Hakai Bulk and Size-Fractionated Chlorophyll and Phaeopigment Concentrations Collected by Niskin Bottle, Provisional

10.21966/90h6-b497

This dataset is comprised of Hakai Institute chlorophyll and phaeopigment concentrations collected from 2014 to present at stations within the Calvert Island, Johnstone Strait, and the Quadra Island study regions. Samples for these data were collected in the field using Niskin bottles. Sample water (250 ml) was filtered through: 1) a single glass fiber filter (GF/F, nominal pore size 0.7 um) to comprise a bulk measure of phytoplankton chlorophyll and phaeopigment concentrations and 2) a stack of filters (GF/F, 3 um, and 20 um polycarbonate filters) to estimate chlorophyll and phaeopigment concentrations from pico, nano, and micro-phytoplankton, respectively. Filters were extracted for 24 hours in 10 ml of 90% acetone and analyzed on Turner Designs Trilogy laboratory fluorometers using the acidification module and following the method of Holm Hansen et al. (1965).

Data have been quality controlled by manual inspection which included a comparison of bulk concentrations against the sum of the size-fractionated filter concentrations. Where available, further comparisons were done with other measures of chlorophyll concentrations including in situ CTD chlorophyll fluorescence and high-performance liquid chromatography (HPLC) data.

Data were collected by the Hakai Institute Oceanography and Nearshore programs.

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Licence: Creative Commons Attribution 4.0
Limitations: The utilized acidification method is sensitive to interference by high concentrations of chlorophyll c and b. High chlorophyll c concentrations can cause a slight overestimation of chlorophyll a and an underestimation of phaeopigments: negative phaeopigment concentrations can occur during bloom events with high chlorophyll c and healthy phytoplankton. High chlorophyll b concentrations can result in underestimations of chlorophyll a and overestimations of phaeopigments. When chlorophyll b is high relative to chlorophyll a, chlorophyll a can be underestimated by as much as 2.5 fold. For more details see Welschmeyer et al. (1994). These two types of interference likely had an influence on the published chlorophyll and phaeopigment dataset. Notably, comparison with HPLC has shown that stations in the Quadra Island region often experience conditions where chlorophyll b is present in high concentrations and is high relative to chlorophyll a. The acidification method used to analyze the Hakai Institute dataset has been shown to highly overestimate phaeopigment concentrations based on comparison to concentrations determined by HPLC (Trees et al., 2003). Care should be used when interpreting the published phaeopigment concentrations. Prior to 2021, samples that exceeded the manufacturer specified instrument sensitivity range were not diluted to bring their concentrations within the specified range. Samples run above the instrument sensitivity range may have underestimated chlorophyll concentrations due to the blockage of light passing through the sample and a corresponding reduction of fluorescence output (see Turner Trilogy user manual for complete description). Comparison with matching HPLC derived chlorophyll a suggests that the affected samples may be useable, but further analysis is required. This provisional dataset includes these data. Prior to 2018, annual calibrations of the Hakai Institute Turner Trilogy benchtop fluorometers showed variability in the calibration slopes and acid ratios that were applied to the data. The inconsistent nature of this variability suggests error due to analytical methods rather than instrument drift. As a result, the chlorophyll and phaeopigment concentrations of the data where these calibrations were applied may have error as high as +/- 12 % from this source alone. These data have been included in this provisional dataset. Prior to 2018, QA/QC analysis suggests potential influence by acid contamination on the chlorophyll and phaeopigment concentrations (i.e. very low chlorophyll a and high phaeopigment concentrations where the CTD fluorometer and HPLC showed high chlorophyll a). In 2018, methodological controls were put in place to limit acid contamination and the issue ceased. Care has been taken to flag the contaminated data, but data with less obvious contamination effects may not have been captured by QA/QC and may be present in this provisional dataset. This provisional dataset includes all data flagged as "suspicious" (show suspicious trends, but may not be incorrect), but excludes data flagged as "discard" (clearly erroneous).

Data and Resources

ERDDAP DatasetERDDAP

Turner Designs Trilogy Laboratory Fluorometer...PDF

User's manual for benchtop laboratory fluorometers used to analyze the Hakai...

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Metadata Reference Date(s) July 12, 2024 (Publication)
July 12, 2024 (Revision)
Data Reference Date(s) July 10, 2014 (Creation)
January 13, 2022 (Publication)
Frequency of Update As Needed

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Source last modified September 06, 2024 at 16:30

Other records harvested from Hakai Metadata Form data

Responsible Party 1
Affiliation
Hakai Institute ROR logo
Role
  • Distributor
  • Owner
  • Publisher
Responsible Party 2
Name
Del Bel Belluz, Justin ORCID logo
Affiliation
Hakai Institute ROR logo
Email
justin.belluz@hakai.org
Role
  • Author
  • Custodian
  • Originator
  • Point of Contact
  • Principal Investigator
  • Publisher
  • Resource Provider
Responsible Party 3
Name
Fedje, Bryn
Affiliation
Hakai Institute ROR logo
Email
bryn.fedje@hakai.org
Role
  • Custodian
  • Processor
  • Editor
  • Contributor
Responsible Party 4
Affiliation
Tula Foundation ROR logo
Role
Funder

Field Value
Ocean Variables Particulate matter
Scope Dataset
Status On Going
Topic Category oceans
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North Bounding Latitude 49.8
South Bounding Latitude 52.27
East Bounding Longitude -124.1
West Bounding Longitude -128.5
Temporal Extent
Begin
2014-07-10
Vertical Extent
Min
0.0
Max
650.0
Default Locale English
Citation identifier
Code
https://doi.org/10.21966/90h6-b497
Projects
  1. Oceanography
Included in Data Catalogue
Included in Data Catalogue 1
Name
Hakai Data Catalogue
Description
Science on the Coastal Margin
URL
https://catalogue.hakai.org