Papers

61,005 results
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Article Tier 2

Size matters more than shape: Ingestion of primary and secondary microplastics by small predators

Researchers offered irregularly shaped secondary microplastics — fragments more realistic than the perfect spheres used in most lab studies — to small fish and shrimp at natural concentrations, finding that particle size was a stronger predictor of ingestion than shape. The study underscores that lab results using uniform plastic beads may overestimate real-world microplastic uptake in marine food webs.

2018 Food Webs 351 citations
Article Tier 2

Size-dependent chronic toxicity of fragmented polyethylene microplastics to Daphnia magna

Researchers tested the long-term effects of irregularly shaped polyethylene microplastic fragments on the freshwater organism Daphnia magna over 21 days. They found that fragmented microplastics were ingested at much higher rates and caused more harm to reproduction and survival than smooth, round plastic beads of similar size, suggesting particle shape matters for toxicity.

2021 Chemosphere 193 citations
Article Tier 2

Size- and shape-dependent effects of microplastic particles on adult daggerblade grass shrimp (Palaemonetes pugio)

Researchers exposed adult grass shrimp to eleven sizes of microplastic spheres, fibers, and fragments and measured effects on survival, ingestion, and particle residence time. They found that mortality was size- and shape-dependent, with larger spheres and fibers causing the highest death rates, while particles smaller than 50 micrometers were not acutely toxic. The study demonstrates that both the size and shape of microplastics are critical factors in determining their toxicity to marine crustaceans.

2017 Environmental Toxicology and Chemistry 445 citations
Article Tier 2

Bioavailability of Microplastics to Marine Zooplankton: Effect of Shape and Infochemicals

The influence of microplastic shape (bead, fiber, and fragment) and algal infochemicals (DMS and DMSP) on microplastic ingestion by marine zooplankton was investigated. Shape significantly affected ingestion rates, and infochemicals influenced zooplankton feeding behavior in ways that altered microplastic uptake, revealing how chemical cues in the ocean shape plastic particle ingestion.

2020 Environmental Science & Technology 165 citations
Review Tier 2

Bioavailability and effects of microplastics on marine zooplankton: A review

This review synthesized laboratory and field evidence on microplastic bioavailability and effects on marine zooplankton, finding that multiple taxa readily ingest microplastics with negative impacts on feeding, reproduction, and energy balance, and that zooplankton represent a critical route for transferring microplastics into marine food webs. The authors identify particle size, concentration, and feeding behavior as the main determinants of microplastic bioavailability to zooplankton.

2018 Environmental Pollution 900 citations
Article Tier 2

Effect of PET Micro/Nanoplastics on Model Freshwater Zooplankton

Researchers created micro- and nanoplastic particles from PET plastic through mechanical grinding in water, mimicking natural degradation processes, and tested their effects on freshwater zooplankton. They found that smaller, irregularly shaped nanoplastic particles were more toxic than larger ones, causing reduced survival and reproduction in the test organisms. The study highlights that as plastic debris breaks down into ever-smaller particles in waterways, the biological risks to aquatic life may actually increase.

2025 Polymers 4 citations
Article Tier 2

Microplastic ingestion in marine mesozooplankton species associated with functional feeding traits

This study examined microplastic ingestion in marine mesozooplankton species with different functional traits, finding that feeding mode, body size, and habitat use are key predictors of plastic uptake across zooplankton communities.

2024 Marine Environmental Research 7 citations
Article Tier 2

The characteristics of plastic nanoparticles and their effect on zooplankton

This thesis reviewed the characteristics of plastic nanoparticles and their potential effects on zooplankton, which are a foundational component of aquatic food webs. Because nanoplastics are smaller than microplastics, they are more easily taken up by tiny organisms and may have more pervasive ecological effects.

2019
Article Tier 2

Comparative impacts of fragmented versus spherical microplastics on the marine rotifer Brachionus koreanus: Multigenerational chronic toxicity and multi-omics perspective

This study found that the shape of microplastic particles matters more than their size when it comes to toxicity. Small, jagged fragments caused more harm to tiny marine animals called rotifers than smooth round beads, reducing their ability to reproduce and shortening their lifespan across multiple generations. The findings suggest that irregularly shaped microplastics, which are the most common type found in the environment, may be more dangerous than the smooth spheres typically used in lab studies.

2025 Journal of Hazardous Materials 5 citations
Article Tier 2

Toxicological effects of irregularly shaped and spherical microplastics in a marine teleost, the sheepshead minnow (Cyprinodon variegatus)

Researchers compared the toxicological effects of irregularly shaped versus spherical microplastics on sheepshead minnows. Both types accumulated in the digestive system and caused intestinal distention, but irregularly shaped particles were more harmful, reducing swimming behavior more than spherical ones. The study highlights that the shape of microplastic particles matters for toxicity assessments, and commonly used uniform spheres may underestimate real-world risks.

2018 Marine Pollution Bulletin 383 citations
Article Tier 2

Assessing the acute differential toxicity of polystyrene microplastic particles and comparing the impacts of bead-shaped versus fragmented particles on Daphnia magna

Researchers compared the toxicity of polystyrene microplastic fragments versus beads on tiny freshwater crustaceans (Daphnia magna) and found that jagged fragments were more harmful than smooth beads, causing greater mortality and triggering more stress-related genes — suggesting that the shape of a microplastic particle matters as much as its chemical makeup.

2025 Applied Biological Chemistry 3 citations
Article Tier 2

Does microplastic ingestion by zooplankton affect predator-prey interactions? An experimental study on larviphagy

Filter feeders consumed significantly fewer zooplankton prey that had ingested microplastics compared to uncontaminated prey, suggesting that microplastic ingestion makes zooplankton less appealing or nutritious. This effect on predation could have cascading consequences for marine food webs.

2019 Environmental Pollution 67 citations
Article Tier 2

Increased food availability reducing the harmful effects of microplastics strongly depends on the size of microplastics

Researchers found that increased food availability reduced microplastic toxicity in the waterflea Daphnia magna, but this protective effect depended strongly on particle size, with the smallest nanoplastics remaining harmful even when food was plentiful.

2022 Journal of Hazardous Materials 34 citations
Article Tier 2

The Effects of Natural and Anthropogenic Microparticles on Individual Fitness in Daphnia magna

Researchers compared the effects of natural and anthropogenic microparticles on the fitness of the water flea Daphnia magna. The study found that both primary microplastics from cosmetic products and secondary microplastics from degraded plastic waste can have detrimental effects on zooplankton feeding and fitness, with particle shape and weathering influencing toxicity.

2016 PLoS ONE 463 citations
Article Tier 2

Bioavailability and ingestion of microplastic by zooplankton in the natural environment

This study reviewed the bioavailability and ingestion of microplastics by marine zooplankton, which are particularly vulnerable because microplastic sizes overlap with their natural prey. Laboratory and field evidence shows zooplankton including copepods readily ingest microplastics, affecting energy budgets and potentially transferring particles up the food chain.

2024 Open MIND
Article Tier 2

Microplastic Ingestion by Zooplankton

This study examined whether tiny marine animals called zooplankton can ingest microplastics, and researchers found that thirteen different zooplankton species consumed plastic beads of various sizes. The plastics also stuck to the animals' outer shells and significantly reduced their normal feeding on algae, suggesting that microplastic pollution could disrupt the base of the marine food web.

2013 Environmental Science & Technology 2641 citations
Article Tier 2

Microplastic Ingestion Induces Size-Specific Effects in Japanese Quail

Researchers found that Japanese quail ingesting environmentally collected microplastics showed size-specific effects, with small particles under 125 micrometers causing different physiological responses than larger 3mm particles, demonstrating that particle size matters for avian microplastic toxicity.

2022 Environmental Science & Technology 37 citations
Article Tier 2

Chronic effects of irregular and fibril microplastics on Artemia franciscana in a benthic environment: Size and shape-dependent toxicity

Researchers studied how irregular and fibril-shaped microplastics of various sizes affect brine shrimp in a simulated seafloor environment over an extended period. They found that the smallest irregular particles and longer fibers caused the most significant reproductive and growth effects. The study demonstrates that both the size and shape of microplastics matter when assessing their impact on bottom-dwelling marine organisms.

2024 Marine Pollution Bulletin 9 citations
Article Tier 2

Ingestion of Microplastics by Marine Animals

This review examines microplastic ingestion by marine animals, assessing how the small size and ubiquity of microplastics in oceans leads to widespread consumption across species, with effects ranging from physical gut blockage to chemical toxicity at organism and ecosystem levels.

2022 29 citations
Article Tier 2

Ingestion and Egestion of Microplastics by the Cladoceran Daphnia magna: Effects of Regular and Irregular Shaped Plastic and Sorbed Phenanthrene

Researchers studied how the water flea Daphnia magna ingests and excretes polyethylene microplastics of different shapes and sizes. They found that irregular-shaped fragments were ingested differently than regular beads, and that neither type caused acute mortality at tested concentrations — but the study raises questions about chronic effects in this key freshwater species.

2017 Bulletin of Environmental Contamination and Toxicology 253 citations
Article Tier 2

Ecotoxicological effects of traditional and emerging microplastics on marine zooplankton: A review

Researchers reviewed how microplastics harm marine zooplankton (tiny animals that form a critical link in ocean food chains) at the molecular level, covering effects like metabolic disruption, oxidative stress, immune damage, and neurotoxicity — and extended the review to include emerging plastics like tire-wear particles and antifouling paint particles that are often overlooked. The review calls for moving beyond treating all microplastics as identical, since their varying physical and chemical properties produce very different toxic effects.

2026 Ecotoxicology and Environmental Safety
Article Tier 2

Shape-driven toxicity of polystyrene microplastics: Impacts on physiology and gut microbiota in Daphnia magna

Researchers studied how the shape of polystyrene microplastics affects toxicity in the water flea Daphnia magna, comparing irregular fragments to smooth beads. The study found that fragment-shaped microplastics were more toxic than spherical beads, triggered stronger reactive oxygen species production, and induced different gut microbiota changes, suggesting that particle shape is an important factor in microplastic toxicity.

2026 Marine Pollution Bulletin
Article Tier 2

Shape, size, and polymer dependent effects of microplastics on Daphnia magna

Researchers systematically tested how the shape, size, and material of microplastic particles affect the water flea Daphnia magna by comparing polystyrene particles to non-plastic control particles with similar properties. They found that small polystyrene beads and fragments caused harmful effects on reproduction and body shape, while none of the non-plastic control particles caused any damage. The study suggests that the toxic effects are specific to the plastic polymer itself, not simply a result of ingesting small particles.

2021 Journal of Hazardous Materials 166 citations
Article Tier 2

Ingestion of Microplastics by Zooplankton in the Northeast Pacific Ocean

Researchers collected zooplankton from the northeast Pacific Ocean and found microplastics ingested by multiple species, demonstrating that microplastic uptake occurs throughout the open ocean zooplankton community far from coastlines.

2015 Archives of Environmental Contamination and Toxicology 994 citations