Ice Age Geology of the Great Barrier Reef: Field Research and Student Experience
During a challenging 2020, field research was one of the first casualties of travel restrictions and border closures.
With many scientific research vessels confined to port, Mardi McNeil and Dr Luke Nothdurft from QUT were fortunate to be able to continue their on-water research aboard the R/V Falkor, which has been operating in Australian waters since December 2019.
“Due to Covid-19 restrictions, a research voyage that we’d been planning since 2016 was cancelled, but we were lucky we could still travel on R/V Falkor to collect important scientific data on reef environments,” McNeil said.
“As a marine geoscientist, I study limestone rocks and sediments from reef environments to understand past and present geological processes, depositional environments, and their response to climatic change.
“We are particularly interested in how these environments and processes have formed and changed over geological timescales, especially in response to the climatic changes that were experienced at the end of the last Ice Age when oceans warmed and sea levels rose rapidly.”
This is McNeil’s fourth voyage on R/V Falkor, and her third in 2020.
The team on board consists of marine geologists, oceanographers, and seafloor mapping specialists, working together to explore and uncover the past shorelines, rivers, deltas and reefs in the southern Great Barrier Reef.
“These geological features formed during the Last Glacial Maximum (LGM) when sea-level was up to 120 m lower than today,” McNeil explained.
“These features have since been flooded and ‘drowned’ when glaciers and ice-sheets melted at the end of the last Ice Age and sea level rose to present levels.
“This was a time of rapid environmental change, and may help scientists to better predict and understand how these environments may respond to present and future climate change, sea-level rise and changes to ocean circulation patterns.”
McNeil was joined on the R/V Falkor by two QUT students, recent graduate Ella Sinclair and PhD student Haydn Trounce.
The two students shared their experience in recent blog posts published by the Schmidt Ocean Institute, who supports the research expedition by providing ship-time to the science party.
My Life as a Student on the R/V Falkor
My name is Ella Sinclair. I have just graduated from QUT with a Bachelor of Science, majoring in biology, and minoring in earth science and wildlife ecology. I am a student on the R/V Falkor, learning from Marine Technicians and Chief Scientists about multibeam sonar mapping, and understanding geological features and processes from thousands of years ago.
Two weeks before the departure date for this cruise, my supervisor for my honours project, Dr. Luke Nothdurft, sent me an email offering me this opportunity to join the month-long cruise. With only two weeks’ notice, I moved everything around and made it happen. After the initial safety inductions on the ship and settling in, we left for sea on the 22nd of November at 0800.
Life on the Falkor is like no other experience. Working with such an experienced and knowledgeable team in this real-world environment is incredibly eye-opening. In the control room, I work 1200–1600 every day, learning from the Marine Technicians about mapping, the software being used, and interpreting and understanding the structures we are finding. I am currently one week into the voyage, and every day is completely different. As a student, I can visit different parts of the ship, including getting a tour of the engine room, the galley and learning about how the communications and internet are run on board. I even got the opportunity to steer the ship on the bridge, and participate in communicating our findings out to the wider community.
Being in a completely new environment every day for a month can be very overwhelming. However, with 29 different crew members from all over the world, working in completely different parts of this ship, all for the same mission — to acquire knowledge about the ocean and communicate it to the greater science community — makes every day completely different and interesting.
Working alongside Marine Technicians and scientists on and off the R/V Falkor, I am constantly learning about the processes and skills required to do this type of research. My job on board involves assisting in the mapping process by ensuring we are getting accurate and reliable data with multibeam technology. I am involved in cleaning the data that we send off to scientists on shore who carry out further study. I also assist in running sound velocity profiles, which involve lowering an instrument into the water while the ship is stationary and measuring the speed of sound using sensors on regular intervals. This gives us an understanding of the depth of the environment and assists in recalibrating the multibeam sensors.
So far, this opportunity has been extremely beneficial as it has provided me with an understanding of how science is achieved and collected in the real world, and how all different disciplines work together in many different ways to collect this knowledge. While we are collecting this data over the course of the next month, I keep reminding myself that I am one of the first people in the entire world to see what is at the bottom of the seafloor in this area. It is one of the best experiences I will ever have, and I am enjoying every minute of it.
Clouds Over the Great Barrier Reef
My name is Haydn Trounce, and I am a PhD candidate currently studying at QUT. My work involves researching the sources and sinks of marine aerosols in the waters around Australia, particularly aerosols able to act as Cloud Condensation Nuclei.
Every cloud droplet starts its life from a Cloud Condensation Nuclei (or CCN). Cloud Condensation Nuclei are aerosols that can activate and grow into cloud droplets. To do so, the aerosols need to be above a certain size diameter (called the critical diameter) and be exposed to conditions where the atmospheric water vapour is supersaturated (relative humidity greater than 100%). The aerosol’s critical diameter largely depends on its chemical composition and hygroscopicity — that is, its tendency to absorb water.
According to the Intergovernmental Panel on Climate Change, aerosols, and particularly their interaction with clouds, currently contribute the largest uncertainty to global climate models. By researching aerosols and CCN, I hope to help reduce this uncertainty and improve climate models.
However, there is another important reason to study CCN. Assuming the amount of liquid water remains constant, having higher concentrations of CCN will result in clouds with higher concentrations of cloud droplets. These clouds will be whiter in appearance and will have a higher albedo — meaning they will reflect more sunlight away from Earth. This is known as the Twomey Effect and has an overall cooling effect on Earth.
This effect ties into our goals aboard R/V Falkor. The Reef Restoration and Adaption Program (RRAP) investigates strategies to reduce the decline of coral reefs in the Great Barrier Reef marine park region. One strategy being investigated is the possibility of brightening clouds over the reef. By increasing the amount of CCN available for marine cloud formation over the reef, the program aims to increase the amount of sunlight reflected away from the reef, and therefore reduce increases in sea surface temperatures due to solar radiation, potentially reducing coral bleaching events.
It is important to note that cloud brightening is not intended as a permanent solution to coral bleaching problems. Nevertheless, these projects could potentially buy precious time for the Great Barrier Reef as researchers work on other strategies to restore and protect the reef.
The Program’s current goal is to monitor background aerosols and CCN in as many sites in the Great Barrier Reef, for as much time as possible, particularly during summer periods. This voyage aboard R/V Falkor is a great opportunity to monitor background aerosols in the Southern Great Barrier Reef region. The data collected from this cruise, along with measurements collected from other sites, will be used by the program when planning cloud brightening strategies in the near future.
More information
Visit the Schmidt Ocean Institute
Explore more research at QUT
Contact Mardi McNeil or Dr Luke Northdurft
