Abstract:
In 2017, the RV METEOR M134 expedition investigated macrobenthic assemblages associated with methane seeps on the South Georgia continental shelf. Six shelf troughs with active methane seepage were sampled to assess species richness, abundance, and environmental conditions. Data were collected from eleven shelf stations, with species richness ranging from 19 to 51 species and abundances from 3,303 to 30,326 individuals per square meter. A total of 103 species were identified, with arthropods (primarily crustaceans) and annelids comprising most of the species richness. Environmental data include methane and sulfate flux, hydrogen sulfide concentrations, and sediment geochemistry. Seep assemblage data is combined with data from non-seep benthic communities from other expeditions.The dataset provides: 1) South Georgia methane seep station locations and environmental data. 2) Macrobenthic species absolute and normalized abundances at seep sites. 3) A combination of seep assemblages with non-seep benthic communities from other expeditions.
Funding:
The fieldwork for this study, was supported by the Deutsche Forschungsgemeinschaft (DFG) in the framework of the priority programme 'Antarctic Research with comparative investigations in Arctic ice areas' (project-id 40464014) and within the DFG-Research Center/Cluster of Excellence EXC 309 'The Ocean in the Earth System' (project-id 49926684). The expedition, titled 'Emissions of free gas around South Georgia: distribution, quantification, and sources for methane ebullition sites in sub-Antarctic waters,' was supported by MARUM - Center for Marine Environmental Sciences, Research Faculty University of Bremen, and the University of Bremen. Additional support came from the Helmholtz Association (Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven). The cruise was funded by the German Research Foundation (DFG) and the Federal Ministry of Education and Research (BMBF). Katrin Linse is part of the British Antarctic Survey Polar Science for Planet Earth Programme (NC Science), funded by the Natural Environment Research Council (NERC).
Studies around South Georgia were conducted under permit RAP 129/2016 (M134) issued by the Foreign & Commonwealth Office, UK. Macrobenthic faunal sorting was supported by the Natural Environment Research Council through a DEI Internship for Madeline PBC Anderson (via the NERC Diversity, Equity and Inclusion engagement funding) and an IAPETUS2 PhD studentship held by Madeline PBC Anderson (grant reference NE/S007431/1).
Keywords:
South Georgia, Sub-Antarctic, hydrocarbon seafloor emission, macrobenthic, methane seep, multicorer (MUC) samples
Anderson, M., Pape, T., & Linse, K. (2025). Macrobenthic assemblages from the methane seeps in six South Georgia troughs collected in 2017 (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/d34fc0d7-3ef5-49df-b626-908d76e28f75
| Access Constraints: | Under embargo until publication of the associated article. |
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| Use Constraints: | This data is governed by the NERC data policy http://www.nerc.ac.uk/research/sites/data/policy/ and supplied under Open Government Licence v.3 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/. |
| Creation Date: | 2025-03-05 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | UK Polar Data Centre |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Ms Madeline Anderson |
| Role(s) | Investigator, Technical Contact |
| Organisation | University of Southampton |
| Name | Thomas Pape |
| Role(s) | Investigator |
| Organisation | University of Bremen |
| Name | Katrin Linse |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Parent Dataset: | N/A |
| Reference: | Associated publication: Anderson, Madeline P B C; Reid, William D K; Bohrmann, Gerhard; Dohrmann, Ingrid; Hollyman, Philip R; Kasten, Sabine; Pape, Thomas; Römer, Miriam; Newton, Jason; Wigham, Ben; Linse, Katrin (in prep.) The abundance, diversity, and assemblage structure of the macrobenthos at the South Georgia shelf methane seeps. Frontiers in Marine Science Dataset includes data from the following publications: Bell, et al. (2016a) Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin, Royal Society Open Science. https://doi.org/10.1098/rsos.160284 Bell, et al. (2016b) Macrofaunal Ecology of Sedimented Hydrothermal Vents in the Bransfield Strait, Antarctica, Frontiers in Marine Science. https://doi.org/10.3389/fmars.2016.00032 Glover et al. (2008) Macrofaunal abundance and composition on the West Antarctic Peninsula continental shelf: Evidence for a sediment 'food bank' and similarities to deep-sea habitats, Deep Sea Research Part II: Topical Studies in Oceanography. https://doi.org/10.1016/j.dsr2.2008.06.008 Saring et al. (2021a) Macrofauna abundance from multicorer and box corer samples for ten stations around the Antarctic Peninsula (POLARSTERN cruise PS 81, ANT-XXIX/3, January-March 2013). https://doi.org/10.1594/PANGAEA.932693 Saring et al. (2021b) Macrofauna abundance from multicorer and box corer samples for seven stations from the Weddell Sea (POLARSTERN cruise PS 96, ANT-XXXI/2, December 2015-February 2016).https://doi.org/10.1594/PANGAEA.932658 Saring et al. (2022) Sea-ice-related environmental drivers affect meiofauna and macrofauna communities differently at large scales (Southern Ocean, Antarctic), Marine Ecology Progress Series. https://doi.org/10.3354/meps14188 Methodology: Rauschert, M., and Arntz, W. (2015). Antarctic macrobenthos: a field guide of the invertebrates living at the Antarctic seafloor. Druckerei Girzig and Gottschalk GmbH. https://doi.org/10.1007/s00300-016-1905-2 |
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| Quality: | NA in Environmental_parameters.csv data - data were not collected Indet - the abbreviation 'indet.' was used to denote an indeterminate specimen. Species were identified to highest taxonomic level possible, and quality checking occurred for consistency in identification. Specialists were contacted to assist in identification for specific taxa. |
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| Lineage/Methodology: | Oceanographic data were collected using RV METEOR's 24 x 10 L Niskin bottle rosette with a Seabird CTD equipped with conductivity, temperature, pressure, and an SBE 43 dissolved oxygen sensor. The near seafloor water data were used to report bottom temperature, salinity, and oxygen. Seafloor sediment cores and macrobenthic assemblages were obtained with a multicorer (MUC) (OKTOPUS GmbH), comprising eight 10 cm diameter and four 6 cm diameter cores per deployment. On arrival on deck, cores were photographed to document sediment height, layering, and colour before being distributed for geochemical, sediment, and biological analyses. Water depth of sediment recovery ranged from 136 m (Cumberland East Bay station CB 07) to 369 m (Church Trough station CT 05). MUC cores allocated for macrobiology (a total of 38) were sliced into 0-2 cm and 2-5 cm horizons using a core extruder, sieved through a 500 micrometer mesh, and preserved in 96 percent ethanol. Specimens were initially sorted to higher taxonomic levels onboard using a Meiji stereomicroscope, then further sorted to morphospecies on land under a Zeiss Stemi SV6 stereomicroscope. Photographs were taken using ScopeTek ScopePhoto 3.1.475, and taxonomic identifications were verified by experts using literature (Arntz and Rauschert, 2015). Due to identification challenges, nematodes were grouped into a single taxon, and indeterminate specimens were marked as 'indet.'. Only individuals with heads were counted to prevent duplication. Abundance data were scaled to m squared for quantitative analyses. Patterns in species richness, abundance, and diversity were assessed by pooling cores per MUC deployment to obtain an assemblage per core. Abundance data were summed at the phylum level and scaled for comparisons between stations. Species richness was verified with a species accumulation curve to ensure observed richness was not an artifact of sampling effort. Data have been combined with other comparable species/polychaete Southern Ocean non-seep assemblage datasets (see references for the publications used). MUC coring was also used for macrofaunal sampling in these studies - full details of sampling can be found in those publications. |
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| Temporal Coverage: | |
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| Start Date | 2017-01-21 |
| End Date | 2017-02-09 |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -76.09883 |
| Northernmost | -53.77015 |
| Longitude | |
| Westernmost | -65.36666 |
| Easternmost | -30.30383 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | 135 |
| Max Depth | 1311 |
| Latitude | |
| Southernmost | -54.8545 |
| Northernmost | -53.81415 |
| Longitude | |
| Westernmost | -38.84446 |
| Easternmost | -35.84446 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | 135 |
| Max Depth | 368 |
| Location: | |
| Location | Antarctica |
| Detailed Location | South Georgia |
| Data Collection: | 1. RV METEOR's 24 x 10 L Niskin bottle rosette - Equipped with a Seabird CTD (Conductivity, Temperature, Depth) sensor. Sensors: Conductivity (psu) Temperature (degCel) Pressure - Depth (m) SBE 43 dissolved oxygen sensor (mLL-10) 2. Multicorer (MUC) (OKTOPUS GmbH) - Used for seafloor sediment and macrobenthic assemblage collection. Core sizes: Eight 10 cm diameter cores Four 6 cm diameter cores 3. Stereomicroscopes: Meiji stereomicroscope - Used onboard for initial macrofaunal sorting. Zeiss Stemi SV6 stereomicroscope - Used in the laboratory for further taxonomic sorting. 4. Core Extruder: Used for sediment slicing at 0-2 cm and 2-5 cm horizons. 5. 500 micrometer sieve - Used for sieving sediment samples on deck. |
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| Distribution: | |
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| Distribution Media | N/A |
| Distribution Size | 5 x csv, 82 KB |
| Distribution Format | N/A |
| Fees | N/A |
| Data Storage: | 5 csv's (82 KB) - Absolute abundance - Normalised abundance, species by core horizon - Environmental data - Southern Ocean combined data - Polychaetes across the Southern Ocean combined data The Absolute_Species_Composition.csv file contains raw counts of individuals collected during the expedition (at a species-phylum level depending on identification possible). Each row includes the station number, core number, and core horizon (0-2 cm or 2-5 cm). After normalising abundances to m squared, the data are provided in Normalised_Species_Composition.csv. The Environmental_Parameters.csv file contains environmental data collected by CTD at these stations. Combined datasets from the Southern Ocean include Southern_Ocean_Species_Composition.csv (at a phylum/class level) and specifically the polychaetes, Southern_Ocean_Polychaete_Abundance_Composition.csv (at the family/class taxonomic level). Stations and GeoB numbers match up to those in the associated cruise report. |