Guest essay by Eric Worrall
Scientists have discovered Antarctic Krill can digest or at least break up lumps of plastic into even smaller lumps – but when the krill were force fed large quantities of radioactive plastic over an extended period their ability to digest plastic deteriorated.
Krill found to break down microplastics – but it won’t save the oceans
Digestion of plastic into much smaller fragments ‘doesn’t necessarily help pollution’, Australian researchers say
A world-first study by Australian researchers has found that krill can digest certain forms of microplastic into smaller – but no less pervasive – fragments.
The study, published in Nature Communications journal on Friday, found that Antarctic krill, Euphausia superba, can break down 31.5 micron polyethylene balls into fragments less than one micron in diameter.
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Unfortunately, Dawson said, krill were unlikely to provide a solution to the levels of plastics and microplastics polluting the oceans.
“It’s not necessarily helping plastic pollution, it’s just changing it to make it easier for small animals to eat it,” she said. “It could be a new source of plastics for the deep ocean.”
A study by Newcastle University in December found microplastics in the stomachs of deep-sea creatures from 11km deep trenches in the Pacific Ocean.
Dawson said microplastics that had been digested by krill were also too small to be detected in most oceanic plastic surveys, meaning the level of microplastics in the ocean could be higher than currently assumed.
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The abstract of the study;
Turning microplastics into nanoplastics through digestive fragmentation by Antarctic krill
Amanda L. Dawson, So Kawaguchi, Catherine K. King, Kathy A. Townsend, Robert King, Wilhelmina M. Huston & Susan M. Bengtson Nash
Microplastics (plastics <5 mm diameter) are at the forefront of current environmental pollution research, however, little is known about the degradation of microplastics through ingestion. Here, by exposing Antarctic krill (Euphausia superba) to microplastics under acute static renewal conditions, we present evidence of physical size alteration of microplastics ingested by a planktonic crustacean. Ingested microplastics (31.5 µm) are fragmented into pieces less than 1 µm in diameter. Previous feeding studies have shown spherical microplastics either; pass unaffected through an organism and are excreted, or are sufficiently small for translocation to occur. We identify a new pathway; microplastics are fragmented into sizes small enough to cross physical barriers, or are egested as a mixture of triturated particles. These findings suggest that current laboratory-based feeding studies may be oversimplifying interactions between zooplankton and microplastics but also introduces a new role of Antarctic krill, and potentially other species, in the biogeochemical cycling and fate of plastic.
Read more: https://www.nature.com/articles/s41467-018-03465-9
The expression of concern about nano-plastic seems a stretch. Breaking micro-plastic into smaller chunks, making it available to even more versatile and varied microorganisms further down the food chain, is likely enough to effect complete clearance. Anyone who has ever owned a boat knows how difficult it is to protect fuel from contamination by the ubiquitous fungus and bacteria which thrives in sea water. It seems highly likely that at least one other organism, somewhere in the world’s oceans, has developed a taste for our plastic waste.
Correction (EW): the plastic wasn’t radioactive, I misread “Triturated” as “Tritiated” (h/t Phil)
In my experience it’s the sun that degrades most kinds of plastic the fastest.
Concerning plastic floating around in the oceans, I must admit it hardly appeals to my personal aesthetic standards. That of course is something different from being hysterical about it. I just primarily wonder how stuff ends up there, although in developing world I can see many ways, through rivers and coastal areas; and of course fishing nets.
Anyway, “doing something” to “clean up” the ocean or – in an alternate vision – to mine the ocean for plastic resources and use it for some purpose, has at least my sympathy. You may have probably heard of the “Ocean Cleanup Project” by the young entrepreneur Boyan Slat, who just happens to live next-door from me. He collected millions by means of crowd funding and is by now testing a new prototype in deep waters.
See https://www.theoceancleanup.com
At least he is beating the Krill competition to it.
Thoughts, anybody?
cyrilthruthseeker March 13, 2018 at 8:01 am: “Thoughts, anybody?”
WR: From above:
Ed bray just a hanger on.sence about 2007. March 12, 2018 at 9:11 pm
“In the pacific high all the barneculs stick to everything and sink everything over time. Ed bray on the schooner de Viento.”
Kip Hansen March 13, 2018 at 7:06 am
“Microbes eat the little bits of plastic. This has been known since 2011 — why it is repeatedly ignored and unreported in Oceanic Plastics research is a mystery to me. The smaller the bits, the faster it is consumed by microbes.”
Kip Hansen March 13, 2018 at 10:06 am
“Pat ==> You are right about the first bit — all kinds of microbiota attach themselves to floating plastic bits — sometimes so many that they eventually sink.”
It seems all floating plastic will desintegrate and/or will sink. But I don’t know about the time frame. As far as I know, not much research – if any – has been done on this subject. So far, nature seems to be able to handle this itself.
What I do know is that any object (!) in the open sea attracts ‘life’. Ships, platforms, weeds, plastic bags. And any object will be covered with chalky (= heavy) objects that in the end will make the object (if originally floating, like plastic bags) sink. But again: I don’t know about the time frame. For plastics: after 5, 10, 15 years? Earlier? Later? It will depend on local conditions like temperature as well.
Much of the plastic is thrown overboard from merchant shipping. This is because disposal in port is very expensive as it must go through quarantine. This could be easily fixed I’m thinking. Charge them for the plastic they must have thrown overboard if they turn up in port with no trash.
And deprive krill of their “roughage”?
One documentary I saw kinda shot itself in the foot. It was predictably scare-mongering about floating plastic, but then let out some video & comments that floating plastic actually attracted life around it as protection in the otherwise barren open ocean. Not saying floating plastic is all good of course, but it’s not as simple as made out to be.
WUWT is krilling it.
Ecofreaks contaminate their own trousers in abject panic at the thought that nature might provide a solution for a human waste problem and in so doing, take away from these societal parasites one of their props for ecopuritannical self-aggrandisement.
Force feeding radiation to Krill may harm them? oh noes.
The authors seem like many climate scientists: Their research points to the problem being over-blown, but they still try to insist it is as worse as they thought.
The also make some pretty foolish comments, such as:
Indeed. That is what the wind and the waves and sunlight/oxygen/ozone does. What kind of a dipstick would suggest that the krill will eat the bottles whole?
Maybe it was the mutant krill that were fed the radioactive plastic.
(Sorry Eric, I couldn’t resist.)
‘Microplastics are fragments of less than 5mm in diameter. Krill cannot consume anything greater than 2mm in diameter.
“They are not going to be able to eat a drink bottle,” Dawson said.
Technically… they could still nibble. Not that I can think of a reason why they’d feel compelled to.
So we should keep dumping plastic in the ocean because some bacteria might evolve that can dissolve it?
Bacteria have already evolved that can eat it.
My understanding is that the majority of the plastic in the oceans that comes from the US doesn’t get there because we “dump it” in the oceans. Most of it gets there by being carried by the fresh water courses which all eventually lead to the oceans. A plastic bag in Indiana blows around and ends up in a stream or ditch that drains into the Wabash river and ends up entering the Gulf of Mexico via the Mississippi river. In my view, pollution or litter is bad, no matter if Krill eat plastic or not just as an oil spill is bad, even if bacteria eat and break down petroleum products are not.
Adding recycled plastic to asphalt makes the roads more resilient and pot holes far less common. google it
One wonders if the term of a human lifetime would enough time to explain to these people the concept of surface to volume ratio.
Three questions from an ignorant truck driver.
Are not krill the most prolific arthropods on earth?
Since many marine species rely on krill as a food source, including the Blue Whale, which is as far as we know now the largest animal to have ever lived on earth; Is there a potential for plastic eating krill to be toxic to the food chain?
What do Krill poop when they eat plastic?