Ocean understanding goes further, deeper
CRUISING the Great Barrier Reef, hitching a ride on the back of a turtle, exploring ancient shipwrecks – no, this isn’t the story of a cartoon clownfish, but the real-life work of Starbug X, a small bright yellow submarine.
It’s just one of many autonomous vehicles that CSIRO is using to navigate the vast oceans – often going where none has gone before.
Ocean processes help drive the Earth’s climate, nourish the food chain, and essentially keep life thriving on the planet. But whether choppy or calm, the ocean’s surface hides the secrets of its depths well.
Starbug X is not only a self-sufficient, smart sub, but small and light too. Once it’s briefed for a mission, all it takes is two people to lift and release it off a boat.
The sub is the latest model Starbug, and was created in CSIRO’s Engineering and Technology program in Hobart. It’s a platform that can be loaded with sensors to sample what’s below and in front of it.
“Starbug X is able to go to 100m depth on a pre-programmed mission and take measurements of the seawater there,” says CSIRO marine ecologist Dr Russ Babcock.
The sub explores the seafloor where divers can’t safely go. With the right types of sensors, it can capture almost anything.
“Starbug X can be used to measure salinity, temperature and depth,” Babcock says.
“It can ask how much oxygen there is, and see what’s growing in the ocean. Is there chlorophyll fluorescence? It can measure the amount of plankton, or take 360-degree photos of the seafloor.
“We can send it for a 6km long mission at 60m depth, which no human can safely do.”
And the seafloor is no flat, sandy bed. Seascapes are as varied as landscapes.
“Parts of the reef aren’t that easy to navigate,” says Babcock. “And it’s nerve-wracking sending expensive robots down there. They can get stuck, and some have! But Starbug X navigates by sonar, and this prevents it from getting stuck. If it’s in a difficult area it can stop, and then move back and up to get out.”
“Starbug X is like a drone, but smarter.”
But drones are getting savvy too.
Far from the drones you see on land, Saildrones are autonomous surface vessels (ASV) that CSIRO uses to measure changes in coastal environments and the Southern Ocean.
They are powered by wind and the sun fuels their sensors. The sensors can detect ocean chemistry, meteorology and marine acoustics. Saildrones can travel for up to 12 months at a time, delivering data in real time via satellite links.
Dr Andy Steven, Coasts Research Director at CSIRO, says, “One day, not too far in the future, we may have a fleet of drones that helps us monitor our coasts and resources. They can undertake a range of surveillance activities such as tracking fish stocks, or monitoring coral bleaching.”
The Wave Glider is another ASV. It can travel immense distances on its own—from San Francisco to Australia.
“Something like this is an efficient and effective platform,” says Steven. “It samples relatively cheaply over great scales and can capture events.”
But those aren’t the only unmanned machines roaming the oceans. CSIRO is part of a major international effort to improve our understanding of the depths through a global array of another bright yellow robot.
Diving deep for climate answers
An Argo float is a cylindrical steel robot that floats up and down in the water column, collecting data. The first Argo models were deployed in 2000, but there are now as many as 4000 floating across the world’s oceans.
CSIRO operates Argo Australia. Other partners include the Bureau of Meteorology, the Integrated Marine Observing System, the Antarctic Climate and Ecosystem Cooperative Research Centre and the Department of Environment and Energy . The program is the second largest contributor to the global Argo array after the USA.
“Argo routinely measures ocean properties in regions that have literally never been measured before,” says CSIRO Research Scientist Dr Peter Oke.
“The Argo program has delivered more than four million profiles of temperature, salinity, and pressure from every part of the world’s oceans. It’s the only platform for comprehensively measuring sub-surface ocean properties on a global scale.”
Every ten days, starting at depths around 2km, the Argo floats rise to the surface measuring temperature and salinity along the ascent. They then transmit the data back to their centre via satellite. “Regional centres around the world collect the data and then disseminate it within 24 hours of collection,” says Oke.
Why? “Argo observations underpin a vast range of ocean research and applications,” Oke explains.
“All operational ocean forecasts exploit Argo observations on a daily basis,” he says.
“This includes forecasts of ocean circulation and properties over the coming days and weeks. Marine industries, defence, environmental monitoring, and search and rescue all rely on this information.
“Forecasts over the coming months support industries including agriculture, and informs policy makers.
“And as far as models go, the incorporation of Argo data has improved quantifying ocean and climate variability and change, and delivered new insights into how oceans work.”
The oceans store and transport a vast amount of heat. Earth’s oceans have around 1000 times the heat capacity of the atmosphere – just the top 3.2 metres alone holds as much heat as all the world’s air.
“Now, virtually all studies of climate variability and change either directly or indirectly use Argo data,” says Oke.
According to Greek mythology, Argo was the name given to the first ship to ever set sail. Legend tells us that the ship’s captain was Jason—which is also the name given to one of the first satellites used to comprehensively monitor ocean circulation. Together, Argo and Jason—as in Greek mythology—represent a turning point for ocean exploration.
Still, this Argo keeps having its share of firsts.
Before Argo, measurements of sub-surface ocean properties were limited to ship-tracks, and expensive scientific cruises. The autonomous nature of Argo floats means they can drift freely around the world’s oceans, measuring hard-to-reach areas that are often critical for understanding the ocean.
Earlier this year, in partnership with the international community, CSIRO deployed a group of 11 Argo floats near Antarctica. These go to depths of six kilometres, four kilometres deeper than previous deployments in the Southern Ocean. And, this is the first time any instrument has been able to continuously measure the deep ocean.
“Argo is at a critical point in time,” says Oke. He explains that the programs have now reached maturity. This includes the initial Core Argo program – tasked with measuring temperature and salinity for most of the ocean – as well as Deep Argo and Biogeochemical Argo.
“The pilot programs expanded Argo measurements not only into deeper waters, but expanded the range of physical ocean properties to include measurements of variables such as nitrate, pH, oxygen, and chlorophyll,” he says.
Oke says a number of engineering challenges still need to be overcome to ensure new Argo floats can perform for long periods. With this, he expects the impact of Argo to be even bigger.
“Argo will be able to, for the first time, monitor ocean properties over the full ocean depths,” says Oke. “And it will be able to quantify the Carbon Cycle and primary productivity of the ocean.”
“This is shedding a light on ocean properties that are so critical to understanding how climate variability and change is impacting the ocean’s ecosystems.”
Babcock adds that platforms like the Starbug X are still fairly new tech, but can move beyond the exploring stage if used as a tool to understand the processes of ecosystems.
“It’s not an everyday item,” he says. “It is difficult for an ecologist to come along and operate one. An engineer needs to be there.”
“The challenge is to refine the engineering and software so that it’s easy to use by all. And once this happens there will be a huge uptake, because no one can monitor at those sorts of depths in consistent ways.”
“The ocean is arguably one of our last great frontiers,” says Oke.
“So critical to the survival of man-kind, the ocean environment is harsh, requiring heavy-duty engineering to endure it; the oceans are vast, requiring high-tech technology to navigate it; and the ocean’s behaviour is complex, requiring an international network of scientists, armed with precise instruments and powerful super-computers, to understand it.”