Earth's deepest ocean trenches contain high levels of pollution

Dani Cooper
Swellnet Dispatch

Deep ocean trenches — considered the most remote places in the world — have levels of toxic, industrial chemicals 50 times higher than a highly polluted river system in China, an analysis of tiny deep-sea animals has found.

The discovery, published in today's Nature Ecology and Evolution journal, highlights the pervasive nature of pollution and destroys the belief these deep-sea wildernesses are largely safe from human degradation.

It also shows a strong connection exists between surface and deep-sea waters and suggests a need for better management and monitoring of these unique environments.

A container of Spam rests at 4,947 meters on the slopes of a canyon leading to the Sirena Deep in the Mariana trench (Photograph: Noaa Office of Ocean Exploration)

The discovery was made by a team of researchers from Scotland who investigated two of the world's deepest marine trenches — the Mariana Trench in the west Pacific Ocean above Australia, and the Kermadec Trench near the north-eastern tip of New Zealand.

The trenches lie in what is known as the ocean's hadal zone, which extends from six to 11 kilometres below the surface.

To collect samples in each of these remote trenches, in 2014 the researchers used a deep-sea lander operated remotely from the surface and baited traps to collect tiny crustaceans.

INFOGRAPHIC: Relative depths of oceanic layers including the hadal zone, named for Hades, the underworld in Greek mythology (Supplied: Katherine Dafforn/Nature)

Crustaceans contaminated by pollutants

Analysis of these marine animals found they were contaminated with mainly two forms of persistent organic pollutants (POPs) — polychlorinated biphenyls (PCBs) and polybrominated diphenyl (PBDEs).

These two POPs — mostly human-made chemicals used mainly in industry or as pesticides — were present in all samples, across all species, at all depths in both trenches.

Lead author Dr Alan Jamieson said the highest levels of PCBs recorded in crustaceans in the Mariana Trench were 50 times greater than that found in crabs from the Liaohe River system, one of the most polluted rivers in China.

The only site in the Northwest Pacific with PCB levels comparable to the Mariana Trench was Japan's Suruga Bay, a heavily industrialised area with high usage of organochlorine chemicals.

The analysis also showed PCB concentrations were higher in the Mariana Trench compared with the Kermadec Trench, said Dr Jamieson, a deep-ocean researcher who was based at the University of Aberdeen during the project.

It was likely this was related to Mariana's proximity to the industrialised Northwest Pacific region and the North Pacific Subtropical Gyre, also known as the Great Pacific Garbage Patch.

As the plastic rubbish in the gyre degraded it absorbed POPs, transporting the chemicals to the ocean floor as the rubbish sank and fragmented.

Dr Jamieson said it was also possible POPs were transported by ocean currents and through contaminated birds falling into the water and sinking to the ocean floor, where they were consumed by marine life.

Discovery in such remote areas 'quite concerning'

In an accompanying opinion piece in Nature, University of NSW researcher Dr Katherine Dafforn said the finding was "quite concerning because these trenches are so removed from any kinds of industrial activity".

"One of the reasons POPs are such a concern is we don't have a method for cleaning them up especially when there are large amounts over a large spatial scale," she said.

"The main method of control has been to regulate and eliminate but we know there is still huge amounts in our landfill and it has the potential to make it into the natural environment via soils and the ocean."

Dr Dafforn said the study was also significant because the hadal trenches had been regarded as pristine and "safe from human disturbance".

"We still know more about the surface of the Moon than that of the ocean floor," she said.

The discovery of pollution in these trenches highlighted the need to better understand the source of the pollution and its consequences on the food chain and marine ecology.

While this study raised many questions it provided clear evidence that far from being remote, the "deep ocean ... is highly connected to surface waters and has been exposed to significant concentrations of human-made pollutants". //DANI COOPER

© Australian Broadcasting Corporation. All rights reserved.

Comments

tonybarber's picture
tonybarber's picture
tonybarber commented Tuesday, 14 Feb 2017 at 11:53am

Strange, such a remote part of the world. Hard to believe the SPAM can has no sign of corrosion.

memlasurf's picture
memlasurf's picture
memlasurf commented Tuesday, 14 Feb 2017 at 12:41pm

Spam is tough stuff and inedible. No surprise even the ocean can't consume it.

stunet's picture
stunet's picture
stunet commented Tuesday, 14 Feb 2017 at 11:58am

Good advertising for Spam.

chook's picture
chook's picture
chook commented Tuesday, 14 Feb 2017 at 12:04pm

no corrosion? i suspect there isn't much oxygen at that depth.

"25% less sodium"...depeche mode are right, God's got a sick sense of humour.

tonybarber's picture
tonybarber's picture
tonybarber commented Tuesday, 14 Feb 2017 at 2:09pm

Water ?

udo's picture
udo's picture
udo commented Tuesday, 14 Feb 2017 at 12:06pm

Agent Brokensha ...can you run that printed code on the bottom of the Spam can through the system for date of manufacture and best use by date.

derra83's picture
derra83's picture
derra83 commented Tuesday, 14 Feb 2017 at 12:14pm

Pollution aside, that photo still kicks my Pavlovian conditioning into gear.

tootr's picture
tootr's picture
tootr commented Tuesday, 14 Feb 2017 at 1:58pm

So a deep ocean submersible needs to be made of 10cm thick steel and even thicker laminated glass to stop being crushed by water pressure, but a can of spam can survive?

stunet's picture
stunet's picture
stunet commented Tuesday, 14 Feb 2017 at 2:03pm

Much as we'd like to believe the can is still full of reconstituted ham and jelly goodness, I'm sure it's been emptied.

Blowin's picture
Blowin's picture
Blowin commented Tuesday, 14 Feb 2017 at 2:16pm

I Thought the Pacific Ocean gyre was meant to be a hoax ?

I just had a thorough 1minute internet search and could not find a picture of it .

If anyone knows of a decent photo of this massive oceanic tip please post it.

dandandan's picture
dandandan's picture
dandandan commented Tuesday, 14 Feb 2017 at 5:15pm

https://www.youtube.com/watch?v=3eUMRbfoSrI

Watched this the other day and it addressed that very well. Worth a watch.

chook's picture
chook's picture
chook commented Tuesday, 14 Feb 2017 at 2:35pm

there is a spam version of spam. i saw a family picnicing with this...

synchrodogcal's picture
synchrodogcal's picture
synchrodogcal commented Tuesday, 14 Feb 2017 at 2:50pm

mmmm, potted

stunet's picture
stunet's picture
stunet commented Tuesday, 14 Feb 2017 at 2:55pm

Guess I can ditch the fake steak now, I've got a new BBQ option.

udo's picture
udo's picture
udo commented Tuesday, 14 Feb 2017 at 3:01pm

Even Honest Don has Spam in his pantry.

Mother Jones .com : The Spam Factorys Dirty Secret.

Blowin's picture
Blowin's picture
Blowin commented Tuesday, 14 Feb 2017 at 3:24pm

I was served a spam and pineapple pizza once.

memlasurf's picture
memlasurf's picture
memlasurf commented Wednesday, 15 Feb 2017 at 1:59pm

Did you keep it down?

Legrope's picture
Legrope's picture
Legrope commented Wednesday, 15 Feb 2017 at 2:39am

I'd normally throw in a joke myself in these forums but this is quite serious. Yep, very little oxygen down there. Takes forever for metal objects to corrode. Probably the same for other materials like plastic without sunlight to help break down. Is this what our kids and future generations have to deal with once we are gone. In the last 100 or so years, heavy industry has damaged the oceans and earth to irreversible levels. What will it take for this to stop and even more so, reverse the effects. Also the Great Pacific garbage patch is a crime from all contributing countries which needs to be dealt with asap. It just gets spoken about but nothing much is being done. Too expensive to handle? No one to take the blame? What are the oceans going to be like in another 50 years? Really depressing to think about. How to stop big industry from continuing this practice? Big industry has affected the climate and the oceans are a big part of that. It's a pipedream for an individual but we need to make this shit stop.

tonybarber's picture
tonybarber's picture
tonybarber commented Wednesday, 15 Feb 2017 at 12:21pm

If we take that SPAM photo to be true. Note the light angles, how the can is sitting. Ok, how did it get there. It looks like a pretty new can, no salt corrosion. Ok, so maybe a yachtie just through it overboard just over the spot or near in the middle of the Pacific. Hmmm, is this SPAM a spam.

nick3's picture
nick3's picture
nick3 commented Wednesday, 15 Feb 2017 at 3:24pm

What a load of bullshit. The can of spam would be crushed like a pancake.
Should we all believe this because it was posted by a scientific organisation??? Remember it has to be true because they are scientists.
I think Dr Jamieson is trying to get funding so he can keep paying his bills.

stunet's picture
stunet's picture
stunet commented Wednesday, 15 Feb 2017 at 3:27pm

It would be crushed if it was unopened, Nick.

Do you know if it's been opened or are you just assuming that?

Terminal's picture
Terminal's picture
Terminal commented Friday, 17 Feb 2017 at 10:08am

Agreed nick3, science is the real conspiracy. Always pushing their agenda of peace, equality and taking a responsible approach to consuming earths resources.

nick3's picture
nick3's picture
nick3 commented Wednesday, 15 Feb 2017 at 3:50pm

Do you know it is opened Stu.
Or are you assuming that???

Legrope's picture
Legrope's picture
Legrope commented Wednesday, 15 Feb 2017 at 4:38pm

Don't they have a rip tab kind of thing around the outside. This looks unopened if so, liquid and liquid filled meat and no oxygen would be equal pressures so it would sink. Otherwise it would float. I wonder if Tsunami water retreating with the millions of tons of pollution have assisted to distribute all the crap and caught in the trenches.

happyasS's picture
happyasS's picture
happyasS commented Wednesday, 15 Feb 2017 at 5:02pm

https://www.google.com.au/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=...

rip tab is on the inside......cant believe I just looked that up.....there is no hope for humans.

Fed's picture
Fed's picture
Fed commented Wednesday, 15 Feb 2017 at 5:24pm

wow!
So, from the comments we learn that the can pic is a fake and that the Pacific Ocean gyre is a oax.
This comes just when I learned that the earth is flat. Don't you know?
It's a conspiracy. Every thing scientists say it's wrong.

There's no hope.

surfer99's picture
surfer99's picture
surfer99 commented Thursday, 16 Feb 2017 at 3:27pm

Here's some actual science...

Solids and liquids do not compress under pressure, only gasses are compressed.

If the can was opened and empty, it would fill with water and not be crushed.

If it was unopened and somehow emptied, it would crush as the air inside it is compressed.

If it was unopened and full of spam, it would not be crushed as the solid/liquid contents would not be compressed under pressure.

I think the real concern here is how do we know how far this can of spam drove to get to the surf, and was it worth the drive?????????

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Thursday, 16 Feb 2017 at 2:59pm

Hey leg rope
Here's a happy bit of news regarding that North Pacific gyre:

https://www.theoceancleanup.com/

Read & enjoy, there are solutions, young fella thought it up too

As for those PCBs, much harder

velocityjohnno's picture
velocityjohnno's picture
velocityjohnno commented Thursday, 16 Feb 2017 at 3:05pm

& anyone, anyone:
Any mention of the weight of a WW2 battleship worth of highly irradiated water still going into the n pacific each year? This would be a huge story Stu