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.

The post A story about fish, plastic debris and sex first appeared on Deep Sea News.

You may have heard me say it once, and I’ll say it again: the oceans are a toilet bowl for our waste. Throughout history, our solution to pollution has oftentimes been “dilution”. As a consequence, chemical pollution is now ubiquitous in our oceans as a result of industrialization, waste-management strategies (and/or lack thereof), natural disasters, etc….

Picture a watershed. Treated or not, our waste often finds its way into the oceans via rivers and streams, like arteries leading to the sea. As a consequence, ocean water, sediments and marine life are contaminated with pollutants (e.g., plastic debris, pesticides such as DDT, flame retardants such as PBDEs and metals such as lead and copper). Due to a large diversity of sources, all leading to our connected oceans, it can be VERY difficult to pinpoint the source of pollution when its fate is the aquatic environment.

As such, it becomes my job to try and solve this mystery and basically play detective on the open sea.  What puzzle am I trying to unravel? Well, I’ll warn you, it’s a trashy one…

Throughout my scientific career, I have been trying to understand whether marine plastic debris is a vector for chemical pollutants to accumulate in marine animals and marine food webs. Over the years I have collected several lines of evidence suggesting that it may be.

Scientific Evidence #1: Plastic is made of a large diversity of chemical ingredients, several of which can be hazardous at large concentrations (e.g., the monomers vinyl chloride and styrenes and the flame retardant PBDEs).

Scientific Evidence #2: When plastic becomes marine debris it accumulates persistent, bioaccumulative and toxic substances (e.g., the banned pesticide DDT and industrial chemical PCBs) and toxic metals (e.g., lead and cadmium).

Thus, plastic marine debris is associated with a cocktail of chemicals that can be hazardous. So, the next question is, can these chemicals accumulate in animals upon exposure?

Scientific Evidence #3: When plastic, that is allowed to soak in the ocean, is fed to fish in the laboratory, some chemicals transfer from the plastic to the fish tissue, thus bioaccumulating. We found greater concentrations of PBDEs in fish fed plastic that had been in the ocean versus fish fed no plastic at all or virgin plastic.

Scientific Evidence from other studies: Plastic ingestion occurs in hundreds of species, including 30 species of marine mammals, 41 species of fish, 119 species of seabirds and 6 out of the 7 species of sea turtles and plastic debris recovered from the oceans globally, even from remote regions, is contaminated with chemical pollutants.

ALL leading to the question: Does what we have observed in the lab occur in nature, i.e., does the plastic ingestion observed in wildlife cause the bioaccumulation of chemical pollutants found associated with marine plastic debris? As mentioned earlier, this is where it gets tricky and one must think like a detective, pulling together pieces of a puzzle to ask a greater question.

I was granted an opportunity to sail across the South Atlantic, leaving from Brazil, with 5Gyres aboard their sailboat, the Seadragon. Despite the fact that I get horribly seasick, I jumped at the opportunity and raised enough funds (from the public!) to spend 4 weeks at sea in some of the worst weather I’ve ever experienced in my life with 12 strangers cramped into a small, small space. After fixing our main sail twice, repairing our water maker several times, and almost running out of fuel we made it to Cape Town, South Africa safe and sound. The experience was a mixture of horrible and awesome all at the same time! Would I do it again? Probably.

While at sea, we sampled lanternfish, plastic debris and water. 

We chose lanternfish because they are known to eat plastic debris in open ocean gyres and these fish are good indicators of contamination in the local environment. They make vertical migrations to the surface to feed, which is where plastic debris accumulates and eat low on the foodchain, mostly zooplankton. As such, one might expect that chemical body burdens in these fish would be similar to patterns in the water column where they were sampled. But, if they were exposed to plastic debris and were ingesting this material, we might expect their chemical body burden to be similar to the plastic debris.

Our objective was to determine if fish living in areas with large accumulations of plastic had larger accumulations of plastic-related chemicals. Thus, we analyzed all samples for a mixture of contaminants that are known to be associated with plastic either as an ingredient and/or that accumulate from the water column (BPA, alkylphenols, PBDEs and PCBs). Each analysis revealed the contamination pattern in each sample. These patterns each provide a piece of the puzzle that could be put together to understand if we could detect the presence of chemicals from plastic in wild-caught fish.

Because this study was conducted in the open ocean, we observed a lot of variability. There was plastic and chemicals contamination in every sample, and concentrations and amounts were variable along our cruise track. Still, one pattern stood out above all else…

The flame-retardants PBDEs are added to plastic products to, as you might have guessed, keep them from going up in flames. These compounds are composed of 2 aromatic rings with differing numbers of bromines. The higher brominated compounds are often used in plastics today and can be found on some plastic products in large concentrations. We found that most of the plastic debris we sampled had a large amount of these higher brominated congeners relative to the lower brominated PBDEs. In water samples, we found an opposite pattern, that 100% of the PBDEs in water samples were these lower brominated congeners. As such, most of the fish we sampled had congener patterns similar to those in the water column. However, some fish had relatively large amounts of higher brominated PBDEs in their tissues and these fish happened to be caught in areas with relatively larger amounts of plastic debris. We found that the amount of higher brominated PBDEs in fish tissue was positively correlated with the amount of plastic sampled in the area. So, our data suggests that YES, chemicals from plastic can accumulate in fish and that higher brominated flame-retardants may be indicative of plastic ingestion in wildlife.

Adding strength to our evidence, others researchers in Japan and at CalEPA have come to the same conclusions finding similar patterns with higher brominated PBDEs and plastic debris in wild-caught fish and seabirds in the North Pacific.

So while it can be difficult to determine the sources of contaminants in nature, good detective work can lead to a greater weight of evidence to better understand sources of chemical pollutants, even in the vast open ocean. And in this case, it seems that the current state of the evidence suggests that marine plastic debris can be a vector for chemical pollutants to accumulate in marine animals and thus potentially marine food webs. So now I’m on to the next piece of the puzzle: how might this affect humans, who sit at the top of some marine foodchains, when our diet includes seafood?

The post Guest post: Playing Detective in the Great Blue Sea first appeared on Deep Sea News.

The long and windy path to a Ph.D. is lined with blood, sweat and tears. Like a roller coaster, it can be filled with joy, anxiety, fear and even nausea. This story is regarding one chapter of my dissertation, one that filled me with all these emotions and lead me to the conclusion that even in science, sh%* happens. But in this story, what we could not control lead us to better scientific conclusions with greater environmental realism. Due to what may seem like an experimental shortcoming, we were able to answer an important “so what?” question related to plastic marine debris.

Today, it’s nearly impossible to avoid the many images of marine mammals, birds and turtles entangled in plastic debris or washed up with large plastic items in their digestive tract. What we don’t see, but may question, is how the chemical pollutants associated with plastic debris interact with marine life and potentially our seafood.

When plastic becomes marine debris it accumulates several chemical pollutants swirling in seawater such as pesticides (e.g. DDT), industrial chemicals (e.g. PCBs) and metals (e.g. lead) adding to the several potentially hazardous ingredients (e.g. PBDEs and bisphenol A) already in the plastic material. Thus plastic debris presents a “cocktail” of chemical contaminants to marine animals when mistaken as a meal.

As such, it has been hypothesized that plastic debris acts as a transporter of these chemicals, several of which can be toxic at certain doses, to animals upon ingestion. While we have strong evidence that hundreds of species eat plastic debris, and several case studies showing that plastic ingestion can physically harm an animal, we have little evidence of the fate of chemicals associated with plastic debris when ingested by marine life.

In our laboratory, the Aquatic Health Program at UC Davis, we designed an experiment to determine if plastic ingestion is indeed a mechanism for persistent organic pollutants (POPs) to accumulate in marine life. Because we wanted to understand how marine plastic debris might interact with both ecology and human health, we chose to conduct our study using fish, suggested as a good indicator of ecosystem health and a common seafood item.

To do this, we devised a rigorous controlled experiment, using clean laboratory-reared Japanese medaka and a contaminant-free diet made in the laboratory. This way we could be sure any contamination in our fish was a product of plastic ingestion. We also bound the plastic to the diet in our two plastic treatments so we could be sure these fish were eating the plastic. OR SO WE THOUGHT…

Similar to nature, and even with our best efforts, sometimes controlled laboratory experiments are not as controlled as planned… Instead, all 3 diets (negative control, virgin polyethylene and polyethylene marine debris) turned out to be contaminated with POPs (as cod liver oil is an ingredient in our formulated diet). Moreover, the plastic particles completely dispersed from the diet when sprinkled into the fish tanks at each feeding.

Immediately, we began to panic. We feared our fish would not eat the plastic at all and if they did that it would be impossible to decipher contamination from plastic versus contamination from their diet. After several days of freaking out, worrying all our work had gone to waste, what seemed to be a catastrophe became a blessing in disguise. HALLELUJAH!!

DUMB LUCK #1: The oceans are a toilet bowl for chemical contaminants, including POPs. As such, these chemicals are ubiquitous in marine foodwebs in the absence of plastic debris. While it is well-known that these chemicals contaminate plastic debris, and there is some evidence that these chemicals transfer to animals (e.g. lugworms) upon ingestion, it is not clear if the source of POPs from plastic to marine animals matters in an already contaminated system. What I mean is: in the presence of plastic debris, is an organism at risk of accumulating a higher dose of POPs? As a consequence of the contamination in the cod liver oil, we were able to examine this question because our experiment included contamination in the foodchain (i.e. the diet) of all treatments with the addition of more POPs on the polytethylene in the marine-plastic treatment.

DUMB LUCK #2: The plastic did not bind to the diet and instead, upon feeding the fish, the plastic dispersed and floated independently in the water as it does in the real world. Fish were not force-fed plastic, but instead were exposed to it and had to “choose” to eat it. In this way, we were able to consider the dose of plastic to the fish in amount of plastic per volume of water. As such, the exposure concentration of plastic floating in our tanks was less than some of the largest concentrations found in the “garbage patches” of the subtropical gyres, and thus environmentally relevant. And to our surprise, the fish ate plastic and continued to do so for the entire 2 months!!

Thus, with a lot of hard work and good attitudes regarding laboratory mishaps, our experiment became ecologically relevant. Initially, we were only able to ask the mechanistic question: “do contaminants on plastic transfer to fish upon ingestion?”. Instead, we could address the more relevant question, “is plastic, at real-world concentrations, an important vector of contaminants to the foodweb, despite widespread and global contamination of these chemicals in seawater, sediment and the marine food chain?”.

After a 2-month exposure to plastic, the concentrations of POPs in the fish demonstrated that despite contamination in the diet, concentrations of POPs were greater in fish fed plastic with sorbed chemical pollutants. For some chemicals, this significantly greater concentration in fish suggests that plastic debris can be an important vector of POPs into marine life and thus potentially into the seafood we put on our own plates.

For more information, check out the published study, and feel free to ask questions in the comment section.

The post Guest post: The invisible consequences of mistaking plastic for dinner first appeared on Deep Sea News.

For those of you without an iron stomach, hang out in the #DSNSuite more often or, a more palatable version:

The Dirty Martini

2 oz gin

1 tbsp dry vermouth

2 tbsp olive juice

2 olives (and an extra bowl on the side so I can put them on my fingers and eat them…cause I’m cool like that)

How to Dirty your Martini:

1. Place an ice cube and a small amount of water in a cocktail glass. Place in freezer for 2 – 3 minutes. 

2. Fill a mixer with all ingredients including garnish. Cover and shake hard 3 – 4 times. 

3. Remove cocktail glass from freezer, and empty. Strain contents of the mixer into the cocktail glass, include one of the olives, and serve with a mysterious smile.

The post The Dirtiest of Martinis first appeared on Deep Sea News.

The intertidal can be a pretty rough place to call home. You have to deal with what seems like a whole web of trophic levels trying to eat you, the constant headache of that damn sun drying you out, and let’s not even get started on the whole wave action problem. Needless to say, for most inhabitants, it can be a downward stressful spiral straight into depression.

Luckily for these seafaring sufferers, more and more antidepressant medications are making it to the intertidal these days! From fluoxetine (Prozac) and fluvoxamine (Luvox) to venlafaxine (Effexor) and citalopram (Celexa), active pharmaceutical ingredients (APIs) are creating an over-the-counter, wastewater cocktail rendering a whole slew of note-worthy side effects you might not exactly find on the label.

Most recently, scientists from Gettysburg College and the University of Flordia, discovered that when exposed to varying doses of these popularly prescribed medications, certain marine snails just couldn’t get a grip. Literally.

Depending on the species and the concentration of exposure, antidepressants would cause snails to suffer from “foot detachment” and be unable to hold onto their petri dishes. (I think we should take this moment to be thankful that the “foot detachment” side effect has yet to be witnessed in human trials.)

Though they don’t yet know why different snail groups are more sensitive than others, scientists can give us insight into the physiological mechanism behind how  antidepressants are causing such snail side effects.

The connection is serotonin. For humans, antidepressants work as selective serotonin reuptake inhibitors. Essentially, that’s a big, fancy way of saying they help your brain in regulating your happiness hormones. In snails however, serotonin works a bit differently and more along the lines of locomotion and movement. Thus, when these systems are disrupted, detachment can ensue.

Now most snails will flat out tell you…for the reasons stated above…detachment just won’t do. Unless someone decided to use that new NeverWet stuff and make a snail slip and slide (which my labmate and I may or may not have seriously thought about), nothing good will come from loosing foot power in the intertidal. If the waves don’t take you away, the birds will.

Currently, environmental concentrations of antidepressant waste and other pharmaceuticals are not necessarily at foot detaching levels (though they can accumulate to them). Studies such as these are important however, in that they give us a look at how sub-lethal chemical concentration are disrupting critter behaviors and offer a foreboding warning as to the influences of human run-off in the marine environment.

{Resources}

P.P. Fong and N. Molnar. 2013. Antidepressants cause foot detachment from substrate in five species of marine snail. Marine Environmental Research. 84: 24-30.

The post The side effects NOT on the label first appeared on Deep Sea News.

For the most part, experiments in ecotox are fairly cut and dry. Expose organism A to increasing concentration of potentially harmful chemical B and determine at what dose you see a response. In this system, we often expect that with an increase in concentration we increase the likelihood of an adverse effect. This “dose makes the poison” ideology can be traced back to the original gangster of toxicology himself, Paracelsus.

The traditional dose-response model comes in one of two delicious flavors: The linear response and the threshold response (witness epic powerpoint graph making below). The linear response represents a direct relationship between a nasty chemical and a negative effect, most usually your test organisms floating upside down in the porcelain throne, though there can be other adverse outcomes associated with critter behavior. The threshold response on the other hand depicts an organism that can tolerate low doses of a chemical to a certain point and then ends up on the same stairway to heaven or highway to hell (take your pick) as the linear response organism. Either way, no good can come of this. However, such information on lethal doses is critical for chemical management purposes.

Recently however, whilst being stumped by my own data, a rather brilliant ecotox friend shed light on the elusive third model known as Hormesis. I know, I know… it sounds like parseltongue, but I checked with some of my peeps over at Hogwarts, rest assured. It’s not.

The hormesis concept puts a very different spin on the original models. Instead of the negative or neutral responses predicted by the linear and threshold examples, organisms undergoing hormesis have a positive response at low chemical concentration levels.

What does this mean exactly? Well, let’s put it in a different context we can all better relate to shall we?

Scenario: You walk into your favorite club/bar and you are ready to get down with your bad self. Looking at our graph, we will put the DSN poison of choice on the x-axis (subliminal advertising so maybe they will give us free stuff) and our favorite sleazy scientist on the y-axis to represent “amount of game” as our response variable. Experiment is a go.

Drink one: You are doing good. Maybe even working up the courage to bust a move or two? Who knows the night is young.

Drink two: Oh man, you are living large and sitting pretty. You are here for the ladies and the dranks and ain’t no one going to stop you. You are at the peak of your game.

Drink three: This is where you become “that guy.” All game is slowly (or quickly) going out the window.

Drink four: Even Ke$ha would be embarrassed for the hot mess you have now turned into.

Drink five: If you are still conscious at this point. We should be friends. However, this is highly unlikely.

Note: Usually when your test organism keels over from alcohol poisoning, it’s safe to say the experiment is over.

This faux, but oddly realistic example provides a perfect depiction of hormesis. At low doses of a toxin, your performance is actually heightened until your alcohol just becomes too much to handle. Why does this happen? Though this response has been seen more and more frequently in many ecotox experiments, the mechanism is a bit more difficult to get at. Some speculate however, that this phenomenon stems from an organism being able to utilize certain chemicals to their benefit or that the chemicals are putting their systems into overdrive mode, thus eliciting a positive response till they can no longer handle the increasing toxic effects.

It’s like Kayne (or Daft Punk depending on your musical preference) always says, “That that that that don’t kill you…”

References:

Calabrese EJ, Baldwin LA (2003) Toxicology rethinks its central belief: Hormesis demands a reappraisal of the way risks are assessed. Nature 421: 691-692

Calabrese EJ, Baldwin LA (2003b) Hormesis: the dose–response revolution. Annu Rev Pharmacol Toxicol 43: 175–197

The post Hormesis: Why drinking in moderation might actually improve your game first appeared on Deep Sea News.