Biologically, the nearshore and coastal environments of Western Australian waters support a diverse array of marine communities including coral reefs, seagrass meadows, mangrove forests and sponge gardens.  These communities in turn provide critical habitat, shelter and food resources for specially protected and culturally and commercially important species including marine turtles, cetaceans, dugongs, birds, fishes, and invertebrates.  Although detailed biological oceanographic studies have been undertaken, processes that regulate nutrient delivery, phytoplankton growth and transfer of productivity to higher trophic levels are relatively unknown in the wider region.

The biological oceanography of Western Australian waters region is poorly studied.  For time series or significant spatial coverage we are completely dependent upon satellites, particularly in north-western waters.  Preliminary assessment of chlorophyll a from satellite data suggests a strong cross-shelf gradient with influence from tropical rivers and a range of offshore features.  The regional seas of Northern Australia can be highly impacted by river run off.  Even without a riverine influence, the shallow seas of northern Australia are characterised by high turbidity that reduces the underwater light and may negate the validity of standard algorithms for remotely sensed products such as chlorophyll a or calcite.  Relationships between light penetration, tidal mixing, suspended particulate material and primary production need to be investigated.

Key Science Questions

Ocean chemistry - nutrients

• What is the natural variability of water quality (particularly under water light, TSS, temperature, Chlorophyll, primary productivity) in the region?
• What is the influence of water quality on ecosystems?
• What are the dynamics of regional nutrient supply associated with production?

Benthos

• What is the influence of tidal and wave stress on bottom habitats?

Mid-trophic levels

• What are the mechanisms of alongshore and cross-shelf dispersals of fish larvae and other biota?

Plankton

• What is the nature and variability of planktonic ecosystems supported by cross-shelf exchange?

Top predators

• What are the migration pathways of mega-fauna in the region?
• How can we monitor over the long term, trends in mega-fauna populations and link these to physical factors?
• How can we use marine vertebrates as platforms to collect oceanographic data?