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2021

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  • The goal of our study was to split the Australian maritime Exclusive Economic Zone (EEZ) into a set of smaller acoustic zones, whereby each zone is characterised by a set of environmental parameters that vary more across than within zones. The environmental parameters chosen reflect the hydroacoustic (e.g., water column sound speed profile), geoacoustic (e.g., sound speeds and absorption coefficients for compressional and shear waves), and bathymetric (i.e., seafloor depth and slope) parameters that directly affect the way in which sound propagates. Mean zone parameters and shape files are available for download. The zones may be used to map, for example, underwater sound from commercial shipping within the entire Australian EEZ.

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    These data are from a voyage (IN2019_V01) on RV Investigator with the Australian Antarctic Division (AAD), that took place during January-March 2019. The Chief Scientist was Mike Double from the AAD. Clara R. Vives collected biogeochemical data on the voyage, and performed a series of incubation experiments for her PhD. The purpose of the study was to investigate the effects of iron and light on phytoplankton growth off East Antarcitca. Data include CTD nutrients, chlorophyll and oxygen as well as underway phytoplankton physiology (measured as the photochemical efficiency) and pCO2. Some data are duplicated but not in exactly the same format on the CSIRO Data Trawler.

  • Ocean alkalinity enhancement (OAE) is a promising carbon removal method, but it may cause a significant perturbation of the ocean with trace metals such as Nickel (Ni). This study tested the effect of increasing Ni concentrations on phytoplankton growth and photosynthesis. The data were the growth rates of 11 phytoplankton species under different Ni concentrations (Master thesis project). The growth rates were calculated using daily fluorescence signal values measured by the fluorometer. Fv/Fm and SigmaPSII data were measured using Fast repetition rate fluorometry (FRRf). The growth rate and photo-physiological response of phytoplankton was analysed using generalised additive models (GAMs) and plotted in RStudio (R packages “mgcv” and “ggplot2”).

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    This dataset is a compilation of published records of 230Thorium - normalised lithogenic and biogenic fluxes from the Southern Ocean, south of 30S. All age models and derived fluxes were taken as published. Lithogenic fluxes are based on 232Th concentrations. Opal and carbonate fluxes are also included where available. In some cases fluxes had to be derived from published data. LGM values for each core represent an average of observations between 28 - 18 ka BP and Holocene values represent an average of observations from 10 - 0 ka BP. These data were collated as part of modelling study of the Southern Ocean during the LGM (Saini et al, Southern Ocean ecosystem response to Last Glacial Maximum boundary conditions, Submitted to Paleoceanography and Paleoclimatology, 2021)

  • This dataset contains temporal and compositional data on the Southern Ocean Time Series (SOTS) 1000 m depth sediment trap between 2010 and 2019. This study has added new data on 40 trace metals and isotopes (TEIs) in addition to the sinking particle flux data available on the Australian Ocean Data Network (AODN portal) and published in Wynn-Edwards et al. (2020; Frontiers in Earth Science). The TEI data was collected by strong acid digestion of archived SOTS 1000 m sinking particle samples collected from sediment trap deployments from 2010 to 2019. Following digestion, sinking particle samples were analysed for TEI concentration at the UTAS Central Science Laboratory using High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). The data presented here contains TEI concentration data, elemental fluxes calculated from the sediment trap mass fluxes (Wynn-Edwards et al., 2020) and a range of lithogenic particle fluxes derived from various upper continental crust concentrations reported in the literature. Several iterations of lithogenic flux are included for key lithogenic tracers Al, Fe, Ti and Th, with some mean fluxes of the combination of these tracers included. Here, several multi-tracer lithogenic fluxes are included based on the inclusion of Th concentrations using isotope dilution or linear calibration methods. The final lithogenic fluxes used in the publication are linearly calibrated Al, Ti, Fe and Th flithogenic fluxes and the mean value of these four tracers. Additional V and Pb tracer concentrations were used to assess anthropogenic influences. These results were used to estimate seasonal and interannual lithogenic particle flux in the subantarctic Southern Ocean. Additionally, particle composition, sources and provenance were examined using the attached data. The findings were used to provide an estimate of dust deposition in the subantarctic Southern Ocean south of Australia, contextualised by particle trajectory reanalysis, satellite data products and biogeochemical processes.

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    Trace element data collected from 18 stations near the Mertz Glacier on the 2019 ENRICH voyage. Sea water was collected using a 12-bottle trace metal rosette (TMR) and acidified for analysis back in Hobart. Samples were measured using an offline seaFAST pre-concentration system and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) at the University of Tasmania. This data contributed to Smith et al., Circumpolar Deep Water and shelf sediments support late summer microbial iron remineralisation in Global Biogeochemical Cycles (2021).

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    These data are from a piggy back voyage to IN2018_V05, October-November 2018. The Chief Scientists were Helen Phillips and Nathan Bindoff. Nic Pittman and Clara Vives collected biogeochemical data on the voyage, and Xiang Yang used these data in his Hons thesis 2020-2021. The purpose of the study was to investigate biogeochemical variability in the region of the Polar Front meander south of Tasmania. Data include CTD nutrients, chlorophyll and oxygen as well as underway phytoplankton physiology and pCO2. Some data are duplicated but not in exactly the same format on the CSIRO Data Trawler.

  • The principle aim of this project was to map the fine-scale spatial distribution of key abalone habitat impacted by urchins in < 25 m water depth using multibeam acoustic imagery. Detailed substrate type (Pavement Reef, Megaclast Reef, Mixed Consolidated Sediment/Reef and Sand), and kelp coverage maps have been produced for the east coast of Tasmania. Large urchin barrens have been predicted and the minimum quantifiable unit of which small incipient barrens can be detected has been identified using this acoustic water column technique. This data provides a snapshot of the 2021 distribution of seafloor habitats and associated vegetation distribution, and will assist in the facilitation of strategic decision making for urchin control and abalone management. Data for download has been split by fishing block (22-24, 27-30). This record describes *FISHING BLOCK 29*. The following data products are available for download, for each fishing block: • 50cm resolution bathymetry • 50cm resolution substrate type (Seamap Australia classification) • bathymetry derivatives (seabed slope, curvature, rugosity, 1 and 2m contours) • water column data - 1m mean signal • water column data - 9m2 raw block statistic • water column data - vegetation likelihood classification See associated records for access to data from other fishing blocks (22, 23, 24, 27, 28, 30).

  • Predicting phytoplankton impacts in response to a changing climate on Tasmania's east coast is presently based on short-term plankton data sets (~75 years). However, given the vital contribution coccolithophores make to oceanic carbon pumps, it is crucial to understand longer-term assemblage trends better. Here, we expand the archive of calcareous nannoplankton in southeast Australian waters by analysing coccolithophore microfossils in a ~2.68m long marine sediment core from the climate hotspot of Maria Island, Tasmania, using polarising light and scanning electron microscopy techniques in combination with analysis of sedimentary ancient DNA (sedaDNA). Coccolith assemblages at this site represent the complex interplay between the East Australian Current, Subantarctic incursions, and the hydrodynamics driving Subtropical Front positioning. Microfossil analysis revealed a shift from a cold to warm-adapted assemblage ~8 200 years BP, expressed by a striking transition from assemblages dominated by the cold-water species Gephyrocapsa muellerae to warmer water species Emiliania huxleyi. This transition compares with similar occurrences in the literature at ~11 000 years reported in the Southern Ocean and 12 000 years in the Tasman Sea, reflecting a broad shift of the Subtropical Front. E. huxleyi microfossils displayed the highest relative abundance, but less abundant larger taxa (including Calcidiscus, Coccolithus, Helicosphaera) accounted for >50% of coccolith CaCO3 sequestration, indicating large densely calcified species do the 'heavy-lifting' in terms of carbon cycling within mixed coccolithophore assemblages. Analysis of sedaDNA showed coccolithophores comprised the largest number of eukaryote molecular sequences recovered (~44%), far exceeding diatoms and dinoflagellates.

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    Annotations of Centrostephanus rogersii sea urchin barrens derived from towed video at selected key abalone blocks along the east coast of Tasmania. The purpose of the study was to examine the patch dynamics of urchin barrens and to provide validation for the identification of urchin barrens from multibeam surveys.