Scientists from the University of Sydney's School of Geosciences have led the creation of the world's first digital map of the seafloor's geology. It is the first time the composition of the seafloor has been mapped in 40 years; the most recent map was hand drawn in the 1970s. The researchers analysed and categorised around 15,000 seafloor samples – taken over half a century on research cruise ships to generate the data for the map.
Published in the latest edition of Geology, the map will help scientists better understand how our oceans have responded, and will respond, to environmental change. "In order to understand environmental change in the oceans we need to better understand what is preserved in the geological record in the seabed," says lead researcher Dr Adriana Dutkiewicz.
"The deep ocean floor is a graveyard with much of it made up of the remains of microscopic sea creatures called phytoplankton, which thrive in sunlit surface waters. The composition of these remains can help decipher how oceans have responded in the past to climate change."
A special group of phytoplankton called diatoms produce approximately a quarter of the oxygen we breathe and make a bigger contribution to fighting global warming than most plants on land. Their dead remains sink to the bottom of the ocean, locking away their carbon. The new seafloor geology map demonstrates that diatom accumulations on the seafloor are nearly entirely independent of diatom blooms in surface waters in the Southern Ocean.
"This disconnect demonstrates that we understand the carbon source, but not the sink," says co-author Professor Dietmar Muller from the University of Sydney.
Dr Dutkiewicz reflected that "Our research opens the door to future marine research voyages aimed at better understanding the workings and history of the marine carbon cycle. Australia's new research vessel Investigator is ideally placed to further investigate the impact of environmental change on diatom productivity. We urgently need to understand how the ocean responds to climate change."
Interested readers can test out the interactive map at http://portal.gplates.org/cesium/?view=seabed