Day 2: Transiting to the first dredging site

By Olivia Belshaw

The second day of our voyage was spent continuing our transit from Cairns to our first dredge site in the Coral Sea. The day provided us with multiple opportunities to meet fellow scientists and researchers, explore the Ships’ labs and operation rooms, and participate in some bird population data collection from the “Monkey tower” at the very top of the ship. During the first two days, we have also been lucky enough hear from lead researchers on the vessel, informing crew and fellow scientists of the aims of the voyage.

The main aim of this voyage, led by Dr Joanne Whittaker, is to obtain data to help scientists determine the spatial (three dimensional) and historical extent of mantle plume activity in the Coral Sea, along the edge of the Australian plate. Researchers are aiming to obtain data and information from processes such as sea floor mapping (geophysical characteristics), swath bathymetry, magnetic data and geological sampling of rocks obtained from various dredging sites. This information will allow Dr Whittaker and her team to test a variety of hypotheses about historic hotspot volcanic activity along the edge of the Australian plate. This is important to help us further understand the dynamics of plate tectonics, continental movement and formation, and the formation of key geological features in the ocean.

The other voyage projects include:

• Investigating and understanding the links between geomorphology and Biodiversity in the Coral Sea Australian Marine Park, led by Dr Vanessa Lucieer
• Investigating the spatial and temporal variability in the distribution and abundance of sea birds, led by Dr Eric Woehler from Birdlife Australia.

Our day concluded with the deployment of the magnetometer, against the backdrop of a glorious sunset. The device was deployed from the back of the ship, and when in the water, it passively records changes in magnetic field strength and direction, whilst the ship uses sonar to map the sea floor.

The data obtained from the magnetometer can help geologists and geophysicists infer the boundaries between continental and ocean rocks. Ocean rocks contain more magnetic material than continental rocks. This means that when the ocean rocks are formed, they can preserve a record of the Earth’s changing magnetic field, and scientists can then observe how the Earth’s magnetic field has flipped throughout geological history.

We’ve been told as well to make sure we check the casing of the magnetometer for bite marks once it is reeled back into the ship – apparently sharks are attracted by the magnetic field it generates and like to take a nibble!