .htmlTable,.csv,.json,.mat,.nc,.tsv,.esriCsv,.geoJson,.odvTxt
attribute NC_GLOBAL acquisition_description String Stable silicon isotopes (e.g. \u03b430Si) in sediment biogenic silica (bSi)
are widely used as a paleoproxy for marine silicic acid usage by pelagic
diatoms. Despite the growing body of work that uses bSi \u03b430Si signals,
there are a lack of \u03b430Si data on other reactive pools of Si in
sediments. This oversight misses valuable information on early diagenetic
products and potentially biases existing sedimentary bSi \u03b430Si, which
only quantified bSi fractions not altered by diagenesis. For the first time,
we quantified \u03b430Si among operationally defined reactive Si pools (using
a pre-leach of mild acid prior to alkaline digestion) in Mississippi River
plume sediments. We compared the \u03b430Si signal within these reactive Si
pools to a traditional alkaline-only digestion of sedimentary bSi. These data
offer proof of concept that \u03b430Si is a higher throughput approach for
quantifying isotopic properties among reactive Si pools marine sediments vs.
the more laborious (albeit powerful) examination of natural silicon
radioisotopes in these chemical leaches.

Core Sampling

Briefly, samples were acquired from the study area using an Ocean Instruments
MC-900 Multi-corer, which preserved the sediment-water interface during
recovery. Overlying bottom water was removed, cores were sectioned into 1cm
slices, homogenized, packed under N2 gas and frozen at -20o C for further
analysis.

Operational Definitions

Operational reactive Si pools have previously been defined by Rahman et al.
(2016) but for consistency and clarity with previous literature (DeMaster,
1981; Michalopoulos and Aller, 2004; Qin et al., 2012; Wang et al., 2015;
Rahman et al., 2016; Krause et al., 2017) it has been restated here. Therefore
we use the following nomenclature;

1\. Si-HCl: Mild acid-leachable pre-treatment; Highly reactive silica
associated with authigenic clays and metal oxide coatings (Michalopoulos and
Aller, 2004).
2. Si-Alk: Mild alkaline-leachable digestion completed after acid
pretreatment; Frees reactive silica associated with the biogenic silica pool
(Michalopoulos and Aller, 2004).
3. Si-NaOH: Harsh NaOH digestion done after Si-HCl and Si-Alk (Rahman et
al., 2016; Rahman et al., 2017); Associated with the reactive lithogenic Si
(LSi) pool and the comparatively refractory \u201cdark bSiO2\u201d (e.g.
sponge spicules and Rhizaria, Maldonado et al., 2019).
4. T-bSi: Following the traditional definition of biogenic silica (DeMaster,
1981), with no acid pre-treatment.

Reactive Silica Pools

Frozen sediment samples were thawed to room temperature (22o C) and triplicate
~50-100 mg subsamples were immediately weighed into 50 mL polyethylene
centrifuge tubes. Samples were never dried or ground before/during
extractions. Procedural blanks were also prepared in triplicate. Additional
subsamples of sediment were dried at 60o C to obtain correction for water
content.

Sequential Extractions

The sequential extraction methodology separates silica into operationally
defined pools based on kinetics, reaction conditions and reaction sequence
(DeMaster, 1981; Michalopoulos and Aller, 2004; Rahman et al., 2016).

Acid Leachable Silica (Si-HCl)

Sediment extractions occurred at room temperature (22o C) using Honeywell
Fluka Trace SELECT 0.1 N HCl for 12 hrs, while keeping particles suspended via
constant motion. Following centrifugation, the Si-HCl leachate was removed and
neutralized. Remaining sediment was rinsed in triplicate with Milli-Q water to
remove any residual acid (Michalopoulos and Aller, 2004). As it had previously
been demonstrated by Rahman et al. (2016) that the rinses contained minor
amounts of Si these rinses were discarded. A weak HCl molarity was purposely
chosen to remove metal coatings, authigenic phases, and activate bSi surfaces
while not affecting the sequential Si-Alk digestion (Michalopoulos and Aller,
2004).

Mild Alkaline Leachable Si (Si-Alk)

The remaining sediment from the acid pre-treatment was subsequently digested
with 0.1 M Na2CO3 (Fisher Scientific Certified ACS) for 20 mins in a 85o C
water bath. Following the 20 min timepoint, samples were placed on ice and
neutralized to stop the digestion. Following centrifugation, the Si-Alk
leachate was removed and stored for further use. The process was stopped after
20 mins to ensure the absence of lithogenic material (DeMaster, 1981;
Michalopoulos and Aller, 2004) and certify that the clear majority of
solubilized silica present is biogenic. Fresh 0.1 M Na2CO3 was added to the
samples and the digestions were continued for a total of 5 hrs (DeMaster,
1981) to completely remove the bSi phase. Concluding after 5 hrs, samples were
placed on ice and neutralized to stop the digestion. Following centrifugation,
the leachate was removed and discarded. Remaining sediment was rinsed in
triplicate with Milli-Q water to remove any residual Na2CO3 and again the
rinses were discarded.

Harsh NaOH Digestion (Si-NaOH)

The remaining sediment from the Si-Alk treatment was subsequently digested
with Honeywell Fluka 4 M NaOH for 2 hrs in a 85o C water bath. After 2 hrs,
samples were placed on ice and neutralized to stop the digestion. Following
centrifugation, the Si- NaOH leachate was removed, the remaining sediment was
rinsed with Milli-Q water to remove any residual leachate and this rinse was
added to the Si-NaOH leachate and stored for further analysis (Rahman et al.,
2016).

Traditional bSi Digestion (T-bSi)

Additionally, a second treatment following the traditional definition of
biogenic silica (DeMaster, 1981), with no acid pre-treatment was used to
derive \u03b430Si from traditional bSi measurements. New subsamples of
sediment were weighed out. 0.1 M Na2CO3 was added to samples and heated in a
85o C water bath for 20 mins to remove the bSi phase. Following the 20 min
timepoint, samples were placed on ice and neutralized to stop the digestion.
Following centrifugation, leachate was removed and stored for further use.
Similar to the Si-Alk digestions, the process was stopped after 20 mins to
ensure the absence of lithogenic material.

A 1 ml aliquot of each resulting liquid (Si-HCl, Si-Alk, Si-NaOH and T-bSi)
was analyzed for dissolved SiOH4 concentration (dSi) as described by
Brzezinski and Nelson (Brzezinski and Nelson, 1986) using the molybdate-blue
method on a Genesys 10S UV-Vis Spectrophotometer. The remaining supernatants
were concentrated via evaporation at 100o C and stored following DeMaster
(1980) in preparation for stable isotope analysis.

Stable Isotope Analysis

Sample purification and isotope analysis were carried out at the University of
Bristol Isotope Group laboratories. Concentrated sample fluids were purified
via cation ion exchange chromatography (Bio-Rad AG50W-X12, 200-400 mesh cation
exchange resin in H+ form). Purified solutions were analyzed in duplicate for
Si isotopes (28Si, 29Si, 30Si) using a multi collector-inductively coupled
plasma-mass spectrometer (MC-ICP-MS, Finnigan Neptune s/n 1002), equipped with
CETAC PFA spray chamber and PFA nebulizer (100ul/min). A standard-sample-
standard bracketing procedure with Mg doping following Cardinal et al., (2003)
was used to correct for both instrumental mass bias and matrix effects.
Additionally, sample and standard solutions were both doped with 0.1 M H2SO4
(ROMIL UpA) and 1 M HCl (in-house distilled) to reduce any matrix effects from
anion loading and guarantee matrix matching between sample and standard
(Hughes et al., 2011). All isotopic composition results are expressed as
\u03b430Si, corresponding to the silicon isotopic abundances in samples
relative to the international reference standard NBS-28 (NIST RM8546, purified
quartz sand). Reference standards Diatomite (Reynolds et al., 2007) and LMG08
(sponge) (Hendry et al., 2011) were run in tandem with samples to assess long-
term reproducibility. Average measured values are reported as +1.27 \u00b1
0.09\u2030 (n=75) and -3.47 \u00b1 0.16\u2030 (n=27) (\u00b1SD) respectively,
which are well within agreement with published values (Reynolds et al., 2007;
Hendry et al., 2011). All samples and standards are consistent with the
kinetic mass fractionation law (Reynolds et al., 2007) with the \u03b429Si =
0.518x\u03b430Si. Procedural blanks were lower than the detection limit and
thus considered negligible on \u03b430Si of the samples.

Major Metal Compositions and Corrections

Additional thawed/wet sediment subsamples were used for duplicate sequential
extractions and digestions (Si-HCl, Si-Alk, Si-NaOH and T-bSi) run as
previously described. Supernatants were concentrated via evaporation at 100o C
and fluids were reconstituted in 2% HNO3 (in-house distilled) to determine
major ion concentrations on an Agilent 7700 Series ICP-MS. The instrument was
calibrated using a blank and seven matrix-matched, mixed standards. Internal
standardization during analysis was monitored via the addition of (50 \u03bcl,
10,000 ppb) 115In and 4Be to all standards and samples. Using Aluminum (Al):Si
corrections (Kamatani and Oku, 2000; Ragueneau et al., 2005), both Si-Alk and
T-bSi \u03b430Si signals (\u2030) and mass of Si released (\u03bcmol/g) were
adjusted for bias from lithogenic material (however, this was more important
for the mass of Si, as isotopic content was derived from 30-minute digestions,
opposed to 5 hour digestions for the former).

Organic Matter

Sediment total organic carbon (TOC) and total organic nitrogen (TON) content
were analyzed at the Dauphin Island Sea Lab using a Costech elemental
combustion system (4010 ECS) following vapor phase acidification to remove
carbonates. Briefly, dried sediment samples were placed in a glass desiccator
and reacted with reagent-grade 12N HCl vapor for 24 hrs at room temperature.
Samples were then dried at 60o C overnight to remove remaining HCl and water
content before TOC/TON analyses (Yamamuro and Kayanne, 1995).
attribute NC_GLOBAL awards_0_award_nid String 712666
attribute NC_GLOBAL awards_0_award_number String OCE-1558957
attribute NC_GLOBAL awards_0_data_url String http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1558957 (external link)
attribute NC_GLOBAL awards_0_funder_name String NSF Division of Ocean Sciences
attribute NC_GLOBAL awards_0_funding_acronym String NSF OCE
attribute NC_GLOBAL awards_0_funding_source_nid String 355
attribute NC_GLOBAL awards_0_program_manager String Dr Simone Metz
attribute NC_GLOBAL awards_0_program_manager_nid String 51479
attribute NC_GLOBAL cdm_data_type String Other
attribute NC_GLOBAL comment String Isotope
Jeffery W. Krause
Data Version 1: 2020-02-04
attribute NC_GLOBAL Conventions String COARDS, CF-1.6, ACDD-1.3
attribute NC_GLOBAL creator_email String info at bco-dmo.org
attribute NC_GLOBAL creator_name String BCO-DMO
attribute NC_GLOBAL creator_type String institution
attribute NC_GLOBAL creator_url String https://www.bco-dmo.org/ (external link)
attribute NC_GLOBAL data_source String extract_data_as_tsv version 2.3 19 Dec 2019
attribute NC_GLOBAL date_created String 2020-01-08T17:06:48Z
attribute NC_GLOBAL date_modified String 2020-03-02T20:28:24Z
attribute NC_GLOBAL defaultDataQuery String &time<now
attribute NC_GLOBAL doi String 10.1575/1912/bco-dmo.786508.1
attribute NC_GLOBAL Easternmost_Easting double -89.75004
attribute NC_GLOBAL geospatial_lat_max double 28.94688
attribute NC_GLOBAL geospatial_lat_min double 28.49884
attribute NC_GLOBAL geospatial_lat_units String degrees_north
attribute NC_GLOBAL geospatial_lon_max double -89.75004
attribute NC_GLOBAL geospatial_lon_min double -90.83464
attribute NC_GLOBAL geospatial_lon_units String degrees_east
attribute NC_GLOBAL infoUrl String https://www.bco-dmo.org/dataset/786508 (external link)
attribute NC_GLOBAL institution String BCO-DMO
attribute NC_GLOBAL instruments_0_acronym String ICP Mass Spec
attribute NC_GLOBAL instruments_0_dataset_instrument_nid String 786513
attribute NC_GLOBAL instruments_0_description String 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.
attribute NC_GLOBAL instruments_0_instrument_external_identifier String https://vocab.nerc.ac.uk/collection/L05/current/LAB15/ (external link)
attribute NC_GLOBAL instruments_0_instrument_name String Inductively Coupled Plasma Mass Spectrometer
attribute NC_GLOBAL instruments_0_instrument_nid String 530
attribute NC_GLOBAL instruments_0_supplied_name String Finnigan Neptune s/n 1002 multi collector-inductively coupled plasma-mass spectrometer
attribute NC_GLOBAL instruments_1_acronym String Spectrophotometer
attribute NC_GLOBAL instruments_1_dataset_instrument_nid String 786512
attribute NC_GLOBAL instruments_1_description String An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples.
attribute NC_GLOBAL instruments_1_instrument_external_identifier String https://vocab.nerc.ac.uk/collection/L05/current/LAB20/ (external link)
attribute NC_GLOBAL instruments_1_instrument_name String Spectrophotometer
attribute NC_GLOBAL instruments_1_instrument_nid String 707
attribute NC_GLOBAL instruments_1_supplied_name String Genesys 10S UV-Vis Spectrophotometer
attribute NC_GLOBAL instruments_2_acronym String Costech ECS 4010
attribute NC_GLOBAL instruments_2_dataset_instrument_nid String 793025
attribute NC_GLOBAL instruments_2_description String The ECS 4010 Nitrogen / Protein Analyzer is an elemental combustion analyser for CHNSO elemental analysis and Nitrogen / Protein determination. The GC oven and separation column have a temperature range of 30-110 degC, with control of +/- 0.1 degC.
attribute NC_GLOBAL instruments_2_instrument_name String Costech International Elemental Combustion System (ECS) 4010
attribute NC_GLOBAL instruments_2_instrument_nid String 793023
attribute NC_GLOBAL keywords String average, Avg_d30Si, Avg_d30Si_2_Stdev, Avg_Si_Released, Avg_Si_Released_2_Stdev, bco, bco-dmo, biological, bottom, Bottom_Depth, carbon, carbonate, chemical, chemistry, co3, collected, concentration, core, cruise, Cruise_Collected, d30, data, dataset, date, Date_Collected, depth, deviation, dmo, earth, Earth Science > Oceans > Ocean Chemistry > Silicate, erddap, iso, latitude, longitude, management, mass, mass_concentration_of_silicate_in_sea_water, multi, MultiCore, nominal, Nominal_Depth, number, ocean, oceanography, oceans, office, organic, particulate, phase, poc, POC_2_Stdev, pon, PON_2_Stdev, pool, porewater, preliminary, reactive, Reactive_Pool_Treatment, sample, Sample_Depth, science, sea, seawater, silicate, standard, standard deviation, station, Station_Number, stdev, time, Time_Collected, treatment, v, vapor, Vapor_Phase_Carbonate, water
attribute NC_GLOBAL keywords_vocabulary String GCMD Science Keywords
attribute NC_GLOBAL license String https://www.bco-dmo.org/dataset/786508/license (external link)
attribute NC_GLOBAL metadata_source String https://www.bco-dmo.org/api/dataset/786508 (external link)
attribute NC_GLOBAL Northernmost_Northing double 28.94688
attribute NC_GLOBAL param_mapping String {'786508': {'Latitude_N': 'master - latitude', 'Longitude_W': 'master - longitude', 'ISO_DateTime_UTC': 'flag - time'}}
attribute NC_GLOBAL parameter_source String https://www.bco-dmo.org/mapserver/dataset/786508/parameters (external link)
attribute NC_GLOBAL people_0_affiliation String Dauphin Island Sea Lab
attribute NC_GLOBAL people_0_affiliation_acronym String DISL
attribute NC_GLOBAL people_0_person_name String Rebecca A. Pickering
attribute NC_GLOBAL people_0_person_nid String 786518
attribute NC_GLOBAL people_0_role String Principal Investigator
attribute NC_GLOBAL people_0_role_type String originator
attribute NC_GLOBAL people_1_affiliation String Dauphin Island Sea Lab
attribute NC_GLOBAL people_1_affiliation_acronym String DISL
attribute NC_GLOBAL people_1_person_name String Jeffrey W Krause
attribute NC_GLOBAL people_1_person_nid String 544582
attribute NC_GLOBAL people_1_role String Co-Principal Investigator
attribute NC_GLOBAL people_1_role_type String originator
attribute NC_GLOBAL people_2_affiliation String Louisiana State University
attribute NC_GLOBAL people_2_affiliation_acronym String LSU-DOCS
attribute NC_GLOBAL people_2_person_name String Kanchan Maiti
attribute NC_GLOBAL people_2_person_nid String 712671
attribute NC_GLOBAL people_2_role String Co-Principal Investigator
attribute NC_GLOBAL people_2_role_type String originator
attribute NC_GLOBAL people_3_affiliation String Dauphin Island Sea Lab
attribute NC_GLOBAL people_3_affiliation_acronym String DISL
attribute NC_GLOBAL people_3_person_name String Rebecca A. Pickering
attribute NC_GLOBAL people_3_person_nid String 786518
attribute NC_GLOBAL people_3_role String Contact
attribute NC_GLOBAL people_3_role_type String related
attribute NC_GLOBAL people_4_affiliation String Woods Hole Oceanographic Institution
attribute NC_GLOBAL people_4_affiliation_acronym String WHOI BCO-DMO
attribute NC_GLOBAL people_4_person_name String Christina Haskins
attribute NC_GLOBAL people_4_person_nid String 746212
attribute NC_GLOBAL people_4_role String BCO-DMO Data Manager
attribute NC_GLOBAL people_4_role_type String related
attribute NC_GLOBAL project String CLASiC
attribute NC_GLOBAL projects_0_acronym String CLASiC
attribute NC_GLOBAL projects_0_description String NSF Award Abstract:
The Louisiana Shelf system in the northern Gulf of Mexico is fed by the Mississippi River and its many tributaries which contribute large quantities of nutrients from agricultural fertilizer to the region. Input of these nutrients, especially nitrogen, has led to eutrophication. Eutrophication is the process wherein a body of water such as the Louisiana Shelf becomes enriched in dissolved nutrients that increase phytoplankton growth which eventually leads to decreased oxygen levels in bottom waters. This has certainly been observed in this area, and diatoms, a phytoplankton which represents the base of the food chain, have shown variable silicon/nitrogen (Si/N) ratios. Because diatoms create their shells from silicon, their growth is controlled not only by nitrogen inputs but the availability of silicon. Lower Si/N ratios are showing that silicon may be playing an increasingly important role in regulating diatom production in the system. For this reason, a scientist from the University of South Alabama will determine the biogeochemical processes controlling changes in Si/N ratios in the Louisiana Shelf system. One graduate student on their way to a doctorate degree and three undergraduate students will be supported and trained as part of this project. Also, four scholarships for low-income, high school students from Title 1 schools will get to participate in a month-long summer Marine Science course at the Dauphin Island Sea Laboratory and be included in the research project. The study has significant societal benefits given this is an area where $2.4 trillion gross domestic product revenue is tied up in coastal resources. Since diatoms are at the base of the food chain that is the biotic control on said coastal resources, the growth of diatoms in response to eutrophication is important to study.
Eutrophication of the Mississippi River and its tributaries has the potential to alter the biological landscape of the Louisiana Shelf system in the northern Gulf of Mexico by influencing the Si/N ratios below those that are optimal for diatom growth. A scientist from the University of South Alabama believes the observed changes in the Si/N ratio may indicate silicon now plays an important role in regulating diatom production in the system. As such, understanding the biotic and abiotic processes controlling the silicon cycle is crucial because diatoms dominate at the base of the food chain in this highly productive region. The study will focus on following issues: (1) the importance of recycled silicon sources on diatom production; (2) can heavily-silicified diatoms adapt to changing Si/N ratios more effectively than lightly-silicified diatoms; and (3) the role of reverse weathering in sequestering silicon thereby reducing diffusive pore-water transport. To attain these goals, a new analytical approach, the PDMPO method (compound 2-(4-pyridyl)-5-((4-(2-dimethylaminoethylamino-carbamoyl)methoxy)phenyl)oxazole) that quantitatively measures taxa-specific silica production would be used.
attribute NC_GLOBAL projects_0_end_date String 2019-03
attribute NC_GLOBAL projects_0_geolocation String Northern Gulf of Mexico, specifically the Louisiana Shelf region dominated by the discharge of the Mississippi River on the western side of the delta
attribute NC_GLOBAL projects_0_name String The biotic and abiotic controls on the Silicon cycle in the northern Gulf of Mexico
attribute NC_GLOBAL projects_0_project_nid String 712667
attribute NC_GLOBAL projects_0_start_date String 2016-04
attribute NC_GLOBAL publisher_name String Biological and Chemical Oceanographic Data Management Office (BCO-DMO)
attribute NC_GLOBAL publisher_type String institution
attribute NC_GLOBAL sourceUrl String (local files)
attribute NC_GLOBAL Southernmost_Northing double 28.49884
attribute NC_GLOBAL standard_name_vocabulary String CF Standard Name Table v55
attribute NC_GLOBAL subsetVariables String Cruise_Collected
attribute NC_GLOBAL summary String Stable isotopes in reactive silica pools of Mississippi River plume sediments collected aboard the R/V Pelican in May 2017
attribute NC_GLOBAL time_coverage_end String 2017-05-06T20:40Z
attribute NC_GLOBAL time_coverage_start String 2017-05-05T18:40Z
attribute NC_GLOBAL title String Stable isotopes in reactive silica pools of Mississippi River plume sediments collected aboard the R/V Pelican in May 2017
attribute NC_GLOBAL version String 1
attribute NC_GLOBAL Westernmost_Easting double -90.83464
attribute NC_GLOBAL xml_source String osprey2erddap.update_xml() v1.3
variable Cruise_Collected   String  
attribute Cruise_Collected bcodmo_name String Cruise Name
attribute Cruise_Collected description String local name chosen by project investigators for a research expedition on a vessel as opposed to the formal/official cruise ID
attribute Cruise_Collected long_name String Cruise Collected
attribute Cruise_Collected units String dimensionless
variable MultiCore   String  
attribute MultiCore bcodmo_name String core_id
attribute MultiCore description String core number/identification
attribute MultiCore long_name String Multi Core
attribute MultiCore units String number/identification
variable Station_Number   String  
attribute Station_Number bcodmo_name String station
attribute Station_Number description String station identifier
attribute Station_Number long_name String Station Number
attribute Station_Number units String dimensionless
variable Bottom_Depth   byte  
attribute Bottom_Depth _FillValue byte 127
attribute Bottom_Depth actual_range byte 20, 47
attribute Bottom_Depth bcodmo_name String depth_bottom
attribute Bottom_Depth description String bottom depth in meters
attribute Bottom_Depth long_name String Bottom Depth
attribute Bottom_Depth units String meters
variable latitude   double  
attribute latitude _CoordinateAxisType String Lat
attribute latitude _FillValue double NaN
attribute latitude actual_range double 28.49884, 28.94688
attribute latitude axis String Y
attribute latitude bcodmo_name String latitude
attribute latitude colorBarMaximum double 90.0
attribute latitude colorBarMinimum double -90.0
attribute latitude description String latitude in decimal degrees
attribute latitude ioos_category String Location
attribute latitude long_name String Latitude
attribute latitude nerc_identifier String https://vocab.nerc.ac.uk/collection/P09/current/LATX/ (external link)
attribute latitude source_name String Latitude_N
attribute latitude standard_name String latitude
attribute latitude units String degrees_north
variable longitude   double  
attribute longitude _CoordinateAxisType String Lon
attribute longitude _FillValue double NaN
attribute longitude actual_range double -90.83464, -89.75004
attribute longitude axis String X
attribute longitude bcodmo_name String longitude
attribute longitude colorBarMaximum double 180.0
attribute longitude colorBarMinimum double -180.0
attribute longitude description String longitude in decimal degrees
attribute longitude ioos_category String Location
attribute longitude long_name String Longitude
attribute longitude nerc_identifier String https://vocab.nerc.ac.uk/collection/P09/current/LONX/ (external link)
attribute longitude source_name String Longitude_W
attribute longitude standard_name String longitude
attribute longitude units String degrees_east
variable Date_Collected   String  
attribute Date_Collected bcodmo_name String date
attribute Date_Collected description String date when core was collected in the format mmddyyyy
attribute Date_Collected long_name String Date Collected
attribute Date_Collected nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/ADATAA01/ (external link)
attribute Date_Collected units String unitless
variable Time_Collected   String  
attribute Time_Collected bcodmo_name String time
attribute Time_Collected description String time GMT when core was collected
attribute Time_Collected long_name String Time Collected
attribute Time_Collected nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/AHMSAA01/ (external link)
attribute Time_Collected units String HHMM
variable Sample_Depth   String  
attribute Sample_Depth bcodmo_name String depth_r
attribute Sample_Depth description String subsection used for analysis
attribute Sample_Depth long_name String Sample Depth
attribute Sample_Depth units String centimeters
variable Nominal_Depth   float  
attribute Nominal_Depth _FillValue float NaN
attribute Nominal_Depth actual_range float 0.5, 9.5
attribute Nominal_Depth bcodmo_name String depth_core
attribute Nominal_Depth description String depth used for data plots
attribute Nominal_Depth long_name String Nominal Depth
attribute Nominal_Depth units String centimeters
variable Porewater   float  
attribute Porewater _FillValue float NaN
attribute Porewater actual_range float 39.76, 274.4
attribute Porewater bcodmo_name String unknown
attribute Porewater description String concentration of dissolved silica acid Si(OH)4 in porewater collected
attribute Porewater long_name String Porewater
attribute Porewater units String uM
variable Vapor_Phase_Carbonate   float  
attribute Vapor_Phase_Carbonate _FillValue float NaN
attribute Vapor_Phase_Carbonate actual_range float 0.65, 6.98
attribute Vapor_Phase_Carbonate bcodmo_name String unknown
attribute Vapor_Phase_Carbonate description String % of carbonates present in the sediment sample via vapor phase acidification
attribute Vapor_Phase_Carbonate long_name String Vapor Phase Carbonate
attribute Vapor_Phase_Carbonate units String %
variable POC   float  
attribute POC _FillValue float NaN
attribute POC actual_range float 0.77, 1.7
attribute POC bcodmo_name String POC
attribute POC description String particular organic carbon
attribute POC long_name String Particulate Organic Carbon
attribute POC nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/CORGCAP1/ (external link)
attribute POC units String %
variable POC_2_Stdev   float  
attribute POC_2_Stdev _FillValue float NaN
attribute POC_2_Stdev actual_range float 0.01, 0.16
attribute POC_2_Stdev bcodmo_name String standard deviation
attribute POC_2_Stdev description String 2 standard deviations of sample variation
attribute POC_2_Stdev long_name String POC 2 Stdev
attribute POC_2_Stdev units String dimensionless
variable PON   float  
attribute PON _FillValue float NaN
attribute PON actual_range float 0.06, 0.19
attribute PON bcodmo_name String PON
attribute PON description String particular organic nitrogen
attribute PON long_name String PON
attribute PON nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/MDMAP013/ (external link)
attribute PON units String %
variable PON_2_Stdev   float  
attribute PON_2_Stdev _FillValue float NaN
attribute PON_2_Stdev actual_range float 0.0, 0.03
attribute PON_2_Stdev bcodmo_name String standard deviation
attribute PON_2_Stdev description String 2 standard deviations of sample variation
attribute PON_2_Stdev long_name String PON 2 Stdev
attribute PON_2_Stdev units String dimensionless
variable Reactive_Pool_Treatment   String  
attribute Reactive_Pool_Treatment bcodmo_name String treatment
attribute Reactive_Pool_Treatment description String which reactive pool the following data is for
attribute Reactive_Pool_Treatment long_name String Reactive Pool Treatment
attribute Reactive_Pool_Treatment units String unitless
variable Avg_d30Si   float  
attribute Avg_d30Si _FillValue float NaN
attribute Avg_d30Si actual_range float -3.32, 2.32
attribute Avg_d30Si bcodmo_name String mean
attribute Avg_d30Si description String Average d30Si (n=3) for each corresponding reactive Si Pool (- per mille)
attribute Avg_d30Si long_name String Avg D30 Si
attribute Avg_d30Si units String 0/00
variable Avg_d30Si_2_Stdev   float  
attribute Avg_d30Si_2_Stdev _FillValue float NaN
attribute Avg_d30Si_2_Stdev actual_range float 0.0, 0.79
attribute Avg_d30Si_2_Stdev bcodmo_name String standard deviation
attribute Avg_d30Si_2_Stdev description String Average d30Si (n=3) for each corresponding reactive Si Pool including 2 standard deviations of sample variation
attribute Avg_d30Si_2_Stdev long_name String Avg D30 Si 2 Stdev
attribute Avg_d30Si_2_Stdev units String dimensionless
variable Avg_Si_Released   float  
attribute Avg_Si_Released _FillValue float NaN
attribute Avg_Si_Released actual_range float 8.0, 1294.3
attribute Avg_Si_Released bcodmo_name String mean
attribute Avg_Si_Released description String Average Si released (n=3) for each corresponding reactive Si Pool (- micromoles per gram dry sediment)
attribute Avg_Si_Released long_name String Mass Concentration Of Silicate In Sea Water
attribute Avg_Si_Released units String umol/g
variable Avg_Si_Released_2_Stdev   float  
attribute Avg_Si_Released_2_Stdev _FillValue float NaN
attribute Avg_Si_Released_2_Stdev actual_range float 0.5, 380.9
attribute Avg_Si_Released_2_Stdev bcodmo_name String standard deviation
attribute Avg_Si_Released_2_Stdev description String Average Si released (n=3) for each corresponding reactive Si Pool including 2 standard deviations of sample variation
attribute Avg_Si_Released_2_Stdev long_name String Mass Concentration Of Silicate In Sea Water
attribute Avg_Si_Released_2_Stdev units String dimensionless
variable Mg   float  
attribute Mg _FillValue float NaN
attribute Mg actual_range float 0.0, 19791.34
attribute Mg bcodmo_name String Mg
attribute Mg description String magnesium concentration for each corresponding reactive Si pool
attribute Mg long_name String MG
attribute Mg units String ppm
variable Al   float  
attribute Al _FillValue float NaN
attribute Al actual_range float 247.93, 62795.01
attribute Al bcodmo_name String Al
attribute Al description String aluminum concentration for each corresponding reactive Si pool
attribute Al long_name String Al
attribute Al units String ppm
variable K   float  
attribute K _FillValue float NaN
attribute K actual_range float 0.0, 91645.12
attribute K bcodmo_name String K
attribute K description String potassium concentration for each corresponding reactive Si pool
attribute K long_name String K
attribute K units String ppm
variable Ti   float  
attribute Ti _FillValue float NaN
attribute Ti actual_range float 0.0, 971.54
attribute Ti bcodmo_name String Ti
attribute Ti description String titanium concentration for each corresponding reactive Si pool
attribute Ti long_name String Ti
attribute Ti units String ppm
variable V   float  
attribute V _FillValue float NaN
attribute V actual_range float 4.46, 142.82
attribute V bcodmo_name String V
attribute V description String vanadium concentration for each corresponding reactive Si pool
attribute V long_name String V
attribute V units String ppm
variable Cr   float  
attribute Cr _FillValue float NaN
attribute Cr actual_range float 0.0, 236.79
attribute Cr bcodmo_name String trace_metal_conc
attribute Cr description String chromium concentration for each corresponding reactive Si pool
attribute Cr long_name String CR
attribute Cr nerc_identifier String https://vocab.nerc.ac.uk/collection/P03/current/C035/ (external link)
attribute Cr units String ppm
variable Mn   float  
attribute Mn _FillValue float NaN
attribute Mn actual_range float 0.0, 1899.04
attribute Mn bcodmo_name String Mn
attribute Mn description String manganese concentration for each corresponding reactive Si pool
attribute Mn long_name String MN
attribute Mn units String ppm
variable Fe   float  
attribute Fe _FillValue float NaN
attribute Fe actual_range float 135.75, 39444.31
attribute Fe bcodmo_name String Fe
attribute Fe description String iron concentration for each corresponding reactive Si pool
attribute Fe long_name String Fe
attribute Fe units String ppm
variable Ni   float  
attribute Ni _FillValue float NaN
attribute Ni actual_range float 0.0, 125.27
attribute Ni bcodmo_name String trace_metal_conc
attribute Ni description String nickel concentration for each corresponding reactive Si pool
attribute Ni long_name String Ni
attribute Ni nerc_identifier String https://vocab.nerc.ac.uk/collection/P03/current/C035/ (external link)
attribute Ni units String ppm
variable Cu   float  
attribute Cu _FillValue float NaN
attribute Cu actual_range float 0.0, 39.61
attribute Cu bcodmo_name String Cu
attribute Cu description String copper concentration for each corresponding reactive Si pool
attribute Cu long_name String Cu
attribute Cu units String ppm
variable time   double  
attribute time _CoordinateAxisType String Time
attribute time actual_range double 1.4940096E9, 1.4941032E9
attribute time axis String T
attribute time bcodmo_name String ISO_DateTime_UTC
attribute time description String Date/Time (UTC) ISO formatted
attribute time ioos_category String Time
attribute time long_name String ISO Date Time UTC
attribute time nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/DTUT8601/ (external link)
attribute time source_name String ISO_DateTime_UTC
attribute time standard_name String time
attribute time time_origin String 01-JAN-1970 00:00:00
attribute time time_precision String 1970-01-01T00:00Z
attribute time units String seconds since 1970-01-01T00:00:00Z

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.


 
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