Data Trawler - Project details

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Project details

Title: Sampling the abyss: latitudinal biodiversity patterns along the base of Australia’s eastern continental margin
Id: 2456
Investigator(s): Tim O'Hara
Museum Victoria [details]

Description: The primary objective of this voyage is to sample the biodiversity of lower bathyal (2500 m) and abyssal (4000 m) seafloor habitats off south-eastern Australia, and in particular deep-water ecosystems of seven Commonwealth marine reserves. We will also sample a few shallower stations at 300 m (to trial the Brenke sled) and at 1000m (to ensure a supply of live animals). The depth and sites listed below are indicative only, and may change slightly based on topography and weather. To meet these objectives we will deploy a variety of gear to sample different components of biodiversity. The gear will also vary depending on the nature of the substratum (soft sediments or rock). We will lodge media stories directly from the vessel, in conjunction with media teams at Museum Victoria, the NESP biodiversity Hub, and the MNF. We will have a live stream to schools from the vessel on World Oceans Day (June 8th), with a potential audience of 5,000 students across Australia (years 5-8), supplemented by video clips obtained aboard the vessel.
Years: 2017
Hierachy: Museums Victoria

Publications

Journal Article

Report

Scientific Highlight

Voyage Summary

Data

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
IN2017_V03

[details]		 Dr Tim O'Hara (Victoria Museum) RV Investigator research voyage in2017_v03, titled "Sampling the abyss: latitudinal biodiversity patterns along the base of Australia's eastern continental margin." The primary objective of this voyage is to sample the biodiversity of lower bathyal (2500 m) and abyssal (4000 m) seafloor habitats off south-eastern Australia, and in particular deep-water ecosystems of seven Commonwealth marine reserves. We will also sample a few shallower stations at 300 m (to trial the Brenke sled) and at 1000m (to ensure a supply of live animals). The depth and sites listed below are indicative only, and may change slightly based on topography and weather. To meet these objectives we will deploy a variety of gear to sample different components of biodiversity. The gear will also vary depending on the nature of the substratum (soft sediments or rock). The prime gear types include: 1. Beam trawl (O&A). This will only be used at sites with soft substrata 2. Heavy sled (Sherman) (MNF). This will only be used for sites that are determined to be hard ground from the multi-beam data. Sherman must be deployed off a stern trawl winch, which will require shifting of a trawl door (there will be plenty of time for this operation as all the soft-sediment gear will not be used at a rocky site). 3. Demersal trawl (NCRA) including floats (NCRA) & doors (Antarctic Division), the latter will be mounted on the stern near the trawl winches when not in use. Soft sediment only. 4. Brenke sled (MNF). Soft sediment or mixed soft-hard ground. It may require 2-3 floats to ensure it remains upright when deployed. It should be retrieved in an upright position using the A-Frame. A stand-alone CTD or camera can be mounted on the frame (see figure). 5. Biological box corer (MNF, previously belonging to Geoscience Australia) of dimensions 500 x 500 mm, sampling size 0.25 m2 (soft sediment only). If possible, this is best deployed on the side winch. 6. Deep-towed camera (MNF) with CTD 7. Surface plankton & mantra nets (O&A and MV), including depression plate and flow meter. In addition, we require multi-beam (Kongsberg EM122 & EM710) and sub bottom profiler for seafloor mapping, and echo sounders for bioacoustics (particularly the Simrad EK60). At each site, the procedure will be to first multi-beam the site to assess the distribution of rock and soft sediment habitats (if previous multi-beam data not available. This will guide the choice of gear and tow track. If the substratum contains mostly rock (possible for some 2500m sites), the heavy sled (Sherman) will be deployed. Otherwise a combination of beam trawl (with mounted camera), Brenke sled, demersal trawl and box core will be deployed. Box cores will be sub-sampled for sediment size and micro-plastics. For shallow water sites within CMRs, the deep-towed camera will be deployed instead of the box corer. The surface plankton net can be deployed during trawling (at appropriate slow ship speeds of under 2 knots). On this voyage there will be a particular emphasis on ensuring that the animals are collected and preserved in excellent condition for photographic and genetic analyses. Keeping the animals cold is the key. Consequently, the catch will be transferred to chilled water (5°C) as soon as it safe to approach the sampling gear. The animals will be sorted, identified and photographed in chilled water to prevent DNA degradation. The box cores will be elutriated (animals separated from mud) in chilled water also (at least for the upper 2 cm). This will require a user-supplied system to chill water in the vessel's walk in cool room. The bulk ethanol and formalin will be stored in the HazMat container, as will the 25L plastic drums full of preserved animals. For more information please refer to the voyage plan
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