URLhttps://www.bco-dmo.org/dataset/798995
Download URLhttps://www.bco-dmo.org/dataset/798995/data/download
Media Type text/tab-separated-values
Created February 28, 2020
Modified July 2, 2020
State Final no updates expected

Acquisition Description

Locations:

Arctic Ocean: P-1-94-AR P21, 84°5' N, 174°58' W
California margin: W-2-98-NC TF1, 41°5' N, 125°1' W
Equatorial Pacific: TT013-06MC, 12°00' S, 134°56' W

Methodology:

Prior to the extraction, we freeze-dried, ground and sieved sediment samples to less than 125 μm (Ruttenberg 1992). For a given sample, we weighed four sample replicates (2 g) and placed each in 250 mL HDPE bottles. Sodium dithionite (F.W. 147.12 g/mol; 7.4 g) was added to each sample split, followed by 200 mL of citrate-bicarbonate solution (pH 7.6). This step produces effervescence, so the solution should be added slowly to the sample. We shook samples for 8 h and then centrifuged them at 3,700 rpm for 15 min. We filtered the supernatants with a 0.4 μm polycarbonate filter. We took 20 mL aliquots from the filtrate for each sample split for MRP and total P analyses, and kept them refrigerated until analysis within 24 h. We added 200 mL of ultrapure water to the solid residue for each sample split as a wash step after the above reductive step, shook samples for 2 h, and then centrifuged them at 3,700 rpm for 15 min. We filtered the supernatants with 0.4 μm polycarbonate filters and set aside 20 mL of filtrate from each sample split for MRP and total P analyses. We then extracted the solid sample residues in 200 mL of sodium acetate buffer (pH 4.0) for 6 h. At the end of this extraction step, we centrifuged the bottles at 3,700 rpm for 15 min, filtered the supernatants with 0.4 μm polycarbonate filters and took a 20 mL aliquot of filtrate from each sample split for MRP and total P analyses. We added 200 mL of ultrapure water to the solid residue for each sample split as a wash step, shook samples for 2 h, and then centrifuged them at 3,700 rpm for 15 min. We filtered the supernatants with 0.4 μm polycarbonate filters and set aside 20 mL of filtrate from each sample split for MRP and total P analyses. We repeated the water rinse step, and collected aliquots for MRP and total P analyses as in the previous steps. The concentrations of MRP were determined as described below.

The MRP concentrations were measured on a QuikChem 8000 automated ion analyzer. Standards were prepared with the same solutions used for the extraction step to minimize matrix effects on P measurements. Sediment extracts and standards (0 30 μM PO4) were diluted ten-fold to prevent matrix interference with color development. The detection limit for P on this instrument is 0.2 μM. We derived MUP concentrations by subtracting MRP from total P concentrations, which are included in a different dataset.

Processing Description

Data were processed in Excel.

BCO-DMO Data Manager Processing Notes:
* Data from originally submitted Excel file Data_MRP_sediments with pretreatment_v2.xlsx in sheet "Step 1" and "Step 2" were combined and exported as csv.
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* blank values in this dataset are displayed as "nd" for "no data." nd is the default missing data identifier in the BCO-DMO system.
* PO4 values with eight decimal places in the Sheet "Step 2" were rounded to two decimal places to match the precision of other values in the column.
* Concentration_Units column with all values uM removed. This information is captured in the Parameter descriptions.

Instruments

QuikChem 8000 automated ion analyzer [Flow Injection Analyzer]
Details
An instrument that performs flow injection analysis. Flow injection analysis (FIA) is an approach to chemical analysis that is accomplished by injecting a plug of sample into a flowing carrier stream. FIA is an automated method in which a sample is injected into a continuous flow of a carrier solution that mixes with other continuously flowing solutions before reaching a detector. Precision is dramatically increased when FIA is used instead of manual injections and as a result very specific FIA systems have been developed for a wide array of analytical techniques.

Parameters

Extract [sample_descrip]
Details
Extract
Extraction solution
text description of sample collected
Details
Step
Step in the sequential extraction scheme (1–4)
text description of sample collected
Dilution [treatment]
Details
Dilution
Sample dilution or "None"

Experimental conditions applied to experimental units.  In comparative experiments, members of the complementary group, the control group, receive either no treatment or a standard treatment.

Date [date]
Details
Date
Date the samples were analyzed in ISO 8601 format yyyy-mm-dd

date; generally reported in GMT as YYYYMMDD (year; month; day); also as MMDD (month; day); EqPac dates are local Hawaii time. ISO_Date format is YYYY-MM-DD (http://www.iso.org/iso/home/standards/iso8601.htm)

Sample_ID [sample]
Details
Sample_ID
Unique sample identifier

unique sample identification or number; any combination of alpha numeric characters; precise definition is file dependent

Analyte_Name [sample_descrip]
Details
Analyte_Name
Element analyzed
text description of sample collected
Peak_Concentration [PO4]
Details
Peak_Concentration
Phosphate concentration (uncorrected)

Orthophosphate (phosphate, reactive phosphorus), Various units. 

blank_corrected [sample_descrip]
Details
blank_corrected
Concentration adjusted after blank
text description of sample collected
Actual_PO4 [PO4]
Details
Actual_PO4
Concentration corrected for dilution

Orthophosphate (phosphate, reactive phosphorus), Various units. 

P_extracted [PO4]
Details
P_extracted
Amount of phosphorus extracted

Orthophosphate (phosphate, reactive phosphorus), Various units. 

Sed_mass [mass_dry]
Details
Sed_mass
Dried sediment mass
mass of freeze-dried specimen
PO4 [PO4]
Details
PO4
Micromoles of phosphorus per gram of sediment (ground dry weight)

Orthophosphate (phosphate, reactive phosphorus), Various units. 

Peak_Area [unknown]
Details
Peak_Area

Peak area

association with a community-wide standard parameter is not yet defined
Peak_Height [unknown]
Details
Peak_Height

Peak height

association with a community-wide standard parameter is not yet defined

Dataset Maintainers

NameAffiliationContact
Adina PaytanUniversity of California-Santa Cruz (UC Santa Cruz)
Delphine DefforeyUniversity of California-Santa Cruz (UC Santa Cruz)
Amber YorkWoods Hole Oceanographic Institution (WHOI BCO-DMO)

BCO-DMO Project Info

Project Title A new marine sediment sample preparation scheme for solution 31P NMR analysis
Acronym Marine Sediment Analysis 31P NMR
URLhttps://www.bco-dmo.org/project/664054
Created November 7, 2016
Modified February 27, 2020
Project Description

We developed and tested a new approach to prepare marine sediment samples for solution 31P nuclear magnetic resonance spectroscopy (31P NMR). This approach addresses the effects of sample pretreatment on sedimentary P composition and increases the signal of low abundance P species in 31P NMR spectra by removing up the majority inorganic P  from sediment samples while causing minimal alteration of the chemical structure of organic P compounds. The method was tested on natural marine sediment samples from different localities (Equatorial Pacific, California Margin and Arctic Ocean) with high inorganic P content, and allowed for the detection of low abundance P forms in samples for which only an orthophosphate signal could be resolved with an NaOH-EDTA extraction alone. This new approach will allow the use of 31P NMR on samples for which low organic P concentrations previously hindered the use of this tool, and will help answer longstanding question regarding the fate of organic P in marine sediments. We developed and tested a new approach to prepare marine sediment samples for solution 31P nuclear magnetic resonance spectroscopy (31P NMR). This approach addresses the effects of sample pretreatment on sedimentary P composition and increases the signal of low abundance P species in 31P NMR spectra by removing up the majority inorganic P  from sediment samples while causing minimal alteration of the chemical structure of organic P compounds. The method was tested on natural marine sediment samples from different localities (Equatorial Pacific, California Margin and Arctic Ocean) with high inorganic P content, and allowed for the detection of low abundance P forms in samples for which only an orthophosphate signal could be resolved with an NaOH-EDTA extraction alone. This new approach will allow the use of 31P NMR on samples for which low organic P concentrations previously hindered the use of this tool, and will help answer longstanding question regarding the fate of organic P in marine sediments. 

NSF C-DEBI Award #156246 to Dr. Adina Paytan

NSF C-DEBI Award #157598 to Dr. Delphine Defforey 

Data Project Maintainers
NameAffiliationRole
Adina PaytanUniversity of California-Santa Cruz (UC Santa Cruz)Principal Investigator
Delphine DefforeyUniversity of California-Santa Cruz (UC Santa Cruz)Co-Principal Investigator
Barbara J. Cade-MenunAgriculture and Agri-Food Canada (AGR GC)Co-Principal Investigator
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