Date (Creation)

2025-05-30

Date (Revision)

2025-05-30

Date (Publication)

2025-05-30

Date (released)

2025-05-30

Edition

1.0

Unique resource identifier

https://doi.org/10.5285/b5c898b1-98e8-483a-838e-456741891d62

Codespace

doi

Unique resource identifier

GB/NERC/BAS/PDC/02068

Codespace

https://data.bas.ac.uk/

Unique resource identifier

NE/S002502/1

Codespace

award

Other citation details

Please cite this item as: Schmidt, K., Graeve, M., Lebreton, B., Welteke, N., Woll, M., & Guillou, G. (2025). Trophic marker composition of Arctic zooplankton and Polar cod sampled under sea ice and throughout the water column of the Central Arctic Ocean during the MOSAiC expedition (2019/2020) (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/b5c898b1-98e8-483a-838e-456741891d62

Credit

No credit.

Status

Completed

Point of contact

Organisation name	Individual name	Electronic mail address	Role
University of Plymouth	Schmidt, Katrin		Author
Alfred-Wegener-Institut Helmholtz-Zentrum fur Polar- und Meeresforschung	Graeve, Martin		Author
Centre National de la Recherche Scientifique	Lebreton, Benoit		Author
Alfred-Wegener-Institut Helmholtz-Zentrum fur Polar- und Meeresforschung	Welteke, Nahid		Author
Alfred-Wegener-Institut Helmholtz-Zentrum fur Polar- und Meeresforschung	Woll, Matthias		Author
Centre National de la Recherche Scientifique	Guillou, Gael		Author
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Point of contact

Maintenance and update frequency

As needed

Maintenance note

Completed

Global Change Master Directory (GCMD) Science Keywords

• EARTH SCIENCE > Oceans > Ocean Chemistry > Hydrocarbons
• EARTH SCIENCE > Oceans > Marine Environment Monitoring

Theme

• δ13C

• δ15N

• Arctic zooplankton

• BSIA

• CSIA

• Central Arctic Ocean (CAO)

• MOSAiC

• Polar cod

• fatty acids

• fatty alcohols

• lipids

• trophic marker

Place

• Central Arctic Ocean Arctic

• Amundsen Basin Arctic

• Nansen Basin Arctic

• Fram Strait Arctic

GEMET - INSPIRE themes, version 1.0

• Oceanographic geographical features

Access constraints

Other restrictions

Other constraints

public access limited according to Article 13(1)(e) of the INSPIRE Directive

Use constraints

License

Other constraints

Open Government Licence v3.0

Use constraints

Other restrictions

Other constraints

Data are supplied under Open Government Licence v3.0

Use constraints

Other restrictions

Other constraints

Data are under embargo until publication of the related manuscript.

Unique resource identifier

url

Codespace

url

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

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doi

Codespace

doi

Association Type

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doi

Codespace

doi

Association Type

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Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

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Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

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Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Unique resource identifier

doi

Codespace

doi

Association Type

Cross reference

Spatial representation type

Text, table

Language

English

Character set

UTF8

Topic category

• Environment
• Oceans

Begin date

2019-11-04

End date

2020-09-27

Supplemental Information

It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk.

Title

European Petroleum Survey Group (EPSG) Geodetic Parameter Registry

Date (Publication)

2008-11-12

Cited responsible party

Organisation name	Individual name	Electronic mail address	Role
European Petroleum Survey Group		EPSGadministrator@iogp.org	Publisher

Unique resource identifier

urn:ogc:def:crs:EPSG::3031

Version

6.18.3

Hierarchy level

Dataset

Statement

Methodology:

The MOSAiC cruise: The MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate; tag MOSAiC20192020 and the Project ID: AWI_PS122_00) expedition represents the first year-round interdisciplinary study of the atmosphere, the sea ice, the ocean, the ecosystem, and biogeochemical processes during the transpolar drift across the CAO, and was a unique opportunity for intensive field sampling (Shupe et al. 2022; Rabe et al. 2022; Nicolaus et al. 2022, Fong et al. 2024). The observational year was divided into 5 legs: Leg 1 started on October 4, 2019 with the setup of the first Central Observatory (CO1) and installations on the research icebreaker RV Polarstern north of the Laptev Sea (Krumpen et al. 2020). The winter Leg 2 and spring Leg 3 continued the work on CO1, before RV Polarstern had to leave the floe, for logistical reasons, on May 16, 2020. The vessel returned to the original ice floe on June 19, 2020, but at a different location some hundred meters away. Leg 4 continued the drift with the new CO2 over the summer until the disintegration of the floe in the Fram Strait on July 31, 2020. During Leg 5, RV Polarstern travelled back into the ice and started the setup of CO3 on August 21, 2020, near the North Pole. The third drift ended on September 20, 2020, when the vessel started the return voyage.

Water column sampling (vertically): High resolution vertical sampling of zooplankton was carried out using a Multi Net. The following five depth intervals were sampled: 2000-1000, 1000-500, 500-200, 200-50 and 50-0 m. The net was equipped with a calibrated electronic flow meter measuring the volume of filtered seawater (m3) for each sample. On deck, each cod end was emptied into a 5 L jar and stored in the cold-room (2°C) until the catch was sorted. For the sorting, the catch was spread into a shallow plastic tray that was kept in an ice bath to prevent warming. Healthy zooplankton were gently lifted from the water by using forceps. The number of individuals pooled for one trophic marker sample varied between ~40 small copepods (e.g. Metridia longa) and one large decapod (Hymenodora glacialis). For the Polar cod, liver and muscle tissue were analysed separately. Once sufficient specimens were collected, they were placed on a slide, photographed (Leica M125 or Wild M5 microscopes), dipped in freshwater to remove the salt, placed in a 7 ml glass vial and frozen at -80°C. Additional samples were taken with the Ring Net, either from the upper ocean (100-0 m or 200-0 m) or deeper water (2000-200 m) using a closing device. At times when the ice hole next to the ship was not available, a Nansen Net or the Ring Net were deployed from the sea ice, either at Ocean City (Leg 3) or from various locations using a tripod and hauling manually from 100 m (Leg 5).

Under sea ice sampling (horizontally): During all seasons, a net was attached to the under-ice remotely operated vehicle (ROV) 'Beast' (ROV Net, Katlein et al. 2017) for sampling 3 depth strata: the ice-ocean interface, 10 m and 50 m under the ice. The ROV was deployed from the ROV hut, several hundred meters away from RV Polarstern. Any net catches taken on the ice were transferred into a 5 L jar, stored in a cool box and brought to the ship using a pulka.

Laboratory analyses: The initial separation of the various trophic markers was carried out at the University of Plymouth. After freeze-drying and homogenising the zooplankton and Polar cod, the dry mass was estimated and each sample was divided into two parts: one subsample for bulk stable isotopes (BSI) analysis and one subsample for lipid analysis. The samples for BSI were placed in tin capsules, compacted, and sent to the Littoral, Environment and Societies Joint Research Unit stable isotope facility (CNRS - University of La Rochelle, France) for analysis. Three internal standards were added to the samples used fo...(35)

Data collection:

In-situ sample collection: A range of nets were used for zooplankton sampling: Multi Net (HYDROBIOS MultiNet 'Midi'; mouth area: 0.25 m2, 150 micrometre mesh size), Nansen Net (mouth area: 0.28 m2, 150 micrometre mesh size), Ring Net (mouth area: 1 m2, 150 micrometre mesh size), ROV Net ('Beast', mouth area: 0.24 m2, 150 micrometre mesh size). During transit to and from the CAO, animals were occasionally sampled from the ship's seawater intake at 11 m depth. The Multi Net was deployed from RV 'Polarstern' to successively sample five depth strata from 2000 m to the surface. The Nansen Net was deployed from the sea ice (Ocean City) to sample one depth stratum between 800 m and the surface, using an electric winch and a time-depth recorder. The Ring Nets were either deployed from 'Polarstern' to sample one depth stratum between 2000 m and the surface, or from the sea ice for shallow, manual casts. The ROV Net was attached to the remotely operated vehicle (ROV) for horizontally tows directly under the ice, at 10 m or 50 m.

BSI: The samples were analysed with a continuous flow isotope ratio mass spectrometer (Delta V Plus with a Conflo IV interface, Thermo Scientific, Bremen, Germany) interfaced with an elemental analyser (EA Isolink, Thermo Scientific, Milan, Italy).

TFA and TFAlc: FAME were quantified using an Agilent 6890N gas chromatograph (Agilent Technologies, USA) with a DB-FFAP capillary column (60 m, 0.25 mm I.D., 0.25 micrometre film thickness, Agilent Technologies, USA) supplied with a splitless injector and a flame ionization detector using temperature programming.

CSIA: Carbon isotopic compositions were determined for key FA and FALc using a GC-c-IRMS system, equipped with a Trace GC Ultra gas chromatograph, a GC Isolink and Delta V Plus isotope ratio mass spectrometer, connected via a Conflo IV interface (Thermo Scientific Corporation, Germany). The FAMEs were injected in splitless mode and separated on a DB-FFAP column (60 m, 0.25 mm I.D., 0.25 micrometre film thickness).

HBI and PS: The HBIs IP25 and IPSO25 and the sterols epi-brassicasterol, beta-sitosterol, chalinasterol, campesterol and cholesterol were quantified using a gas chromatograph (7890A, Agilent Technologies, USA), coupled to a mass selective detector (Agilent 5975 mass spectrometry), fitted with an Agilent HP-5ms column with auto-splitless injection.

Chromatogram data evaluation: The Clarity chromatography software system (version 8.8.0, Data Apex, Czech Republic) was used to quantify FA and FAlc; and the GC/MSD Productivity ChemStation software (version 7.01.01.2317, Agilent Technologies, USA) was used for sterols and HBIs.

Data quality:

Due to restrictions on ship-time, replicate net tows were not feasible. The same is true for the sorting of animals onboard: to cover all the selected target species and parameters in a timely manner, only one sample per species and developmental stage was prepared for trophic marker analysis. From the dried material only one sample was prepared for each BSI and lipid analysis, but a small back-up of dried material was kept in case one of the analyses failed. A very few BSI samples had to be repeated due to problems with the autosampler, while all lipid analyses were carried out successfully at first attempt. Therefore, the back-up material was subsequently used for tissue density analysis. The FA and FAlc profiles were compared to both commercial- (Supelco 37 Component FAME mix, Supelco, Germany) and self-produced standards (e.g. Arctic algae standard, bacteria standard, Calanus spp. standard), and were identified accordingly. In a few cases, samples were also analysed with the mass spectrometer and peaks were identified via (1) the mass of the compound, (2) the retention time of the compound and (3) the equivalent chain length method. For sterols, cultured algae of known sterol composition were used to clarify the identity of the five phytosterol peaks. Therefore, the mass spectra of their trimethylsilylethers were compared with published data. For several samples, parallel analysis of the extracts was carried out at the AWI, benefitting from the long-term experience in sterol identification by our colleague Dr. Kirsten Fahl. The uncertainty of the reported isotope-delta values (BSI) was evaluated as the standard deviation of repeated measurements (n = 5) for the reference material, USGS61 and USGS63 (Geological Survey, Reston, VA, USA), based on their assigned carbon and nitrogen isotope-delta values and standard uncertainties. For our measurements the uncertainty did not exceed 0.10 per mille for both delta13C and delta15N values. The delta13C values of the individual FAMEs were calibrated by analysing the certified standard FAMEs 14:0 (certified delta13C value: -29.98 per mille, measured delta13C value: -29.54 per mille) and 18:0 (certified delta13C value: -23.24 per mille, measured delta13C value: -23.29 per mille) at regular intervals (~ every five samples). The analytical error was ± 0.3 per mille for both 14:0 and 18:0 (representing 1 standard deviation of 10 analyses each). Furthermore, for quality assurance and analytical precision of the determined carbon stable isotope composition, the laboratory standard 23:0 was measured intermittently during the sample runs with an analytical error of ± 0.4 per mille (representing the standard deviation of 10 analyses).

Metadata

File identifier

b5c898b1-98e8-483a-838e-456741891d62 XML

Metadata language

English

Character set

UTF8

Hierarchy level

Dataset

Hierarchy level name

dataset

Date stamp

2025-05-30

Metadata standard name

ISO 19115 Geographic Information - Metadata

Metadata standard version

ISO 19115:2003(E)

Metadata author

Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		polardatacentre@bas.ac.uk	Point of contact