CENTER for DARK ENERGY BIOSPHERE INVESTIGATIONS
Datasets
Sediment TP MRP MUP
Data Project: A new marine sediment sample preparation scheme for solution 31P NMR analysis
Dataset Maintainers: Adina Paytan, Delphine Defforey, Amber York, Amber York, Amber York
Data Project Maintainers: Adina Paytan, Delphine Defforey, Barbara J. Cade-Menun
Last Modified: July 2, 2020
URLhttps://www.bco-dmo.org/dataset/805206
Download URLhttps://www.bco-dmo.org/dataset/805206/data/download
Media Type text/tab-separated-values
Created March 2, 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:

We used the ignition method to determine total P and molybdate-reactive P concentrations (MRP, which includes primarily free orthophosphate) for each sediment sample used for this study. Samples for total P analyses were ashed in crucibles at 550oC for 2 h and then extracted in 25 mL of 0.5 M sulfuric acid for 16 h. Samples for MRP analyses were extracted in the same manner, without the ashing step (Olsen and Sommers 1982; Cade-Menun and Lavkulich 1997). We derived molybdate-unreactive P concentrations (MUP, which includes primarily organic P and polyphosphates) in supernatants by subtracting MRP from total P concentrations. For ashed and unashed extracts, MRP was determined as described below.

Total P concentrations in sediment extracts were measured using inductively coupled plasma optical emission spectroscopy (ICP-OES). Standards were prepared with the same solutions as those used for the extraction procedure in order to minimize matrix effects on P measurements. Sediment extracts and standards (0 μM, 3.2 μM, 32 μM and 320 μM) were diluted to lower salt content to prevent salt buildup on the nebulizer. Concentration data from both wavelengths (213 nm and 214 nm) were averaged to obtain extract concentrations for each sample. The detection limit for P on this instrument for both wavelengths is 0.4 μM. 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.

Processing Description

Data were processed in Excel.

BCO-DMO Data Manager Processing Notes:
* Data from originally submitted Excel file Data_sediment_TP_MRP_MUP_v2.xlsx 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.

Instruments

QuikChem 8000 automated ion analyzer [Flow Injection Analyzer]
Details
Flow Injection Analyzer
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

Replicate [replicate]
Details
Replicate
Replicate of an individual sample
replicate

an identifier used to distinguish between one or more replicate samples

Sample_Name [sample]
Details
Sample_Name
Sample name
sample

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

Peak_Concentration [PO4]
Details
Peak_Concentration
Phosphate concentration (uncorrected)
PO4

Orthophosphate (phosphate, reactive phosphorus), Various units. 

Actual_PO4 [PO4]
Details
Actual_PO4
Phosphate concentration corrected for dilution
PO4

Orthophosphate (phosphate, reactive phosphorus), Various units. 

umol_PO4 [P]
Details
umol_PO4
Amount of phosphorus extracted
P

P (Phosphorus). May be reported in parts per million, nanomoles per liter, or other units. Refer to dataset metadata for units.

Sediment_mass [weight]
Details
Sediment_mass
Dried sediment mass
weight
weight, various units
umol_PO4_per_g [P]
Details
umol_PO4_per_g
Micromoles of phosphorus per gram of sediment (ground dry weight)
P

P (Phosphorus). May be reported in parts per million, nanomoles per liter, or other units. Refer to dataset metadata for units.

Dataset Maintainers

NameAffiliationContact
Adina PaytanUniversity of California-Santa Cruz (UC Santa Cruz)✓
Delphine DefforeyUniversity of California-Santa Cruz (UC Santa Cruz)✓
Amber YorkUniversity of California-Santa Cruz (UC Santa Cruz)
Amber YorkUniversity 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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