Data Trawler - Project details

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Project details

Title: BGC Argo floats
Id: 2489
Acronym: BGC Argo
Investigator(s): Tom Trull
CSIRO Oceans & Atmosphere - Hobart [details]

Peter Strutton
University of Tasmania [details]

Description: Biogeochemical-Argo is the extension of the Argo array of profiling floats to include floats that are equipped with biogeochemical sensors for pH, oxygen, nitrate, chlorophyll, suspended particles, and downwelling irradiance.. Newly developed sensors now allow profiling floats to also observe biogeochemical properties with sufficient accuracy for climate studies. This extension of Argo will enable an observing system that can determine the seasonal to decadal-scale variability in biological productivity, the supply of essential plant nutrients from deepwaters to the sunlit surface layer, ocean acidification, hypoxia, and ocean uptake of CO2. Biogeochemical-Argo will drive a transformative shift in our ability to observe and predict the effects of climate change on ocean metabolism, carbon uptake, and living marine resource management. The Australian contribution to global Biogeochemical-Argo is coordinated through the Australia-India Strategic Research Fund (AISRF) Indian Ocean Bio-Argo project and the IMOS Argo-Australia facility.
Years: 2019 to 2022

List of surveys that this project was on. Click on column header to sort.

Use [details] link to view survey details (map, reports, metadata etc) including links to download data.

Survey InvestigatorDescription

Alix Post (GA) This study has two main scientific objectives: i) to understand past changes in Antarctic Bottom Water (AABW) production using long sediment cores from the continental slope over multiple warm periods during the Pleistocene; ii) develop an improved bathymetry model to support oceanographic modelling of AABW pathways. Sediment core records of previous warmer interglacials will provide an analogue for understanding the impact of any future changes in bottom water production associated with a warming climate. This project will recover long sediment cores from the shelf and slope off Cape Darnley to provide palaeoceanographic records over multiple glacial-interglacial cycles, including previous interglacials when Antarctic air temperatures were 2 to 4.5°C warmer than today. A multi-proxy approach, combining sedimentological, geochemical and biological proxies, will provide evidence of the nature and timing of past changes in AABW formation, and associated variations in meltwater input, and the extent of the Cape Darnley polynya. AABW has previously been associated with unique and diverse benthic ecosystems, including hydrocorals. We will investigate the presence and distribution of hydrocorals, and, if present, analyse their carbonate skeletons to understand past water mass variability over recent centuries, complementing the sediment core records.

John Keesing The Gascoyne region of Australia’s seafloor was identified for protection as an area of national significance and a new marine park (MP) was proclaimed in 2013 and the management plan came into force in 2018. The Gascoyne MP lies in an area with great but poorly known biological diversity and potential for economic development. The voyage will determine the diversity of fishes and of key habitat forming and mobile marine invertebrates across the range of depth regions and in each of the three zoning categories (IUCN II, IV, VI) in the MP. The data collected during the surveys will also provide descriptions of the physical and biological habitat types in the MP and will form the basis for future monitoring and reviews of marine park performance and zoning. The data obtained will likely refine the bioregionalization boundaries of the slope provinces and bathomes in the NW of Australia and resolve debate around the importance of the region from the point of view of the levels of endemicity of fishes and the voyage will also sample the very deep waters of the NW continental margin for the first time. A recent comparative study of the lower bathyal and abyssal depths on the eastern coastal of Australia and the Great Australian Bight found significant differences in assemblages between these locations. This study will enable a further comparison of these areas with the north-west of Australia at the same depths. In lay terms: This project will describe the habitats and quantify fish and seabed biodiversity of one of Australia’s newest marine parks which stretches from depths of less than 100 m to over 5000 m. The project is likely to discover new species of marine animals and ensure that conservation needs are more fully understood. This will identify and assist managers to maintain the park’s natural values into the future.

MNF The primary objective of voyage IN2022_T01 is movement of RV Investigator from Cairns to Darwin in preparation for IN2022_V08. Underway training, repairs, maintenance and science operations will occur whilst en route without impacting the voyage departure and arrival times. Piggyback Projects: Project 3D-GBR & underway scientific mapping. Sea Surface Temperature Radiometer Comparisons/Calibrations. 1x ARGO BioGeoChemical (BGC) float deployment.

V. Puigcorbe (Edith Cowan University) RV Investigator transit voyage between Brisbane and Darwin: in2021_T01, with the following supplementary and piggyback projects:
  • Microplastics in the food chain: impact on the microbial and planktonic organisms
  • Linking the Biological Carbon Pump flux to microbial colonisation of sinking particles in the Coral Sea
  • Dinoflagellates & broader planktonic assemblage observation
  • BGC-Argo Float Deployment
  • Cosmic Ray Measurements
  • Carbon Sampling
  • Flow cytometric classification of the phytoplankton community across Australia’s top end
    The primary objective of voyage IN2021_T01 is movement of RV Investigator from Brisbane to Darwin in preparation for IN2021_V04. Up to 72 hours of the transit voyage have been allocated to conduct scientific operations which will consist of a minimum of 12hrs devoted to the Supplementary Project: Microplastics in the food chain: impact on the microbial and planktonic organisms. The remaining time can be available for multiple Piggyback Projects. Some opportunistic mapping has been prepared should we be ahead of schedule.
  • IN2021_V03

    Dr Sloyan

    This voyage will recover and re-deploy an array of six full-depth current meter and property (temperature, salinity and pressure) moorings from the continental slope to the abyssal waters off Brisbane (27oS). The observing system is designed to capture the mean and time-varying flow of the EAC. In order to resolve interannual and decadal signals we aim to maintain multi-year deployments of the array.

    The data from the EAC mooring array and other oceanographic sampling are essential for understanding, at the regional to global scale, the role of boundary current in the climate system, and, at the local scale, simulating cross-shelf flows, upwelling, and frontal eddy formation. These local-scale processes have a fundamental impact on nutrient and phytoplankton concentrations and therefore far-reaching effects on annual fisheries productivity and coastal shark interactions along the eastern seaboard.

    We will undertake CTD casts, sampling salinity and 02, and numerous Triaxus and ship ADCP sections across the EAC mooring line and at several locations during the transit from Hobart to the mooring sites. Additionally, we aim to complete two oceanographic surveys: one in the Fraser Island area between 28oS and 26oS; and the other on and over the continental shelf in the vicinity of the North Stradbroke Island National Reference Station. These surveys will include bongo net tows and Triaxus/SADCP sections and will occur in between the mooring operations and at the completion of the mooring operations, as well as opportunistic sampling of jellyfish and salps over the side of the vessel when it is stationary using the extendable “pool scoop”. We aim to sample small scale, ephemeral frontal eddies flowing down from Fraser Island and shelf – continental slope boundary exchanges.  These observations will enable us to characterise the spatial and temporal variability of shelf water and plankton around the Stradbroke Island National Reference Station (NRS) mooring, and their connection to the offshore regions. We will also deploy numerous eXpendable Bathymetric Thermographs (XBTs) during the transit from Hobart north.

    We will also aim to perform Triaxus and bongo net tows during the northward transit at various locations, with top priority given to a location off the coast of Newcastle NSW (near 32.5oS) to supplement the IMOS mooring and HF radar installation at that location. We will also deploy a number of floats (core Argo and BCG-Argo) during the voyage.

    We will collect salinity and oxygen samples for calibration of the CTD salinity and oxygen sensors. Limited dissolved inorganic carbon samples may be collected if we deploy BGC Argo floats).

    The following specific objectives will be completed:

    1. Moorings recovery and deployment at appropriate locations;
    2. Full depth CTD/rosette stations at each mooring recovery location with only salt and O2 water samples;
    3. Pre-deployment CTD casts for calibration of Seabird 37 and 39 mooring instruments to a depth of 2000 m;
    4. Triaxus and Ship ADCP sections at various locations during the transit from Hobart to the mooring locations, across the mooring line, at the shelf-slope and Fraser Island survey regions;
    5. Bongo net tows along the EAC mooring line, and as part of the shelf-slope and Fraser Island survey areas to study the significance of re-circulation features;
    6. Bongo nets, CTD and bio-acoustic samplings at various locations during the transit from Hobart to the mooring sites; and surrounding the Stradbroke NRS site including opportunistic sampling of frontal eddies; and
    7. Deploy Surface Velocity Program drifters, XBTs and Argo (core and BGC) floats during the voyage, with supporting CTDs in the case of BGC Argo floats.

    B. Sloyan (CSIRO O&A, Hobart) The East Australian Current (EAC) is the complex and highly energetic western boundary current of the South Pacific Ocean. The EAC is the dominant mechanism for the redistribution of heat and freshwater between the ocean and atmosphere in the Australian region; it is a vital component of the eastern Australian coastal ecosystem. The monitoring of the EAC is central to our understanding of how climate variability is communicated through the global ocean. This ocean current time-series will provide significant insights into the interactions between the EAC, the Pacific basin and the local shelf ocean circulation.
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