Stable isotope ratios and elemental contents of C, N and S in benthic organisms sampled during the PROTEKER 5 summer campaign in Kerguelen Islands (2016) - data

Study Extent

This dataset describes the abundance and distribution of benthic organisms of the PROTEKER 5 campaign at Kerguelen Islands between 19/11/2016 and 04/12/2016.

Sampling

All samples were taken in or next to (within a few meters) coastal kelp forests in the vicinity of the Port-aux-Français scientific station. Most samples were hand collected by SCUBA divers between 5 and 13 m depth. They included benthic primary producers, large macrophytodetritus, surface sediments and biomass-dominant benthic macroinvertebrates belonging to various taxa and feeding guilds: sponges, bivalves, gastropods, sedentary and mobile polychaetes, arthropods and echinoderms. SCUBA diving sampling events were complemented with intertidal collections on the shore and in rock pools at low tide. Those samples also comprised macrophytodetritus (wrack algae) as well as invertebrate consumers. Finally, for suspended particulate organic matter (SPOM), subsurface seawater samples were taken using a Niskin bottle. Water was subsequently filtered (1.8 to 2.1 dm3) on pre-combusted (400°C, 4 h) Whatman GF/F filters, and retained SPOM was kept for analysis.

Quality Control

All records were validated. - Coordinates were converted into decimal latitude and decimal longitude and plotted on map to verify the actual geographical location corresponds to its locality. - All scientific names were checked for typo and matched to the species information backbone of Worlds Register of Marine Species (http://marinespecies.org/) and LSID were assigned to each taxa as scientificNameID. - Event date was converted into ISO 8601 format.

Method steps

1. Sample preservation: After diving, samples were placed in oxygenated water containers and transferred to the Port-aux-Français station lab facilities where they were processed.
2. Sample preparation: Samples were immediately dissected to retrieve the tissue selected for stable isotope analyses (cf. "measurementRemarks" field of the dataset), which was then dried at 60°C during 72 hours. Samples were then homogenised into powder prior to SIA using a mortar and a pestle or a mixer mill (MM301, Retsch, Haan, Germany) depending on toughness. Whenever necessary (cf. "preparations" field of the dataset), carbonates were removed from subsamples by exposing subsamples to 37 % hydrochloric acid vapor during 48 hours. Acidified subsamples were then kept at 60°C until further sample preparation.
3. Stable isotope analysis: The subsamples were then precisely weighed (ca 2.5-3 mg) in 5×8 tin cups with ca 3 mg of tungsten trioxide. Their elemental composition and their stable isotope values were analyzed with an elemental analyser coupled to a continuous-flow isotope-ratio mass spectrometer. Isotopic ratios were expressed in ‰ using the widespread δ notation (Coplen 2011) and relative to the international references Vienna Pee Dee Belemnite (for carbon), Atmospheric Air (for nitrogen) and Vienna Canyon Diablo Troilite (for sulfur). Sucrose (IAEA-C-6; δ13C=−10.8 ± 0.5‰; mean ± standard deviation), ammonium sulfate (IAEA-N-1; δ15N= 0.4 ± 0.2‰; mean ± SD) and silver sulfide (IAEA-S-1; δ34S = −0.3‰) were used as primary analytical standards for stable isotope ratios. Sulfanilic acid (Sigma-Aldrich; δ13C=−25.6 ± 0.4‰; δ15N=−0.13 ± 0.4‰; δ34S = 5.9 ± 0.5‰; means ± SD) was used as a secondary analytical standard for stable isotope ratios and as elemental standard. Standard deviations on multi-batch replicate measurements of secondary and internal laboratory standards (sea star tegument), analyzed interspersed with samples (one replicate of each standard every 15 analyses), were 0.3‰ for δ13C and δ15N and 0.5‰ for δ34S.
4. Instrumentation: Stable isotope ratio measurements were performed by continuous flow–elemental analysis–isotope ratio mass spectrometry (CF-EA-IRMS) at University of Liège (Belgium), using a vario MICRO cube C-N-S elemental analyzer (Elementar Analysensysteme GmbH, Hanau, Germany) coupled to an IsoPrime100 isotope ratio mass spectrometer (Isoprime, Cheadle, United Kingdom).

1. Animalia
   rank: kingdom
2. Chromista
   rank: kingdom
3. Plantae
   rank: kingdom
4. Annelida
   rank: phylum
5. Arthropoda
   rank: phylum
6. Chlorophyta
   rank: phylum
7. Echinodermata
   rank: phylum
8. Mollusca
   rank: phylum
9. Ochrophyta
   rank: phylum
10. Porifera
    rank: phylum
11. Rhodophyta
    rank: phylum
12. Asteroidea
    rank: class
13. Bivalvia
    rank: class
14. Echinoidea
    rank: class
15. Florideophyceae
    rank: class
16. Gastropoda
    rank: class
17. Holothuroidea
    rank: class
18. Malacostraca
    rank: class
19. Phaeophyceae
    rank: class
20. Polychaeta
    rank: class
21. Ulvophyceae
    rank: class

Kerguelen Island, Gulf of Morbihan, close to Port-aux-Français scientific station