Dataset: chlorophyll a

Name: Chlorophyll a estimates from Niskin bottle casts from R/V Seward Johnson cruise SJ0516 in the North Atlantic, largely between Ireland and Iceland in 2005 (NASB 2005 project)
Published: 2009-04-13
Keywords: oceans

Cite This Dataset

Spatial Extent: N:66.5507 E:-15.4971 S:29.2753 W:-76.097

Project:

North Atlantic Spring Bloom 2005 (NASB 2005)

Principal Investigator:

David A. Hutchins (University of Southern California, USC-HIMS)

Co-Principal Investigator:

Giacomo DiTullio (College of Charleston - Hollings Marine Lab, CoC-HML)

Steven W. Wilhelm (University of Tennessee)

BCO-DMO Data Manager:

Cynthia L. Chandler (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

13 April 2009

Version Date:

2009-04-13

Validated:

Yes

Current State:

Final no updates expected

Chlorophyll a estimates from Niskin bottle casts from R/V Seward Johnson cruise SJ0516 in the North Atlantic, largely between Ireland and Iceland in 2005 (NASB 2005 project)

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Description

Fluorometric chlorophyll a estimates from Niskin bottle cast samples

Methods & Sampling

NOTE: station 1- or 2- refers to either cruise leg 1 (Florida to the Azores) or cruise leg 2 (Azores to Iceland)

Only 'surface' samples were taken while dead-heading on leg 1. The surface samples are recorded as being from nominal depth of 3 meters as that was the approximate depth of the ship's underway intake system.

Calibration notes

Instrument was calibrated prior to the cruise (~ May 1, 2005) using extracted chlorophyll a standards.

Extracted standards were checked with a spectrophotometer to determine chlorophyll a concentrations.

Extracted standards were used to calibrate the solid standard (Turner Designs).

Solid-standard normalizations were completed each day upon initiation of the fluorometer.

Size-fractionated chl a concentrations were determined on replicate samples collected on 0.22, 2.0, and 20.0 um nominal pore size, 47 mm diameter polycarbonate filters (Osmonics). Samples were extracted in 90% acetone for 24 h at 4°C and quantified using a solid-standard normalized 10-AU field fluorometer (Turner Designs) using the nonacidification protocol (Welschmeyer 1994).

Welschmeyer NA (1994) Fluorometric analysis of chlorophyll
a in the presence of chlorophyll b and phaeopigments.
Limnol Oceanogr 39:1985-1992

Data Processing Description

DMO processing notes:

1. reported longitudes corrected to negative (Western hemisphere)

2. depth_n of 'surface' replaced with a nominal depth of 3 meters (to enable plotting of data)

Data Files

File
chlorophyll.csv (Comma Separated Values (.csv), 36.34 KB) MD5:e602b7fe7fda820d1fa65e950344736a Primary data file for dataset ID 3105

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-0423418

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
SJ0516	JOH/05/0063 SJ-2004-126 33SW0516	2005-06-03	R/V Seward Johnson	David A. Hutchins (Chief Scientist)	data info

Instruments

Niskin bottle

Supplied Name: Niskin Bottle

Supplied Description:

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

Generic 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.

Turner Designs Fluorometer 10-AU

Supplied Name: Turner Designs Fluorometer -10-AU

Supplied Description:

Instrument Type

Generic Name: Turner Designs Fluorometer 10-AU

Acronym: Turner Fluorometer 10-AU

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0393/

Generic Description:

The Turner Designs 10-AU Field Fluorometer is used to measure Chlorophyll fluorescence. The 10AU Fluorometer can be set up for continuous-flow monitoring or discrete sample analyses. A variety of compounds can be measured using application-specific optical filters available from the manufacturer. (read more from Turner Designs, turnerdesigns.com, Sunnyvale, CA, USA)

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
station	station identifier (leg-station number optionally followed by a or b)	dimensionless	station
depth_n	nominal (target) depth of sample	meters	depth_n
chl_a	mean chlorophyll a concentration from duplicate samples; fluorometric method with nonacidification protocol (Welschmeyer 1994)	micrograms/liter	chl_a
size	polycarbonate filter pore size in microns; investigators looked at size-fractionated distribution of chlorophyll a	micrometers	no_bcodmo_term
range_n2	range of the duplicate samples	dimensionless	no_bcodmo_term
date	date (GMT) start of sampling (from event log)	dimensionless	date
time	time (GMT) at start of sampling (from event log)	dimensionless	time
lat	latitude, in decimal degrees, North is positive, negative denotes South (from event log)	decimal degrees	lat
lon	longitude, in decimal degrees, East is positive, negative denotes West (from event log)	decimal degrees	lon

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Database

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Dataset: chlorophyll a