The ocean has long been the end of the pipe for plastic pollution, with ocean wildlife bearing the brunt of the overproduction and overconsumption of single-use plastics. The world now produces more plastics than at any point in history—hundreds of millions of tons each year—and more than 11 million metric tons are flowing into the ocean annually. That is equivalent to more than a garbage truck’s worth of plastics entering our ocean every minute.

How does plastic kill ocean animals?

When swallowed, these plastics can be deadly—causing blockages, twisting organs or even puncturing organ walls. Ingested plastics have been found in nearly 1,300 ocean animal species, including every family of mammals and seabirds, and all seven species of sea turtles. Concern about the ecological implications of plastic-induced death rates has fueled calls for policy solutions at every level of government, from the local to the international. However, it is hard to set policy goals without understanding the measurable risk plastic ingestion poses to these species.

Ocean Conservancy scientists, along with top researchers at the University of Toronto, Federal University of Alagoas in Brazil and the University of Tazmania, worked together to answer the question: how much plastic is too much? They sought to determine how much ingested plastic is likely to cause death in seabirds, sea turtles and marine mammals. In other words, we sought to figure out the actual number of pieces and volume of macroplastics (plastics greater than 5 milimeters) that those animals must have in their gut to cause death 90% of the time.

How much ingested plastic does it take to kill an ocean animal?

We compiled data from more than 10,000 necropsies—animal autopsies—of seabirds, sea turtles and marine mammals collected between the years 1900 and 2023 where we knew both the cause of death and whether and how much plastic the animal had eaten.

The results were alarming. We were surprised by the very small amount of plastic it takes to kill a seabird. We found that rubber (the kind balloons are made from) is the deadliest form of plastic to seabirds when ingested. It only takes six small pieces of rubber—each, on average, smaller than a pea in size—to kill a seabird.

Sea turtles are also surprisingly vulnerable, given their massive size: Less than half a baseball’s worth of plastics is likely to kill one in two Loggerhead turtles. Shockingly, nearly half of all sea turtles in our database had plastics in their guts at their time of death, which is especially troubling when you consider that five of the world’s seven sea turtle species are International Union for the Conservation of Nature (IUCN) red-listed as threatened.

Our models found that marine mammals are especially vulnerable to the impacts of lost fishing debris, also known as ghost gear; when swallowed, with just 28 pieces—each smaller than a tennis ball—enough to kill a sperm whale. Additional key findings from our research for each of the animal groups we studied include:

• Seabirds
  • About 35% of seabirds in our dataset had plastic in their digestive tracts.
  • Roughly 5% of seabirds who had plastics in them died specifically from plastic ingestion.
  • Hard plastics were consumed more frequently than all other material types, followed by soft plastics, fishing debris, rubber and foams.
  • When a seabird consumes only three pieces of rubber, like balloon shreds, our models predict there is a 50% chance this consumption will lead to the animal’s death.
• Marine Mammals
  • In marine mammals, fishing debris was the most frequently ingested plastic material, followed by soft plastics, rubber, hard plastics, foam and cloth.
  • Roughly 12% of marine mammals in our dataset had plastic in their digestive tracts.
  • Nearly 6% of marine mammals from our dataset with plastics inside died as a result of eating those plastics. 
  • When a marine mammal consumes just 12 pieces of soft plastic—like grocery bags—our models predict a 50% chance this action will lead to the animal’s death.
  • Half a soccerball’s worth of soft plastic (by volume) is enough to kill 90% of individuals in most seal, sea lion, dolphin and porpoise species. 
• Sea Turtles
  • In sea turtles, soft plastics like grocery bags were found to be the most frequently ingested plastic material, followed by fishing debris, hard plastics, foams, rubber and cloth.
  • Nearly 50% of individual sea turtles in our dataset had plastic in their digestive tracts
  • About 9% of turtles that ingested plastic in our dataset died as a result of eating it. 
  • Over 4% of all turtles in our dataset died directly from plastic ingestion. 
  • Just 1.5 golf ball’s worth of plastic (by volume) is enough to kill 50% of adult loggerhead sea turtles.

What can this research do?

This research emphasizes the risks macroplastic pollution poses to the life of marine animals, and the risk varies by species and plastic type. Our findings provide key insights to inform future research and policy actions aimed at reducing plastic pollution and the harm it causes to ocean wildlife and ecosystems. These results also underscore that important interventions like beach cleanups and better management of plastic waste are critical for protecting marine species. Because some types of plastics are deadlier than others when swallowed by marine life, policies targeting those specific items (e.g., plastic bags and balloons) can play an important role in protecting vulnerable species from the harms of plastic pollution in the future.

It is imperative to tackle the global plastics crisis by taking actions at all levels, from local to federal to international. In the U.S., bills like the REUSE Act—bipartisan legislation that would require examination and enhancement of existing reuse and refill systems—is just one way to make a difference. Add your name now and call on lawmakers to support and pass the REUSE Act.

The post Does Eating Plastics Really Kill Ocean Animals? appeared first on Ocean Conservancy.

Does Eating Plastics Really Kill Ocean Animals?

From DAAD Summer School to Doctorate: Reflections at ICON 9

Hi! I am Riel Carlo O. Ingeniero from the Chemical Oceanography Department at GEOMAR. I recently had the opportunity to attend ICON 9 (International Conference on Nitrification and Related Processes) last July 2025, one of the leading conferences focused on advances in the nitrogen cycle. It was an honour to be selected to present my research twice – first during the Early Career Workshop on the opening day, and then through a poster presentation on the second day of the main conference.

ICON 9 brought together many of the most prominent names in marine nitrogen cycle research. I was fortunate to meet and engage with inspiring scientists, including Dr. Boran Kartal, Dr. Hanna Marchant from the Max Planck Institute in Bremen, Dr. Claudia Frey from the University of Vienna, Dr. Scott Wankel from Woods Hole Oceanographic Institution, Dr. Bo Thamdrup from the University of Southern Denmark, and Dr. Qixing Ji from HKUST. I also had the chance to see Dr. Bess Ward in person, someone whose work I’ve long admired.

The conference was hosted by the Max Planck Institute for Marine Microbiology in Bremen, a place that holds deep personal significance. I first visited it 13 years ago during a DAAD International Summer School Biodiversity: Diversity of Ecosystems, Genes, and Species at the University of Osnabrück. That visit, including a tour of the Max Planck Institute and MARUM led by Prof. Dr. Rudolf Amann, played a pivotal role in my decision to pursue a career in marine science.

I recently completed my doctorate at Kiel University in June this year, and I am incredibly grateful for the excellent education and world-class research environment that Germany offers. Under the supervision of Prof. Dr. Hermann W. Bange and funded by the DAAD Research Grants – Doctoral Programmes in Germany and the SO305-BIOCAT-IIOE2 project, I have had the opportunity to work on cutting-edge research in marine biogeochemistry, with a particular focus on nitric oxide (NO) dynamics in the ocean.

Presenting in front of over 100 participants during the ICON 9 was not only a rewarding experience but also excellent preparation just days before my doctoral defense and oral examination. Overall, ICON 9 was a meaningful and inspiring milestone, a full-circle moment in my scientific career. 

Special thanks to FYORD and Kiel Marine Science for supporting my growth as an early-career marine scientist.

Riel Carlo

15th International Conference on Palaeoceanography, India

When my Uber wound through the chaotic traffic of Bengaluru at 2 am, I knew this conference would be different from the ones I was used to in Germany. I had just arrived in India for the 15th International Conference on Palaeoceanography (ICP15), supported by the FYORD Travel Grant, and was about to spend a week combining science with new cultural impressions.

ICP is a conference with a unique size and structure. It takes place only every three years, and everyone in the field is looking forward to the meeting – indeed, it rather feels more like a “big get-together” than a conference. The program is linear, with one topic per day and no parallel sessions. This allows for focus and provides more room for discussions. I also had the feeling that this format is more comfortable for Early Career Scientists. You don´t have to plan a lot in advance, and you never feel like you´re missing out on anything. But perhaps the best way to capture the spirit of ICP is to take you on a walk through a typical day:

The days started with a short ride in one of the green-yellow tuk-tuks to the conference venue, which was located in one of the few green spots of the city on the campus of the Indian Institute of Science. The mornings were covered by talks by invited speakers. Actually all talks at ICP are only given by invited speakers, and you can only be selected for a talk once in a lifetime! Accordingly, we were able to enjoy some excellent presentations. Before lunch, there was a long plenum discussion with the five speakers from the morning. It was not only a great opportunity to hear different opinions on specific sub-topics, but also to show the connections between different talks, highlighting the most urgent research topics and gaps different groups are currently working on.

During lunch break, we could choose between a variety of typical Indian foods. Even though the chefs took care that the food was not too spicy for the foreign wimps, you never knew if you would sweat after the next bite. The highlight was definitely the daily Dosa, a South Indian speciality: It´s a thin, savory and crispy fried pancake made from fermented dough served with chutneys and sambars.

Long poster-sessions took place in the afternoons. All posters were put up during the whole week, which is also a big difference from huge conferences, where you usually just have a slot of one day or a few hours. It was enough time to look at the other posters, get inspired and exchange ideas. I also presented a poster with the results of the first two years of my PhD, in which I investigate climatically controlled changes in sedimentation at a site in the Southern Ocean close to Antarctica. We were able to link these changes on glacial-interglacial time scales with the ocean circulation and gain insights into the evolution of deep-water formation during times of rapid warming. Onall days, I had fruitful discussions about my work with experts in the field.

Each day was concluded with a perspective lecture by leading scientists fromthe different fields. These lectures were inspiring and an amazing summary, as they provided a broader context and deep insights into challenges and directions of palaeoceanographic research.

With the end of the scientific program, networking was not over yet, but had just started. The evenings offered a great opportunity to approach people and get into contact in a casual atmosphere. Whether at the icebreaker, conference banquet or at the Palaeomusicology Concert – another ICP tradition, which goes back to Nicholas Shackleton, paleoceanographer and skilled clarinet player. It´s an evening where the musical ones among the scientists show their skills. Singing, bagpipes, and even a small spontaneously formed band made the evening unforgettable!

Looking back, I am grateful for the opportunity to attend ICP15 with the support of the FYORD Travel Grant. It was both a scientific and cultural experience, and a great chance to meet old and new friends and colleagues. I can highly recommend ICP to other early career researchers in the field due to its unique format and special atmosphere!

Moritz

Gordon Research Conference in Animal-Microbe Interactions

My name is Igor Duarte, and I am a third-year PhD student at the Marine Symbiosis Lab, where we explore the origins and molecular novelties of close associations between bacteria and marine animals. The partnership I am mostly focused on in my PhD is between a free-living, mouthless flatworm from the genus Paracatenula, and the chemosynthetic bacteria from the genus Candidatus Riegeria that live inside its cells. In this system where no mouth is present to let nutrients in, the bacteria and are chemosynthetic, which means. After hundreds of millions of years of coevolution, this highly specialised symbiosis is now the only way by which each of these organisms can survive, and a topic of high interest to understand the evolution of such longstanding partnerships.

The FYORD Travel Grant programme supported my participation in the Gordon Research Conference (GRC) in Animal-Microbe Interactions, which this year took place in Portland, Maine, USA. Throughout the five days of the Conference, about 180 attendees from all over the world shared their main findings from the field of symbiosis, including the topics microbiome, intracellular microorganisms, parasitism, and evolution and molecular novelties of symbiotic associations. Additionally, the event was combined with a Gordon Research Seminar, which allowed early-career researchers to network more freely and exchange experiences from each one’s PhD and postdoctoral trajectories. I had the opportunity to present a poster entitled “Clade-specific genome evolution of Ca. Riegeria, the obligatory endosymbiont of a mouthless flatworm”, where I summarised the latest results from my PhD project.

What I liked most about participating in this conference was how nicely it was conceptualised, with the goal of creating a relaxed environment to foster relevant connections between new and veteran attendees. In such a set-up, not only was I introduced to cutting-edge methods which are being used to answer relevant questions from the field, but I also had the opportunity to discuss them directly with the authors. Another positive aspect was that the speakers were encouraged to share problems that they faced during their experiments to show what real science looks like and to showcase how such issues can be overcome. Overall, I believe the conference was a game-changer for my PhD as I could get to know the main researchers in the field, whom I had so far only read about, and build the feeling of being part of a diverse community of symbiosis-enthusiasts.

Igor

FYORD Travel Grant Reports: November 2025

It’s one of the best weeks of the year: Shark Week. As our finned friends get a lot of extra attention this week, I am reflecting on my love of sharks and the threats they’re facing. In fact, before I was an ocean plastics guy, I was a shark guy. And sadly, on a perfect sunny day in the tropics while searching for sharks, I also found plastics.

Two decades ago, I was researching these magnificent animals in the crystal-clear waters of the Turks and Caicos Islands (TCI) at the School for Field Studies. Each day, we’d take our research boats out in hopes of tagging juvenile lemon sharks to better understand their movements, site fidelity and nursing habitats in the shallow waters surrounding South Caicos. Every interaction with these animals was exhilarating, and quite often we’d get the bonus of spotting or tagging other species like bonnethead sharks, Caribbean reef sharks and even the awe-inspiring tiger shark—my personal favorite!

While out on shark patrol one Sunday afternoon along the eastern reef of South Caicos, I first encountered plastic pollution on a magnitude I had never previously seen. Due to the steep cliffs that backed the beach and the shallow reefs that protected it seaward, piles of plastics and debris that drifted over the reef and onto the sand remained stranded. And with little to no human access to these beaches in the early 2000s, the accumulations grew with each passing day.

Sharks are increasingly threatened by plastic pollution, primarily through entanglement and ingestion. At least 34 species have been reported entangled in plastic debris, although actual numbers are likely much higher due to underreporting. The most common item causing entanglement is abandoned, lost or discarded fishing gear (also known as “ghost gear”), though plastic strapping bands also pose a major risk. Looped plastics like strapping bands can constrict sharks, interfering with feeding and breathing.

Sharks are at risk from eating plastics, too. Plastic bags, plastic packets and even a boot have been found inside shark stomachs. And scientists believe microplastics may pose a particular risk to filter-feeding species like whale sharks, although hundreds to thousands of microplastics have been documented inside individual tiger and hammerhead sharks as well. There is still much more to learn and understand about the interactions and effects of plastics on sharks, but what is known raises concerns about the long-term impacts of plastic ingestion on shark health and ocean health more broadly.

It was on that same reef in South Caicos in 2006, during a break from shark patrol and long before joining Ocean Conservancy where I first participated in the International Coastal Cleanup® (ICC). And like the millions of ICC volunteers around the world who participate each year, I too collected data on every item I picked up. And with each item, I was more and more curious, asking the questions: “Where did these plastics come from? “How the heck did they end up here?” and “This can’t be good for ocean animals, can it?”

I would later learn that the piles of debris that littered that stretch of coast came from all over the Caribbean. This was also my first glimpse of how the brands and languages on plastics provide valuable information to trace where trash comes from, an approach I still use to this day in fieldwork around the world. Further, it showcased the interconnectedness of the waters and people throughout the Caribbean Sea and North Atlantic Ocean.

These early, formative encounters with ocean plastics have stuck with me over the past 20 years, as have the sights of sharks effortlessly navigating their natural environments in those TCI waters. It is something that is forever lodged in my memory, something I never forget or tire of. Sharks have existed in our ocean for more than 400 million years, and over this time, they have perfected every aspect of their design. However, sharks were never meant to contend with the plastic pollution that now overwhelms every dimension of their marine environment.

Today, the most harrowing fact this Shark Week is that the plight of sharks has never been greater. And the scariest thing in the ocean isn’t a shark, it’s plastic pollution. Join Ocean Conservancy for Plastic Free July and beyond and call on your elected leaders to phase out wasteful, harmful single-use plastics.

The post How are Sharks Affected by Plastic Pollution? appeared first on Ocean Conservancy.

How are Sharks Affected by Plastic Pollution?