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Cited by 16Microplastics and Plastic PollutionEnvironmental Toxicology and EcotoxicologyPharmaceutical and Antibiotic Environmental Impacts

No Effect of Realistic Concentrations of Polyester Microplastic Fibers on Freshwater Zooplankton Communities

Open access
Klasios, Natasha, Kim, Jihyun O., Tseng, Michelle·2024·Environmental Toxicology and Chemistry
DOI 10.1002/etc.5797
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Abstract

Zooplankton are a conduit of energy from autotrophic phytoplankton to higher trophic levels, and they can be a primary point of entry of microplastics into the aquatic food chain. Investigating how zooplankton communities are affected by microplastic pollution is thus a key step toward understanding ecosystem-level effects of these global and ubiquitous contaminants. Although the number of studies investigating the biological effects of microplastics has grown exponentially in the last decade, the majority have used controlled laboratory experiments to quantify the impacts of microplastics on individual species. Given that all organisms live in multispecies communities in nature, we used an outdoor 1130-L mesocosm experiment to investigate the effects of microplastic exposure on natural assemblages of zooplankton. We endeavored to simulate an environmentally relevant exposure scenario by manually creating approximately 270 000 0.015 × 1– to 1.5–mm polyester fibers and inoculating mesocosms with zero, low (10 particles/L), and high (50 particles/L) concentrations. We recorded zooplankton abundance and community composition three times throughout the 12-week study. We found no effect of microplastics on zooplankton abundance, Shannon diversity, or Pielou's evenness. Nonmetric multidimensional scaling plots also revealed no effects of microplastics on zooplankton community composition. Our study provides a necessary and realistic baseline on which future studies can build. Because numerous other stressors faced by zooplankton (e.g., food limitation, eutrophication, warming temperatures, pesticides) are likely to exacerbate the effects of microplastics, we caution against concluding that polyester microfibers will always have no effect on zooplankton communities. Instead, we encourage future studies to investigate the triple threats of habitat degradation, climate warming, and microplastic pollution on zooplankton community health. Environ Toxicol Chem 2024;43:418–428. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

AI snapshot

Written from the paper’s full text.

TL;DR

In a 12-week outdoor mesocosm experiment, environmentally relevant concentrations of polyester microplastic fibers (0, 10, and 50 particles/L) had no detectable effect on freshwater zooplankton abundance, Shannon diversity, Pielou’s evenness, or community composition. The authors caution that these null results should not be generalized to all conditions, especially where additional stressors such as warming, food limitation, or eutrophication may interact with microplastics.

Key findings

  • Microplastic treatment did not affect total zooplankton abundance (linear mixed effects model: microplastics F₂,₁₂ = 1.12, p = 0.36), although abundance declined over the experiment (mean ± SD per 10-L sample: 258 ± 207 pre-addition, 42.9 ± 58.2 at 1 month post, 55.3 ± 58.2 at 3 months post).
  • There was no effect of microplastics on Shannon diversity (F₂,₁₂ = 0.22, p = 0.8) or Pielou’s evenness (F₂,₁₂ = 1.46, p = 0.27); sampling event significantly affected both metrics.
  • Nonmetric multidimensional scaling showed no microplastic effect on community composition, with 95% confidence ellipses for control, low, and high treatments overlapping completely (stress = 0.13).
  • Microplastics also had no effect on abundance of the three main taxonomic groups—cladocerans, copepods, and ostracods (microplastics F₂,₁₂ = 1.47, p = 0.27).

Methods

  • Outdoor mesocosm experiment at the University of British Columbia using 15 cattle tanks (1130-L nominal volume, filled with 900 L unfiltered pond water), seeded with natural zooplankton assemblages and randomly assigned to control (0 fibers/L), low (~10 fibers/L, ~9000 fibers/mesocosm), or high (~50 fibers/L, ~45,000 fibers/mesocosm) treatments (n = 5 per treatment).
  • Polyester microplastic fibers were made by cutting red 100% polyester sewing thread into 0.015 mm × 1–1.5 mm pieces, confirmed as polyester by Raman spectroscopy; approximately 270,000 fibers were produced in total and added in August 2021.
  • Zooplankton were sampled four times from August to November 2021, but October samples were not analyzed; analyses used linear mixed effects models for abundance, Shannon diversity, and Pielou’s evenness, plus NMDS with a Bray-Curtis similarity matrix (k = 3) for community composition.

Limitations

  • Stated: the use of large 1130-L mesocosms came at the cost of low replication (n = 5 per treatment).
  • Stated: the study did not quantify microplastic ingestion or external physical contact/deformities, so whether fibers were ingested or caused physical harm is unknown; fibers were observed qualitatively in samples from microplastic-addition mesocosms.
  • Stated and evident: the experiment tested only one polymer type, one morphology, and a small size fraction of microplastics; “environmentally relevant concentrations” may not represent all natural scenarios because microplastic concentrations are spatially and temporally heterogeneous, and local pollution or flooding could temporarily increase concentrations. Evident: October samples were not analyzed, and Bosmina were omitted from analyses because only four individuals were found.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1002/etc.5797

Cites

66 of 66 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

21 of 47 cited sources checked · 13 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    Published microplastic concentrations in lentic surface waters range from <0 to approximately 10 particles/L.

    “published microplastic concentrations in lentic surface waters range from <0 to approximately 10 particles/L (D' Avignon et al., 2022).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites D' Avignon et al., 2022 source

      Section 2.1 (p. 11) reports very low concentrations in Patagonian lakes, but also says individual samples reached 44 particles/L. The table on p. 54 lists lake concentrations up to 34 particles/L. These reported values contradict the claimed upper end of approximately 10 particles/L; the copy does not report a concentration below zero. (LLM, conf=0.86)

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
  • Premisecitation

    Concentrations up to approximately 50 particles/L have been reported in standing waters.

    “Concentrations up to approximately 50 particles/L have been reported in standing waters (Alfonso et al., 2020).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites Alfonso et al., 2020 source

      Section 3.1 reports microplastics in lakes, including a cited concentration of up to 34,000 particles/m³ (34 particles/L) in a Chinese lake. It does not report approximately 50 particles/L; its own Patagonian-lake maximum is 1.9 particles/m³. No page number is available in our copy. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
  • Premisecitation

    Tested microplastic morphologies in micro- and mesocosm studies have been mostly limited to fragments and spheres, with only Rauchschwalbe et al. (2022) including fibrous particles.

    “While different polymer types are well represented in micro-and mesocosm studies (Aljaibachi et al., 2020;Rauchschwalbe et al., 2022;Silva et al., 2022;Yıldız et al., 2022), the tested microplastic morphologies have been mostly limited to fragments and spheres, with only Rauchschwalbe et al. (2022) including fibrous particles.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Aljaibachi et al., 2020 source
    • cites Rauchschwalbe et al., 2022 source
    • cites Silva et al., 2022 source
  • Findingown data

    Microplastic treatment had no effect on zooplankton Shannon diversity.

    “We found no effect of microplastics on zooplankton abundance, Shannon diversity, or Pielou's evenness.”
    • Also stated in: § Zooplankton community composition · plain
      “There was no effect of microplastic treatment on zooplankton Shannon diversity or Pielou's evenness”
    • Also stated in: § DISCUSSION · boosted
      “The results from our 12-week outdoor experiment demonstrated that environmentally relevant concentrations of polyester microplastic fibers did not affect zooplankton abundance, diversity, or evenness, across multiple time points.”
    Quote in the paperSubstantial claim
  • Findingown data

    Microplastic treatment had no effect on zooplankton Pielou's evenness.

    “We found no effect of microplastics on zooplankton abundance, Shannon diversity, or Pielou's evenness.”
    • Also stated in: § Zooplankton community composition · plain
      “There was no effect of microplastic treatment on zooplankton Shannon diversity or Pielou's evenness”
    • Also stated in: § DISCUSSION · boosted
      “The results from our 12-week outdoor experiment demonstrated that environmentally relevant concentrations of polyester microplastic fibers did not affect zooplankton abundance, diversity, or evenness, across multiple time points.”
    Quote in the paperSubstantial claim
  • Classified as probably not a substantial claim. 26
  • May combine two claims. 16
  • The quote only partly states this claim. 1

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Organisms of various trophic levels ingest or uptake microplastics, either directly or indirectly.

    “Both laboratory experiments and in situ observations have confirmed that organisms of various trophic levels ingest or uptake microplastics, either directly or indirectly (Cole et al., 2013;Provencher et al., 2018;Scherer et al., 2017;Setälä et al., 2014).”
    Quote in the paperNot a substantial claim3 of 3 sources checked
    • cites Cole et al., 2013 source

      The Results (p. 10) document direct microplastic ingestion by several zooplankton taxa, and the Introduction (p. 3) reports ingestion in other marine organisms. But this paper’s experiments used laboratory exposures (Methods, p. 6); its Discussion (p. 15) treats indirect trophic transfer as a possibility, not a confirmed observation. It therefore supports the ingestion claim but not the sentence’s full assertion of confirmed in situ and indirect uptake. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites Provencher et al., 2018 source
    • cites Scherer et al., 2017 source

      The Abstract reports laboratory ingestion of microplastics by five freshwater invertebrate species, and the Introduction reports ingestion in field-collected marine and freshwater species. The Results and Discussion (Species) describe transfer through trophic levels as a possibility, not a confirmed observation of indirect uptake. Thus, the source supports ingestion across species and settings, but not the claim that indirect uptake has been confirmed. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    The mixed effects of microplastics at the community scale, coupled with several reports of negative impacts at the individual or population scale, point to an apparent mismatch in effects across scales.

    “The mixed effects of microplastics at the community scale, coupled with several reports of negative impacts of microplastics at the individual or population scale (Bosker et al., 2019;Liu et al., 2022;Ogonowski et al., 2016;Schür et al., 2020) point to an apparent mismatch in effects across scales.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites Bosker et al., 2019 source
    • cites Liu et al., 2022 source
    • cites Ogonowski et al., 2016 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Microplastics are bioavailable to a wide range of organisms because of their small size (typically <5 mm).

    “In addition to their widespread distribution, because of their small size (typically defined as <5 mm), microplastics are believed to be bioavailable to a wide range of organisms (Botterell et al., 2019;Galloway et al., 2017).”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites Botterell et al., 2019 source
    • cites Galloway et al., 2017 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The uptake of microplastics has demonstrated potential to adversely affect organisms, but observed effects are nonuniform across levels of biological organization and are complicated by exposure concentration and particle characteristics.

    “The uptake of microplastics has demonstrated potential to adversely affect organisms; however, the effects observed in laboratory studies have been nonuniform across levels of biological organization and are further complicated by exposure concentration and both the physical characteristics and chemical composition of the particle (Bucci et al., 2020;Castro-Castellon et al., 2022;Zimmermann et al.”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites Bucci et al., 2020 source
    • cites Castro-Castellon et al., 2022 source
    • cites Zimmermann et al., 2020 source

      The Introduction describes adverse effects of microplastics in aquatic species, and section 4.1 reports that effects in Daphnia magna vary by endpoint, polymer type, and exposure concentration. The paper also discusses physical and chemical differences among particles. It does not establish that uptake itself causes the effects or compare effects across levels of biological organization; its experiments assess life-history endpoints in one species. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Some studies have demonstrated null or positive effects of microplastics on Daphnia, such as increased growth and swimming activity.

    “Although many studies have reported adverse effects, others have demonstrated null (Canniff & Hoang, 2018) or positive effects, such as increased growth and swimming activity (De Felice et al., 2019).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Canniff & Hoang, 2018 source
    • cites De Felice et al., 2019 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    At the population scale, exposure to microplastics has resulted in reduced Daphnia population biomass, microalgae biomass, and population size of calanoid copepods.

    “At the population scale, exposure to microplastics has resulted in reduced Daphnia population biomass (Bosker et al., 2019), microalgae biomass (Green et al., 2016), and population size of calanoid copepods (Heindler et al., 2017).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Bosker et al., 2019 source
    • cites Green et al., 2016 source
    • cites Heindler et al., 2017 source

  • May combine two claims.

    Premisecitation

    Our exposures of 10 and 50 microplastics/L are slightly higher than the average concentration reported in lake water in nature but significantly lower than the majority of published laboratory studies and lower than those used in other mesocosm studies.

    “Our exposures of 10 (low treatment) and 50 (high treatment) microplastics/L are slightly higher than the average concentration reported in lake water in nature but significantly lower than the majority of published laboratory studies (Bucci et al., 2020) and lower than those used in other mesocosm studies (Aljaibachi et al., 2020;Marchant et al., 2023;Yıldız et al., 2022).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Bucci et al., 2020 source
    • cites Aljaibachi et al., 2020 source
    • cites Marchant et al., 2023 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Polyester microplastic fibers are one of the most commonly reported microplastic types documented in environments.

    “Polyester microplastic fibers, often sourced from synthetic textiles, are one of the most commonly reported microplastic types documented in environments (Burns & Boxall, 2018;Hernandez et al., 2017;Rebelein et al., 2021).”
    Quote in the paperNot a substantial claim1 of 3 sources checked
    • cites Burns & Boxall, 2018 source

      The “Microplastic type and chemical characterization” section reports that fibers were the most common particle shape in the reviewed water-column and sediment samples, and that polyethylene terephthalate was among the more common polymers in water. It does not establish that polyester fibers specifically were among the most commonly reported types, because it reports polymer and shape separately. Its data also chiefly concern aquatic samples, rather than environments generally. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites Hernandez et al., 2017 source
    • cites Rebelein et al., 2021 source

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Microplastics have been shown to have a range of effects on freshwater Daphnia, including decreased filtration capacity, food intake, growth, swimming velocity, and reproductive output, and increased mortality.

    “Microplastics have been shown to have a range of effects on freshwater Daphnia.For example, the uptake of microplastics decreased filtration capacity (Colomer et al., 2019), food intake (Ogonowski et al., 2016;Rist et al., 2017), growth (Castro-Castellon et al., 2022;Eltemsah & Bøhn, 2019), swimming velocity (Magester et al., 2021), and reproductive output (Huang et al., 2022;Jaikumar et al., 2019”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Colomer et al., 2019 source
    • cites Ogonowski et al., 2016 source
    • cites Rist et al., 2017 source

  • May combine two claims.

    Premisecitation

    The low (~10 fibers/L) and high (~50 fibers/L) treatments represent environmentally relevant concentrations for standing freshwater systems.

    “We believe these treatments represent environmentally relevant concentrations for standing freshwater systems because published microplastic concentrations in lentic surface waters range from <0 to approximately 10 particles/L (D' Avignon et al., 2022).”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites D' Avignon et al., 2022 source

      Section 2.1 (p. 11) reports low concentrations in lentic waters, but also notes individual samples from Patagonian lakes reaching 44 particles/L. It therefore supports the general environmental relevance of concentrations near 10 and 50 particles/L, but not the citing sentence’s stated range ending at approximately 10 particles/L. Section 4 (p. 26) also cautions that field concentrations from a single compartment can misrepresent realistic exposure. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Interpretationcitation

    The null effect of microplastics in this study is consistent with other community-level studies and parallels results from single-species laboratory studies that used low or environmentally relevant exposure concentrations.

    “The null effect of microplastics observed in our study not only was consistent with other community-level studies but also parallels results from single-species laboratory studies that used low-or environmentally relevant exposure concentrations (Schell et al., 2022;Wang et al., 2019).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Schell et al., 2022 source
    • cites Wang et al., 2019 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Studies evaluating fiber toxicity on single species are currently underrepresented in ecotoxicity research and even less represented in community-level studies.

    “Despite fibers emerging as a dominant morphology found in nature, studies evaluating fiber toxicity on single species are currently still underrepresented in ecotoxicity research (Bour et al., 2020) and evidently even less represented in community-level studies.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Bour et al., 2020 source

  • May combine two claims.

    Study design and conductcitation

    The use of large mesocosms allowed mimicking some dynamics of small ponds but came at the cost of low replication.

    “The use of large mesocosms allowed us to mimic some of the dynamics that occur in small ponds but, similar to other studies that utilize large-sized mesocosms, came at the cost of low replication (Stewart et al., 2013).”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Stewart et al., 2013 source

      Section 1.2, “Balancing control, replication, and realism,” describes trade-offs between spatial scale and replication, and Section 1.3 says large-scale experiments carry substantial resource costs. But the paper does not specifically say that using large pond-like mesocosms results in low replication; the citing authors’ description of what their mesocosms mimicked is their own. (LLM, conf=0.78)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Sampling event had a significant effect on Pielou's evenness, with evenness increasing over time.

    “There was a significant effect of sampling event on both of these metrics, with diversity decreasing slightly over time and evenness increasing over time”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Sampling event had a significant effect on Shannon diversity, with diversity decreasing slightly over time.

    “There was a significant effect of sampling event on both of these metrics, with diversity decreasing slightly over time and evenness increasing over time”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Microplastic treatment had no effect on the abundance of cladocerans, copepods, or ostracods.

    “When the abundance data were partitioned into the three main taxonomic groups (cladocerans, copepods, ostracods), there was no effect of microplastic treatment on abundance”
    • Also stated in: § DISCUSSION · plain
      “In our study, we did not observe changes in total zooplankton abundance or the abundance of cladocerans, copepods, and ostracods in response to microplastic treatments.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    There was a significant interaction between microplastic treatment and sampling event for Shannon diversity.

    “For Shannon diversity, the linear mixed effects model revealed a significant interaction between microplastic treatment and sampling event”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Findingown data

    Microplastics had no significant effect on Pielou's evenness (F2,12 = 1.46, p = 0.27).

    “F 2,12 = 1.46,”
    • Also stated in: § DISCUSSION · plain
      “p = 0.27”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Based on the limited published literature, the effects of microplastics on community dynamics appear to be highly variable.

    “Based on the limited published literature, the effects of microplastics on community dynamics appear to be highly variable.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    The lack of harmonization in concentrations, polymer types, and particle shapes within and among individual-level and community-level microplastics studies makes cross-scale comparisons difficult.

    “Ultimately, the lack of harmonization in the concentrations, polymer types, and particle shapes within and among individual-level and communitylevel microplastics studies also makes cross-scale comparisons difficult (Provencher et al., 2020).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Provencher et al., 2020 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Studies investigating population- and community-level impacts of microplastics have increased in recent years but are still limited.

    “Studies investigating population-and community-level impacts of microplastics have increased in recent years but are still limited (Bucci et al., 2020).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bucci et al., 2020 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    In freshwater ecosystems, most individual-level studies have focused on cladoceran zooplankton, specifically Daphnia.

    “In freshwater ecosystems in particular, most individual-level studies have focused on cladoceran zooplankton, specifically Daphnia.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Polyester microplastic fibers are one of the most dominant morphologies and polymer types found in the environment and within organisms.

    “We chose to investigate the effects of polyester microplastic fibers because they are one of the most dominant morphologies and polymer types found in the environment (Klasios & Tseng, 2023;Napper et al., 2023) and within organisms (Rebelein et al., 2021).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Klasios & Tseng, 2023 source
    • cites Napper et al., 2023 source
    • cites Rebelein et al., 2021 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Community-level studies have documented varying effects of microplastics on different communities.

    “Similar to the effects of microplastics on individual organisms such as Daphnia, these studies have documented varying effects of microplastics on different communities.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Total abundance was log-transformed to remove heteroscedasticity among treatment groups.

    “We logtransformed total abundance to remove heteroscedasticity among treatment groups.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The study did not quantify entangled appendages or physical deformities on the zooplankton.

    “However, we did not quantify entangled appendages or physical deformities on the zooplankton.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    Zooplankton were sampled four times between August and November 2021, including a pre-microplastic-addition sample to determine initial community composition.

    “To examine whether microplastic fibers affected zooplankton community composition over time, zooplankton were sampled a total of four times between August and November 2021.The first sampling event occurred in August (hereafter Pre MP Addition, MP = microplastic), 2 days before the addition of microplastics, to determine the initial zooplankton community composition in each mesocosm.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Microplastic concentration is spatially and temporally heterogeneous.

    “In addition, microplastic concentration is known to be spatially and temporally heterogeneous (Tamminga & Fischer, 2020)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Tamminga & Fischer, 2020 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The October zooplankton samples were not analyzed due to logistical constraints.

    “Because of logistical constraints, we did not analyze the October zooplankton samples.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Linear mixed effects models were used with mesocosm as a random effect to account for repeated measures.

    “We used linear mixed effects models to investigate whether sampling event and microplastic treatment (control, low, high) significantly explained variation in total zooplankton abundance per mesocosm (n = 5 per treatment).In this model, sampling event and microplastic treatment were classified as fixed effects and mesocosm as a random effect.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Mesocosms were randomly assigned to a treatment of no microplastics (control), low (~10 fibers/L), or high (~50 fibers/L) concentration.

    “Mesocosms were randomly assigned a treatment of no microplastics (control; 0 polyester microplastic fibers/L), low (~10 fibers/L, ~9000 total fibers per mesocosm), or high (~50 fibers/L, ~45 000 total fibers per mesocosm) concentration (Figure 1).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The number of fibers per cut was confirmed by counting the bundle three times and repeating the triplicate counting five additional times.

    “We confirmed this fiber number by counting the bundle three times and then repeated the triplicate counting five additional times.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    The study did not quantify microplastic ingestion, so whether the particles were actually ingested is unknown.

    “Because we did not quantify microplastic ingestion, whether the particles were actually ingested is unknown.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The null effect of larger microplastics at the tested concentrations is not all-encompassing.

    “Although larger microplastics such as those used in our study do not appear to affect the zooplankton community at these concentrations, this scenario is not all-encompassing.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Local pollution events or flooding can increase microplastic concentrations temporarily.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Microplastics are a diverse suite of contaminants.

    “Microplastics are a diverse suite of contaminants (Rochman et al., 2019)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Rochman et al., 2019 source
35 of 35

  • The paper relies on this without support.

    Numerous other stressors faced by zooplankton (e.g., food limitation, eutrophication, warming temperatures, pesticides) are likely to exacerbate the effects of microplastics.

    “Because numerous other stressors faced by zooplankton (e.g., food limitation, eutrophication, warming temperatures, pesticides) are likely to exacerbate the effects of microplastics, we caution against concluding that polyester microfibers will always have no effect on zooplankton communities.”

  • The paper relies on this without support.

    The impacts of microplastics on other freshwater zooplankton have been largely overlooked.

    “The impacts of microplastics on other freshwater zooplankton have been largely overlooked.”

  • The paper relies on this without support.

    Most community-level studies have used relatively small mesocosms, pristine plastic particles purchased from scientific supply companies, or unrealistic particle types or exposure concentrations.

    “Although these studies have collectively improved our understanding of the potential effects of microplastics on invertebrate communities, most have used relatively small mesocosms, pristine plastic particles purchased from scientific supply companies, or unrealistic particle types or exposure concentrations.”

  • The paper relies on this without support.

    Local pollution events or flooding can increase microplastic concentrations temporarily.

    “Local pollution events or flooding can increase microplastic concentrations temporarily”

  • The paper relies on this without support.

    Organisms are exposed to a plethora of diverse microplastics in their environment.

    “In reality, organisms are exposed to a plethora of diverse microplastics in their environment”
5 of 5

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Bosmina is both omitted from and included in analyses

    Minor

    The methods say Bosmina was omitted from further analyses, but the abundance analysis explicitly lists Bosmina among the cladocerans analyzed.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Stewart, 2013, Advances in Ecological Research: Vol. 48. Global change in multispecies systems, 71

Cited by

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Related

Authors
Klasios, N., Kim, J. O., & Tseng, M.
Affiliations
University of British Columbia (CA)
Corresponding author
Klasios, Natasha
ORCID
Venue
Environmental Toxicology and Chemistry
Publisher
Oxford University Press (OUP)
Published
2023-11-29
Volume
43
Issue
2
Pages
418-428
ISSN
  • 0730-7268 (ISSN-L)
  • 1552-8618
DOI
10.1002/etc.5797
OpenAlex
W4389140566
Cited by
16
References
66
Citations by year
2026: 5 · 2025: 6 · 2024: 5
FWCI
0.98
Type
journal article
Language
en
Open access
Licence
Locations
  • Environmental Toxicology and Chemistry (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
Funders
Natural Sciences and Engineering Research Council of Canada
Topics
  • Physical Sciences › Environmental Science › Pollution › Microplastics and Plastic Pollution
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Environmental Toxicology and Ecotoxicology
  • Physical Sciences › Environmental Science › Pollution › Pharmaceutical and Antibiotic Environmental Impacts
Keywords
polyester microfibers, microplastics, zooplankton community, freshwater ecosystems, mesocosm experiment, community composition, zooplankton abundance, biodiversity, microplastic pollution, trophic transfer, multiple stressors
MeSH terms
Microplastics, Animals, Fresh Water, Plastics, Polyesters, Water Pollutants, Chemical, Zooplankton, Ecosystem

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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