Salt water is a building block of the human body, essential to the planet’s temperature regulation, could help mitigate climate change, but is not very well understood, a researcher says.
It's everywhere, but apart from swimming, fishing or boating on it, most people don't think about salt water that much.
Photo: 123RF
University of Queensland chemistry researcher Timothy Duignan tells Afternoons' Wallace Chapman that study of mundane substances is hugely important to life on this planet.
"You hear a lot of people talking about fascinating science like the origins of the universe and black holes and how to cure cancer ... but sometimes you don’t hear about a lot of the science that is going on which is much more about understanding the mundane substances around us," he says.
Postdoctoral Research Fellow at the University of Queensland Timothy Duignan. Photo: Supplied
He says salt water - the most common substance on Earth's surface - is a prime example of one of these "mundane" but valuable fields of research.
He has written a list of five things that make salt water essential for the planet.
Human bodies - salt of the earth
Salt water is key to how the human body works.
"Ions, which are what salt is made up of in water, carry electrical charges just like a balloon that’s been rubbed against the carpet.
"So all of the electrical signals in your brain between your neurons communicating are all carried by the flow of ions, just like a computer uses electricity to communicate, your brain uses electricity to communicate as well."
The human brain relies on ions to communicate. Photo: 123rf
He says the body's balance of ions is delicate too.
Inside cells there are potassium ions and outside of them sodium ions and disrupting that balance can be lethal.
"If you disrupt that by say injecting someone with potassium chloride it can actually stop their heart - so that’s an ingredient in the lethal injection."
Gulf Stream cooling system
Duignan says salt water is also an important temperature regulator for the planet - primarily through the Gulf Stream.
"In winter, when the Arctic freezes over all of the fresh water is extracted and you can actually see the salt crystals coming out of it."
He says that effect, and the electrical charge of the ions in salt water, makes it denser and more compact so the salt water sinks to the bottom of the ocean.
"So that kind of mixes the ocean and drives these currents which carry the warm water from the equator north - and kind of keep the earth nice and more evenly warm so that it’s habitable for life."
Although he says climate change could be disrupting some of these processes by melting the ice caps.
A salt and a battery
Salt water is also being used to develop new battery technology that could offer an alternative to ithium-ion batteries which are in cellphones, cars and even in grid-scale storage, he says.
Rechargable lithium-ion batteries are used in all sorts of modern devices. Photo: 123rf
"These use a liquid to carry the lithium ions between the positive and the negative terminals of the battery.
"Now, if we could replace that liquid with something simpler - something like sodium ions in water - that would be really advantageous.
"This would be cheaper to manufacture, these things wouldn't catch fire like the lithium-ion batteries can do."
A saline solution to greenhouse gases
Scientists have recently made progress using salt water to extract carbon dioxide from the air.
"Basically the idea is to use the same process that the ocean uses to extract carbon dioxide from the air ... the ocean actually takes out more than a quarter of the emissions of carbon dioxide that we put into the air.
"The carbon dioxide dissolves with the water and breaks apart into ions, and so we could harness the same process to extract carbon dioxide from the air."
Emissions reduction is hugely important to curbing the effects of climate change, but extracting carbon dioxide from the atmosphere could be used to help cut total greenhouse gases. Photo: 123RF
"This isn’t an alternative to cutting our emissions … but in the long run this may be able to take some of the carbon dioxide out of the air."
