Data Trawler - Project details

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Project details

Title: Acoustic estimates of zooplankton and fish distribution
Id: 2512
Investigator(s): Rudy Kloser
CSIRO Oceans & Atmosphere - Hobart [details]

Description: The voyage objective is to map the top 1000m of the water column for micronekton organisms (small fish, crustaceans, gelatinous and squids of ~2-20 cm in length) at the SOTS site using the PLAOS acoustic optical system. Commonly nets, optic and acoustic samplers are used to determine the taxonomy, size, biomass, trophic linkage and energetics of zooplankton and micronekton. Each of these sampling methods have bias and uncertainty that need to be quantified prior to attributing changes within and between regions. In particular for the gelatinous community that covers a wide range of taxonomic and energetic groups that are difficult to sample with nets. To improve vessel mounted acoustic and net sampling methods of macro-zooplankton and micronekton a new profiling multi-frequency acoustic optical system has been developed with the ultimate aim of it being used as a remote sampling tool. On this voyage we will be testing the next phase of a profiling lagrangian acoustic and optical probe (PLAOS) to sample these organisms to depths of 1000 m. These tests will involve detailed sampling of the repeatability of the measurements when varying lighting, using new broadband acoustic sensors and a new buoyancy engine to enable the system to do repeat profiles. Development of this methodology and technology will significantly advance our knowledge of micronekton biomass and distribution and provide the necessary structure and function understanding for the development of carbon and ecosystem models of the open ocean linking to the ACE CRC carbon program as well as the MESOPP ecosystem program.
Years: 2017

List of surveys that this project was on.

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

Survey InvestigatorDescription

Thomas W Trull (CSIRO/ACE CRC) Eric Schulz (BOM) The Southern Ocean Time Series provides world-leading automated observations from deep-ocean moorings of the exchanges of heat, water, carbon dioxide, and oxygen between the ocean and atmosphere, and the physical and biological processes that control them. These results contribute to forward projections of anthropogenic climate warming, inform the setting of emissions targets, illuminate controls on climate variability, and provide a baseline for impacts on ocean pelagic ecology. Sensor data is returned live to the internet and samples are returned annually for further study in shore laboratories. The primary objective is to first deploy a new set of SOTS moorings (SAZ-19 and SOFS-6) and then recover the existing SOTS moorings (FluxPulse-1 lower section, and SAZ-18). Additional work will obtain ancillary information on atmospheric and oceanographic conditions using CTD casts, underway measurements, the Triaxus towed body, and autonomous profiling "Bio-Argo" floats. Each of the SOTS moorings delivers to specific aspects of the atmosphere-ocean exchanges, with some redundancy: * the SAZ sediment trap mooring collects samples to quantify the transfer of carbon and other nutrients to the ocean interior by sinking particles, and investigate their ecological controls. * the Southern Ocean Flux Station (SOFS) measures meteorological properties and ocean properties important to air-sea exchanges, ocean stratification, waves, and currents. * the (now superceded) Pulse biogeochemistry mooring focused on processes important to biological CO2 consumption, including net community production from oxygen measurements and nitrate depletion, biomass concentrations from bio-optics and bio-acoustics, and collection of water samples for nutrient and plankton quantification. * the FluxPulse mooring combines some elements of Pulse onto the SOFS platform to create a combined mooring, and was deployed for the first time in 2016, but broke into two sections. The top section has been recovered. The bottom section remains to be recovered. This combined mooring was intended to meet financial constraints. In 2017 we will use the simpler SOFS design, while redesigning FluxPulse for relaunch in 2018. Piggyback projects: * International Nutrient Intercalibration Exercise * Spatial and Temporal Variability in the Distribution and Abundance of Seabirds * Trace Element Cycling * Acoustic estimates of zooplankton and fish distributions
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