‘Scratching’ more than the ocean’s surface to map global microplastic movement
FAU joins first-ever global effort to map microplastics’ path through critical ocean systems
Florida Atlantic University
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Tracy Mincer, Ph.D., co-author and an associate professor of biology and biochemistry in FAU’s Harriet L. Wilkes Honors College.
view moreCredit: Florida Atlantic University
Marine plastic pollution is a global crisis, with 9 to 14 million metric tons of plastic entering the ocean every year. Tiny fragments called microplastics – ranging from 1 micron to 5 millimeters – make up the vast majority of plastic pieces found and pose serious risks to ocean health.
Most research has focused on surface waters, usually sampling just the top 15 to 50 centimeters using net tows. However, microplastics come in many forms with different properties, influencing how they move and interact with their surroundings.
A researcher from Florida Atlantic University is among an international team of scientists who has moved beyond just “scratching the surface,” marking a turning point in our understanding of how microplastics move through and impact the global ocean.
For the first time, scientists have mapped microplastic distribution from the surface to the deep sea at a global scale – revealing not only where plastics accumulate, but how they infiltrate critical ocean systems. For the study, researchers synthesized depth-profile data from 1,885 stations collected between 2014 and 2024 to map microplastic distribution patterns by size and polymer type, while also evaluating potential transport mechanisms.
Results, published in Nature, reveal that microplastics are not just surface pollutants – they’re deeply embedded in the ocean’s structure. Ranging from a few to thousands of particles per cubic meter, their size determines how they move: smaller microplastics (1 to 100 micrometers) spread more evenly and penetrate deeper, while larger ones (100 to 5,000 micrometers) concentrate near the surface, especially within the top 100 meters of gyres. Gyres act like massive, slow-moving whirlpools that trap and concentrate floating debris – especially plastic.
Strikingly, microplastics are becoming a measurable part of the ocean’s carbon cycle, making up just 0.1% of carbon particles at 30 meters but rising to 5% at 2,000 meters. This suggests that microplastics are not only persistent pollutants but may also be altering key biogeochemical processes in the deep sea.
“Microplastics are not just floating at the surface – they’re deeply embedded throughout the ocean, from coastal waters to the open sea,” said Tracy Mincer, Ph.D., co-author and an associate professor of biology and biochemistry in FAU’s Harriet L. Wilkes Honors College.
Researchers identified more than 56 types of plastic polymers in their synthesized microplastic dataset. While buoyant plastics dominate overall, denser microplastics are more prevalent offshore – likely because they fragment more readily. Dense polymers become brittle and break down faster, particularly after prolonged exposure to environmental weathering. These small, persistent particles – often originating from fishing gear and containers like polyester bottles – can remain in the ocean for decades.
Polypropylene, commonly found in items like yogurt containers and rope, photodegrades more quickly than polyethylene, which is used in plastic bags and water bottles. This may account for its lower abundance in offshore waters. Nonetheless, significant uncertainties remain in subsurface microplastic data due to inconsistent sampling techniques and limited coverage, highlighting the need for specialized equipment and greater collaboration to improve data reliability.
The ocean’s water column – the largest habitat on Earth – plays a crucial role in global carbon cycling, supporting half of the planet’s primary production and absorbing human-made CO₂. As microplastics move through this vast space, they interact with natural particles and processes, potentially affecting how the ocean functions.
“Our findings suggest microplastics are becoming a measurable part of the ocean’s carbon cycle, with potential consequences for climate regulation and marine food webs,” said Mincer. “This work sets the stage for taking the next steps in understanding the residence time of plastic in the interior of the ocean.”
The study was led by the Japan Agency for Marine-Earth Science and Technology in collaboration with FAU; Aotearoa Blue Ocean Research in New Zealand; Northeastern University; East China Normal University; NIOZ Royal Netherlands Institute for Sea Research, The Netherlands; The Ocean Cleanup, The Netherlands; Egger Research and Consulting, Switzerland; University of Amsterdam, The Netherlands; Utrecht University, The Netherlands; Universidad Catolica del Norte, Chile; Smithsonian Environmental Research Center; Harvard University; University of Siena, Italy; and the National Biodiversity Future Center, Italy.
Several authors were FAU researchers in the Mincer lab including Luisa Galgani, Ph.D., who served as a Marie Curie Postdoctoral Fellow and is now faculty at the University of Siena; Ryan Bos, Ph.D., who was a Ph.D. student in the integrative biology program at FAU and is now a postdoc at Harvard; and Shiye Zhao, Ph.D., the lead author, who was an FAU postdoc for several years and is now tenured faculty at the Japan Agency for Marine-Earth Science and Technology.
- FAU -
About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, Florida Atlantic serves more than 30,000 undergraduate and graduate students across six campuses located along the Southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, Florida Atlantic embodies an innovative model where traditional achievement gaps vanish. Florida Atlantic is designated as a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report, and holds the designation of “R1: Very High Research Spending and Doctorate Production” by the Carnegie Classification of Institutions of Higher Education. Florida Atlantic shares this status with less than 5% of the nearly 4,000 universities in the United States. For more information, visit www.fau.edu.
Journal
Nature
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
The distribution of subsurface microplastics in the ocean
Article Publication Date
30-Apr-2025
Plastics may trigger hormone disruption in seabirds, new study finds
Scientists uncover how plastics ingested by seabirds leak chemicals that impact hormone receptors
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Plastic pieces recovered and analyzed
view moreCredit: Liesbeth Van Hassel
SAN DIEGO (April 30, 2025) — Many are aware of the dire challenges with plastic waste polluting the ocean, but new research shows it may harm wildlife in ways not previously understood. In a new study just published in the journal Environmental Pollution, researchers from the University of California, Santa Cruz and San Diego Zoo Wildlife Alliance found that plastic swallowed by northern fulmars— seabirds found in the North Atlantic and North Pacific Oceans—can leak chemicals that interfere with the birds’ hormone systems.
This is the second study from a collaboration between San Diego Zoo Wildlife Alliance and UC Santa Cruz to reveal wild seabirds exposed to ocean plastics may experience endocrine disruption from chemicals released by the plastics inside their bodies. Endocrine disruption can impair fertility, development, and behavior with consequences that threaten species’ survival and ripple through ecosystems. While researchers have long suspected plastics might trigger such effects, by using fulmar endocrine receptors, this study provides the first species-specific evidence in a wild seabird.
“We’ve long known that plastic ingestion can cause physical harm to seabirds, but this study shows it may also have hidden biological effects,” said lead author Liesbeth Van Hassel, whose Ph.D. work at UC Santa Cruz contributed to this study. “What’s especially concerning is that these chemicals don’t just pass through—they interact with key hormone receptors in the body.”
In lab tests, researchers soaked plastic from the birds’ stomachs in solvents to draw out chemicals. They then tested those chemicals on cloned hormone receptors from northern fulmars to see if they disrupted hormonal activity. Nearly half the birds (13 of the 27) had plastic that either activated or blocked hormone receptors.
Strikingly, the fulmar receptors mirrored how human hormone receptors react to the same chemicals, raising red flags for species across the food web. Notably, this response was unrelated to the type of plastic, but the authors suggest the chemical additives the plastics contained—like BPA and phthalates, known hormone disruptors in humans and other animals—were responsible.
“Some of these plastics kept leaching active chemicals for two weeks,” Christopher Tubbs, co-author and Associate Director of Reproductive Sciences at San Diego Zoo Wildlife Alliance. “This suggests seabirds are not only swallowing harmful materials—they may be getting a continuous dose of hormone-altering chemicals.”
This research was made possible through this incredible collaboration and partnership. San Diego Zoo Wildlife Alliance is committed to continuing to collaborate with like-minded partners like UC Santa Cruz to uncover hidden threats to wildlife and use science to protect species worldwide.
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About UC Santa Cruz
A global research university, UC Santa Cruz is part of the world’s most celebrated system of public higher education, and stands among the most renowned institutions of higher learning. Leading at the intersection of innovation and social justice, UC Santa Cruz faculty and students conduct transformative research and scholarship that serves society. Undergraduate students experience a small liberal-arts college environment with the depth and rigor of a major research university through the pairing of high-impact research with 10 tight-knit residential colleges—a rare combination among U.S. public universities.
About San Diego Zoo Wildlife Alliance
San Diego Zoo Wildlife Alliance, a nonprofit conservation leader, inspires passion for nature and collaboration for a healthier world. The Alliance supports innovative conservation science through global partnerships and groundbreaking efforts at the world-famous San Diego Zoo and San Diego Zoo Safari Park, both leading zoological institutions and accredited botanical gardens. Through wildlife care expertise, cutting-edge science and continued collaboration, more than 44 endangered species have been reintroduced to native habitats. The Alliance reaches over 1 billion people annually through its two conservation parks and media channels in 170 countries, including San Diego Zoo Wildlife Explorers television, available in children’s hospitals across 14 countries. Wildlife Allies—members, donors and guests—make success possible.
Link includes: https://sandiegozoo.app.box.com/s/72i9gsij1ip8g5t91ia8iocc23shubxu
- Plastic pieces recovered and analyzed
