Iron recycling and export from Antarctic krill faecal pellets

• Other Authors: AODN Data Manager (distributor), Ashley Townsend (author), Australian Antarctic Division (AAD), Department of the Environment and Energy, Australian Government (hasAssociationWith), Corkill, Matthew (author), Data Officer (distributor), IMAS Data Manager (hasAssociationWith), Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) (resourceProvider), Kawaguchi, So (author), Lannuzel, Delphine (author), Nelson, Talitha (author), Ratnarajah, Lavenia (author), Smith, Abigail (author), Townsend, Ashley (author), University of Tasmania (UTAS) (hasAssociationWith)
• Format: Dataset
• Language: unknown
• Published: University of Tasmania, Australia
• Subjects: oceans; Antarctic krill; iron; iron recycling; iron export; faecal pellets; euphausia superba; OCEAN CHEMISTRY; EARTH SCIENCE; BIOGEOCHEMICAL CYCLES; BIOGEOCHEMICAL PROCESSES; SOLID EARTH; GEOCHEMISTRY; Biological Oceanography; EARTH SCIENCES; OCEANOGRAPHY; Marine and Estuarine Ecology (incl. Marine Ichthyology); BIOLOGICAL SCIENCES; ECOLOGY; Antarc*; Antarctic; Antarctic Krill; Australian Antarctic Division; Euphausia superba; Southern Ocean
• Online Access: https://researchdata.edu.au/iron-recycling-export-faecal-pellets/3341131; https://doi.org/10.25959/b7s1-3p96

Maintenance and Update Frequency: notPlanned Statement: Firstly, faecal pellets were collected from Antarctic krill at the Australian Antarctic Division using a plastic pipette with the tip enlarged to avoid fragmentation. Krill were fed a diet of 75% of the diatom Phaeodactylum triconutum and 25% of the flagellate Pyramimonas gelidicola. Faecal pellets were photographed for analysis of length, diameter and area on Image J. Once collected, faecal pellets were placed in a 1 L glass cylinder filled with filtered seawater, and the time the faecal pellets took to sink within a 10 cm range was recorded. To determine the relationship between faecal pellet length and dry weight, faecal pellets were photographed, rinsed in milliQ water to remove any salt, dried in an oven at 60°C for 12 h (Clarke et al., 1988), and weighed dry (Mettler Toledo AG285, measurement error of ± 0.03 mg). This allowed an estimation of the dry weight of our faecal pellets used during the dissolution experiment to determine the total Fe concentrations (in mg Fe g-1). For the leaching experiment, fragmented and intact faecal pellets were placed on a 0.2um acid-washed filter paper, and then placed into a filter holder on a continuous flow leachate system. This system allowed for the continuous flow of Southern Ocean seawater over the particles to avoid saturation and hence is more representative of natural conditions. Seawater was collected for dissolved Fe analysis continuously between 0 mins and 72 mins, and then again at 372 minutes, and lastly at 732 minutes. After 732 minutes, the filter papers with the particles were collected and stored for the analysis of particulate Fe. Dissolved Fe samples were immediately acidified to pH 2 with ultrapure HCl, stored at room temperature and analysed after pre-concentration on an ICP-MS. Following the final sampling period, filters were frozen at -20° C prior to analysis for particulate Fe. Seawater sub-samples were analysed for dFe (<0.2µm) using an offline seaFAST preconcentration system (SC-4 DX ...