Today I have been under an avalanche of questions about plastic pollution in the ocean. It seems hard to trust a reliable source of information or maybe it is the science that is moving very fast. People ask me maybe because I have sailed across the gyre myself, collected plastic samples in Hawaii, and nowadays working on an optical plastic sensor with a team of young students in Hong Kong when I am not developing a fleet of sailing robots that I hope one day will be out there measuring plastic and other pollutions like radioactivity, acidification, oil spills, overfishing and other urgent ocean issues. But to be honest I have much more questions than I have answers – at this stage we all do. I am writing to compile some informations I came across recently, trying to make sense and propose some ideas.
When we found out
“Every year we produce about 300 million tons of plastic, a portion of which enters and accumulates in the oceans. […] In 2012 alone, 288 million tons of plastic were produced (PlasticsEurope 2013), which is approximately the same weight of the entire human biomass (Walpole et al., 2012). […] The discovery of fragmented plastic during plankton tows of the Sargasso Sea in 1971 led to one of the earliest studies of plastic in the marine environment. Using a 333 micron surface net trawl, Carpenter and Smith collected small fragments of plastics in 1971, resulting in estimates of the presence of plastic particulates at an average of 3,500 pieces and 290 g/km2 in the western Sargasso Sea (Carpenter and Smith, 1972). Shortly after, Colton et al., (1974) surveyed the coastal waters from New England to the Bahamas and confirmed distribution of plastic all along the North Atlantic. These studies have been recently updated in two comprehensive studies of the North Atlantic gyre (K. L. Law et al., 2010; Moret- Ferguson et al., 2010). Indeed, plastic is found in most marine and terrestrial habitats, including bays, estuaries, coral reefs, lakes and the open oceans. (Rochman et al., 2014, Wright et al., 2013). The ingestion rate of plastic particles by mesopelagic fish species in this area is estimated between 12,000 and 24,000 ton/year (Davison and Asch, 2011).
“How the oceans can clean themselves, A feasibility Study” Ocean Cleanup Array, June 2014.
What we thought we knew
I trust Algalita Foundation and 5 gyres for that I was lucky to meet them in person and they had been to several gyres many times as an independent non-profit organisation. Below are some journeys they have done with a manta trawler as you see a picture of above. They explain their method very well and in simple words here.
In 2008, we had a horrifying map but we felt somehow confident about the data.
In 2010, Dohan and Maximienko (Illustration above, 2010. Oceanography 23, 94–103.), based on the trawler data by Algalita and other organisations produced this famous simulation of where we should expect plastic to be. Don’t be fooled by some pictures you probably saw of the “plastic continent”, such thing does not exist in the middle of the ocean.
So at this stage, we thought, we would find tens of millions of tons of plastic debris in the gyres. Well…
What we think we know now
Thanks to Dr Blurton of the Hong Kong Harbour School who sent me the pdf, I was quite shocked with this new publication “Plastic debris in the open ocean” by Andrés Cózara, Fidel Echevarríaa, J. Ignacio González-Gordilloa, Xabier Irigoienb, Bárbara Úbedaa, Santiago Hernández-Leónd, Álvaro T. Palmae, Sandra Navarrof, Juan García-de-Lomasa, Andrea Ruizg, María L. Fernández-de-Puellesh, and Carlos M. Duartei. Good job ladies and gentlemen. The pdf is here : http://www.pnas.org/content/early/2014/06/25/1314705111.full.pdf I am selecting only some essential information but I recommend you to read the paper, it’s short, only 5 pages + references.
In 2010 (yes, 4 years ago – but the paper has been published June 6th 2014), the team embarked on a sailing journey around the world as the “Malaspina science expedition” , doing 3,070 ocean samples with a manta trawler. The grey areas is where prior research ( explained above) suggest they would find plastic accumulation, and that was verified as you see with the yellow, orange and red dots. But…
“Those little pieces of plastic, known as microplastics, can last hundreds of years and were detected in 88 percent of the ocean surface sampled during the Malaspina Expedition 2010,” lead researcher and the author of the study Andres Cozar from the University of Cadiz, told AFP. The total amount of plastic in the open-ocean surface is estimated at between 7,000 and 35,000 tons, according to the report. This amount, though big, is lower than the scientists expected.” http://rt.com/news/169564-ocean-surface-covered-plastic/
Before this paper, much of the attention was focused toward the North Pacific Garbage Patch => turns out all the other oceans are in bad shape too.
Before this paper, we knew plastic was present in all oceans but the general consensus was that it was accumulating in the center of the gyres mostly => Now we have measured plastic to be present on 88% of the world ocean surface. Pretty much everywhere.
Before this paper, the estimates were ranging from tens of millions of tons to hundred of millions of tons => Now maximum 35’000 tons. [silence] 35’000 tons? That’s it!!!??? Is that amazing good news, or is that bad news!?
What we (think we) really know now
Out of the estimated millions of tons of plastic debris we emit, we can now only find at most 35’000 tons spread over 88% of the oceans. S0 we know now where is less than 1% of the plastic we anticipated finding. Where is the 99%+ of the rest of the plastic? This is really embarrassing.
The articles about this are popping out from all part, I wont try to keep track of all the links, because they are pretty much all based on the same paper I mentioned above. Many are spreading panic, instead of awareness unfortunately.
Back in October 2012 “according to Boyan Slat’s calculations, a gyre could realistically be cleaned up in five years’ time, collecting at least 7.25 million tons of plastic combining all gyres. He however does note that an ocean-based cleanup is only half the story, and will therefore have to be paired with ‘radical plastic pollution prevention methods in order to succeed.” (Wikipedia, retrieved July 2nd, 2014).
In June 2014, in the feasibility study : “The Ocean Cleanup Array is estimated to be 33 times cheaper than conventional cleanup proposals per extracted mass of plastics. In order to extract 70 million kg (or 42 percent) of garbage from the North Pacific Gyre over 10 years, we calculated a total cost of 317 million euro.”
Sure, the “multi-level trawler” (p102 0f the Feasibility Study) used by the Ocean Cleanup team is radically different from the “regular manta trawler” everybody else uses. But the difference of plastic quantity is not found here either. There are so many variables to making a correct plastic measurement, the speed of the boat, the size of the mesh, the position of the trawler in the regards to the wake of the boat, the wind and the waves …
So, how can the Ocean Cleanup collect 70’000 tons from the North Pacific Gyre alone if the most recent estimate of ALL the plastic in ALL ocean surface combined is only of 35’000 tons? And how can this information even be trusted when ” Last year, an estimated 150,000 tons of marine plastic debris ended up on the shores of Japan and 300 tons a day on India’s coasts (http://plastic-pollution.org/ retrieved July 3rd 2014)”. If this recent study from the Malaspina expedition confirms true, would the collection of plastic debris with the Ocean Cleanup array be less meaningful? And less profitable if at all? But wait, that is not the question. Of course we need to stop emitting plastic in the ocean – that’s not a new idea and that is self-evident. And of course we must collect the plastic that is already out there and will continue to accumulate in the ocean – even if it is expensive instead of profitable. I personally support Boyan Slat and his team. No matter how many people say “this is impossible” someone has got to try. Even if it is to fail, we must try and try again, again we succeed. This technology, or another technology.
But the real question remains : where is the plastic? How can we have plastic measurements dropping so dramatically?
How can we find out what is really going on?
Such a large amount of plastic has not disappeared over night, between 2008 (Algalita estimate) and 2010 (Malaspina measurements).
Scientists argue that :
some plastic breaks down so small, it goes through the fine plankton net they use. Plastic still floats but we can’t be measured unless we use an extra finer mesh that is probably more fragile, forcing the ship to move the trawler even slower (it was already recommended to sail at 2 Nautical Knots, well up to 8 knots for the fast Erikson trawler).
the plastic chemical composition changes causing it to distribute in the water column or sink at the bottom of the ocean
the plastic is being ingested by animals and is being pooped, dropping to the bottom of the ocean, or it moves into the food web with all it’s toxics and until it eventually reached our plates
But we don’t know yet in which proportions each of these phenomenon happen at all yet.
If the plastic is so small that it go through the mesh, maybe it is not a mesh we should be using to measure plastic. What about optics?
For a long time Laser Optical Plankton Counters (LOPC) have been in use to measure plankton. We don’t collect physical sample, we collect data, the machine can keep running without interruption, the data is more granular and instantly processed.
In the LOPC, water carrying plankton is flowing. The plankton is being “flashed” by a laser and it is from the outline it that is then counted automatically.
Mobile sensing platform
With a motivated group of young students, we hacked a low cost water video channel.
We attached our optical sensor to a small Remote Controlled (RC) power boat. As we sailed, some water that contains plastic debris was video recorded and the plastics bits were also captured in the pink net at the back of the video channel. The point of the pink net is too measure the plastic physically collected that has travelled through the video channel, and compare it with the estimate that we can make from the video alone. We have not done that experiment comparison yet, but it would give us an idea of how reliable our video estimate is in comparison to the real measured weight of plastic collected.
We managed to capture video of plastic particles moving through the video channel. This still very rough.
Now, it would be great if we could find out what is plastic and what is not. One of the greatest difficulty being that plastic debris becomes a habitat or a transport for a lot of marine life. How can an untrained software (as opposed to a machine learning based software) distinguish plastic from something else? Typically a plastic fragment would be wrapped into a “bubble” of organic matter, making it more difficult to isolate from an optical perspective. Thankfully, one student in our team, Brandon Wong found out this research : http://www.idec.com/sgen/technology_solution/our_core_tech/plastic_sensing.html
It was discovered that upon measuring light absorption spectra in plastics, in the wavelength range of 300 to 3000 nm, the peak values were always observed at or near 1700 nm, regardless of plastic types. This discovery opened the possibility for simple optical sensing of plastics with the use of a LD in this wavelength range. Observation of unique light absorption characteristics within the near infra-red spectrum of each different plastic type has led us to develop the world’s first technology capable of detecting different types of plastics with the use of a LD (with three different wavelengths).”
If we manage to get that optical detection running, the last but not least challenge may be to scale from a regular webcam to a microscope-scaled system.
According to the research done during the Malaspina Ocean Expedition the plastic particles we are trying to measure are very very small… Could we be heading in the direction of microfluidic systems?
If the plastic debris we are trying to test are incredibly small, could we control the flow in a very precise yet robust way to perform spectral and / or chemical analysis? Many questions to explore…
So with such a system, could we answer the 2 first questions? :
sensing plastic that is extremely small
sensing plastic that is small and broken and sunk at the bottom of the ocean – that would imply that this machine can be taken thousands of meter deep : super high-pressure resistant
I day dream that a fleet of autonomous sailing robots doing the remote sensing work. In fact the Ocean Cleanup feasibility study mentions the relevance of deploying such sensor network system in it’s recommandation pages :
And now the third question ? What part do animals have in the “plastic disappearing” plot? We wont be able to see that in an optical system unless we’re dealing with tiny transparent animals.
I feel terrible for even thinking about this but that is just an idea at this stage. What I am about to propose might be totally unethical, I don’t know. Marine biology and toxicology are not my areas at all. Forgive my ignorance and please correct anything wrong that I may propose, please comment to help.
As I used as this post introduction, our experience with dispersing 138gr of plastic had become a spill in a few seconds on which turtles and fishes came to feast. We had to interrupt the experiment and it took 10 of us during 40 minutes to collect 138gr of plastic debris with 4 boats on a lake that had no current, no waves and very moderate wind. What we learnt is that turtles and fishes love to eat plastic. In fact many studies about suffering, dead animal dissection and observation of carcasses indicate that birds, and marine animals feed abundantly on plastic. But how do you measure how much plastic an animal is willing to eat when given the choice?
In a controlled environment – say a box – we place an aquatic animal. We feed this animal a mix of plastic and “real” food in equal quantities with an excess of overall quantity.
Will the animal eat more food or plastic (behaviour)? Will that behaviour change over time? Does the animal develop a preference for certain plastic? By the taste? Smell? Texture? Colour? Motion?
How much plastic would still remain untouched in the environment?
How much plastic will travel through the digestive system?
How much plastic would remain within the digestive system? And if so, how much would the plastic be digested if at all?
What are the short term symptoms of plastic poisoning (mechanical) ?
What are the long term symptom of plastic poisoning (chemical)?
What is the lethal dose for type A / B / C / D / Plastic?
What is the most lethal shape or size of plastic fragment?
Is an animal dead by plastic attractive as a food form for another carcasses-eating animals?
When an animal dies and decompose, how much of the overall plastic of the experiment remains?
many more questions could be asked and variables included such as the size of the box, the season, the age of the animal, the sex, social learning doing the experiment with multiple animals simultaneously.
Who is active in Hong Kong?
There are several groups in Hong Kong interested in the topic of plastic pollution
Many local residents living near the beach are concerned and actively cleaning the beach
What we thought we know about plastic pollution has just been challenged in a very big way. And I believe this will happen again soon as we investigate.
The plastic pollution is present at a whole different scale, both small for the particle size and huge by it’s distribution over pretty much the entire ocean surface (88%) and abyssal depths.
The effects of plastic pollution at theses scales are still very unknown. As we keep developing new concepts for ocean cleaning we are still lacking understanding of where is the plastic, how is it transformed while travelling great distances? How does it impact marine life? How does plastic and it’s chemical compounds travel through the food chain to our plates? What are the consequences on human health? What can we do about it?
The more we learn about plastic in the ocean and the more we understand how harmful of a substance it is. And as André Cózar concludes in this important paper.
The abundance of nano-scale plastic particles has still not been quantified in the ocean, and the measurements of microplastic in deep ocean are very scarce, although available observations point to a significant abundance of microplastic particles in deep sediments, which invokes a mechanism for the vertical transport of plastic particles, such as biofouling or ingestion. Because plastic inputs into the ocean will probably continue, and even increase, resolving the ultimate pathways and fate of these debris is a matter of urgency.
So many more questions now… But 2 ideas how to investigate. More ideas? Suggestions? Readings?
In a nutshell and richly illustrated :
The ocean have millions of tons of plastic, but it tend to be broken down so small, the naked eye cannot see it.
Currently we are using large extremely expensive research vessels to drag plankton manta trawlers and we count plastic bits manually under a microscope. It is slow, expensive and potentially dangerous.
I suggest we use a machine similar to an LOPC (Laser Optical Particle Counter) that marine biologist use to count plankton, but refit them to measure plastic. This machine could be installed at the bow of ship. A vertical stack of them would allow the continuous collection of plastic as well as plankton data, at different depth. I insist, we would not collect physical samples, only data. This system would provide near-real-time plankton / plastic qualification and quantification, much higher resolution, and all of that without human repetitive labour. I believe that such installation at the bow of a ship would be safer and attractive since the ship could sail much faster than with a trawler. The idea is to make the system lightweight and low cost so it could be mounted not only on research vessels, but on any type of vessel becoming a sort of Ship of Opportunity.
In the document I outline a roadmap to develop the sensor, from the lab, to the river, to the ocean. I am aware that few micro-plastic debris can be found in rivers, mostly large debris that end in the ocean where they are broken down with the action of UV, salt, the mechanical action of wave and animal bites.
Step 1 : recreate the elements of study and the conditions.
Step 2 : create a “loop” where water flows carrying plastic debris as well as plankton and contaminated plastic debris.
Step 3 : Get out of the lab and test the counter in an open channel.
Step 4 : try out a stack of channels in the open sea.
Step 5 : map the data.
This is a very exciting topic for me and I look forward to update you about our progress – that will be logged on Scoutbots.com.
We just completed this application for Think Beyond Plastic for plastic debris sensing and mapping in the ocean. It is a really rough proposal for now, for the first step of selection.
We made those new images to push the concept forward :
Protei ecosystem for plastic sensing and collection
Operating many sailing robots instead of one large oceanographic vessel.
A Protei with sensors at the forefront to avoid disturbing flow. A vertical stack of optical plankton sensor (laser optical particle counter) to capture the image of plastic debris, not plastic samples.
The beauty and luxurious landscape of Hawaii big island welcomed us after a few days at sea.
I realised I became slightly anxious to come on land as the ship became our new home.
I adapted quickly to the motion of the ship and felt strongly land-sick for the first few hours in Hawaii.
Design Thinking workshop at Hilo University
We had a fruitful Design Thinking session in Hilo University with big Island locals. We brainstormed with another company Evolving Technologies building low cost endoscopes. Many new creative uses of Protei, based on discussion came up. Asymmetrical hulls have been in use for a very long time in Hawaii, some early designs of Protei have been drawing inspiration directly from Hawaiians traditional boats. Another interesting information was that local schools organise every year a robotic competition, so we naturally thought building plastic collecting robots would be a smart challenge to submit and perhaps support with the Protei team.
Meeting with Hank Carson, Anna Cummins & Markus Erikson
We had a great conversation with Dr Hank Carson, that explained us a little bit about his research. He showed us samples of what can be found on the beach, and the message is : “don’t buy plastic toys anymore, they are freely available at Kamilo Beach” :)
We also played with these very cool red blocks that has been used to study the currents around the island.
Together with Levine, Carson, and Eriksen we had a detailled discussion of how plastic measurements could be improved both with new trawler designs and swarms of sailing robots such as Protei. Carson evoked an optical plankton counting so Protei could collect data instead of physical samples. Eriksen talked about his high-speed trawling devices and was very inspirational for us. Carson Suggested that if Protei was capable of carrying multiple instruments, useful information would be provided by
We are very eager to continue this conversation and contribute Protei technology to improve how we study plastic in the oceans.
Lava Tube and Kamilo “Plastic” Beach
Following the advice of Carson, Eriksen and the locals we met at Hilo University, we rented a Jeep and headed down south towards Kamilo Beach.
We had a bumpy ride, several drivers had been less lucky than ourselves :/
We got stuck in the sand and volcanic rocks twice, but thanks to the experience of the film crew and hippie muscle power, we got out of trouble.
On our way to Kamilo Beach, we passed a large “hole” in the ground.
I could not manage not to explore this cavity, and soon we were exploring (for me the first ever) lava tube with our little headlamps.
One of the thing I like the least is wrapping myself in spiderwebs in dark caves in exotic locations. The questions that occur to me are “What’s the size, color, weight and poisonousness of the spider that’s crawling on my neck now?”. But it was all worth it! What an incredible space!
It took us some time to find Kamilo beach as there is no real road that leads to it. We got lost several times on lava fields but only to enjoy spectacular volcanic cliffs.
After searching GPS coordinates, we finally located Kamilo Beach and witnessed the ecological horror of the infamous “plastic beach”.
Some parts of the beach have simply become rainbow, with much more plastic that there is sand.
We collected sand and plastic mixed samples at 3 levels :
What we also witnessed underwater a great population of little fishes, anemones, corals and sea cucumbers that seemed to be thriving in this highly polluted environment.
One of the most famous picture when it comes to plastic pollution, is the picture below : a bird that probably died with his digestive system saturated and obstructed with plastic debris. We only stayed a few hours and did not find such carcass.
We also took some samples of water and applied some oil sorbent samples that we carry around to detect the trace of hydrocarbon in the seawater.
We want to come back to Hawaii and collect plastic debris.
Finally received the 3 -in progress- prototypes and we cannot wait to get our hands dirty !
Today,we got allocated a corner of a corridor, that will allow us to complete the prototypes. Above, the box “sleeping” above my berth. The prototypes are in good shape so prepare to see some progress on that front in the next few days ! :) Here, one of the prototypes on the sunny deck !
For those who keep asking, I removed the stitches and it’s getting better everyday. Unfortunately I have been coughing a lot lately, but it’s also getting better now thanks to the kind advices of my indian Unreasonable fellows, with honey, lemon and ginger :)
More bumpy road?
We have now left Honolulu since yesterday and the librairian has attached the books to the book shelves. Not a good sign. That means we expect large waves and agitated weather between Hawaii and Japan. We are one day behind schedule and we are now cruising fast, at about 21 knots in average. We will see land next in about 10 days. I’m excited to be on this journey with you.
Gabriella Levine and Cesar Harada have been selected to participate to the Unreasonable at sea for the Protei project.
Please watch the video above and you will understand why we are excited to be part of this great adventure. For several months on the sea, we will be in the company of some of the world most forward thinking entrepreneurs that will be our mentors. This is an immense honor for me and for the Protei Project and we will document this journey as well as possible to share this incredible privilege with the greatest number. You can see our dates of the travels and where we will stop on my time line.