Biophysical processes in the Torres Strait marine ecosystem (T2.2)

Task leader: Dr Andrew Heap, Geoscience Australia

The aim of this task is to investigate important ocean processes operating in the Torres Strait ecosystem. This information will be used to develop computer models that will represent physical processes, such as tidal currents, sandwave movement and turbidity. In addition, later inclusion of biological processes, such as the cycling of nutrients and evolution of important seabed communities will be possible.

A focus for both the field program and model scenarios will be the impacts of oceanographic variability on seabed stability and water turbidity. Implications for seagrass distributions will be investigated, with a view to explaining dieback events observed in northern Torres Strait and their potential impacts on species which rely critically on seagrass habitat (e.g. dugong and juvenile rock lobster).

Connectivity patterns across the region will also be quantified, including exchanges through Torres Strait, larval dispersal patterns for key species, and contaminant dispersion. The information from this task will provide fundamental inputs into evaluation of management strategies and regional planning for the Torres Strait region.

Objectives

• To gain an improved understanding of the processes controlling seabed stability, turbidity, nutrient cycling, and productivity in Torres Strait, through field measurements and integrated modelling.
• To use calibrated models to investigate the Torres Strait system response to natural and anthropogenic variability (e.g. spring-neap tidal cycles, seasonal cycles, riverine inputs), with particular emphasis on the changes in turbidity and sandwave migration in northern Torres Strait, and its implications for seagrass distributions.
• To inform related research on ecosystem characterisation and impacts of human activities on the ecosystem.

Outcomes

• Better understanding of the processes controlling sediment movements and seagrass health in Torres Strait and associated improvements in planning and management practices where appropriate.
• Better understanding of the potential impacts of biophysical variability on selected fisheries (e.g. dugong and rock lobster) and associated improvements in management practices where appropriate.
• Improved risk assessments for shipping activities in Torres Strait.