Dataset: Moss Landing Phosphate Data

Name: Phosphate Time Series Data Obtained from an Autonomous Programmable Flow Injection (pFI) Analyzer at CeNVOOS Moss Landing Shore Station during February 2022 (pFI-SI-LOV project)
Published: 2024-07-08
Keywords: phosphate, CeNCOOS, oceans

View Data: Data not available yet

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Spatial Extent: N:36.8004 E:-121.7884 S:36.8004 W:-121.7884

Moss Landing Shore Station, Central California

Temporal Extent: 2022-02-01 - 2022-02-07

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:

2024-07-08

Restricted:

Validated:

Current State:

Preliminary and in progress

Phosphate Time Series Data Obtained from an Autonomous Programmable Flow Injection (pFI) Analyzer at CeNVOOS Moss Landing Shore Station during February 2022 (pFI-SI-LOV project)

Abstract:

In this dataset, we report phosphate (PO4) data obtained with our recently developed programmable Flow Injection (pFI) analyzer. The dataset represents a six-day hourly phosphate time series obtained in February 2022 using an autonomous pFI analyzer deployed at the Central & Northern California Ocean Observing System (CeNCOOS) Moss Landing Shore Station. During this 6-day deployment, we configured the pFI analyzer to create a four-point calibration curve (0, 0.5, 1.5 and 3.0 µmol L-1 PO4) every 12 hours using a single MQ phosphate standard (3.0 µmol L-1 PO4). In the intervals between these calibrations, the pFI was programmed to withdraw and analyze a sample from the seawater intake line hourly.

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Methods & Sampling

We deployed a pFI analyzer at the Central and Northern California Ocean Observing System (CeNCOOS) Moss Landing shore station in February 2022. The instrument was equipped with an auxiliary diaphragm pump and sample loop for hourly phosphate analysis of samples withdrawn from the station’s seawater intake line. The samples were then analyzed using a pFI analyzer running on the assay described in Murphy and Riley (1962), adapted for pFI use. During this 6-day deployment, we configured the pFI analyzer to create a four-point calibration curve (0, 0.5, 1.5 and 3.0 µmol L-1 PO4) every 12 hours using a single MQ phosphate standard (3.0 µmol L-1 PO4). In the intervals between these calibrations, the pFI was programmed to withdraw and analyze a sample from the seawater intake line hourly. The calibration procedure involved aspirating a fixed volume of the concentrated standard into one of the holding coils and simultaneously dispensing a variable volume of diluent (MQ carrier) to set the appropriate dilution factor.

Data Processing Description

The pFI analyzer was calibrated every 12 hours 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 curves.

The instrument was controlled and the data was processed using FloZF software (v 5.2).

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 removed from parameter names in primary data file
- Spaces in parameter names replaced with underscores ("_")

More Information about this dataset

Funding Sources

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

Deployments

None available yet

Instruments

Flow Injection Analyzer

Supplied Name: miniSIA-2 (GlobalFIA, USA)

Supplied Description:

Samples were analyzed autonomously at the station 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). The instrument was controlled and the data processed using FloZF software (v 5.2).

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.

Spectrophotometer

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

Supplied Description:

Instrument Type

Generic Name: Spectrophotometer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB20/

Generic Description:

An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Latitude	Latitude of ship location when underway sample was made with the pFI analyzer in decimal degrees; a positive value indicates a Northern coordinate.	decimal degrees	lat
Longitude	Longitude of ship location when underway sample was made with the pFI analyzer in decimal degrees; a negative value indicates a Western coordinate.	decimal degrees	lon
Time_UTC	Date and time when underway sample was made with the pFI analyzer in UTC. Format: %Y-%m-%dT%H:%M:%S	unitless	ISO_DateTime_UTC
pFI_PO4	Phosphate concentration withdrawn and analyzed by the programmable Flow Injection (pFI) analyzer.	micromoles per liter (umol/L)	PO43-
pFI_flag	Phosphate concentration flag. 1 = good, 2 = bad, 3 = below detection limit.	unitless	q_flag

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Dataset: Moss Landing Phosphate Data