Dissolved cobalt, nutrients, and hydrography from the Pacific ProteOMZ Expedition, FK160115, on R/V Falkor in 2016

Website: https://www.bco-dmo.org/dataset/831323
Data Type: Cruise Results
Version: 1
Version Date: 2020-11-25

Project
» The ProteOMZ Expedition: Investigating Life Without Oxygen in the Pacific Ocean (ProteOMZ (Proteomics in an Oxygen Minimum Zone))
ContributorsAffiliationRole
Saito, Mak A.Woods Hole Oceanographic Institution (WHOI)Principal Investigator
Chmiel, Rebecca J.Woods Hole Oceanographic Institution (WHOI)Contact
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
Dissolved cobalt, nutrients, and hydrography from the Pacific ProteOMZ Expedition, FK160115, on R/V Falkor in 2016. Dissolved cobalt (dCo) samples were analyzed in Nov-Dec 2017 by cathodic stripping voltammetry (CSV) as originally described by (Saito and Moffett 2001) and modified by (Saito et al. 2010; Hawco et al. 2016).


Coverage

Spatial Extent: N:17 E:-139.8 S:-10.563 W:-156
Temporal Extent: 2016-01-18 - 2016-02-04

Methods & Sampling

Dissolved seawater samples were collected on the ProteOMZ FK150116 expedition (Jan-Feb 2016) using a 12-bottle trace metal clean rosette equipped with 8 L X-Niskin bottles (Ocean Test Equipment), a titanium frame, and a Kevlar cable, as described in (Cutter and Bruland 2012). Seawater from the Go-Flo bottles was subsampled in a trace metal clean plastic "bubble" equipped with HEPA filters providing positive air pressure. Dissolved Co subsamples were filtered using a 142 mm polycarbonate plastic sandwich filter (Geotech Environmental Equipment) equipped with a 0.2 um Supor membrane filter (Pall Corporation) and stored until analysis in the laboratory in a 60 mL LDPE bottle (Nalgene) that had been soaked for ~1 week in Citranox, an acidic detergent, rinsed with Milli-Q water (Millipore), soaked for ~2 weeks in 10% trace metal grade HCl (Optima), and rinsed with lightly acidic Milli-Q water (<0.1% HCl). To preserve the samples for future analysis after the cruise, all samples were filled entirely with no remaining headspace, stored with one oxygen-absorbing satchel (Mitsubishi Gas Chemical, model RP-3K) per 60 mL water sample, heat-sealed in plastic bags, and stored at 4⁰C.

Dissolved cobalt (dCo) samples were analyzed in Nov-Dec 2017 by cathodic stripping voltammetry (CSV) as originally described by (Saito and Moffett 2001) and modified by (Saito et al. 2010; Hawco et al. 2016). One portion of the samples (stations 1-10) were analyzed in the Saito laboratory in Woods Hole, MA, and the remaining samples (stations 11-14) were analyzed at sea on the CICLOPS NBP-1801 cruise in the trace metal plastic "bubble". This was done so that all of the samples could be run together using the same batch of DMG and EPPS reagents.

Dissolved Co was measured using a Metrohm 663 VA and uAutolabIII system equipped with a hanging mercury drop working electrode. All reagents were run through treated Chelex-100 resin columns (BioRad) to remove trace metal contaminates, except DMG which was purified by recrystallization. The Chelex was resin prepared as described in (Price et al. 1988/89) and reagents were purified as described in Saito et al., 2002. 0.2 um filtered water samples were UV-irradiated in acid-washed quartz tubes for one hour using a water-cooled UV irradiation system (Metrohm 705 UV Digestor) to destroy natural ligand-bound Co complexes. Then, 11 mL of sample seawater was aliquoted into 15 mL acid-washed polypropylene vials, and 100 uL of 0.1 M dimethyglyoxime (DMG, Sigma Aldrich) and 130 uL of 0.5 M N-(2-hydroxyethyl)piperazine-N-(3-propanesulfonic acid) (EPPS, Sigma Aldrich) buffer was added. The samples were then processed on an autosampler (Metrohm 858 Sample Processor), which added 8.5 mL of the sample solution and 1.5 mL of a 1.5 M NaNO₂ reagent (Merck) to a Teflon cup for electrochemical analysis. The mercury electrode performed a fast linear sweep from -1.4 V to -0.6 V at a rate of 5 V s⁻¹, which reduced the Co bound in the Co(DMG)₂ complex from Co(II) to Co(0) and produced a Co reduction peak at -1.15 V (Saito and Moffett 2001) with a height linearly proportional to the amount of dCo present in the sample. A standard addition curve was generated for each sample analyzed with 4 automated additions of a 25 pM CoCl₂ (Fisher Scientific) standard made fresh in for this sample batch.


Data Processing Description

Data Processing:
Peak heights were determined by NOVA 1.10 software. A linear regression of the standard addition peak heights allowed for the calculation of the initial amount of Co present in the sample, as described in (Saito and Moffett 2001). Triplicate technical replicates were run on every sample.

Quality Flags:
The dataset includes quality assurance flags described in the GEOTRACES Quality Flag Policy, which is available at https://www.geotraces.org/geotraces-quality-flag-policy/. Some dCo values reported are suspected misfires and are accordingly labeled with a QC flag of 3.
Brief flag descriptions:
0 = no quality control;
1 = good value;
2 = probably good value;
3 = probably bad value;
4 = bad value;
5 = changed value;
6 = value below detection;
7 = value in excess;
8 = interpolated value;
9 = missing value.

BCO-DMO Processing:
- renamed fields;
- added fields for date-time in ISO8601 format;
- replaced 'NaN' with 'nd' as the missing data identifier;
- rounded Cobalt values as specified by data submitter;
- 2022-09-08: made a correction to the Acquisition Description section of the metadata. The filter size used on dissolved Co subsamples was 0.2 um (not 0.4 um as previously stated).


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Data Files

File
dCo.csv
(Comma Separated Values (.csv), 34.52 KB)
MD5:767380b69da625df4bdf49ae7d11ed30
Primary data file for dataset ID 831323

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Related Publications

Cutter, G. A., & Bruland, K. W. (2012). Rapid and noncontaminating sampling system for trace elements in global ocean surveys. Limnology and Oceanography: Methods, 10(6), 425–436. doi:10.4319/lom.2012.10.425
Methods
Hawco, N. J., Ohnemus, D. C., Resing, J. A., Twining, B. S., & Saito, M. A. (2016). A dissolved cobalt plume in the oxygen minimum zone of the eastern tropical South Pacific. Biogeosciences, 13(20), 5697–5717. doi:10.5194/bg-13-5697-2016
Methods
Neil M. Price, Gail I. Harrison, Janet G. Hering, Robert J. Hudson, Pascale M. V. Nirel, Brian Palenik & François M. M. Morel (1989) Preparation and Chemistry of the Artificial Algal Culture Medium Aquil, Biological Oceanography, 6:5-6, 443-461, DOI: 10.1080/01965581.1988.10749544
Methods
Saito, M. A., & Moffett, J. W. (2001). Complexation of cobalt by natural organic ligands in the Sargasso Sea as determined by a new high-sensitivity electrochemical cobalt speciation method suitable for open ocean work. Marine Chemistry, 75(1-2), 49–68. doi:10.1016/s0304-4203(01)00025-1
Methods
Saito, M. A., & Moffett, J. W. (2002). Temporal and spatial variability of cobalt in the Atlantic Ocean. Geochimica et Cosmochimica Acta, 66(11), 1943–1953. doi:10.1016/s0016-7037(02)00829-3
Methods
Saito, M. A., Goepfert, T. J., Noble, A. E., Bertrand, E. M., Sedwick, P. N., & DiTullio, G. R. (2010). A seasonal study of dissolved cobalt in the Ross Sea, Antarctica: micronutrient behavior, absence of scavenging, and relationships with Zn, Cd, and P. Biogeosciences, 7(12), 4059–4082. doi:10.5194/bg-7-4059-2010
Methods

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Parameters

ParameterDescriptionUnits
Station_IDStation ID number unitless
Start_Date_UTCDate at start of sample collection; format: DD/MM/YYYY unitless
Start_Time_UTCTime (UTC) at start of sample collection; format: hh:mm unitless
Start_ISO_DateTime_UTCDate and time (UTC) at start of sample collection formatted to ISO8601 standard: YYYY-MM-DDThh:mmZ unitless
End_Date_UTCDate at end of sample collection; format: DD/MM/YYYY unitless
End_Time_UTCTime (UTC) at end of sample collection; format: hh:mm unitless
End_ISO_DateTime_UTCDate and time (UTC) at end of sample collection formatted to ISO8601 standard: YYYY-MM-DDThh:mmZ unitless
Start_LatitudeLatitude at start of sample collection degrees North
Start_LongitudeLongitude at start of sample collection degrees East
End_LatitudeLatitude at end of sample collection degrees North
End_LongitudeLongitude at end of sample collection degrees East
Event_IDEvent ID number unitless
Sample_IDSample ID number unitless
Sample_DepthSample depth meters (m)
Co_D_CONC_BOTTLE_cc9oxzConcentration of dissolved Co (after UV oxidation) from Niskin bottle picomolar (pM)
SD1_Co_D_CONC_BOTTLE_cc9oxzOne standard deviation of Co_D_CONC_BOTTLE_cc9oxz picomolar (pM)
Flag_Co_D_CONC_BOTTLE_cc9oxzQuality flag for Co_D_CONC_BOTTLE_cc9oxz unitless
PHOSPHATE_D_CONC_BOTTLE_fxqtprConcentration of dissolved phosphate, samples may or may not have been filtered micromoles per kilogram (umol/kg)
SD1_PHOSPHATE_D_CONC_BOTTLE_fxqtprOne standard deviation of PHOSPHATE_D_CONC_BOTTLE_fxqtpr micromoles per kilogram (umol/kg)
Flag_PHOSPHATE_D_CONC_BOTTLE_fxqtprQuality flag for PHOSPHATE_D_CONC_BOTTLE_fxqtpr unitless
NO2_NO3_D_CONC_BOTTLE_h3f4lhConcentration of dissolved NITRITE plus NITRATE, samples may or may not have been filtered micromoles per kilogram (umol/kg)
SD1_NO2_NO3_D_CONC_BOTTLE_h3f4lhOne standard deviation of NO2_NO3_D_CONC_BOTTLE_h3f4lh micromoles per kilogram (umol/kg)
Flag_NO2_NO3_D_CONC_BOTTLE_h3f4lhQuality flag for NO2_NO3_D_CONC_BOTTLE_h3f4lh unitless
SILICATE_D_CONC_BOTTLE_jdlfinConcentration of dissolved silicate, samples may or may not have been filtered micromoles per kilogram (umol/kg)
SD1_SILICATE_D_CONC_BOTTLE_jdlfinOne standard deviation of SILICATE_D_CONC_BOTTLE_jdlfin micromoles per kilogram (umol/kg)
Flag_SILICATE_D_CONC_BOTTLE_jdlfinQuality flag for SILICATE_D_CONC_BOTTLE_jdlfin unitless
NITRITE_D_CONC_BOTTLE_h9224xConcentration of dissolved NITRITE, samples may or may not have been filtered micromoles per kilogram (umol/kg)
SD1_NITRITE_D_CONC_BOTTLE_h9224xOne standard deviation of NITRITE_D_CONC_BOTTLE_h9224x micromoles per kilogram (umol/kg)
Flag_NITRITE_D_CONC_BOTTLE_h9224xQuality flag for NITRITE_D_CONC_BOTTLE_h9224x unitless
NH4_D_CONC_BOTTLE_enhcwuConcentration of dissolved ammonium, samples may or may not have been filtered micromoles per kilogram (umol/kg)
SD1_NH4_D_CONC_BOTTLE_enhcwuOne standard deviation of NH4_D_CONC_BOTTLE_enhcwu micromoles per kilogram (umol/kg)
Flag_NH4_D_CONC_BOTTLE_enhcwuQuality flag for NH4_D_CONC_BOTTLE_enhcwu unitless
NITRATE_D_CONC_BOTTLE_wmeegnConcentration of dissolved NITRATE, samples may or may not have been filtered micromoles per kilogram (umol/kg)
SD1_NITRATE_D_CONC_BOTTLE_wmeegnOne standard deviation of NITRATE_D_CONC_BOTTLE_wmeegn micromoles per kilogram (umol/kg)
Flag_NITRATE_D_CONC_BOTTLE_wmeegnQuality flag for NITRATE_D_CONC_BOTTLE_wmeegn unitless
CTDTMP_zcmqyuTemperature from CTD sensor in the ITS-90 convention degrees Celsius
SD1_CTDTMP_zcmqyuOne standard deviation of CTDTMP_zcmqyu degrees Celsius
Flag_CTDTMP_zcmqyuQuality flag for CTDTMP_zcmqyu unitless
CTDSAL_po5mdsPractical salinity from CTD sensor on the PSS-1978 scale unitless
SD1_CTDSAL_po5mdsOne standard deviation of CTDSAL_po5mds unitless
Flag_CTDSAL_po5mdsQuality flag for CTDSAL_po5mds unitless
CTDOXY_rfrw1nConcentration of dissolved oxygen from sensor on CTD micromoles per kilogram (umol/kg)
SD1_CTDOXY_rfrw1nOne standard deviation of CTDOXY_rfrw1n micromoles per kilogram (umol/kg)
Flag_CTDOXY_rfrw1nQuality flag for CTDOXY_rfrw1n unitless


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Instruments

Dataset-specific Instrument Name
8 L X-Niskin bottles (Ocean Test Equipment)
Generic Instrument Name
Niskin bottle
Generic Instrument Description
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.

Dataset-specific Instrument Name
Metrohm 663 VA and µAutolabIII system
Generic Instrument Name
Metrohm 663 VA Stand mercury electrode
Generic Instrument Description
The Metrohm 663 VA stand forms the wet chemical part of a polarographic and voltammetric analytical system. It features a mercury electrode, an Ag/AgCl reference electrode and a glassy carbon counter electrode. The size of the mercury drop and the stirrer speed are set manually on the VA Stand. The VA Stand can be operated in Dropping Mercury Electrode (DME), Hanging Mercury Drop Electrode (HMDE) and Static Mercury Drop Electrode (SMDE) modes. The VA Stand can be controlled by a potentiostat in conjunction with the Metrohm IME663 interface.

Dataset-specific Instrument Name
Metrohm 705 UV Digestor
Generic Instrument Name
UV Digester
Generic Instrument Description
Digestion instrument for UV photolysis of water samples

Dataset-specific Instrument Name
Metrohm 858 Sample Processor
Generic Instrument Name
Laboratory Autosampler
Generic Instrument Description
Laboratory apparatus that automatically introduces one or more samples with a predetermined volume or mass into an analytical instrument.


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Deployments

FK160115

Website
Platform
R/V Falkor
Report
Start Date
2016-01-16
End Date
2016-02-11
Description
Project: Using Proteomics to Understand Oxygen Minimum Zones (ProteOMZ) More information is available from the ship operator at https://schmidtocean.org/cruise/investigating-life-without-oxygen-in-the... Additional cruise information is available from the Rolling Deck to Repository (R2R): https://www.rvdata.us/search/cruise/FK160115


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Project Information

The ProteOMZ Expedition: Investigating Life Without Oxygen in the Pacific Ocean (ProteOMZ (Proteomics in an Oxygen Minimum Zone))


Coverage: Central Pacific Ocean (Hawaii to Tahiti)


From Schmidt Ocean Institute's ProteOMZ Project page:

Rising temperatures, ocean acidification, and overfishing have now gained widespread notoriety as human-caused phenomena that are changing our seas. In recent years, scientists have increasingly recognized that there is yet another ingredient in that deleterious mix: a process called deoxygenation that results in less oxygen available in our seas.

Large-scale ocean circulation naturally results in low-oxygen areas of the ocean called oxygen deficient zones (ODZs). The cycling of carbon and nutrients – the foundation of marine life, called biogeochemistry – is fundamentally different in ODZs than in oxygen-rich areas. Because researchers think deoxygenation will greatly expand the total area of ODZs over the next 100 years, studying how these areas function now is important in predicting and understanding the oceans of the future. This first expedition of 2016 led by Dr. Mak Saito from the Woods Hole Oceanographic Institution (WHOI) along with scientists from University of Maryland Center for Environmental Science, University of California Santa Cruz, and University of Washington aimed to do just that, investigate ODZs.

During the 28 day voyage named “ProteOMZ,” researchers aboard R/V Falkor traveled from Honolulu, Hawaii to Tahiti to describe the biogeochemical processes that occur within this particular swath of the ocean’s ODZs. By doing so, they contributed to our greater understanding of ODZs, gathered a database of baseline measurements to which future measurements can be compared, and established a new methodology that could be used in future research on these expanding ODZs.



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Funding

Funding SourceAward
Gordon and Betty Moore Foundation: Marine Microbiology Initiative (MMI)
NSF Division of Ocean Sciences (NSF OCE)

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