WOBEC SOP MUC BC

Weddell Sea Observatory of Biodiversity and Ecosystem Change – WOBEC Standard Operating Procedures Technical Documentation December 2025 To be cited as Werna, Werna, Nils Van den Steen, Heike Link, and Anton Van de Putte. ‘WOBEC SOP MUC BC’. Zenodo, 15 December 2025. https://doi.org/10.5281/zenodo.17937164. Co-funded by the European Union (c) The authors This report is licensed under the Creative Commons Attribution International license Versions Date Comment Responsible Approved 14/11/2024 Request data format and parameters 12/12/2025 Formatting N. Van den Steen Table of Contents 1 Description of sampling gear.................................................................................................................... 4 2 Sampling gear deployment........................................................................................................................ 6 3 Sample sorting-collection-preservation procedure ........................................................................ 6 3.1 Sediment core sample collection ............................................................................................................... 6 3.1.1 Sediment core for benthic fluxes and biodiversity assessment (“incubations”) ...... 6 3.1.2 Detail procedure for MUC: ............................................................................................................. 6 Safety ................................................................................................................................................................. 6 Preparation...................................................................................................................................................... 6 Deployment ..................................................................................................................................................... 6 3.1.3 Detail procedure for BC: ................................................................................................................. 7 3.1.4 Sediment core for determination of sediment properties and pigment concentration ...................................................................................................................................................... 8 3.2 Bottom water collection ................................................................................................................................ 8 4 Sample analysis method ............................................................................................................................. 9 4.1 Sediment core incubation (cold room) .................................................................................................... 9 4.2 Filtration of water samples for nutrient analyses from incubation water phase (cold room) ..................................................................................................................................................................................... 11 4.2.1 Preparation on land ....................................................................................................................... 12 4.2.2 Preparation on board before incubation ............................................................................... 12 4.2.3 Filtration ............................................................................................................................................ 12 4.2.4 Sample storage ................................................................................................................................ 13 4.2.5 Post Filtration .................................................................................................................................. 13 4.3 Ammonium protocol (adaptation of method proposed by Holmes et al., 1999) ................. 13 4.4 Sieving (benthic lab) .................................................................................................................................... 13 4.5 Further analysis post expedition ............................................................................................................ 13 4.5.1 Nitrate, Nitrite, Phosphate, Silicic acid ................................................................................... 13 4.5.2 Sediment pigment concentration ............................................................................................. 13 4.5.3 Porosity .............................................................................................................................................. 14 4.5.4 δ 13C org δ 15N ............................................................................................................................... 14 4.5.5 Total organic carbon (TOC) and Total nitrogen (TN) ...................................................... 14 4.5.6 Sediment grain size ........................................................................................................................ 14 4.5.7 Biomass .............................................................................................................................................. 14 5 Raw and analyzed data formats ........................................................................................................... 14 6 References .................................................................................................................................................... 15 Method responsible: Heike Link 1 Description of sampling gear A multicorer (MC) or/and a giant box corer (BC) (by subsampling) will be used to collect sediment cores (10 cm i.d., 20-25 cm length) and bottom water (tbd l) at (tbd)sites, depth (tbd), and replicate (tbd). Additionally, CTD-rosette installed aboard R/V Polarstern will be use to sample bottom water. The required equipment and materials (chemicals) for the corresponding measurement is listed below. NO Activity EquipmentMaterial Amount Safety considerati on 1 Sampling of bottom water Canister (10 L) Tube 2 Sampling of sediment with Multicorer (MC) Core liners Oxygen Sensor spots Core holders Rubber plugs (top + bottom) Running seawater Buckets Freshwater Alu foil Cap toe shoes Helmets Towel, cloth Nitril gloves Ruler 3 Sampling of sediment with Box corer (BC) Core liners Syringes Rubber plugs (top + bottom) O-rings Alu foil White cap NO Activity EquipmentMaterial Amount Safety considerati on Ruler 4 Sediment core incubation Acid-cleaned Syringes (60 ml) with tube Alu foil Stirring tops (rinsed with bw) + controller Bucket or bowl Fibox Ruler 5 Water (from incubation) filtration Filter holders Syringe Tubes 15 ml vials 10% HCL nanopue/milli Q water GF/F Filters Filter tweezers Ethanol Bucket Alu foil Ziplock Sample slips Tray or dish Nitril gloves 6 Sediment sieving Ruler Sieves Container (500 ml) 4 % formaldehyde 2 Sampling gear deployment Deployment, calibration, and maintenance of MC, BC, and CTD should be performed according to standard routine of R/V Polarstern. 3 Sample sorting-collection-preservation procedure Before deploying MC or BC, double-check the availability of the cold room for sediment storage and prepare the necessary equipment for sediment collection. Sediment core sample collection 3.1.1 Sediment core for benthic fluxes and biodiversity assessment 3-U5 sediment cores from the MC or sub-sample from BC will be used. 3.1.2 Detail procedure for MC: Safety • Check if deck is slippery helmets on? • cap toe shoes • Regarding safety pin in MC:--> release when MC over water; put back as soon as possible when MC reachable (no contact with the ship/ground!!!) Preparation Select 8 liners + put them into MC holders • Charge top and bottom lids • pull safety pin when MC is lifted Deployment • Lower MC at 0.3–0.5 m/s at great depths:max. 1.0 m/s) • →take care that pressure on cable is constant • Lower MC at 0.3 m/s to the seafloor(20-30m above the seafloor) • Upontouchdown,give 3–5 m more cable at deep sea stations give 8m more cable) • Heaveslowly (0.2–0.3 m/s)until liftoff (watch cable or cable drag display) • After lift off heave MC at 0.5 m/s until sea surface • Take cores from MC with rubber stoppers • Measure sediment height; if > 25cm, adjustment needed. • Sit core onto its bottom • Adjustment: with top stopper vacuum control, let core glide down slowly, cut of extra sediment and slowly, steadily insert bottom by pushing the core liner onto it. • slowly, steadily insert bottom by pushing the core liner onto it • Clean cores and bring to temperature controlled room (2°C) Sediment core samling with Multicorer (© H.Link) 3.1.3 Detail procedure for BC: • Insert cores to ca. 15-25 cm into the sediment (you may want to mark a line in the core) • Once the cores are pushed into the sediment, protect cores from external disturbance (sediment falling onto surface) – aluminum foil or white caps • Sampling order in the BC: push in big cores first, then syringes 60ml, syringes 10ml, in the end take surface sediments • Retrieve samples in the opposite order! Small syringes first, then larger, then the incubation cores • reach/grab underneath the core (use the full hand to avoid core from falling out) to retrieve it from the BC Box core sampling (© H.Link) • Sit core onto its bottom and slowly, steadily insert bottom by pushing the core liner onto it. Make sure that the larger of the 2 O-rings on the bottom piece is up (and maybe slightly grease the O-ring with the grease in the repair box). You may need to remove the white cap while pushing, thus that air can escape from the core volume. • Keep away from sun and bring cores as fast as possible into the cold room to prepare incubations 3.1.4 Sediment core for determination of sediment properties and pigment concentration Additional (tbd)sub cores ( tbd cm i.d., tbd cm leght) will be taken to later asses sediment solid phase, water content, and sediment pigment concentration. • Store the surface sample (0-1 cm) in pre-weighed plastic vials and freeze immediately at - 80°C for later sediment solid phase analysis and at -20°C for later pigment analysis Bottom water collection Bottom water samples will be collected from MC, BC, or the ship’s Niskin bottles. Sample will be filled into canister (10 L) and store in cold room (0.8 - 4° C) prior to incubation. 4 Sample analysis method Sediment core incubation (cold room) Sediment cores and bottom water will be incubated to measure benthic mineralization (sediment oxygen demand: SOD, silicic acid, nitrate, ammonium and phosphate)rates (mmol m-2 d-1). After incubation, the same sediment core will be used to assess species diversity, abundance, and biomass. Illustration of the general sampling processing of microcosm incubations (Link and Piepenburg, 2013) Sediment core incubations are performed in a dark and temperature controlled room(0.8 - 4° C) for 24 – 72 h. SOD was determined as the decrease in oxygen concentrations in the water phase and was measured periodically (2 to 8 h intervals) with a non-invasive optical probe(Fibox 3 LCD, PreSens, Regensburg, Germany). To determine changes in nutrient concentrations, samples of the overlying water phase were taken at three times during the incubation, including the onset and end. Oxygen and nutrient fluxes are determined as the slope of the linear regression of the oxygen and nutrient concentration on incubation time and corrected for solute concentration in the replacement water. The detail procedure is describe as follow: Prior to the onset of incubation MC Link H, Piepenburg D (2013) 3.2 Dynamics of benthic ecosystem functioning in response to predicted environmental shifts. In:Gutt J (ed) The expedition of the research vessel ‘Polarstern’ to the Antarctic in 2013 (ANT-XXIX/ 3). Ber Polar Meeresforsch 665. Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, p 20−25 Riaux-Gobin, C. and Klein, B.: Microphytobenthic Biomass Measurement Using HPLC and Conventional Pigment Analysis, in: Handbook of methods in aquatic microbial ecology, edited by: Kemp, P., Sherr, B., Sherr, E., and Cole, J., Lewis Publishers, Boca Raton, 369–376, 1993 Säring F, Veit-Köhler G, Behrend B, Seifert D, Liskow I, Link H (2021b) Sediment characteristics (Chla, Phaeo, TOC, TN, δ13C, δ15N, grain size) at stations in the Weddell Sea (POLARSTERN cruise PS 96, ANT-XXXI/2, December 2015−February 2016). PANGAEA. https: //doi.pangaea. de/10.1594/PANGAEA.932718 Vanreusel A, Hauquier F, Beuselinck B, Van Gansbeke D, Viaene N, Veit-Köhler G (2021b) Abiotic and biotic sediment characteristics for stations from the NorthWestern Weddell Sea, Bransfield Strait, and Drake Passage (POLARSTERN cruise PS 81, ANT-XXIX/3, JanuaryMarch 2013). PANGAEA Veit-Köhler G, Durst S, Schuckenbrock J, Hauquier F and others (2018) Oceanographic and topographic conditions structure benthic meiofauna communities in the Weddell Sea, Bransfield Strait and Drake Passage (Antarctic). Prog Oceanogr 162: 240−256