A new modified clay from Western Australia could help stop algal blooms
February 24, 2024 2:33 PM   Subscribe

A new modified clay from Western Australia could help stop algal blooms. Modified clay helping reduce algal blooms by binding to phosphorus which causes phenomenon. Large-scale fish deaths caused by harmful algal blooms could be a thing of the past if positive trials of a specially developed clay that absorbs phosphorus are anything to go by. Developed by Western Australian environmental scientists, the treatment is sprayed, in a slurry form, from a boat onto the surface of estuaries, lakes and other water bodies, sinking down and taking the phosphorus with it. Even though phosphorus is a natural plant nutrient required by plants to grow, an excess of it fuels extensive algal blooms which can lead to low oxygen concentrations in the water that can harm fish and other species.

Algal blooms also cause water to turn bright green and emit a strong smell.

During a recent trial in the Peel-Harvey Estuary, 80 kilometres south of Perth, the clay successfully bound up to 95 per cent of phosphorus, spurring hopes it could eventually be rolled out across the country and potentially further afield.

Natural clay is modified with a material called hydrotalcite which allows it to bind with any phosphorus it comes into contact with.

The phosphorus becomes part of the clay and is removed from the surrounding water, so that bright green water turns clear again.

"So algae can't access this phosphorus, it's locked up with the clay," explains Svenja Tulipani, an environmental chemist at the state's Department of Water and Environmental Regulation (DWER).
posted by chariot pulled by cassowaries (11 comments total) 12 users marked this as a favorite
 
This is neat, and I'm glad there's something that can be done in the short term, but we need to stop the pollution, and I'm afraid that the short term solution will become the new go-to.
posted by BlueHorse at 3:14 PM on February 24 [2 favorites]


Very cool. Where are the phosphate mines in Australia? in the USA, Mosaic is east of Tampa, Florida

could we recycle the phosphate?
posted by eustatic at 3:43 PM on February 24


Where are the phosphate mines in Australia?

The phosphate in Australian rivers and lakes mostly isn't coming from mines - it is coming from
a) agricultural fertiliser run off;
b) lawn fertiliser run off;
c) farm animal manure run off;
d) dog poo on lawns run off;
e) phosphate in laundry detergent run off.
posted by chariot pulled by cassowaries at 4:41 PM on February 24 [2 favorites]


Eh, those uses all had to buy phosphate from somewhere, probably a mine, increasingly expensive. I also want to know how to get the phosphate back.

Maybe add this clever clay to the “socks” of straw that we ought to be using to intercept and filter runoff anyway. The closer to the source, the easier.

I am thinking about this a lot because I have a market garden in a winter-sodden shared locale, and the Received Knowledge is that you put all your amendments down in fall to protect the soil, but I think we should be monitoring the ditches to find out if we are basically fertilizing the lake.
posted by clew at 6:40 PM on February 24 [1 favorite]


It is important to recover some of that phosphorous, because it is supposed to move through the ecosystem in a cycle which has been disrupted by human activities.

Eutrophication is a problem, but so is phosphorous being sequestered in the ocean. Humans are rapidly digging out phosphorous-bearing mineral deposits, mostly in rock that has been uplifted up from deep ocean deposits onto continental plates by very slow—geologically slow, even—motion in the Earth's crust. Normally, phosphorous would gradually weather out of the rock and move through the terrestrial food chain, where it is needed by all life on land, before washing into the oceans, then get slowly returned to the land through geological processes again. Instead, humans doing agriculture are digging it up and letting it be washed away and a significantly higher rate than is natural.

If we want to fend off an approaching phosphorous crisis, we'd better figure out how to get it back out of the ocean. (And lakes, too.)
posted by BrashTech at 7:43 PM on February 24 [5 favorites]


What happens to the organisms at the bottom where this settles will need to be fully understood before we add another "fix" to a problem we've already created.
posted by mightshould at 3:31 AM on February 25 [2 favorites]


"We achieved 95 per cent phosphorus reduction, which is astonishing," said DWER environmental scientist Ryan Kam.

Cool. Now the agriculture and cattle industry can pollute waterways even more.

...

There's no point in applying brakes without letting up on the gas.

There's no point in applying brakes if it's used as an excuse to step on the gas even harder.
posted by AlSweigart at 6:34 AM on February 25 [2 favorites]


What happens to the organisms at the bottom where this settles will need to be fully understood before we add another "fix" to a problem we've already created.

In the ocean, at least, much of the phosphate gets hoovered up by the algae blooms and then is locked inside decaying organic matter which sinks, and is really only eaten by certain bacteria, so there is little additional bioavailable phosphate at depth.
posted by BrashTech at 10:27 AM on February 25


Well, right now, the phosphate algae blooms create dead zones, anoxic and hypoxic bottom areas that kill most living things, so

It may be hard for a "marine snow" created out of clay to make things worse (although if the clay Floccs up the bottom it might be worse)

But still, there might be a way to capture the marine snow created by the clay bonded to the phosphate, and that snow might be marketable, somehow


I was reading that Australia imports 80% of its phosphorus as fertilizer, and so likely imports fertilizer from China, which has the MAP factories and the mines. Also Morocco.

But if this tech makes phosphate -laden marine snow, there could, in theory, be a company working to sell that snow back to the miners, Chinese or whomever they are.

Humanity is slowly running out of phosphate. It s so sad to see these.blooms

Of course I also agree with Clean Water legislation to stop the fertilizers from being dumped in the first place. Just that this tech seems to be most useful after all of those mistakes have been made
posted by eustatic at 6:38 PM on February 25


Sorry that my previous comment was a downer, but skepticism keeps us from praising the emperor's new clothes. We already know what causes algae blooms. We need to call this what it is: geoengineering. And we know (or rather, often don't know) the risks associated with geoengineering.

"And in the winter, the gorillas simply freeze to death!"
posted by AlSweigart at 7:28 AM on February 27


Sounds like a great idea, there seems to be a lot of knowledge in WA re solving phosphate issues - I spoke with a researcher from there some time back about growing plants in an ultralow P containing soil to make the hungry for phosphate - it's an epigentic effect that stays with the plant.

New Zealand's freshwaters and littoral area is rapidly being destroyed by a farming culture of not valueing phosphate and turning a blind eye to it's effects. NZ gets at least 70% of its Phosphate quite cheaply as it's getting it from Western Sahara at 'friendly' rates, some background, but looks like theft and genocide. At the same time the P has Cadmium in it and that's also polluting our land - that damage is near permanent and land is taken ourt of production and use.

I understand in Sweden where composting toilets are more common there's a program to collect the phosphate from the urine separation part of that process.

Just as oil is undervalued to a 50th to a 70th of it’s gearing value, likewise Phosphate – and when phosphate becomes rare there are NO replacements - that would be the end of growing food, and no one’s going to ‘innovate’ around that.
posted by unearthed at 7:07 PM on February 27 [1 favorite]


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