Outer Darwin Harbour Marine Survey 2015: Porosity and Chlorins in seabed sediments.  

Authors / CoAuthors

Radke, L.C. | Trafford, J.M.

Abstract

This resource contains surface sediment data for Outer Darwin Harbour collected by Geoscience Australia (GA), the Australian Institute of Marine Science (AIMS) and the Northern Territory Government (Department of Land Resource Management) during the period from 28 May and 23 June 2015 on the RV Solander (survey SOL6187/GA0351). This project was made possible through offset funds provided by INPEX-led Ichthys LNG Project to Northern Territory Government Department of Land Resource Management, and co-investment from Geoscience Australia and Australian Institute of Marine Science. The intent of this four year (2014-2018) program is to improve knowledge of the marine environments in the Darwin and Bynoe Harbour regions by collating and collecting baseline data that enable the creation of thematic habitat maps that underpin marine resource management decisions. The specific objectives of the survey were to: 1. Obtain high resolution geophysical (bathymetry) data for outer Darwin Harbour, including Shoal Bay; 2. Characterise substrates (acoustic backscatter properties, grainsize, sediment chemistry) for outer Darwin Harbour, including Shoal Bay; and 3. Collect tidal data for the survey area. Data acquired during the survey included: multibeam sonar bathymetry and acoustic backscatter; physical samples of seabed sediments, underwater photography and video of grab sample locations and oceanographic information including tidal data and sound velocity profiles. A detailed account of the survey is provided in: Siwabessy, P.J.W., Smit, N., Atkinson, I., Dando, N., Harries, S., Howard, F.J.F., Li, J., Nicholas, W.A., Potter, A., Radke, L.C., Tran, M., Williams, D. and Whiteway, T., 2015. Outer Darwin Harbour Marine Survey 2015: GA0351/SOL6187 Post-survey report. Record 2016/008. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2016.008

Product Type

dataset

eCat Id

89835

Contact for the resource

Digital Object Identifier

http://dx.doi.org/10.4225/25/570201635E1BE

Keywords

• Marine Data

( Theme )

• marine environmental baselines

( Theme )

• marine survey

( Theme )

• continental shelf

( Theme )

• seabed

( Theme )

• geochemistry

• NT

Australian and New Zealand Standard Research Classification (ANZSRC)

• Marine Geoscience

• Published_External

Publication Date

2015-01-01T00:00:00

Creation Date

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Access - license

Use - license

Status

Purpose

Maintenance Information

asNeeded

Topic Category

oceans

Series Information

Lineage

Bottom sediments were collected using a Smith McIntyre grab. Bulk sub-samples (6.5 ml) of surface sediment (0-2 cm) were extruded into vials which were wrapped in Al foil and immediately frozen. Porosity was determined by calculation of the wet volume as a percentage of the total volume, after freeze drying and correction for seawater salts. The accuracy of the wet/dry measurements were >1%. The precision of the volume measurements were >2%. The residual sediments were then ground under dark conditions and each successive sample was quickly returned to the freezer. Chlorins were then extracted from freeze-dried sediment using the method of Schubert et al. (2005). Relative standard deviations of the precisions on duplicate samples averaged 4 ± 2.7 for total chlorins and 3 ± 2.1 for chlorin indices (the data for each sample is provided). Schubert, C.J., Niggemann, J., Klockgether, G., and Ferdelman, G., 2005. Chlorin Index: A new parameter for organic matter freshness in sediment. Geochemistry Geophysics and Geosystems 6(3), 1-12. Thanks to the crew of the RV Solander for help with sample collection.

Parent Information

Extents

[-12.236594, -12.236548, 130.595233, 130.9833]

Reference System

Spatial Resolution

Service Information

Associations

Downloads and Links

Download the data (xls)  

Link to collection record  

Source Information

Source data not available.