Brief description
Geoscience Australia (GA) conducted a marine survey (GA0345/GA0346/TAN1411) of the north-eastern Browse Basin (Caswell Sub-basin) between 9 October and 9 November 2014 to acquire seabed and shallow geological information to support an assessment of the CO2 storage potential of the basin. The survey, undertaken as part of the Department of Industry and Science's National CO2 Infrastructure Plan (NCIP), aimed to identify and characterise indicators of natural hydrocarbon or fluid seepage that may indicate compromised seal integrity in the region. The survey was conducted in three legs aboard the New Zealand research vessel RV Tangaroa, and included scientists and technical staff from GA, the NZ National Institute of Water and Atmospheric Research Ltd. (NIWA) and Fugro Survey Pty Ltd. Shipboard data (survey ID GA0345) collected included multibeam sonar bathymetry and backscatter over 12 areas (A1, A2, A3, A4, A6b, A7, A8, B1, C1, C2b, F1, M1) totalling 455 km2 in water depths ranging from 90 - 430 m, and 611 km of sub-bottom profile lines. Seabed samples were collected from 48 stations and included 99 Smith-McIntyre grabs and 41 piston cores. An Autonomous Underwater Vehicle (AUV) (survey ID GA0346) collected higher-resolution multibeam sonar bathymetry and backscatter data, totalling 7.7 km2, along with 71 line km of side scan sonar, underwater camera and sub-bottom profile data. Twenty two Remotely Operated Vehicle (ROV) missions collected 31 hours of underwater video, 657 still images, eight grabs and one core. This catalogue entry refers to chlorophyll a, b, c and phaeophytin a conentrations in the upper 2 cm of seabed sediments.Lineage
Maintenance and Update Frequency: asNeeded
Statement: Bottom sediments were collected using a Smith McIntyre grab. 0.4 ml samples of surface sediment (0-0.5 cm) were syringed into pre-weighed falcon vials. The samples were wrapped in Al foil and frozen. Chlorophyll concentrations were calculated on sediment extracts (90% acetone + 0.1% MgCO3) at spectrophometric readings at wavelengths of 647, 630, 750 and 664 nm. For chlorophyll-a (Chl-a) and phaeophytin-a, wavelengths of 664 nm and 750 nm (before and after the addition of 200 -L-1 0.1 mol L-1 HCl per 2 mL extractant) and the equation derived by Lorenzen (1967) were used. Chlorphyll b and c concentrations were calculated according to equations provided by Jeffrey and Welschmeyer (2003).
Lorenzen, C. J. (1967). Determination of chlorophyll and pheopigments: Spectrophotometric equations. Limnology and Oceanography 12, 343-346.
Jeffrey, S.W., and Welschmeyer, N.A. (2003). Spectrophotometric and fluorometric equations in common use in oceanography. In 'Phytoplankton pigments in oceanography: guidelines to modern methods' (Eds. S.W. Jeffrey and R.F.C. Mantoura, and S.W. Wright.) pp. 597-615. (UNESCO Paris.)
The error associated with the measurement is estimated at +/-10%.
Created: 2015
Issued: 03 06 2016
Modified: 09 05 2019
text: westlimit=122.3883; southlimit=-14.2865; eastlimit=124.6521; northlimit=-12.8678; projection=WGS 84 / UTM zone 52S
Subjects
Earth Sciences |
Geology |
Marine Data |
Marine Geoscience |
Published_External |
WA |
geochemistry |
geological storage of CO2 |
marine |
marine environmental baselines |
marine survey |
oceans |
seabed |
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Other Information
Download the data (xls)
uri :
https://d28rz98at9flks.cloudfront.net/83197/TAN1411_Chlabc.xls
Caswell Sub-basin - Browse Basin CO2 data package
Identifiers
- DOI : 10.4225/25/575F8D297FF03
- URI : pid.geoscience.gov.au/dataset/ga/83197
- global : 145bdd0a-3e53-44c1-e053-12a3070a6188
