Title

Dataset Authors 1

Name

Mundy, CJ

Type of Name

Personal

Email

cj.mundy@umanitoba.ca

Affiliation

Centre for Earth Observation Science - University of Manitoba

ORCID ID

0000-0001-5945-8305

ORCID

http://orcid.org/

Contributors 1

Name

Gosselin, Michel

Role

ProjectMember

Email

michel_gosselin@uqar.ca

Affiliation

Université du Québec à Rimouski

ORCID ID

Sample Collection 1

Sampling Instrument Name

Metre stick

Standardized Sampling Instrument Name

metre stick

Sample Collection Method Name

Snow depth measurements

Comment

Method Link

Method Summary

Method Description Type

Methods

Sample Collection 2

Sampling Instrument Name

Sea-Bird SBE 19plus V2 conductivity-temperature-depth (CTD) probe

Standardized Sampling Instrument Name

Seabird CTD

Sample Collection Method Name

Water column salinity

Comment

Method Link

Method Summary

2-m water depth salinities were extracted from CTD casts.

Method Description Type

Methods

Sample Collection 3

Sampling Instrument Name

Bran-Luebbe 3 autoanalyzer

Standardized Sampling Instrument Name

Sample Collection Method Name

Nutrient concentration

Comment

Method Link

Method Summary

Sample was filtered through pre-combusted (450degC for 5 hr) Whatman GF/F filters using a sterilized syringe. Filtrate was collected in acid-cleaned polyethylene tubes after three rinses with the filtrate, and stored at -20degC until analysis within 6 months using a Bran-Luebbe 3 autoanalyzer (adapted from (Grasshoff et al. 1999)). Samples were analyzed for nitrate+nitrite, phosphate and silicic acid. Samples for Si(OH)4 determination were thawed for at least 24 hr to minimize the issue of silicate polymerization when samples have been stored by freezing (Macdonald et al. 1986). **Bulk ice nutrients** - samples were from ice cores melted without filtered seawater addition. **Water Column** - 2 m water depth **Intracellular Nutrients** - The method used to extract the intracellular nutrient pool was adapted from (Dortch 1982). Within 3 hr of collection, a subsample from the scrape sample was filtered onto a pre-combusted (450°C for 5 h) Whatman GF/F filter within an acid-cleaned filter head mounted on a large Erlenmeyer flask. Once enough material was concentrated on the filter (visible confirmation), vacuum pressure was released and a 60-mL acid-cleaned polyethylene tube, rinsed with boiling reverse osmosis water, was suspended below the filtration head within the Erlenmeyer flask. Then, 40 mL of boiling reverse osmosis water was poured directly into the filter funnel. The water was left for 10 minutes and then vacuum pressure restored and the filtrate was collected in the suspended tube. Following collection of the filtrate, the tube was sealed and placed immediately into the -20degC freezer. Following the above-mentioned protocol, a subsample of the boiling reverse osmosis water was also collected as a blank for every sample day. ** References** 1. Q. Dortch, Effect of growth conditions on accumulation of internal nitrate, ammonium, amino acids, and protein in three marine diatoms. Journal of Experimental Marine Biology and Ecology 61, 243–264 (1982). 2. K. Grasssshoff, K. Kremling, M. Ehrhardt, “Frontmatter” in Methods of Seawater Analysis, (John Wiley & Sons, Ltd, 1999), pp. i–xxxii. 3. R. W. Macdonald, F. A. McLaughlin, C. S. Wong, The storage of reactive silicate samples by freezing. Limnology and Oceanography 31, 1139–1142 (1986).

Method Description Type

Methods

Sample Collection 4

Sampling Instrument Name

Ice thickness tape

Standardized Sampling Instrument Name

Sample Collection Method Name

Ice sample collection

Comment

Method Link

Method Summary

Data were collected every 4 days between 19 May and 8 June. Snow depths were measured at every core extraction location, with targeted sampling of three different sites to capture the available range of snow depth conditions, including thin (<10 cm), medium (10-17 cm), and thick (>17 cm) snow covers. Bottom-ice samples were collected from each of these extraction locations using a Kovacs Mark II coring system (9-cm inner diameter) and processed for analysis of i) bottom-ice chlorophyll a concentration (chl a) and community composition, ii) intracellular nutrients and, iii) bottom-ice bulk nutrients. For quantitative measurements of bottom-ice chl a and community composition, up to three ice cores were extracted from each site and the bottom 3 cm were pooled into isothermal containers before melt in 0.2-m filtered seawater (FSW) to limit osmotic shock to the algae during melt processing. The FSW-diluted core solution was melted in the dark over a 15 to 20-hr period. For intracellular nutrient measurements, a bottom-ice scrape sample was collected from 1-3 cores per sampling site depending on visible algal coloration. The scrape procedure used a stainless-steel knife to scrape off the soft skeletal bottom-ice layer, which contained the strongest coloration of algal matter (<0.5 cm), directly into 500 mL of FSW at a temperature near freezing. This technique minimizes stress on algal cells during ice melt processing by: i) maintaining sample salinities similar to growth conditions at the ice-ocean interface, and ii) reducing time of exposure to potentially stressful melt conditions, as all scrape samples were processed within 3 hr of collection. For bulk ice nutrient measurements, the bottom 3 cm of an ice core was collected and placed immediately into a sterile bag (Nasco Whirl-Pak) and then melted over a 15 to 20-hr period in the dark.

Method Description Type

Methods

Sample Collection 5

Sampling Instrument Name

Niskin sampler

Standardized Sampling Instrument Name

Niskin Bottle

Sample Collection Method Name

Water sampling

Comment

Method Link

Method Summary

A Niskin sampler was lowered through an ice hole to collect water at a 2-m depth.

Method Description Type

Methods

Analytical Instrument 1

Analytical Instrument Name

Cond 330i, WTW

Standardized Analytical Instrument Name

Analytical Instrument Identifier Id

Analytical Instrument Title Type

Alternative Title

Analytical Instrument Identifier Type

Analytical Instrument 2

Analytical Instrument Name

10-005R Turner Designs fluorometer

Standardized Analytical Instrument Name

Analytical Instrument Identifier Id

Analytical Instrument Title Type

Alternative Title

Analytical Instrument Identifier Type

Analytical Method 1

Analytical Method Name

Bulk Ice Salinity

Method Link

Method Summary

**Instrument**: Cond 330i, WTW Melt ice core without filtered seawater dilution and measure salinity at room temperature.

Laboratory

Comments

Variables Measured

Salinity

Analytical Method 2

Analytical Method Name

Bottom ice chlorophyll (chl) a concentration

Method Link

Method Summary

**Instrument**: 10-005R Turner Designs fluorometer Melted ice core samples were filtered onto Whatman GF/F glass fiber filters (nominal pore size of 0.7 µm) for analysis of bottom-ice chl a. Filters were placed in 90% acetone for 18 to 24 hr, and the extracted chl a was measured before and after acidification with 5% HCl using a 10-005R Turner Designs fluorometer. All measurements were made with ice core melt using 3:1 filtered seawater dilution and corrected for the dilution.

Laboratory

Comments

Variables Measured

Chl a concentration

Analytical Method 3

Analytical Method Name

Algal Taxonomy

Method Link

Method Summary

**Instrument**: Inverted Microscope Melted ice core samples were preserved with acidic Lugol’s solution (Parsons et al. 1984) and stored in the dark at 4°C for later analysis of cell identification and enumeration. Cells > 4 µm were identified to the lowest possible taxonomic rank using inverted microscopy according to (Lund et al. 1958); however, information is only presented on total autotrophic cell abundance and percent contribution of pennate diatoms. All measurements were made with ice core melt using 3:1 filtered seawater dilution and corrected for the dilution. **References:** 1. T. R. Parsons, Y. Maita, C. M. Lalli, A Manual of Chemical and Biological Methods for Seawater Analysis. (Pergamon Press, 1984) https:/doi.org/10.25607/OBP-1830 (March 4, 2024). 2. J. W. G. Lund, C. Kipling, E. D. Le Cren, The inverted microscope method of estimating algal numbers and the statistical basis of estimations by counting. Hydrobiologia 11, 143–170 (1958).

Laboratory

Comments

Variables Measured

Percent contribution of main algal taxa

Analytical Method 4

Analytical Method Name

Macronutrient concentrations

Method Link

Method Summary

Sample was filtered through pre-combusted (450degC for 5 hr) Whatman GF/F filters using a sterilized syringe. Filtrate was collected in acid-cleaned polyethylene tubes after three rinses with the filtrate, and stored at -20degC until analysis within 6 months using a Bran-Luebbe 3 autoanalyzer (adapted from (Grasshoff et al. 1999)). Samples were analyzed for nitrate+nitrite, phosphate and silicic acid. Samples for Si(OH)4 determination were thawed for at least 24 hr to minimize the issue of silicate polymerization when samples have been stored by freezing (Macdonald et al. 1986). **Bulk ice nutrients** - samples were from ice cores melted without filtered seawater addition **Water Column** - 2 m water depth **Intracellular Nutrients** - The method used to extract the intracellular nutrient pool was adapted from (Dortch 1982). Within 3 hr of collection, a subsample from the scrape sample was filtered onto a pre-combusted (450°C for 5 h) Whatman GF/F filter within an acid-cleaned filter head mounted on a large Erlenmeyer flask. Once enough material was concentrated on the filter (visible confirmation), vacuum pressure was released and a 60-mL acid-cleaned polyethylene tube, rinsed with boiling reverse osmosis water, was suspended below the filtration head within the Erlenmeyer flask. Then, 40 mL of boiling reverse osmosis water was poured directly into the filter funnel. The water was left for 10 minutes and then vacuum pressure restored and the filtrate was collected in the suspended tube. Following collection of the filtrate, the tube was sealed and placed immediately into the -20degC freezer. Following the abovementioned protocol, a subsample of the boiling reverse osmosis water was also collected as a blank for every sample day. Q. Dortch, Effect of growth conditions on accumulation of internal nitrate, ammonium, amino acids, and protein in three marine diatoms. Journal of Experimental Marine Biology and Ecology 61, 243–264 (1982). K. Grasssshoff, K. Kremling, M. Ehrhardt, “Frontmatter” in Methods of Seawater Analysis, (John Wiley & Sons, Ltd, 1999), pp. i–xxxii. R. W. Macdonald, F. A. McLaughlin, C. S. Wong, The storage of reactive silicate samples by freezing. Limnology and Oceanography 31, 1139–1142 (1986).

Laboratory

Comments

Variables Measured

Macronutrient concentrations

Awards 1

Award Title

Discovery and Northern Research Supplements

Website

Funder Name

NSERC

Funder Identifier Code

Funder Identifier Type

Funder Identifier Scheme

Grant Number

Awards 2

Award Title

Network Project and Aircraft support

Website

Funder Name

ArcticNet NCE

Funder Identifier Code

Funder Identifier Type

Funder Identifier Scheme

Grant Number

Awards 3

Award Title

Start-up Grant (Mundy)

Website

Funder Name

University of Manitoba

Funder Identifier Code

Funder Identifier Type

Funder Identifier Scheme

Grant Number

Awards 4

Award Title

Logistical Support

Website

Funder Name

Polar Continental Shelf Project

Funder Identifier Code

Funder Identifier Type

Funder Identifier Scheme

Grant Number

Related Resources 1

Related Resource Name

Resource Code

Identifier Type

Relationship To This Dataset

Resource Type

Online Resource

Type

Series Name

Publications 1

Publication Name

Identifier Code

Identifier Type

Relationship to this dataset

Resource Type

Online Resource

Publication Type

Name

IC Nutrients

Description

Nutrient availability influences maximum production, speciation, cellular composition, and overall phenology of the Arctic spring ice algal bloom. However, how ice algae obtain nutrients from their environment is not well-understood. Previously documented positive relationships between sea ice nutrient concentrations and algal biomass evidenced that ice algae maintain an intracellular nutrient pool. Here we provide direct evidence that sea ice diatoms store intracellular nitrate+nitrite and silicic acid well above that available in their ambient environment.

Format

XLSX

Resource Category

data