On Thursday, The Ocean Cleanup published a blog post in reply to my concerns. I was incredibly hopeful up until this point that they would listen. After all, my efforts to raise awareness have been met with tremendous support from fellow scientists and the general public.

I’m not going to lie, the frustration I felt when reading their response was real and heavy. I love this ecosystem, I wouldn’t be putting myself out there if I didn’t. But their response felt profoundly dismissive, not only of me, but of the scientific evidence. So this is my second attempt at explaining to The Ocean Cleanup, and to its funders, why it’s logic is flawed, and why it is putting entire species and whole ecosystems at risk as a result.

1) Boyan Slat and The Ocean Cleanup claim floating animals are ubiquitous.

Here are the exact words of their blog post reply, with the exact studies they reference, and what those exact studies actually say.

The studies they reference almost immediately prove them wrong. The third sentence of the first study says, “Analyses of neustonic concentration and population structure showed regional and temporal differences in the fauna.” And the second study states: “The present study represents an original insight into the structure of the neuston community in the Mediterranean Sea, providing strong evidence of the spatial variability of its diversity patterns.”

Perhaps The Ocean Cleanup and Boyan Slat meant to point out that some species are mentioned in both papers. But species identification for poorly-known invertebrates is notoriously difficult. Often biologists will unknowingly use the same species name for many similar species. Only when we study them more do we realize our oversight. In fact, two newly discovered blue sea dragons were only described in 2014, before this time they were all called by one name. Even worse, these two species are only found in the North Pacific Subtropical Gyre, exactly where The Ocean Cleanup plans to launch their massive fleet.

To sum it all up? No matter how you look at it, neuston are not ubiquitous.

Now, let’s go a step further.

Why has The Ocean Cleanup been so obsessed with documenting the distribution of plastics in the ocean? Because they know floating objects are not ubiquitous. Why they understand this fact for plastic, yet fail to grasp it for floating animals, is beyond me.

2) Boyan Slat and The Ocean Cleanup claim they will be in only one small spot in the ocean, so they will not have a big impact on floating animals.

But wait, are they admitting they will only clean this small spot of the ocean? No. They are not.

They’re not just working in a small spot of the ocean. They’re working in very special small spots. These spots in the ocean are akin to giant whirlpools, called gyres. Just like the whirlpool in your kitchen sink, gyres spin on a massive scale, concentrating objects at the surface, just like soap bubbles going down the drain. The Ocean Cleanup is focusing on these gyres because floating objects collect in them.

So let’s look at their logic again: The Ocean Cleanup is intentionally working where floating objects are most concentrated. They claim they that they will remove 90% of ocean plastic by 2040, even while working in these tiny spots, because much of the ocean’s surface plastics are funneled into these regions at some point.

If you are collecting plastic that is continually entering the ocean by using these spots, you will also be collecting neuston even if they are continuously reproducing.

Some animals, like the two new species of blue sea dragon, have only been found in the gyres. Harvest plastic from one gyre, potentially harvest two newly discovered species.

3) Boyan Slat and The Ocean Cleanup claim that floating life likely multiplies quickly, so it’ll be ok.

They justify this by talking about bacteria. It’s true: Some floating bacteria do reproduce quickly. Animals are not bacteria. We do not know how long it takes floating animals to reproduce. But let’s say they do reproduce quickly. Does that mean there is no problem? No.

Quick reproduction may help floating animals overcome destructive storms, which can kill floating life. But storms pass. The Ocean Cleanup’s proposed fleet of 60 systems in the open ocean are not storms. They are intended to be at sea for years. They will not pass.

4) Boyan Slat and The Ocean Cleanup claim they are collecting lots of data on these issues.

But who are the biologists performing this work? I offered to speak with biologists at The Ocean Cleanup nearly a month ago, and was placed in touch with the person who conducted the Environmental Impact Assessment. We had a thoughtful exchange, but he informed me that he’s not part of the actual Ocean Cleanup team, and doesn’t work for them. If The Ocean Cleanup is so open to feedback, why aren’t they actually talking to people with the greatest concerns for the ecosystem?

5) Boyan Slat and The Ocean Cleanup claims also reveal something else:

They knew about floating animals, and they know we need more data, yet they still argue that there is no scientific basis for environmental concern. In his blog post Boyan Slat defends his Environmental Impact Assessment by saying “all species that have previously been observed near the deployment site of our cleanup system are referenced [in a table of the Environmental Impact Assessment].” Of course, this is not true: nowhere in his EIA or in his post does he mention the two species of blue sea dragon found only in his deployment area. Further, the fact that some floating animals were in a table only proves that they have known about the issue of floating surface life for some time.

He also attempts to brush aside some of the best information we have: a massive ocean survey of floating animals conducted by USSR scientist Savilov, which shows 7 distinct floating ecosystems, including one unique ecosystem found right where The Ocean Cleanup intends to work. Yet Boyan Slat says that “the validity of using a single, 51-year-old source could be questioned,” before going on to justify why it’s not worth worrying about anyway (because neuston are “ubiquitous”). But this is exactly my point: we don’t have good modern data. Why does The Ocean Cleanup brush off the data we do have?

In summary: The Ocean Cleanup’s claims only reiterate what we already know: neuston are not ubiquitous. Neuston may be concentrated where The Ocean Cleanup wants to work, due to the same physical forces that concentrate plastic. The life cycles of floating animals are poorly understood and The Ocean Cleanup may have major negative consequences on this ecosystem.

Far from alleviating my concerns, Boyan Slat’s reply to my article only increases my alarm. The Ocean Cleanup underestimates the negative impacts they will have and are not looking at the scientific evidence to the contrary.

The concerns of myself and others are very well-founded, Mr. Slat. You may be putting whole ecosystems at risk, and threatening species that were only recently discovered. Any attempt to suggest a “lack of scientific basis” for our claims only serves to prove what we’re already suggesting: that you’re not listening to scientists, and that you may be endangering an entire ecosystem as a result.

The post The Ocean Cleanup struggles to prove it will not harm sea life first appeared on Deep Sea News.

Introduction

The Ocean Cleanup, brainchild of Dutch inventor Boyan Slat, was in the news again this past week after announcing that in addition to the fact that their system is unable to collect plastic as intended, it suffered a mechanical failure. “Wilson” is currently being towed to Hawaii, where it will undergo repairs and upgrades, presumably to be towed back out to the garbage patch for a second trial.

I am not a mechanical engineer, so I don’t intend to comment on the details of their mechanical failure. I am, however, a sea-going oceanographer. Which means that I am used to the sorts of situations with scientific research equipment that was so succinctly paraphrased by Dr. Miriam Goldstein:

Designing for physics

But beyond the engineering, there are the questions of what the *physics* are that TOC are relying on for their system to be successful. Some of you may recall that the original design was to moor (i.e. *anchor*) their device in 6000m (20000 feet) of water, and let existing ocean currents sweep garbage into the U-shaped structure. Thankfully, they realized the challenges associated with deep-ocean moorings, and abandoned that idea.

The latest design iteration (misleadingly called “System 001”, as though they haven’t built and tested any other previous to it), is to have a freely-drifting system, avoiding the use of anchors. TOC claim that under the influence of current, wind, and waves, their design will drift *faster* than the plastic — causing it to accumulate in the U, making for easy pickup. They summarize the concept with a little explainer video on their website, with a representative screen shot below:

Based on a quick Twitter rant that I had after thinking about all this for a few minutes (see here), I wanted to explain out the various points that have either a) been missed by TOC design team, or b) deliberately excluded from their rosy assessment of how they expect their system to actually collect garbage. What follows is a “first stab” at a physical oceanographic assessment of the basic idea behind “System001”, and what TOC would need to address to convince the community (i.e. scientists, conservationists, etc) that their system is actually worth the millions of dollars going into development and testing.

The premise

As outlined in the video, the premise of System001 as a garbage collection system is that through the combined action of wind, waves, and currents, the U-shaped boom will travel faster through the water than the floating plastic, thereby collecting and concentrating it for eventual removal. This appears to be based on the idea that while both the boom and the plastic will drift with the current, because the boom protrudes from the water (like a sail), it will actually move faster than the surface water by catching wind.

There are some issues with this premise. Or, at least, there are some real aspects of oceanography that have either been ignored or missed in thinking that such a system will behave in the predictable way described by TOC. I’ll try and outline them here.

Stokes drift

Any of you who may have had an introduction to ocean waves may have heard that during the passage of a wave, the water particles move in little circles (often called wave orbital motion). While not a bad “first-order” description, it turns out that for real ocean waves there is also some drift in the direction of wave propagation. This drift is named after Gabriel Stokes, who first described it mathematically in 1847 (see wikipedia article here).

The amount of drift depends nonlinearly on both the amplitude and the wavelength of the wave. For example, for a 0.5m amplitude wave with a wavelength of 10m and period of 10s (something like typical ocean swell), the drift velocity is about 10 cm/s right at the surface.

Of course, the Stokes’ solution describes the motion of the water parcels being moved by the wave. For those water parcels to then have an effect on anything in the water, one would need to consider the various components of force/impulse/momentum (i.e. our buddy Sir Isaac Newton). Needless to say, it seems obvious that a smallish piece of neutrally buoyant plastic will respond to the Stokes drift much more readily than a 600m long floating cylinder with a large mass (and therefore large inertia).

This alone could be enough to quash the idea of a passive propagating collection system. Mr Slat?

Ekman currents

While we’re talking about long-dead European fluid mechanics pioneers, any study of the effect of winds and currents wouldn’t be complete without a foray into the theories proposed by Swedish oceanographer Vagn Walfrid Ekman in 1905. What Ekman found was that when the wind blew over the surface of the ocean, the resulting current (forced by friction between the air and the water) didn’t actually move in the same direction as the wind. The reason for this is because of the so-called “Coriolis effect”, whereby objects moving on the surface of the Earth experience an “acceleration” orthogonal to their direction of motion that appears to make them follow a curved path (for those who want to go down the rabbit hole, the Coriolis acceleration is essentially a “fix” for the fact that the surface of the Earth is non-inertial reference frame, and therefore doesn’t satisfy the conditions for Newton’s laws to apply without modification).

Anyway — the consequence is that in an ideal ocean, with a steady wind blowing over the surface, the surface currents actually move at an angle of 45 degrees to the wind direction! Whether it’s to the left or right of the wind depends on which hemisphere you are in — I’ll leave it as an exercise to determine which is which. And what’s cooler, is that the surface current then acts like a frictional layer to the water just below it, causing it to move at an angle, and so on, with the effect being that the wind-forced flow actually makes a SPIRAL that gets smaller with depth. This is known as the Ekman spiral.

The actual depth that the spiral penetrates to depends on a mysterious ocean parameter called Az, which describes the vertical mixing of momentum between the layers — kind of like the friction between them. What is clear though, is that a small particle of plastic floating close to the surface and a 3m deep floating structure will likely not experience the same wind-forced current, and therefore won’t move in the same direction. Hmmm … that’s going to make it hard to pick up pieces of plastic.

What is a “Gyre” anyway?

The final point I wanted to make in this article (I have more, which I’ll summarize at the end for a possible future article), is to try and give a sense of what currents in the ocean (including in the “gyre” or in the region often referred to as the “Great Pacific Garbage Patch”) actually look like. The conception that there is a great swirling current 1000’s of km across is true only when the currents are averaged for a very long time. At any given instant, however, the ocean current field is a mess of flows at various space and time scales. An appropriate term for describing typical ocean flow fields is “turbulent”, as in an oft-viewed video made by NASA from satellite ocean current data.

To illustrate this, I took some screenshots of current conditions from the wonderful atmosphere/ocean visualization tool at earth.nullschool.net showing: ocean currents, surface waves, and wind.

These images illustrate the potential problem with TOC idea, by highlighting the fact that the wind, wave, and current fields of the ocean (including even in the “quiet” garbage patch) are highly variable spatially and temporally, and are almost never aligned at the same period in time. What’s more, is that the currents and waves at a given time and location are not always a result of the wind at that location. Eddies in the ocean are generated through all kinds of different processes, and can propagate across ocean basins before finally dissipating.

Similarly, surface waves have been measured to cross oceans (i.e. the famous “Waves across the Pacific” study pioneered by the transformative oceanographer Walter Munk).

Other issues

Following the “rule of three”, I tried to hit what I consider to be the biggest concerns with TOC system design and principle, from my perspective as a physical oceanographer. However, there are other issues that should be addressed, if the system as designed is really believed by the TOC team to be capable of doing what they say. And really, it seems like a crazy waste of time on behalf of everyone involved to have spent this much time on something if they aren’t sure it will even work theoretically … not to mention the money spent thus far. So, part of me *has* to believe that all the dozens of people involved care deeply about making something that might actually work, and they have studied and considered all the effects and potential issues I (and others) have raised.

Anyway, the other issues are:

• What is the actual response of the system to a rapid change in wind/wave direction? Wind can change direction pretty quickly, especially compared to ocean currents. What’s to prevent a bunch of accumulated plastic getting blown out the open end of the U after a 180 degree shift in wind but before the system can re-orient?
• What about wave reflection from the boom structure itself? It is a well-known fact that objects (even floating ones) can reflect and “scatter” waves (scattering is when the reflected waves have a shorter wavelength than the original ones), and it seems like this could create a wave field in the U that might actually causes drift *out* of the system.
• The idea that all wildlife can just “swim under” the skirt (because it’s impermeable) is not supported by anything that I consider to be rigorous fluid mechanics, aside from the fact that much of what actually lives in the open ocean are non-motile or “planktonic” species. There are a lot of communities in the open ocean that float and drift at the surface, and I see no way that if the System collects floating plastic as it is designed that it won’t just sweep up all those species too. The latest EIA brushed off the effect of the System on planktonic organisms by stating that they “are ubiquitous in the world’s oceans and any deaths that occur as a result of the plastic extraction process will not have any population level effects”. But that doesn’t take into account that the stated mission is to deploy 60 such systems, which are estimated to clean the garbage patch of surface material at a rate of 50% reduction every 5 years. It stands to reason that they would also clean the Pacific of its planktonic communities by the same amount.

The post The (ocean) physics of The Ocean Cleanup’s System 001 first appeared on Deep Sea News.

boon·dog·gle
/ˈbo͞onˌdäɡəl/

noun:  work or activity that is wasteful or pointless but gives the appearance of having value.

verb: waste money or time on unnecessary or questionable projects.

The end of 2018 was tough for the Ocean Cleanup and its founder, inventor, and CEO Boyan Slat.   In September, the 2000 foot-boom and supposed plastic collection device, was first deployed about 240 nautical miles offshore of San Francisco where it was tested for two weeks.  The boom was then towed an additional 1,400 miles off the West Coast, about halfway between California and Hawaii, to begin collecting plastic in the Great Pacific Garbage Patch.  This was supposed to be the first real-world proof of concept and trials of the device in the Pacific Garbage Patch.

Note that the previous prototype in the North Sea also failed at a shallower depth in calm seas. Of course, the next step is to build a bigger one and place it in rougher and deeper seas.

But in November, Ocean Cleanup stated the system was not holding plastic it collected.  This lack of plastic collection arose from the system moving too slowly at times to hold plastic within the U-shaped collection area.  The system is supposed to work by currents pushing plastics into the booms and nets.  Yet slow and complex currents in this region of the Pacific allowed plastics to float out of the device again.

In late December, 60-feet of boom had detached due to material fatigue.  Slat then indicated that this likely occurred due to wave action placing stress on the boom. The fracture was caused by material fatigue, he wrote. That’s likely because of the intense action of the waves that puts tremendous stress on objects in the water.

So to recap, the Ocean Cleanup system cannot either collect plastic or withstand the Pacific Ocean.

 In a September interview with NPR, he said the device averages about four inches per second, which his team has now concluded is too slow. The break in the barrier was due to an issue with the material used to build it.

However, both of these issues could have easily been avoided by more appropriate simulations, analyses, and information prior to construction and deployment.

When the material failure occurred, it wasn’t due to the result of a major Pacific storm. It was just normal wear and tear, Slat said

Understanding material stresses is a key component of an engineering project and one that is well understood before construction.   Note as well that the system is not something actually new, but is a modification of RO-BOOMS used in oil spill clean up since 1988.  I am confident the specifications for use and the ocean states the booms can operate in are well known by the manufacturer and previous users alike. [UPDATE: The booms used ar eno longer the RO-BOOMS.  It is a completely different design, a recent internal iteration which may explain the failure.]

And while currents are complex, a whole field of physical oceanography exists and provides readily the information to know the current regime in the area.  If more detailed temporal or spatial resolution is needed, the Ocean Cleanup team should have conducted more field studies to gain the data on the currents beforehand.    The Ocean Cleanup has always seemed poorly developed and executed, ignorant of the best science and data available, blatantly dismissive of critique, and far too hurried.

This rush to place the device in the ocean for both good publicity and for the feeling of accomplishing something is unproductive at best and dangerous at the worst.  And it clear that Slat is committed to an overly ambitious timeline no matter the consequences.

Founder & CEO Boyan Slat announced the news in a December 31 blog post, saying “setbacks like this are inevitable when pioneering new technology at a rapid pace”, and maintaining that ” these teething troubles are solvable, and the cleanup of the Great Pacific Garbage Patch will be operational in 2019″.
Read more at http://www.mysailing.com.au/latest/ocean-cleanup-s-20-million-plastic-catcher-breaks#1R7mecWOPU9tLbJl.99

I get no pleasure in saying I told you so but…

As noted in a recent article featuring Dr. Goldstein,

But a critic who has followed Slat’s project since he unveiled it more than five years ago said the failure was predictable and that systems deployed closer to shore stand a greater chance of slowing the deluge of plastics spilling into the world’s oceans.

“I certainly hope they will be able to get it to work, but this is a very difficult environment where equipment breaks, which is why you normally do things closer to shore, where things are easier to repair,” said [Dr.] Miriam Goldstein, director of ocean policy at the Center for American Progress

In 2014, Drs. Kim Martini and Drs. Miriam Goldstein, a physical and biological oceanographer, provided a detailed technical review of the feasibility study here at DSN. Note the two of them pointed nearly 4 years ago about these issues.

….The modeling studies severely underestimate potential loads and tensions on the moored array and boom. Therefore, they are insufficient to properly design a mooring concept and estimate potential costs…

Since the authors had access to ORCAFLEX, a professional software package to design offshore marine structures, a full-scale mooring array could have been modeled to estimate loads and tensions on the moored array, but was not.

Structural deformation of the array and loss of functionality by ocean currents are not addressed…

Yeah. So these exact failures were predicted four years ago.

As this article clearly lays out, we should focus our funding and time, on more promising solutions to the ocean trash problem.

The post The Continued Boondoggle of the Ocean Cleanup first appeared on Deep Sea News.

Gloop from gaby bastyra on Vimeo.

The post GLOOP. first appeared on Deep Sea News.

They deployed a 100-m long prototype

that is really 30-year old RO-BOOM technology

with some new fancy hardware.

Deployed in only 30 m of water

during a calm summer

the prototype failed after 2 months.

Because shackles.

It cost $2 million euros

and collected ZERO pieces of plastic.

If you, like me, are concerned about plastic in the ocean consider helping groups like The Ocean Conservancy who collected more than 18 million pounds of trash during the 2015 Coastal Ocean Cleanup or Mr. Trash Wheel and Professor Trash Wheel who has collected 1,050,540 lbs. of trash from Baltimore’s Inner Harbor since May 9, 2014. The problem of ocean plastic isn’t solved yet.

The post What did the Boyan Slat and the Ocean Cleanup do last summer? first appeared on Deep Sea News.

Why are they using RO-BOOM oil booms?

Andrew Thaler over at Southern Fried Science pointed this out. RO-BOOMS are commercially available oil containment spill booms that have been around at least since 1988. I would assume that something is known about their durability?

Yup, definitely a RO-BOOM.

Excuse my language, BUT WHY THE F** ARE THEY BLACK?

You just spent all this money to add a custom paint job to a floating advertisement potential maritime hazard and it’s one of the least visible colors at sea. I CAN’T EVEN.

Where are the booms?

There’s gotta be a notice to mariner’s out there somewhere. In case you don’t know what this is, it’s a public announcement that you have to put out when ever you deploy anything at sea. So people don’t run over it or anything cause it’s camouflaged.

Are these the booms the 1 km deployment planned for Japan will use?

ARE THEY? I NEEDS TO KNOW. They look a lot different from the booms that were tested at the Marin Facility. 

which also seems to be different than what was tested at the Deltares facility.

Do the maybe intended booms actually collect plastic?

No seriously, there seems to have been a lot of effort to test the structural stability, but no testing whether they actually collect plastic and debris. I would have liked to see them drag the barrier around a bit just to see before deploying a big and expensive mooring if it is indeed the one they are going to use. As the Feasibility study indicated, sometimes the barriers can’t collect plastic so it would be useful to know when this is.

How did they get funding EUR 0.5 Million from the Dutch Government?

Is there a public proposal? It would be great to see, especially since this is now a publicly funded project and it would be great resource for reporters interested in the project (instead of them asking Miriam and I to constantly peer review it…grumble grumble).

That’s all I got for now. Any more questions you can ask Andrew Thaler at Southern Fried Science who also has questions.

The post The Ocean Cleanup deployed a prototype and I honestly have A LOT of questions first appeared on Deep Sea News.

The results? You had better put most of your 29 giant plastic scooping machines close to where the biggest litter bugs reside, near coastal Asia. Where you shouldn’t put them? In the center of the North Pacific Gyre.

But it’s not all doom and gloom people, this study lends support for reducing plastic use and just stopping it from getting into the ocean. That’s why I think projects like the Baltimore’s Mr. Trash Wheel and Seabin are so awesome, they are stopping trash and plastic from getting into the ocean right now. And while it’s known that I am not an ardent fan of the Ocean Cleanup, and this is certainly not an endorsement, this study does lend some support for relocating the proposed array closer to the coasts in shallower water which would be easier to design, build and service**. Here’s to hoping the Ocean Cleanup takes the conclusions of this research to heart, but I’m not holding my breath since they are only oceanographers.

*This paper judiciously doesn’t address engineering or even feasibility, but rightfully so. It just assumes that no matter where a plastic sink was put it operates at 45% efficiency (the number put forth by the Ocean Cleanup people), which is all you need to figure out the best place for your ocean cleanup booms.

** This is totally ignoring that when the array is moved inshore, you might not be in international waters anymore, subject to maritime laws of different countries and will now have to contend with much more ship traffic and larger sea life.

REFERENCES:

P. Sherman and E. van Sebille. Modeling marine surface microplastic transport to assess optimal removal locations. Environmental Research Letters, 11(1):014006, 2016.

The post Where is the best place to put your ocean cleanup device? Not where currently proposed. first appeared on Deep Sea News.

2. One Fish. Two Fish. Red Fish… No Fish.

3. Snow Caps Cones for Everyone.

4. Too Many Lionfish on the Dance Floor.

5. I See Deadzones.

6. No Escape from Plastic Monstas.

7. Where Have All the Coral Reefs Gone and Where are all the Cod?

8. Goodness Gracious, Great Plumes of Oil…and Mercury…and all that other crap we put in the sea.

9. I’m all alone and there’s no zooxanthellae inside me.

10. Fin.

The post 10 Reasons Why the Ocean’s Struggle is Real first appeared on Deep Sea News.

“Artivism: An explosion of creativity, a marrying of art and activism”

Over the past three years, street artists across the globe have taken up their brushes, prepped their spray cans, and united for one common mission. To Save Our Seas.

From endangered species and coral decline to ocean plastics and loss of global biodiversity, these artists have depicted a myriad of environmental issues for all the world to see. Last year, I covered their decent upon the tiny Mexican island of Isla Mujeres under the conservation flagship PangeaSeed.

“PangeaSeed is an international organization who collaborates with members of the art, science, and environmental activist communities. They are dedicated to raising public awareness and education surrounding the conservation and preservation of sharks and other marine species in peril.”

In 2014, they created over 15 murals on Isla Mujeres alone that have inspired the community and thousands of tourists that flock to this summertime haven.

Recently, the extraordinary team at PangeaSeed, rallied the troops yet again, this time in Cozumel, Mexico. With over thirty supported artists, PangeaSeed nearly tripled this years mural count. An entire island brimming with beautiful ocean artwork. A bold statement to the current status and peril of our global oceans.

Below is just a small glimpse of the larger festival. If you would like to learn more about PangeaSeed or how to support this amazing conservation organization please visit: www.PangeaSeed.org

For more information about the SeaWalls project and other installations: www.pangeaseed.org/swmfo/

You can also view the other murals on Instagram @SeaWalls_ and @SeaWalls_Stories

#SeaWalls #SeaWallsMX #PangeaSeed #StayWild

The post The Art of Saving Our Seas first appeared on Deep Sea News.

This is a guest post by Chelsea Rochman. Chelsea is a post-doc at the University of California Davis. This is her fourth 

WARNING: Some content may not be acceptable for a younger audience. (Note from Miriam: It’s ok, Chelsea, nothing in this post is at all out of the ordinary for DSN. It’s salty in these here parts.)

Strange title you say? What can sex possibly have to do with the combination of fish and plastic debris? NO, this is not related to the recent news article regarding a strange object found in the stomach of a fish! Instead, it arises from a recent study performed in our laboratory whereby we were equally perplexed to find something very fishy (no pun intended!) in the testes of a male fish exposed to plastic marine debris.

Sex

Since the release of Rachel Carson’s Silent Spring in 1962, we have heard eerie stories about alligators with abnormal penises from exposure to DDT, amphibians with eggs in their testes from exposure to atrazine and snails turning hermaphroditic from exposure to tributyltin —all considered hard evidence for endocrine disruption.

Well, this all sounds frightening, depressing and/or a bit like a dark comedy sketch, BUT what is endocrine disruption really?? Well, put simply it is literally any disruption to the endocrine system. The endocrine system is the system in the body of an organism that controls our hormones. As such, it’s critical for functions we all know well including stress before a deadline, the infamous running high, the dreaded PMS, sexual pleasures and arguably most importantly, reproduction (critical to maintaining a population).

What does this have to do with fish??

Well, fish are often used in scientific research assessing the endocrine disrupting hazards of chemicals on wildlife. Fish are a) important for human consumption, b) arguably great ecological indicators of the health of aquatic habitats, c) sensitive to endocrine disruption and d) live in regions that ultimately receive our waste (ever read the phrase, “all drains lead to the ocean”). As such, fish are exposed to many of the chemicals produced and consumed by us and we must understand the hazards of the cocktail of contaminants entering our water bodies. This keeps researchers very busy, as the number of new chemicals synthesized and marketed has increased exponentially over the past fifty years.

OK… and plastic debris?

In the past, endocrine-disruption was not addressed when assessing the hazards associated with synthetic chemicals, and as a consequence chemicals once considered benign have become ubiquitous as environmental contaminants and threaten biodiversity. Similarly, hazards associated with plastic in marine habitats were also likely not addressed when assessing hazards associated with plastic products. Today, plastic debris is ubiquitous in the marine environment and is a contaminant of concern recognized by several countries and international organizations.

As I’ve mentioned before, plastic debris should be considered as a multiple stressor in aquatic habitats as a consequence of the physical toxicity and large mixture of chemical contaminants (i.e. ingredients and environmental contaminants that accumulate on plastic debris) associated with it. Several of these plastic-associated chemicals have been linked to endocrine disrupting effects. Bisphenol-A, now banned on baby products in several states including California and in Europe, can disrupt endocrine-system function. Furthermore, there is evidence that phthalates and nonylphenol, additives to several plastic types, are estrogenic. As such, plastic marine debris is likely associated with a mixture of endocrine-disrupting chemicals. As such, it is critical to assess if the plastic debris that thousands of animals associate with food could initiate any of these eerie hormonal effects described.

The story

Somebody has to do the dirty work, so we dove in and asked if fish experience endocrine disrupting effects when they eat our plastic waste for dinner. Some of you may remember this experiment from a previous blog post. What we did not share then, and will share here, are some troubling results sparked by hypotheses spun from one strange discovery: the very abnormal testes of a male fish fed marine plastic debris.

The image above shows the testes of a normal fish fed a control diet (left) next to the testes of a fish exposed to plastic marine debris (right). The testes of this adult male fish exposed to plastic marine debris has rather abnormal germ cell proliferation. We are unsure whether these abnormal germ cells will lead to intersex or reproductive impairment, but the abnormality of these gonads and the similarity to female germ cells is cause for concern.

Our results show early-warning signs of endocrine disruption in fish exposed to a mixture of plastic and sorbed contaminants, suggesting that plastic marine debris, reportedly ingested by multiple wildlife species, may alter the functioning of the endocrine system in aquatic animals.

Most importantly, we report evidence at the molecular and organ level, for disruption to the endocrine system caused by the “cocktail” of contaminants associated with polyethylene deployed in an urban bay. Of major concern should be the permanent effects that exposure can have during critical early- life stages of organism development, which may impair reproductive success and harm wildlife populations. Still, chronic exposure to environmentally-relevant levels of endocrine-disrupting chemicals can have an effect after maturity as reported here. Chronic exposure is typical of marine plastic debris as it accumulates in habitats and is a persistent material that can last for decades.

Current waste-management strategies for plastics remain ineffective, and in parallel global production of plastics continue to increase at an average rate of about 9% per year. Thus the current rate of infiltration of this material into aquatic habitats is likely to increase. Because there have been several reported incidents in wildlife of population declines resulting from the release of endocrine-disrupting chemicals, our results suggest the need for future studies to test hypotheses regarding endocrine disruption in wildlife as a result of exposure to the growing accumulation of plastic debris.

The published study is found here: Rochman et al., 2014, Science of the Total Environment.

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