Contributors | Affiliation | Role |
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Haley, Brian | Oregon State University (OSU) | Co-Principal Investigator |
McManus, James | Bigelow Laboratory for Ocean Sciences | Co-Principal Investigator |
Rauch, Shannon | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Water column, sediment, and pore water samples were collected following the methods in Abbott et al. (2015) during R/V Kilo Moana cruise KM2012 in October and November 2020. Water column samples were collected and filtered (<0.45 micrometers (μm)) from Niskin bottles on a CTD Rosette. See 'Related Datasets' for the data from pore water and sediment cores.
Elemental concentrations, including the REEs, were analyzed at Oregon State University (OSU) using an Elemental Scientific seaFAST-pico offline preconcentration technique, and the procedure has been extensively documented as part of the GEOTRACES intercalibration effort (Behrens et al., 2016). Elemental concentrations of the εNd aliquots (~10 milliliters (mL)) were analyzed at ETH Zurich using Nobias Chelate-PA1 resin in a manual column procedure (K. Deng et al., 2022).
Isotope analysis of the εNd aliquots (400~700 mL of pore water or ~1.5 liters (L) of seawater) were done at ETH Zurich. Samples were buffered to a pH of 5.5 ± 5 and pre-concentrated using an in-house extraction manifold containing Nobias Chelate-PA1 resin. After pre-concentration, separation of Nd from the matrix elements and other REE was done using Eichrom RE and LN spec resins. Procedural blanks are <3 picograms (pg). Isotope analysis was done on an Neptune Plus MC-ICP-MS (Thermo-Fisher) following the procedure of Vance and Thirlwall (2002). Internally normalized sample data was renormalized to the 143Nd/144Nd ratio of La Jolla (Thirlwall, 1991). Repeated analysis of 8 parts per billion (ppb) La Jolla solutions results in a long-term external reproducibility of 0.27 ε (2σ). Nd isotope analysis was also quality-controlled by repeated measurements of the USGS reference materials BCR-2 (εNd = -0.11 ± 0.25, 2σ) and BHVO-2 (εNd = 6.70 ± 0.24, 2σ) at the same concentration (5-10 ppb) as the pore water samples in agreement with literature results (Jochum et al., 2005).
Nutrients were analyzed at Oregon State University using Technicon AutoAnalyzer II (phosphate and ammonium) and Alpkem RFA 300 (silicic acid, nitrate+nitrite). The method and data processing follow Gordon et al. (1993). DOC was analyzed with a V-CSN/TNM-1 (Shimadzu Corp, Kyoto, Japan) at the Scripps Institution of Oceanography following White et al. (2023).
Sediment samples were analysed for total organic carbon contents using a GVI (now Elementar) Isoprime 1000 with Eurovector EA at Bigelow Laboratory for Ocean Sciences. Samples were measured for the total carbon (organic plus inorganic) and a separate sample split was acidified to remove carbonate and then measured for the organic fraction.
X-ray diffraction (XRD) of freeze-dried raw samples were made at K/T GeoServices Inc. (Colorado, USA), using a Siemens D500 automated powder diffractometer equipped with a copper X-ray source (40kV, 30mA) and a scintillation X-ray detector. Semi-quantitative determinations of whole-sediment mineral amounts were done using Jade Software (Materials Data, Inc.) with the Whole Pattern Fitting option.
- Imported sheet "BCO-DMO water column" from original file "BCO-DMOv2.xlsx" into the BCO-DMO system.
- Renamed fields to comply with BCO-DMO naming conventions.
- Saved the final file as "928152_v1_water_column_geochemical_composition.csv".
File |
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928152_v1_water_column_geochemical_composition.csv (Comma Separated Values (.csv), 6.15 KB) MD5:91b8cc17e22abbfa94663bfb49ff82d6 Primary data file for dataset ID 928152, version 1 |
Parameter | Description | Units |
Station_Number | Station number | unitless |
Latitude | Latitude of sampling site in degrees North | degrees North |
Longitude | Longitude of sampling site in degrees East (negative values are West) | degrees East |
Date | Date of sampling | unitless |
bottom_depth | Depth to seafloor | meters (m) |
sample_name | Sample name | unitless |
Depth | Depth of sample | meters (m) |
La_pM | REE concentration: Lanthanum (filtered at | picomolar (pmol/L) |
Ce_pM | REE concentration: Cesium (filtered at | picomolar (pmol/L) |
Pr_pM | REE concentration: Praseodymium (filtered at | picomolar (pmol/L) |
Nd_pM | REE concentration: Neodymium (filtered at | picomolar (pmol/L) |
Sm_pM | REE concentration: Samarium (filtered at | picomolar (pmol/L) |
Eu_pM | REE concentration: Europium (filtered at | picomolar (pmol/L) |
Gd_pM | REE concentration: Gadolinium (filtered at | picomolar (pmol/L) |
Tb_pM | REE concentration: Terbium (filtered at | picomolar (pmol/L) |
Dy_pM | REE concentration: Dysprosium (filtered at | picomolar (pmol/L) |
Ho_pM | REE concentration: Holmium (filtered at | picomolar (pmol/L) |
Er_pM | REE concentration: Erbium (filtered at | picomolar (pmol/L) |
Tm_pM | REE concentration: Thulium (filtered at | picomolar (pmol/L) |
Yb_pM | REE concentration: Ytterbium (filtered at | picomolar (pmol/L) |
Lu_pM | REE concentration: Lutetium (filtered at | picomolar (pmol/L) |
Co_nM | Trace metal concentration: Cobalt (filtered at | nanomolar (nmol/L) |
Ni_nM | Trace metal concentration: Nickel (filtered at | nanomolar (nmol/L) |
Cu_nM | Trace metal concentration: Copper (filtered at | nanomolar (nmol/L) |
Zn_nM | Trace metal concentration: Zinc (filtered at | nanomolar (nmol/L) |
Mo_nM | Trace metal concentration: Molybdenum (filtered at | nanomolar (nmol/L) |
Pb_nM | Trace metal concentration: Lead (filtered at | nanomolar (nmol/L) |
U_nM | Trace metal concentration: Uranium (filtered at | nanomolar (nmol/L) |
Nd143_Nd144_ratio | Isotope ratio of Neodymium-143 to Neodymium-144 | unitless |
SD2_int_1 | Two sigma standard deviation of 143Nd/144Nd integrated measurements | unitless |
eNd | Neodymium isotope composition given in epsilon notation (deviation of 143Nd/144Nd ratio from CHUR) | unitless |
SD2_int_2 | Two sigma standard deviation of 143Nd/144Nd integrated measurements in epsilon notation | unitless |
pH | pH | unitless |
NO3_NO2_uM | Total dissolved nitrate plus nitrite | micromolar (umol/L) |
PO4_uM | Total dissolved phosphate | micromolar (umol/L) |
Si_uM | Dissolved silicious acid | micromolar (umol/L) |
Dataset-specific Instrument Name | Alpkem RFA 300 |
Generic Instrument Name | Alpkem RFA300 |
Generic Instrument Description | A rapid flow analyser (RFA) that may be used to measure nutrient concentrations in seawater. It is an air-segmented, continuous flow instrument comprising a sampler, a peristaltic pump which simultaneously pumps samples, reagents and air bubbles through the system, analytical cartridge, heating bath, colorimeter, data station, and printer. The RFA-300 was a precursor to the smaller Alpkem RFA/2 (also RFA II or RFA-2). |
Dataset-specific Instrument Name | GVI (now Elementar) Isoprime 1000 |
Generic Instrument Name | Elemental Analyzer |
Generic Instrument Description | Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material. |
Dataset-specific Instrument Name | Niskin bottles on a CTD Rosette |
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 | Elemental Scientific seaFAST-pico |
Generic Instrument Name | SeaFAST Automated Preconcentration System |
Generic Instrument Description | The seaFAST is an automated sample introduction system for analysis of seawater and other high matrix samples for analyses by ICPMS (Inductively Coupled Plasma Mass Spectrometry). |
Dataset-specific Instrument Name | V-CSN/TNM-1 (Shimadzu Corp) |
Generic Instrument Name | Shimadzu TOC-V Analyzer |
Generic Instrument Description | A Shimadzu TOC-V Analyzer measures DOC by high temperature combustion method. |
Dataset-specific Instrument Name | Technicon AutoAnalyzer II |
Generic Instrument Name | Technicon AutoAnalyzer II |
Generic Instrument Description | A rapid flow analyzer that may be used to measure nutrient concentrations in seawater. It is a continuous segmented flow instrument consisting of a sampler, peristaltic pump, analytical cartridge, heating bath, and colorimeter. See more information about this instrument from the manufacturer. |
Dataset-specific Instrument Name | Neptune Plus MC-ICP-MS (Thermo-Fisher) |
Generic Instrument Name | Thermo Finnigan Neptune inductively coupled plasma mass spectrometer |
Generic Instrument Description | A laboratory high mass resolution inductively coupled plasma mass spectrometer (ICP-MS) designed for elemental and isotopic analysis. The instrument is based on a multicollector platform, comprising eight moveable collector supports and one fixed center channel equipped with a Faraday cup and, optionally, an ion counter with or without a retardation lens. The Faraday cup is connected to a current amplifier, whose signal is digitized by a high linearity voltage to frequency converter. The instrument was originally manufactured by Thermo Finnigan, which has since been replaced by Thermo Scientific (part of Thermo Fisher Scientific). This model is no longer in production. |
Website | |
Platform | R/V Kilo Moana |
Start Date | 2020-10-09 |
End Date | 2020-11-02 |
Description | See more information at R2R: https://www.rvdata.us/search/cruise/KM2012 |
NSF Award Abstract:
Circulation of water is a fundamental trait of the oceans that impacts its physics, chemistry and biology; however, understanding modern and past patterns of circulation - especially in the vast bodies of deep water - is challenging because global circulation defies direct measurement. The problems with direct measurement largely stem from the vast scales of space and time that are of interest in understanding global circulation. One tool for estimating global circulation patterns that holds promise is seen in neodymium isotopes which appear to be powerful tracers of deep ocean circulation, over a variety of timescales. Unfortunately, the elemental behavior of neodymium contrasts the isotopic behavior of neodymium in the oceans, a puzzle branded the "neodymium paradox." This inconsistency of geochemical behavior opens to question the application of neodymium isotopes as a tracer of circulation. Therefore, scientists from Oregon State University, Tulane University, and Bigelow Laboratory of Ocean Sciences propose to test the hypothesis that there is a yet unconstrained (even poorly identified) source of neodymium to the oceans that can explain the discrepancies seen between the elemental and isotopic neodymium marine budgets. The scientists further seek to understand the mechanistic cause of this source and thus be able to start making global constraints on its influence. Understanding these processes will fundamentally change our interpretations of neodymium data and allow us to more accurately quantify ocean circulation with a greater degree of confidence. For outreach activities, the scientists plan to participate in open house days held at Oregon State University, da Vinci days, National Ocean Science Bowls, Salmon Bowl and Bigelow Laboratory for Ocean Sciences' Cafe Scientifique. Undergraduate students and one graduate student from Tulane University would be supported and trained as part of this project.
Scientists from Oregon State University, Tulane University, and Bigelow Laboratory for Ocean Sciences propose to test the hypothesis that there is a benthic source of neodymium (Nd) to the oceans that exerts a primary control over the distribution of this element and its isotopes (eNd) in the ocean. This benthic flux results from early diagenetic reactions that release rare earth elements (REEs) from the solid phase to pore fluid. The scientists contend this flux will explain eNd distributions throughout the modern and past global oceans. The planned research will be guided by three questions:
(1) What are the mechanisms that control the magnitude and isotope composition of the benthic flux?
(2) What are the relationships among bottom water, pore fluid, and the terminal solid phase compositions? Particularly, how and under what chemical conditions does an eNd signature become part of a preserved archival record of [Nd] and eNd?
(3) Can our understanding of the deep water benthic fluxes account for the integrated bottom water eNd as a function of apparent water mass age and circulation path (e.g., how do the pore fluid and solid phase values reconcile with the existing water column signature and water mass age data)?
To test these ideas, sediments and their pore fluids will be collected from a diverse set of deep sea sites in the Pacific Ocean that reflect slow-to-fast sedimentation rates, carbonate-, terrigenous-, volcaniclastic- and siliceous-sediment, and low-to-high organic carbon. The sediments and porewater samples, as well as samples from the overlying water column will be characterized for the following parameters: major, minor, and trace metals, Nd isotopes, carbonate chemistry, oxygen, nutrients, particulate organic carbon, particulate organic nitrogen, radiocarbon, porosity, and grain size. With these observations we will build a quantitative numeric geochemical model (e.g., PHREEQC, Geochemist's Workbench, Humic Ion Binding Model) that can capture the cardinal controls over the benthic source. Our goal is to provide a new interpretive framework for Nd and eNd, such that we can offer quantitative estimates of benthic fluxes for use in models of global circulation. This work has potentially transformative implications on our understanding and application of REEs and Nd isotope data in both the modern and ancient oceans.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
Funding Source | Award |
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NSF Division of Ocean Sciences (NSF OCE) | |
NSF Division of Ocean Sciences (NSF OCE) |