Dataset: Hawaii Ocean Time Series Comparison

Name: Phosphate Profile Data Comparison between Programmable Flow Injection (pFI) and AA3 Autoanalyzer Methods from R/V Kilo Moana KM2210 in the North Pacific Subtropical Gyre during September 2022 (pFI-SI-LOV project)
Published: 2024-07-05
Keywords: HOT, phosphate, pFI, oceans

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Cite This Dataset

Spatial Extent: N:22.75 E:158 S:22.75 W:158

North Pacific Subtropical Gyre

Temporal Extent: 2022-09-01

Project:

Collaborative Research: Developing Automated Nutrient and Trace Metal Methodology using Programmable Flow Injection (pFI-SI-LOV)

Principal Investigator:

Maxime Grand (Moss Landing Marine Laboratories, MLML)

Student:

Marine Lebrec (Moss Landing Marine Laboratories, MLML)

BCO-DMO Data Manager:

Sawyer Newman (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2024-07-05

Restricted:

Validated:

Current State:

Preliminary and in progress

Phosphate Profile Data Comparison between Programmable Flow Injection (pFI) and AA3 Autoanalyzer Methods from R/V Kilo Moana KM2210 in the North Pacific Subtropical Gyre during September 2022 (pFI-SI-LOV project)

Abstract:

These data represent a full depth profile collected at the Hawaii Ocean Time Series station ALOHA in September 2022. The pFI_PO4 column shows phosphate concentrations from unfiltered samples analyzed onboard the RV Kilo Moana using a programmable Flow Injection (pFI) analyzer, calibrated with phosphate standards prepared in Milli-Q water. The SIO_PO4 column contains data from replicate samples taken from the same depths. These samples were frozen, shipped on dry ice to the Scripps Institution of Oceanography (SIO) Nutrient Facility, and analyzed there using an AA500 nutrient auto analyzer.

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Methods & Sampling

We collected unfiltered seawater samples directly from the Niskin bottles. One set was analyzed in triplicate for phosphate using the pFI analyzer calibrated with MQ standards (0-3 µmol L-1). The duplicate samples were frozen, shipped to Scripps Institution of Oceanography (SIO) Ocean Data Facility chemistry laboratory on dry ice and analyzed at SIO’s lab using an AA3 autoanalyzer.

The pFI analyzer was calibrated with working phosphate standards prepared in MQ water (0-3 µmol L-1). To calculate phosphate concentrations at each depth, we took the mean of the baseline corrected absorbance at 880 nm minus the reference absorbance at 1050 nm. Phosphate concentrations were then calculated using the slope and intercept of the MQ calibration curve.

pFI LOD: 0.06 umol/L

pFI precision: 4.1%

Data Processing Description

Quality flags represented in the primary data file

1 = good
2 = bad*
3 = below detection limit

Data were flagged when the data were inconsistent with adjacent depths and visual observation of the absorbance spectra confirmed an issue during the analysis.

BCO-DMO Processing

- Units and format details removed from parameter names
- Special characters removed from parameter names
- Spaces in character names replaced with underscores ("_")
- Latitude and longitude values rounded to 6 degrees of precision
- Date format converted from %m%d%y to %Y-%m-%d
- A datetime column was added to the data file by merging the original separate date and time columns (the original date and time columns have also been retained)
- Time format converted from %H%M%S to %H:%M:%S

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1924539

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
KM2210		2022-08-30	R/V Kilo Moana	Angelicque E. White (Chief Scientist)	data info

Instruments

Flow Injection Analyzer

Supplied Name: pFI analyzer (miniSIA2, GlobalFIA, USA)

Supplied Description:

One set of samples was analyzed using a pFI analyzer (miniSIA2, GlobalFIA, USA). This instrument was furnished with two High Flow milliGAT pumps with stainless steel heads, a plexiglass 8-port Lab-On-Valve, a 20 cm Long Path Linear Flow cell equipped with a Tungsten-Halogen lamp and a VIS-NIR Flame spectrophotometer (Ocean Insight, USA).

Instrument Type

Generic Name: Flow Injection Analyzer

Acronym: FIA

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB36/

Generic Description:

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.

Flow Injection Analyzer

Supplied Name: SIO's AA3 analyzer (Seal Analytical, USA)

Supplied Description:

Samples not analyzed with the mini SIA2 pFI analyzer were analyzed using a SIO's AA3 analyzer (Seal Analytical, USA) following the vendor's established GO-SHIP protocols.

Instrument Type

Generic Name: Flow Injection Analyzer

Acronym: FIA

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB36/

Generic Description:

Spectrometer

Supplied Name: VIS-NIR Flame spectrophotometer (Ocean Insight, USA)

Supplied Description:

Instrument Type

Generic Name: Spectrometer

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0460/

Generic Description:

A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
Latitude	Water sample latitude in decimal degrees; a positive value indicates a Northern coordinate.	decimal degrees	lat
Longitude	Water sample longitude in decimal degrees; a negative value indicates a Western coordinate.	decimal degrees	lon
ISO_DateTime_UTC	Water sample date time in UTC. Format: %Y-%m-%dT%H:%M:%SZ	unitless	DateTime
Date_UTC	Water sample date in UTC. Format: %Y-%m-%d	unitless	date
Time_UTC	Water sample time in UTC. Format: %H:%M:%S	unitless	time
Depth	Water sample depth in the water column in meters.	meters (m)	depth
pFI_PO4	Phosphate concentration from pFI analyzer.	umol/L	PO43-
pFI_flag	pFI flag. 1 = good, 2 = bad, 3 = below detection limit.	unitless	q_flag
SIO_PO4	Phosphate concentration from AA3 analyzer (SIO).	umol/L	PO43-
SIO_flag	SIO flag. 1 = good, 2 = bad, 3 = below detection limit.	unitless	q_flag

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Database

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Dataset: Hawaii Ocean Time Series Comparison