INCREASING THE OCEAN'S ABSORPTION OF CARBON DIOXIDE

 

INCREASING THE OCEAN'S ABSORPTION OF CARBON DIOXIDE 

A Nova Scotia company has received a million-dollar prize from Elon Musk for its plan to increase the ocean’s ability to absorb carbon dioxide — essentially by dosing it with an antacid.

Dartmouth-based Planetary Technologies announced Friday it has received the cash infusion from XPRIZE Carbon Removal — a four year, international competition backed by the Elon Musk Foundation with the aim of speeding up climate solutions.

 Planetary was one of 15 companies to win XPRIZE’s Milestone Award out of an initial pool of more than 1,000.

The company’s plan involves treating mine tailings — the debris left behind when mines are dug — to remove toxic substances and any valuable metals, then treating the tailings to produce an alkaline powder. When that powder is distributed into the ocean, it lowers the acidity of the water, thereby increasing its absorption of carbon dioxide.

The company projects that by 2035, it could be able to remove one gigaton of carbon dioxide from the Earth’s atmosphere and sequester it in the ocean.

“The climate problem is a gigatonscale problem,” Planetary Technologies CEO Mike Kelland said. “I think we’ve cracked the code on how to permanently store CO2 at scale in a way that is restorative for the Earth in general, and almost infinitely scalable.”

The company’s efforts are looking to amplify what the world’s oceans are already doing.
Oceans absorb about 31 per cent of anthropogenic carbon dioxide — the gas released by human activities — according to a recent study by the National Oceanic and Atmospheric Administration (NOAA).
Normally, the atmosphere and the ocean strike a balance between the amount of carbon dioxide they hold. As atmospheric carbon dioxide increases, the ocean also absorbs more of the gas.

 The more CO2 it absorbs, however, the less capacity it has to take on more of the gas. And, in the process, it becomes slightly more acidic.

Among other problems, that also means that organisms that use calcium carbonate to make shells sometimes have trouble doing so.
One of the ways the ocean absorbs carbon is when falling rain dissolves atmospheric carbon dioxide and becomes slightly acidic.

 It falls on rocks, which are a little bit alkaline, or in the ocean, which has many similar alkaline substances.

 Those substances neutralize the acid and trap the carbon in a bicarbonate — similar to baking soda. Bicarbonates are the dominant form of dissolved inorganic carbon in the ocean. 

As carbon sinks go, it’s an effective, but slow process.

Planetary Technologies aims to turbocharge that process by distributing into the ocean — through existing wastewater discharges — a powdered antacid.
It would have the dual effect of reducing the ocean’s acidity and absorbing carbon dioxide in the water.

 The ocean water would then be more receptive to absorbing more CO2 from the atmosphere.
“I think our system is the only system that is producing a very, very pure, very well understood, very mild, very non-toxic way of essentially adjusting the pH of the ocean to make it more basic — to fight ocean acidification — while at the same time it essentially pulls down CO2 out of the atmosphere and turns it into essentially baking soda,” Kelland said.

Douglas Wallace, the Canada Research Chair (Tier 1) in Ocean Science and Technology at Dalhousie University, is evaluating the effect the Planetary process might have on the ocean.
“Over the last 200 years, we’ve been using up the ability of the ocean to neutralize the extra CO2 we’re pumping into it,” he said.

“What Planetary are doing is they’re seeking to take advantage or enhance the natural ability of the ocean to take up CO2 from the atmosphere via chemistry.”
He has two main sets of questions. First: Will it work? Will it be efficient? And will it be effective enough on a big enough scale to make a difference?

Those are questions he’s initially posing in Dalhousie’s Aquatron, a 15-metre-wide, 684,000-litre circular tank into which he’s introduced an alkaline substance to see how it affects the water’s uptake of CO2.

What he’s interested in is not just whether the antacid promotes further CO2 absorption, but the rate at which it might do so.

 If it takes 100 years to sequester a gigaton of carbon, the process is not going to be particularly useful to mitigating the current climate crisis.
The second set of questions revolve around whether there are any inadvertent consequences to dosing the ocean with what amounts to a giant dose of Tums?

Hugh MacIntyre, a professor of biological oceanography at Dalhousie University, is exploring whether there’s a possibility that Planetary Technologies’ antacid could damage phytoplankton.

He said his preliminary research has shown him that, at the concentrations proposed by Planetary Technologies, the antacid will not interfere with the marine organisms’ metabolic functions.
But given that there are thousands of species of phytoplankton, he said, it’s conceivable that, over time, there might be “winners and losers” in marine ecosystems .

To get a handle on that, he’s looking to the Bedford Basin, where he’ll collect mesocosms — essentially natural ecosystem communities — to see how changes to the water affect the communities as a whole.

Planetary plans to have a full-scale pilot demonstration facility up and running by the beginning of 2024.