This report contains the preliminary results of Geoscience Australia survey 266 to central Torres Strait. The survey was undertaken to investigate the seabed geomorphology and sedimentary processes in the vicinity of Turnagain Island and to infer the possible effects (if any) on the distribution, abundance and survival of seagrasses. The Turnagain Island region was chosen because it is a known site of recent widespread seagrass dieback. The present survey is the first of two by Geoscience Australia to be carried out in 2004 and is part of a larger field-based program managed by the Reef CRC aimed at identifying and quantifying the principal physical and biological processes operating in Torres Strait. The impetus for the program is the threat of widespread seagrass dieback and its effects on local dugong and turtle populations and the implications for indigenous islander communities.

This report contains the preliminary results of Geoscience Australia survey 266 to central Torres Strait. The survey was undertaken to investigate the seabed geomorphology and sedimentary processes in the vicinity of Turnagain Island and to infer the possible effects (if any) on the distribution, abundance and survival of seagrasses. The Turnagain Island region was chosen because it is a known site of recent widespread seagrass dieback. The present survey is the first of two by Geoscience Australia to be carried out in 2004 and is part of a larger field-based program managed by the Reef CRC aimed at identifying and quantifying the principal physical and biological processes operating in Torres Strait. The impetus for the program is the threat of widespread seagrass dieback and its effects on local dugong and turtle populations and the implications for indigenous islander communities.

This report contains the preliminary results of Geoscience Australia survey 266 to central Torres Strait. The survey was undertaken to investigate the seabed geomorphology and sedimentary processes in the vicinity of Turnagain Island and to infer the possible effects (if any) on the distribution, abundance and survival of seagrasses. The Turnagain Island region was chosen because it is a known site of recent widespread seagrass dieback. The present survey is the first of two by Geoscience Australia to be carried out in 2004 and is part of a larger field-based program managed by the Reef CRC aimed at identifying and quantifying the principal physical and biological processes operating in Torres Strait. The impetus for the program is the threat of widespread seagrass dieback and its effects on local dugong and turtle populations and the implications for indigenous islander communities.

This report contains the preliminary results of Geoscience Australia survey 273 to northwest Torres Strait. This survey was undertaken as part of a research program within the Torres Strait CRC aimed at understanding marine biophysical processes in Torres Strait and their effect on seagrass habitats. Two Geoscience Australia surveys were undertaken as part of this program, survey 266 measured monsoon season conditions (Heap et al., 2005), and survey 273 measured trade wind conditions. Section 6 compares and contrasts the survey results acquired for both surveys. Section 7 addresses the results of the survey program in light of the objectives of the CRC proposal. Survey 273 acquired numerous different data types to assist with characterising the mobile sediments and hydrodynamic nature of the region. Multibeam sonar, current meters, grab samples, vibro-cores, underwater video, meteorological data (from the Bureau of Meteorology), Landsat imagery, were all used to characterise the seabed hydrodynamics of Torres Strait.

This report contains the preliminary results of Geoscience Australia survey 273 to northwest Torres Strait. This survey was undertaken as part of a research program within the Torres Strait CRC aimed at understanding marine biophysical processes in Torres Strait and their effect on seagrass habitats. Two Geoscience Australia surveys were undertaken as part of this program, survey 266 measured monsoon season conditions (Heap et al., 2005), and survey 273 measured trade wind conditions. Section 6 compares and contrasts the survey results acquired for both surveys. Section 7 addresses the results of the survey program in light of the objectives of the CRC proposal. Survey 273 acquired numerous different data types to assist with characterising the mobile sediments and hydrodynamic nature of the region. Multibeam sonar, current meters, grab samples, vibro-cores, underwater video, meteorological data (from the Bureau of Meteorology), Landsat imagery, were all used to characterise the seabed hydrodynamics of Torres Strait.

This report contains the preliminary results of Geoscience Australia survey 273 to northwest Torres Strait. This survey was undertaken as part of a research program within the Torres Strait CRC aimed at understanding marine biophysical processes in Torres Strait and their effect on seagrass habitats. Two Geoscience Australia surveys were undertaken as part of this program, survey 266 measured monsoon season conditions (Heap et al., 2005), and survey 273 measured trade wind conditions. Section 6 compares and contrasts the survey results acquired for both surveys. Section 7 addresses the results of the survey program in light of the objectives of the CRC proposal. Survey 273 acquired numerous different data types to assist with characterising the mobile sediments and hydrodynamic nature of the region. Multibeam sonar, current meters, grab samples, vibro-cores, underwater video, meteorological data (from the Bureau of Meteorology), Landsat imagery, were all used to characterise the seabed hydrodynamics of Torres Strait.

This report contains the preliminary results of Geoscience Australia survey 273 to northwest Torres Strait. This survey was undertaken as part of a research program within the Torres Strait CRC aimed at understanding marine biophysical processes in Torres Strait and their effect on seagrass habitats. Two Geoscience Australia surveys were undertaken as part of this program, survey 266 measured monsoon season conditions (Heap et al., 2005), and survey 273 measured trade wind conditions. Section 6 compares and contrasts the survey results acquired for both surveys. Section 7 addresses the results of the survey program in light of the objectives of the CRC proposal. Survey 273 acquired numerous different data types to assist with characterising the mobile sediments and hydrodynamic nature of the region. Multibeam sonar, current meters, grab samples, vibro-cores, underwater video, meteorological data (from the Bureau of Meteorology), Landsat imagery, were all used to characterise the seabed hydrodynamics of Torres Strait.

These data are the result of Geoscience Australia survey 266 to the central Torres Strait region, with the survey being the first of two by Geoscience Australia carried out in 2004. They form part of a larger field-based program managed by the Torres Strait CRC aimed at identifying and quantifying the principal physical and biological processes operating in Torres Strait. The impetus for the program is the threat of widespread seagrass dieback and its effects on local dugong and turtle populations and the implications for indigenous islander communities. The principal aim of the survey was to investigate the seabed geomorphology and sedimentary processes in the vicinity of Turnagain Island and to infer the possible effects (if any) on the distribution, abundance and survival of seagrasses. The Turnagain Island region was chosen because it is a known site of recent widespread seagrass dieback. The survey consisted of a detailed geophysical survey using swath (multi-beam) sonar and shallow seismic equipment that was supplemented with a detailed sampling program consisting of 301 near-bed water samples, 54 seabed grabs, 5 vibrocores and 69 camera stations. Four oceanographic moorings were also deployed for the duration of the survey to measure the local tide, wave and wind-driven currents. A regional survey was initially undertaken, followed by a detailed study of two areas: Area A - located approximately 2.5 km SW of Turnagain Island which contained sand ridges and seagrass beds, and Area B - located approximately 2.0 km SE of Turnagain Island which contained sandwaves and no seagrass beds. In a new application of the swath (multi-beam) data, the total volume of sediment transported during the survey was estimated from changes in the high-resolution seabed bathymetry collected during the repeat surveys. Preliminary results of the study found that seagrasses in the region are subject to frequent and significant changes in environmental conditions, with implications for limited dispersal and survival. A follow-up survey was undertaken in October 2004.

This article is the introduction to a special issue of Continental Shelf Research containing papers giving research results produced as part of Australia's Torres Strait Co-operative Research Centre (CRC) Program.

This article is the introduction to a special issue of Continental Shelf Research containing papers giving research results produced as part of Australia's Torres Strait Co-operative Research Centre (CRC) Program.