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Title Sum-
Institution Dataset ID
     data   graph     files  public 234Th flux in epipelagic waters at Station ALOHA and the Equatorial Pacific from R/V Kilo
Moana cruises KM1407, KM1418, & KM1515 during 2014-2015
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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
attribute NC_GLOBAL acquisition_description String Total \u00b2\u00b3\u2074Th was measured in samples of seawater collected at
discrete depths using Niskin bottles as described in Umhau et al. (2019).
Briefly, 2 L of seawater was collected at each selected depth. Samples were
spiked with \u00b2\u00b3\u2070Th as a yield tracer and acidified to pH ~ 1
using concentrated nitric acid. After equilibration, ~ 6 hours later,
KMnO\u2084 and MnCl\u2082 were added and the pH adjusted to ~ 9 with
concentrated NH\u2084OH in order to co-precipitate Th via the formation of
MnO\u2082. After eight hours, total \u00b2\u00b3\u2074Th samples were filtered
onto 25 mm QMA filters, air dried, and frozen.

The \u00b2\u00b3\u2074Th flux (dpm m\u207b\u00b2 d\u207b\u00b9) was calculated
from the \u00b2\u00b3\u2074Th:\u00b2\u00b3\u2078U disequilibrium and assuming
a steady state (Umhau et al. 2019). The \u00b2\u00b3\u2074Th flux at each
depth was obtained by integrating the flux for the overlying depths using
trapezoidal integration.

Thorium counts were made using a low level RISO beta counter within 2 weeks of
sample collection.
attribute NC_GLOBAL awards_0_award_nid String 537122
attribute NC_GLOBAL awards_0_award_number String OCE-1333734
attribute NC_GLOBAL awards_0_data_url String http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1333734 (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 David L. Garrison
attribute NC_GLOBAL awards_0_program_manager_nid String 50534
attribute NC_GLOBAL awards_1_award_nid String 560590
attribute NC_GLOBAL awards_1_award_number String OCE-1433846
attribute NC_GLOBAL awards_1_data_url String http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1433846 (external link)
attribute NC_GLOBAL awards_1_funder_name String NSF Division of Ocean Sciences
attribute NC_GLOBAL awards_1_funding_acronym String NSF OCE
attribute NC_GLOBAL awards_1_funding_source_nid String 355
attribute NC_GLOBAL awards_1_program_manager String Donald L. Rice
attribute NC_GLOBAL awards_1_program_manager_nid String 51467
attribute NC_GLOBAL cdm_data_type String Other
attribute NC_GLOBAL comment String 234Th Flux
PI: Claudia R. Benitez-Nelson (University of South Carolina)
Co-PIs: Brain N. Popp & Jeffrey C. Drazen (Univeristy of Hawaii)
Version date: 19-March-2020
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 2020-03-19T14:25:49Z
attribute NC_GLOBAL date_modified String 2020-03-31T21:12:48Z
attribute NC_GLOBAL defaultDataQuery String &time<now
attribute NC_GLOBAL doi String 10.26008/1912/bco-dmo.806471.1
attribute NC_GLOBAL Easternmost_Easting double -155.0
attribute NC_GLOBAL geospatial_lat_max double 22.0
attribute NC_GLOBAL geospatial_lat_min double 5.0
attribute NC_GLOBAL geospatial_lat_units String degrees_north
attribute NC_GLOBAL geospatial_lon_max double -155.0
attribute NC_GLOBAL geospatial_lon_min double -158.0
attribute NC_GLOBAL geospatial_lon_units String degrees_east
attribute NC_GLOBAL geospatial_vertical_max double 200.0
attribute NC_GLOBAL geospatial_vertical_min double 5.0
attribute NC_GLOBAL geospatial_vertical_positive String down
attribute NC_GLOBAL geospatial_vertical_units String m
attribute NC_GLOBAL infoUrl String https://www.bco-dmo.org/dataset/806471 (external link)
attribute NC_GLOBAL institution String BCO-DMO
attribute NC_GLOBAL instruments_0_acronym String Niskin bottle
attribute NC_GLOBAL instruments_0_dataset_instrument_description String Total 234Th was measured in samples of seawater collected at discrete depths using Niskin bottles.
attribute NC_GLOBAL instruments_0_dataset_instrument_nid String 806480
attribute NC_GLOBAL instruments_0_description String A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24 or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.
attribute NC_GLOBAL instruments_0_instrument_external_identifier String https://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/ (external link)
attribute NC_GLOBAL instruments_0_instrument_name String Niskin bottle
attribute NC_GLOBAL instruments_0_instrument_nid String 413
attribute NC_GLOBAL instruments_0_supplied_name String Niskin bottles
attribute NC_GLOBAL instruments_1_acronym String Riso Beta Counter
attribute NC_GLOBAL instruments_1_dataset_instrument_description String Thorium counts were made using a low level RISO beta counter within 2 weeks of sample collection.
attribute NC_GLOBAL instruments_1_dataset_instrument_nid String 806481
attribute NC_GLOBAL instruments_1_description String Low-level beta detectors manufactured by Riso (now Nutech) in Denmark. These instruments accept samples that can be mounted on a 25mm filter holder. These detectors have very low backgrounds, 0.17 counts per minute, and can have counting efficiencies as high as 55%.

attribute NC_GLOBAL instruments_1_instrument_name String Riso Laboratory Anti-coincidence Beta Counters
attribute NC_GLOBAL instruments_1_instrument_nid String 687
attribute NC_GLOBAL instruments_1_supplied_name String RISO beta counter
attribute NC_GLOBAL keywords String bco, bco-dmo, biological, chemical, cruise, data, dataset, date, Date_final, depth, dmo, erddap, error, final, flux, initial, latitude, longitude, management, oceanography, office, preliminary, season, site, Th_flux, Th_flux_error, time
attribute NC_GLOBAL license String https://www.bco-dmo.org/dataset/806471/license (external link)
attribute NC_GLOBAL metadata_source String https://www.bco-dmo.org/api/dataset/806471 (external link)
attribute NC_GLOBAL Northernmost_Northing double 22.0
attribute NC_GLOBAL param_mapping String {'806471': {'Latitude': 'flag - latitude', 'Depth': 'flag - depth', 'Longitude': 'flag - longitude'}}
attribute NC_GLOBAL parameter_source String https://www.bco-dmo.org/mapserver/dataset/806471/parameters (external link)
attribute NC_GLOBAL people_0_affiliation String University of South Carolina
attribute NC_GLOBAL people_0_person_name String Claudia R. Benitez-Nelson
attribute NC_GLOBAL people_0_person_nid String 51092
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 University of Hawaii at Manoa
attribute NC_GLOBAL people_1_affiliation_acronym String SOEST
attribute NC_GLOBAL people_1_person_name String Jeffrey C. Drazen
attribute NC_GLOBAL people_1_person_nid String 491313
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 University of Hawaii at Manoa
attribute NC_GLOBAL people_2_affiliation_acronym String SOEST
attribute NC_GLOBAL people_2_person_name String Brian N. Popp
attribute NC_GLOBAL people_2_person_nid String 51093
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 Woods Hole Oceanographic Institution
attribute NC_GLOBAL people_3_affiliation_acronym String WHOI BCO-DMO
attribute NC_GLOBAL people_3_person_name String Shannon Rauch
attribute NC_GLOBAL people_3_person_nid String 51498
attribute NC_GLOBAL people_3_role String BCO-DMO Data Manager
attribute NC_GLOBAL people_3_role_type String related
attribute NC_GLOBAL project String SuspendSinkPart,Hg_Biogeochemistry
attribute NC_GLOBAL projects_0_acronym String SuspendSinkPart
attribute NC_GLOBAL projects_0_description String Description from NSF award abstract:
The ocean's midwaters are the largest living space on the planet. The mesopelagic food web plays key roles in the biological carbon pump and the production of food for commercially harvested species, but its functioning is understudied because it is remote and technologically challenging to sample. Recent estimates indicate respiratory demand outstrips measured sinking particle supply by up to 2-3 orders of magnitude suggesting that some food inputs to the mesopelagic food web have been underestimated or missed. Suspended particles frequently are not sampled effectively and may be an overlooked food source. Because identifying the principal inputs of organic matter to the deep-sea food web is critical to understanding its function, the investigators propose to evaluate the relative importance of suspended and sinking particles to the meso- and bathypelagic food web in the central North Pacific. They will characterize the isotopic compositions of specific groups of mesopelagic and bathypelagic zooplankton and micronekton, and identify the extent to which they consume suspended or sinking particles using mass balance approaches. The investigators recently have recognized differences in delta 15N and delta 13C values of amino acids (AA) of sinking and suspended particles; these patterns diverge with depth, providing a means to distinguish between food web pathways. The research will define the source-specific isotopic values of suspended and sinking particles at several depths from the surface to the bathypelagic and test proposed microbial mechanisms driving these depth patterns. At corresponding depths, MOCNESS trawls will sample diverse metazoa: zooplankton size fractions, plus targeted resident, migrating and likely suspension-feeding taxa of zooplankton and micronekton. Preliminary data suggest that suspended particles are a secondary food source, containing less labile organic matter than sinking particles that exhibit a seasonal cycle in flux in the central North Pacific. This study will determine if suspended particles become more important to zooplankton and micronekton during a time of year when sinking particle flux is low (Jan/Feb) in comparison to when it is high (Aug), allowing an evaluation of how temporal change in surface ocean productivity affects the functioning of mesopelagic food webs.
Recent research has called for additional study of the ocean's deep midwaters. This study will provide new insights into the functioning of the meso- and bathypelagic food web and its coupling with surface ocean processes in the central North Pacific. The recently-demonstrated ecological tool of amino acid-specific isotopic analysis will provide a novel and comprehensive approach with which to address our hypotheses, and the project will develop the first AA isotopic dataset spanning particles to fish. Results will help identify the ecological underpinnings of increasing delta 15N values with depth in zooplankton -- apparently a common pattern. Zooplankton consumption of suspended particles also could constitute a mechanistic link between the microbial loop and higher trophic levels. The processes controlling the enormous attenuation of particle flux by mesopelagic consumers -- and thereby the strength of carbon sequestration to the deep ocean -- are not understood. Seasonal sampling will help us relate mesopelagic food web processes to changes in surface ocean productivity, furthering our understanding of future climate change impacts on deep-sea food webs and carbon flux. With regard to fisheries, many oceanic top predators such as tuna and swordfish feed on mesopelagic micronekton. A clearer understanding of the structure of mesopelagic food webs will help inform ecosystem models which are used to understand variation in fisheries production.
attribute NC_GLOBAL projects_0_end_date String 2016-12
attribute NC_GLOBAL projects_0_geolocation String Subtropical waters north of Hawaii; Station Aloha (22° 45'N, 158° 00'W)
attribute NC_GLOBAL projects_0_name String Evaluating the relative importance of suspended and sinking particles to the meso and bathypelagic food web in the central North Pacific
attribute NC_GLOBAL projects_0_project_nid String 537123
attribute NC_GLOBAL projects_0_start_date String 2014-01
attribute NC_GLOBAL projects_1_acronym String Hg_Biogeochemistry
attribute NC_GLOBAL projects_1_description String NSF award abstract:
Mercury is a pervasive trace element that exists in several states in the marine environment, including monomethylmercury (MMHg), a neurotoxin that bioaccumulates in marine organisms and poses a human health threat. Understanding the fate of mercury in the ocean and resulting impacts on ocean food webs requires understanding the mechanisms controlling the depths at which mercury chemical transformations occur. Preliminary mercury analyses on nine species of marine fish from the North Pacific Ocean indicated that intermediate waters are an important entry point for MMHg into open ocean food webs. To elucidate the process controlling this, researchers will examine mercury dynamics in regions with differing vertical dissolved oxygen profiles, which should influence depths of mercury transformation. Results of the study will aid in a better understanding of the pathways by which mercury enters the marine food chain and can ultimately impact humans. This project will provide training for graduate and undergraduate students, and spread awareness on oceanic mercury through public outreach and informal science programs.
Mercury isotopic variations can provide insight into a wide variety of environmental processes. Isotopic compositions of mercury display mass-dependent fractionation (MDF) during most biotic and abiotic chemical reactions and mass-independent fractionation (MIF) during photochemical radical pair reactions. The unusual combination of MDF and MIF can provide information on reaction pathways and the biogeochemical history of mercury. Results from preliminary research provide strong evidence that net MMHg formation occurred below the surface mixed layer in the pycnocline and suggested that MMHg in low oxygen intermediate waters is an important entry point for mercury into open ocean food webs. These findings highlight the critical need to understand how MMHg levels in marine biota will respond to changes in atmospheric mercury emissions, deposition of inorganic mercury to the surface ocean, and hypothesized future expansion of oxygen minimum zones. Using field collections across ecosystems with contrasting biogeochemistry and mercury isotope fractionation experiments researchers will fill key knowledge gaps in mercury biogeochemistry. Results of the proposed research will enable scientists to assess the biogeochemical controls on where in the water column mercury methylation and demethylation likely occur.
Related background publication with supplemental data section:
Joel D. Blum, Brian N. Popp, Jeffrey C. Drazen, C. Anela Choy & Marcus W. Johnson. 2013. Methylmercury production below the mixed layer in the North Pacific Ocean. Nature Geoscience 6, 879–884. doi:10.1038/ngeo1918
attribute NC_GLOBAL projects_1_end_date String 2017-07
attribute NC_GLOBAL projects_1_geolocation String Pacific Subtropical Gyre, Station ALOHA 22.75N 158W; equatorial Pacific (10N 155W, 5N 155W)
attribute NC_GLOBAL projects_1_name String Collaborative Research: Isotopic insights to mercury in marine food webs and how it varies with ocean biogeochemistry
attribute NC_GLOBAL projects_1_project_nid String 560580
attribute NC_GLOBAL projects_1_start_date String 2014-08
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 5.0
attribute NC_GLOBAL standard_name_vocabulary String CF Standard Name Table v55
attribute NC_GLOBAL summary String 234Th flux in epipelagic waters at Station ALOHA and the Equatorial Pacific from R/V Kilo Moana cruises KM1407, KM1418, & KM1515 during 2014-2015.
attribute NC_GLOBAL title String 234Th flux in epipelagic waters at Station ALOHA and the Equatorial Pacific from R/V Kilo Moana cruises KM1407, KM1418, & KM1515 during 2014-2015
attribute NC_GLOBAL version String 1
attribute NC_GLOBAL Westernmost_Easting double -158.0
attribute NC_GLOBAL xml_source String osprey2erddap.update_xml() v1.3
variable Cruise   String  
attribute Cruise bcodmo_name String cruise_id
attribute Cruise description String Cruise identifier
attribute Cruise long_name String Cruise
attribute Cruise units String unitless
variable Date_initial   String  
attribute Date_initial bcodmo_name String date
attribute Date_initial description String Sampling initial date (UTC); format: yyyy-mm-dd
attribute Date_initial long_name String Date Initial
attribute Date_initial nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/ADATAA01/ (external link)
attribute Date_initial source_name String Date_initial
attribute Date_initial time_precision String 1970-01-01
attribute Date_initial units String unitless
variable Date_final   String  
attribute Date_final bcodmo_name String date
attribute Date_final description String Sampling final date (UTC); format: yyyy-mm-dd
attribute Date_final long_name String Date Final
attribute Date_final nerc_identifier String https://vocab.nerc.ac.uk/collection/P01/current/ADATAA01/ (external link)
attribute Date_final time_precision String 1970-01-01
attribute Date_final units String unitless
variable Site   String  
attribute Site bcodmo_name String site
attribute Site description String Site identifier
attribute Site long_name String Site
attribute Site units String unitless
variable latitude   double  
attribute latitude _CoordinateAxisType String Lat
attribute latitude _FillValue double NaN
attribute latitude actual_range double 5.0, 22.0
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
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 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 -158.0, -155.0
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
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 standard_name String longitude
attribute longitude units String degrees_east
variable Season   String  
attribute Season bcodmo_name String season
attribute Season description String Season
attribute Season long_name String Season
attribute Season units String unitless
variable depth   double  
attribute depth _CoordinateAxisType String Height
attribute depth _CoordinateZisPositive String down
attribute depth _FillValue double NaN
attribute depth actual_range double 5.0, 200.0
attribute depth axis String Z
attribute depth bcodmo_name String depth
attribute depth colorBarMaximum double 8000.0
attribute depth colorBarMinimum double -8000.0
attribute depth colorBarPalette String TopographyDepth
attribute depth description String Sampling depth
attribute depth ioos_category String Location
attribute depth long_name String Depth
attribute depth nerc_identifier String https://vocab.nerc.ac.uk/collection/P09/current/DEPH/ (external link)
attribute depth positive String down
attribute depth standard_name String depth
attribute depth units String m
variable Th_flux   String  
attribute Th_flux bcodmo_name String thorium-234
attribute Th_flux description String Integrated 234Th flux; BD = below detection
attribute Th_flux long_name String Th Flux
attribute Th_flux units String dpm m-2 d-1
variable Th_flux_error   short  
attribute Th_flux_error _FillValue short 32767
attribute Th_flux_error actual_range short 6, 187
attribute Th_flux_error bcodmo_name String thorium-234
attribute Th_flux_error colorBarMaximum double 50.0
attribute Th_flux_error colorBarMinimum double 0.0
attribute Th_flux_error description String Integrated 234Th flux error
attribute Th_flux_error long_name String Th Flux Error
attribute Th_flux_error units String dpm m-2 d-1

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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