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

This dataset is comprised of Hakai Institute chlorophyll and phaeopigment concentrations collected from 2017 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.

Access and Use

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, which can result in negative phaeopigment concentrations. 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). As a result these samples were removed and the dataset lacks many concentrations from phytoplankton bloom events. Comparison with matching HPLC derived chlorophyll a suggests that the affected samples may be useable, but further analysis is required. These data can be shared upon request.

Data and Resources

Dates

Metadata Reference Date(s) December 14, 2021 (Revision)
Dataset Reference Date(s) April 14, 2017 (Creation)
Frequency of Update As Needed

Citation

Dataset extent

Map data © OpenStreetMap contributors

Additional Info

Field Value
Ocean Variables Other
Scope Dataset
Status On Going
Topic Category oceans
Maintenance Note Generated from https://cioos-siooc.github.io/metadata-entry-form
Point of Contact
Point of Contact 1
Name
Justin Del Bel Belluz
Affiliation
Hakai Institute
Email
justin.belluz@hakai.org
Role
Custodian
Responsible Party
Responsible Party 1
Name
Bryn Fedje
Affiliation
Hakai Institute
Email
bryn.fedje@hakai.org
Role
Author
Responsible Party 2
Name
Jennifer Jackson
Affiliation
Hakai Institute
Email
jennifer.jackson@hakai.org
Role
Author
Distributor
Distributor 1
Name
Justin Del Bel Belluz
Affiliation
Hakai Institute
Role
Distributor
Spatial Extent {"type": "Polygon", "coordinates": [[[-128.5, 52.27], [-127.4, 52.21], [-127.2, 51.66], [-125.6, 51.13], [-124.8, 50.96], [-124.1, 50.43], [-124.7, 49.98], [-124.9, 49.8], [-126.7, 50.45], [-128.1, 51.37], [-128.4, 51.69], [-128.5, 52.27]]]}
North Bounding Latitude 49.8
South Bounding Latitude 52.27
East Bounding Longitude -124.1
West Bounding Longitude -128.5
Temporal Extent
Begin
2017-04-14
Vertical Extent
Min
0.0
Max
650.0
Default Locale English
Citation identifier
Code
10.21966/wsvt-ew96