Just like Nemo, Australia’s blue water Research Vessel Investigator has just spent three days drifting in the Eastern Australian Current. Researchers on board have been investigating microscopic marine life that forms the base of the marine foodweb.
Normally hidden from view, these microbes are exceptionally diverse and play a critical role in the ocean, absorbing carbon dioxide, producing oxygen and breaking down organic matter, all of which influence the distribution and abundance of fish and other marine life.
The scientists’ mission was to examine how the composition and activity of microbes change as they drift. “The EAC has a significant impact on the ecology of eastern Australia, and is well known for transporting organisms southward. However we know almost nothing about how EAC microbial communities, adapted to warm tropical conditions, change in structure or function as they are advected into temperate regions”, said Dr Mark Brown, research fellow at the University of New South Wales. Dr Martin Ostrowski of Macquarie University explained that “by using novel sampling methods and molecular techniques we can gain new insight about the dynamics of these critical microbial assemblages and better understand their impact on southern Tasman Sea waters.”
Using satellite technology, the ship tracked neutrally buoyant drifters 15 m deep that were released near Coffs Harbour. After 3 days they travelled about 300 km southwards to Port Stephens, moving at over 1 metre per second. Experiments conducted along the way measured important biological processes such as mortality, photosynthesis, nutrient uptake and changes in microbial composition in response to warming.
Capturing data at unprecedented resolution, researchers will compare the productivity of the EAC with waters all along the New South Wales coast.
“With climate projections indicating the current will warm 2 – 3 °C by 2070, our shipboard experiments will provide useful insight into how these communities will change in the longer term”, says Associate Professor Martina Doblin, Chief Scientist.
“Impacts seen at the base of the foodweb will have cascading effects on other parts of the marine foodweb, including commercial fisheries”.
Investigator, with its team of CSIRO staff and marine researchers from the University of Technology Sydney, the University of New South Wales and Macquarie University, is now in waters north of Byron Bay continuing their research on the hidden diversity of microscopic marine life.
Associate Professor Martina Doblin leads the Productive Coasts research program in the UTS Climate Change Cluster (C3). She was recently a finalist in the UTS Vice Chancellor's Award for Research Excellence - Research Impact category.