Thank you everyone for writing in – this has been a wonderful conversation! I will try to come back and address any questions that I did not get to today, but I have to log off for now. In the meantime, please feel free to follow me on Twitter at @randirotjan or take a look at

I am the Principal Investigator of the Rotjan lab, focusing on marine ecology and global change ( The main goal of my work is to examine how marine species, communities, and ecosystems respond to the complex stressors emerging in the contemporary world ocean, and how they will respond to the future ocean change that we expect in the coming decades. Recent research in my lab found that some wild corals prefer feeding on tiny shreds of plastic trash, or ‘microplastics,’ over their natural food – even when the plastic is carrying bacteria that can kill them – and that seagrass is littered with microplastics. I am also the co-Chief scientist of the Phoenix Islands Protected Area [PIPA], which is a large (California-sized) marine protected area in the Central Pacific and the largest and deepest UNESCO World Heritage Site. PIPA has coral reef, open ocean, and deep-sea habitat.

Ask me anything about: -How is plastic entering all ocean food chains? - How did our research team come across these plastic discoveries (and harsh reality)? - What is the impact? - How can we help stop this? - How are humans harming the ocean and marine ecosystems? - What is the long-term impact? - How can humans help with ocean conservation? - What action can we take to make a positive, long-term impact? - How do marine protected areas work, and what can they accomplish? - What differences and similarities exist between wild and remote, versus urban and coastal ecosystems?

I am a Research Assistant Professor at Boston University in the Biology Department and in the Boston University Marine Program. I am a member of Women Working for Oceans (W2O) and the Explorers Club, and I’m on the Board of Directors for The Nature Conservancy – Caribbean, and the Friends of the Middlesex Fells.


Comments: 67 • Responses: 23  • Date: 

tessccc7 karma

How can I, as an average citizen with no scientific background, become more involved in protecting our oceans? What clubs can I volunteer for? What are some career options for people with business background to get involved in the world of environmental management and conservation?

randirotjan1 karma

There are already a lot of great responses posted below, so I'll add just a bit more... Make sure your elected representatives know that you care about our oceans! It's important that politicians know that your vote is dependent on their environmental values. I know that is a bit nebulous, but it is one of the most important things - individuals can do a lot, but major change is going to require government support. More locally, check out your environmental action nonprofits like the Sierra Club or The Nature Conservancy or others; A lot of those organizations do great work and always need volunteers to help or dollars to support them. Some of the hyper-local organizations can make a very big difference in a single area; where I live, the Friends of the Fells and the Mystic River Watershed Association have a huge impact on my watershed, which impacts the Boston Harbor. Hope this helps! ;-)

cflemsscientist5 karma

What exactly is a microplastic?

randirotjan6 karma

Microplastics are plastic pieces less than 5mm in size. They can be primary microplastics [deliberately made this size (microbeads, fibers)] or be secondary microplastics [originate as macro-plastic and degrade over time (i.e. a plastic water bottle breaking into fragments in the environment)].

hrycyna5 karma

As river advocates, we often say that most plastic in the ocean comes from rivers. First, is that true? Is that what the most recent research shows? In Atlantic as much as Pacific? Would efforts to reduce plastic pollution in rivers reduce microplastics in the ocean?

randirotjan6 karma

Approximately, 80% of all marine debris comes from land-based sources, the remaining 20% comes from offshore vessels/activities. Of the 80%, microplastic sources include clothing, tires, personal care products and city dust and are transported via road runoff, wastewater, winds and waterways (we just quickly reviewed this in our recent pub - Rotjan et al. 2019). According to Lebreton et al., 2017, approximately 1.15 and 2.41 million tonnes of plastic waste enter the ocean each year from rivers (74% of emissions occurring between May and October). Research on freshwater plastic pollution is an upcoming field and most has been done in industrialized countries of Europe and North America. However, the top 20 polluting rivers (mostly in Asia) account for 67% of the global total (Lebreton et al. 2017). Riverine input of microplastics can vary between rivers which is attributed to population density, levels of urbanization and industrialization, rainfall rates and the presence of artificial barriers such as weirs and dams (Labereton et al. 2017) - More research is needed to better understand freshwater contamination by plastic pollution, but the evidence is mounting - the Hudson River (NYC), for example, is a major source of microplastics (Miller et al, 2017 - As you are well-aware, the Mystic River is one of the most urban rivers in the world - I think it would be an important one to survey for microplastics. Efforts to reduce plastic pollution to river systems (i.e. artificial barriers) might help mitigate the input of microplastics into the ocean. Given that the top 20 polluting rivers are mostly in Asia, monitoring and mitigation efforts in those countries are necessary (i.e better waste management). To prevent plastics going into our watersheds, we are going to need a holistic approach that also tackles road tires… especially in highly urbanized areas, that will be a key problem to solve. Thanks Andy! :-) Keep our beautiful Mystic River watershed amazing!!

Brian_RC_Kennedy5 karma

Do marine protected areas really work?

randirotjan7 karma

Marine Protected Areas (MPAs) are one of (but not the only!) the key tools in the marine conservation toolbox. There is conflicting evidence, but that is likely because the zonation, maintenance and enforcement of MPAs is highly variable. Many MPAs are no-take, but not all are well-enforced. Still others \are* well-enforced, but are NOT no-take, and therefore still allow a substantial amount of exploitation. In the end, the concept of MPAs is one of the most tractable and promising tools we have available, and they certainly achieve the credo put forth by the medical community: “First, do no harm”. But most MPAs are relatively recently created, and I think time, money, and resources are needed to answer this question fully. On a more personal note, I work very closely with the Phoenix Islands Protected Area (PIPA), owned and operated by the Republic of Kiribati. PIPA is the largest and deepest UNESCO World Heritage Site on the planet, and recently closed to all large-scale commercial and extractive activities as of Jan 1 2015. A paper published in collaboration with SkyTruth and Oceana and published in Science (McCauley et al 2016:* looked at ship traffic (mostly related to tuna fishing) in PIPA pre- and post-closure and found that there was a dramatic reduction in ship traffic, suggesting that the MPA was effective in eliminating fishing pressure. Now, 4 years later, we are just starting to answer the question of whether PIPA is effective at protecting tuna (so stay tuned!).

thehilz3334 karma

What policy changes would be most impactful in helping to ensure the long-term preservation and health of our oceans?

randirotjan6 karma

We must address climate change. But simultaneously, we can’t forget all the other stresses and pressures that we (humans) are putting on ocean life. There is not a “one size fits all” answer to this, and the biggest problems facing one area may not be the same everywhere, so regional management is extremely important. For example the most important issues facing corals in the Florida Keys may be very different than the problems facing corals in the Central Pacific. Education and awareness are the first and most important things (I always say that we can’t fix problems that we don't know or care about), which is part of this AMA - so great job! As for policy changes, I think we need a sea-change. The UN is about to launch the Decade of Ocean Science, which I think will go a long way towards identifying the most urgent and important and immediate policy changes globally, and will help catalyze the holistic and global change we so desperately need.

Rapturos4 karma

Often times we (common-folk who aren't immersed in the subject) hear only the "doom & gloom" side of things. Can you share one fascinating or encouraging thing that has emerged from your research/studies?


randirotjan8 karma

Thank you for asking a happy question! YES, the Phoenix Islands Protected Area (PIPA) has had some incredibly encouraging data emerge in the past two years. NPR did excellent coverage of a PIPA reef regaining biodiversity after a bleaching event, see here:

Also, I’ve been working more and more in the deep sea (#DeepCoralsofPIPA) and we’ve found corals there that are thousands of years old. I love thinking about ancient organisms - they are fascinating in their own right, but also give me so much hope.

I’ve also seen the power of individuals: one person can truly change the world. It took one person to have the idea to create the Phoenix Islands Protected Area (not me!), but they started an unexpected catalytic movement of conservation across the globe. I have Rosie the Riveter in my mind as I write this: Let’s do this!

polychaos1 karma

I've worked with Randi a little bit, and I can say that if there's one takeaway from her conservation work it's that conservation efforts have an impact! The marine protected area in PIPA is a case-study for that. What we need to do is increase compliance with the rules of these types of areas, and to establish more of them!

randirotjan5 karma

Thanks polychaos!! Appreciated :-)

a1208003 karma

Do you personally think there’s a possibility that we can stop and turn around everything that is happening to our oceans?

randirotjan6 karma

We (humans) have already had a major impact on the world's oceans, but we are still learning how to measure the impact of our own footprint. Human populations are growing at an alarming rate, and I can’t see a path to total reversal. BUT, I’m still optimistic about the future! Step one is admitting the problem, right? Countries and people around the world are now realizing the effects we are having on the oceans: climate change, overfishing, pollution, etc, and for the first time in a long time, we are taking major steps to solve those problems. When I think about what Rachel Carson did to inspire the environmental movement, I am heartened - if she can do it, so can we. Momentum is building - join us. :-)

wolmanj3 karma

Do you have a favorite coral reef? If so, which and why? Are there any you haven’t visited? Why not?

randirotjan6 karma

How can you pick a favorite when they are all so different? Raja Ampat reefs (in Indonesia) are my favorite for biodiversity. Saudi Arabian reefs (Red Sea) are my favorite ones that I never thought I’d get the chance to see, until I did. Belizean Reefs are my “home” reef - I learned to be a coral reef biologist in Belize, and Caribbean reefs just feel comfortable and familiar. And Phoenix Islands reefs are the ones where I’ve spent the most recent professional effort, and the most conversation attention. Rhode Island reefs have secret New England corals. Sorry buddy - I love ‘em all. :-) And there are so many I haven’t yet been to - I hope I can get to them all before… well, before they’ve fundamentally changed forever. But I’m an optimist, so let’s just say: I hope I can get to more soon.

thejives3 karma

How do you work with journalists to make sure your science is accurately presented in news stories?

randirotjan3 karma

Hi Jives :-) This is a really hard skill to learn, and I’m not sure I have perfected it! But my advice is to think about your messaging in advance, and try to even craft some choice phrases or soundbytes that make the point really clear. You can also offer the journalist the opportunity to come back to you to fact-check (though they often cannot share their story with you to protect journalistic integrity). I also sometimes say something that I instantly regret (it comes out sounding weird, etc), and ask the journalist to strike that and give me an opportunity to re-answer. Yes, you can have do-overs! When it comes to talking about plastic/microplastic research in particular, it’s a loaded topic that definitely requires thoughtfulness. Plastics/microplastics are a challenging issue because they involves a wide variety of types (fibers, beads, bags, bottles, etc.) and polymers (polyester, polyamide, polyethylene, etc.). As such, it is easy for a reader to get lost in the details. So thinking about phrasing and what points are critical, versus which are “in the weeds” is something to be aware of. But you're the pro at this, and much of what I've learned, I've learned from you. :-) It takes a whole village. :-)

thejives2 karma

You’re a great partner to work with communicating important information, hopefully journalists realize they need to budget the time necessary get it right. The biggest enemy here is often tight deadlines with insufficient communication.

randirotjan3 karma

Agreed, thanks Jives. It takes a village - the world moves so fast these days. What's that quote? "Stop the world, I want to get off"?! :-)

mudpuppy182 karma

How do microplasics hurt coral reefs?

randirotjan4 karma

This is an important question, and the research on this is just beginning - not much is known. For starters, macroplastics have recently been found to correlate with the potential for disease incidence on reefs - And, it’s also known that corals can ingest microplastics. For example, Hall et. al 2015 noted the integration of microplastic particles by scleractinian corals and the presence of particles in waters adjacent to the Great Barrier Reef (2015). In the study by Hall et. al, microplastic particles were consumed and localized at a significant depth within the polyp, wrapped by mesenterial tissue making it difficult to remove from the polyp. Given that those tissues are primarily responsible for digestion, there is concern for the digestion of natural food sources being impeded. However, ingestion dynamics are most likely species-specific. For example, Chapron et al. found that the cold-water coral Lophelia pertusa experienced reduced skeletal growth rates when exposed to microplastics (2018). But for two shallow Caribbean reef species, no effect on calcification was shown as a result of ingestion (Hankins et al. 2018). Our recent research has shown that Astrangia poculata corals preferred microplastic beads and declined subsequent offerings of brine shrimp eggs of the same diameter, which suggests that microplastic ingestion can inhibit food intake (Rotjan et al. 2019). More research is needed to better understand the coral response mechanisms to microplastics, however some corals may use chemoreception to preferentially ingest microplastic particles (Allen and Rittschof 2017), which is super cool!

My awesome collaborator Koty Sharp had an awesome quote recently in IFLScience that I’ll re-post here:

"Nearly every surface in the ocean is coated with microbes, but bacterial communities on microplastics are different. In fact, they are so different that researchers have assigned a new word for them – the "plastisphere," added Sharp. "We are barely getting to know the plastisphere, and we know almost nothing about the fate of the plastisphere in the environment."

To me, the scariest part about plastics and corals is their potential for pathogenic microbes to hitch a ride. I think we collectively suffer from the delusion that when we do something in a human setting - be it use plastics or release CO2 or any other action - it only affects humans. But in reality, our actions are impacting all of the citizens of earth - all organisms and ecosystems. I hope people will be inspired by our article to make the necessary changes to clean up our world, if not for themselves, then for the corals.

thehilz3332 karma

What areas of marine research are the most underfunded?

randirotjan3 karma

Mine. And all of them. I have yet to meet a marine scientist who feels adequately funded. And yes, that's the understatement of the century. If you are looking to add someone to your philanthropic dance card, look me up. :-)

TheLegend1212122 karma

Is nuclear energy really that awful for our oceans and environment ?

randirotjan6 karma

I personally am a fan of nuclear power, but my lab has been informally debating this point and have not reached consensus. Given that, I'm uncomfortable giving a strong answer to this because I don't feel like I am as informed as I want to be. So, I'll simply say "I don't know", but I'll try to have a better answer for the next time I'm asked! :-)

UDBN_yaboi2 karma

If we didn’t care about the reefs at all and everybody stopped saving them, how much time would we have left to go see them? Ballpark.

And what reef would be the last one to die? In other words, which reef would have the best chance to win a hypothetical bar fight with microplastics, if humans didn’t have its back?

randirotjan4 karma

Oof, tough question. Well, I’ll start with the obvious punt: First off coral reefs are so awesome I can’t imagine why people would stop caring about them or stop trying to save them. :-) But I get your point. And of course, it is difficult for the average person who has never seen a reef, to connect to them, which is why popular books such as Coral Reefs by Maris Wicks are so important:

As for an estimate of how long they have I truly don’t have a guess. Some corals like Big Momma in American Samoa have lived for 500+ years, dealing with everything that we’ve done to the oceans so far. Why is she so resilient? Lots of scientists like Steve Palumbi and others are looking for strong corals that might be able to survive the coming future, or that have already survived the challenging past. In the Phoenix Islands, there are resilient reefs that have come back from severe bleaching ( - Mangubhai et al. 2018, Mollica et al. 2019, and others. Trying to find resilient reefs, and the mechanisms behind them, is at the cutting edge of current reef research, and many of my colleagues are doing some incredible research on these topics.

However, climate change aside, in a bar fight between microplastics and a coral, microplastics would most likely win in the end. Our research has shown that corals in the wild ingest, but survive, microplastics to some extent… but at some point, ingestion of too many microplastics will likely cause mortality. And if ingestion alone doesn’t kill them, the potential for pathogenic microbes to hitch a ride on plastics might. But then again…. Corals have one sucker punch move available: they are animals and have behavior. So maybe they will learn to avoid eating microplastics over time? That might prove adaptive if it’s possible. I think this conversation needs a beer. :-)

UDBN_yaboi2 karma

Thanks for the great answer! Let’s hope Big Momma learns how to punch plastic’s teeth in! 🍻

randirotjan1 karma


peaches23182 karma

Since it’s almost impossible to get rid of plastic in our daily lives and it’s very likely that the plastics will keep accumulating, what steps are being done to help remove and prevent micro plastics from bioaccumulating and potentially harming important food chains in the ocean? And what can we do to lower the amount of plastics in our lives? I know plastic ocean project is attempting to work with universities and local businesses to reduce the amount of plastic they use (mainly straws and plastic or styrofoam cups). But what can people actually do that can help reduce the plastics being put into the environment?

randirotjan4 karma

As a consumer, you can make educated decisions about the amount of single-use plastic that you use. A large emphasis needs to be put on reducing rather than recycling, due to the fact that most recycling practices are not as efficient as they should be ( That means reducing the amount of take-out plasticware, bags, and every-day plastics (plastic baggies, coffee cups, water bottles) in favor of paper and silicone products. A favorite of mine to use as an alternative to take out plasticware is a set of bamboo cutlery: ( I’m a mother of two kids, so I totally get it - this is certainly not easy, and I definitely make mistakes, but if we all implemented lifestyle changes to make single-use plastic simply not an option, we will reduce plastic waste! Let’s try it together. :-) However, I think it’s also important to remember that we need to fully revolutionize our systems, and that’s hard to do as a single individual. We need governments to help by regulating plastic use (and hooray for all of the plastic bag bans - California is on the verge of creating a state-wide ban, and there are 122 cities and town in MA (representing more than 50% of MA’s population) that have thus far made the commitment to ban plastic bags. These actions were made by individuals, and then affect whole communities.

That said, there isn’t a ‘one-size fits all’ solution to getting rid of plastic in our daily lives. Each type of plastic (i.e. bags vs. bottles; fibers vs. beads) requires its own mitigation/reduction efforts and not all of them may be via legislation. Some types of legislation at the local (see examples in New Jersey: and state levels have been successful in reducing plastic bags, for example, but only the Microbead Free Waters Act of 2015, banning microbeads in rinse-off cosmetics, was passed at the federal level. Non-legislative solutions can come in the form of products such as the Cora Ball by the Rozalia Project. Given that washer machines are a major contributor of microfiber pollution, the Rozalia Project has developed the world’s first microfiber-catching laundry ball to be placed in the washer machine with your clothes. My awesome hubby (who does all of the laundry in our house), just installed the Lint Luv-R, and… it’s SUPER GREAT! We’ve been really impressed so far. Here’s some more info:

At the end of the day, we are where we are now because we rely on lives of convenience, and plastics won the convenience war. In the recent past, when there were no plastics, we were able to accomplish what we needed to without plastics, but the infrastructure was different. We need to remember what we once knew, and push governments and consumers to think responsibly.

tabbycatartist2 karma

What are the differences between rural and urban marine ecosystems?

randirotjan5 karma

Urban marine ecosystems can be greatly impacted by dense human populations, which produce sewage, fertilizer runoff, coastal degradation, impervious surfaces, and other problems. Naturally existing coastal ecosystems, like marshes or mangrove forests, can naturally help to mitigate land-derived issues, but until recently, many of those “ecosystem services” were not factored in to urban coastal design. That is now changing. For example a recent design competition in Boston challenged the city to think about how it could live with water (and at the same time, try not to further pollute. Again, “first, do no harm”). Remote (rural) ocean areas have issues as well, and one of the challenging things is that the issues that once plagued only urban marine areas now reach open ocean. For example, microfibers from industrial and commercial waste have been shown to accumulate in the guts of deep sea organisms ( But the good news is that is we change our behaviors and practices on land, we can change what happens in the ocean. :-)

DCMcDonald2 karma

Are there areas of the sea experiencing more stressors than others? What are the reasons for the increase in those areas?

randirotjan6 karma

If there’s one thing I’ve learned in my time as a biologist, it’s that the biological world is complex and diverse. I have yet to see two places that are exactly the same naturally on their own, let alone in the face of varying stressors! Depending on the location, the stressor type, the resilience of the system, the season, etc, there are certainly differences and that complexity is what makes answering these questions so hard! That said, there are some overall trends and patterns by region or ocean province. For example, the Western Atlantic Ocean, where my lab at Boston University is located, is actually warming faster than any other oceanic province in the US ( Shipwrecks on Palmyra have been shown to have acute iron poisoning in the iron-poor Pacific that hurts corals Disease outbreaks in the Caribbean are ravaging reefs right now There are problems everywhere, but the optimist in me says that all of these problems are simply opportunities to find solutions… so let’s find ‘em!

riskarb2 karma

Coral reefs look so beautiful. It seems like eco tourism is a good way to get people interested in preserving them but the downside is swimming near the reefs can damage them. How do you balance these competing interests?

randirotjan3 karma

Coral reefs are indeed some of the prettiest places I have ever been in the world and sharing their beauty with people globally is an important step in raising awareness about the danger they are in. But, as you point out, ecotourism is a bit of a double edged sword; we don’t want to love a reef to death. However, there are ways to manage ecotourism -- in some places -- in such a way that the reef is protected while people are still able to experience it. Ecotourism also plays a very important role in helping to build an economic case for \some* Marine Protected Areas (MPAs), but ecotourism isn’t and shouldn’t be the only path to economic sustainability. In my opinion, there are some places that are too fragile to survive ecotourism, and some places that really should just remain untouched. But for the places where ecotourism makes sense, having tourist dollars flow into an area that used to be reliant on extractive processes for their economy can enable a conversation-based economy providing more money to the community and protecting the ocean around them. Like everything, the answer to this is complicated and nuanced (sorry). Bottom line: ecotourism makes sense in some places, but not in all.*

thewhitesuburbankid1 karma

What conservation/technological developments in your field do you feel most optimistic about?

randirotjan3 karma

I am most excited by the idea of huge datasets that can be combined to look at large scale trends within a single reef or across reefs. It has been said that humanity has created more than 90% of the data ever created in the last 2 years, and we are just beginning to learn how to use this much of these data. Until the last couple years, most ocean studies were based on relatively small data sets extrapolated to a global scale. This big data revolution has the potential to allow researchers to use much larger data sets to look for emergent behaviors of ecosystems on an unprecedented scale. Additionally, improvement with automation and autonomy of unmanned submarines will have a huge impact in being able to collect long time series in remote locations. So the research that is needed is partly in the computer science realm to develop new tools to parse and analyze these new giant datasets to make them useful. There’s also some pretty great new coral tech out there - the 100IslandsChallenge has developed some new coral tech that makes it possible to ask spatially-explicit reef questions on a fine scale -- it’s awesome.

UDBN_yaboi1 karma

Can you farm coral or keep it “in captivity” like an elephant? It probably wouldn’t be a solution to the plastics, but would something like that buy a little time or save some species as a backup plan?

I’m joining the coral conversation without much background. Kinda shooting from the hip here, so I apologize if these are dumb.

randirotjan2 karma

Your questions are great! We are happy to be hearing from non-scientists. Corals can actually be farmed in the ocean or in the lab (! Although I have no experience farming corals in a controlled environment, I was involved in a recent study involved with “outplanting” corals to see the impacts on fish recruitment (Opel et al 2017). But I have mixed opinions on gardening. It works really well for some species like Acroporids, but not for all. But there are many people who have more expertise in this field than me. :-) I recommend reading about work from Austin Bowden-Kerby in Fiji, who has been working extensively with coral gardening. A similar program in Belize called “Fragments of Hope” is also working on coral restoration. The Nature Conservancy-Caribbean also has a huge coral conservation science effort, which is doing really cutting edge work with microfragmentation in collaboration with David Vaughn, and community involvement in the DR. These efforts can help bolster populations of some corals, but underlying problems must still be addressed.

questifer1 karma

If you could invest 100% of your time addressing a single challenge facing the oceans, that you believed could be improved with your efforts, what would that be?

randirotjan1 karma

This is an interesting question, because each person has a different skillset, and thus a different way to contribute. Different skillsets might be better suited to helping with different challenges. For me, I am spending 100% of my time doing the things that academic scientists do, but all with ocean conservation in mind. For me, that is educating the next generation through classes and research mentoring, conducting novel research that hopefully will provide the platform for knowledge and policy, and working directly with governments and the UN on ocean conservation issues to hopefully move the needle on ocean conservation, globally. Plus outreach events like Reddit! ;-) So, that's my 100% (more like 150%!). But there is so much to be done - the oceans are 71% of our planet and we need EVERYONE on Team Ocean. :-) So, without knowing your skillsets and talents, it's hard to answer this Q, but I greatly encourage you to take the skills you have and apply them to the oceans, to whichever challenge best suits. We need to solve ALL the problems: We must address climate change, overfishing, nutrient pollution and all other stresses; we can't just solve one. So my best advice is to pick the most do-able thing for you and let's get started. :-) Thanks for the Q and for helping the seas!