Prevalence of microplastics and anthropogenic debris within a deep-sea food web

Bm Hamilton,Bh Robison,Ks Van Houtan,Tj Hoellein,Ca Choy,Cm Rochman

doi:10.3354/meps13846

Bm Hamilton, Bh Robison + Show 4 more

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https://doi.org/10.3354/meps13846

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Abstract

Microplastic particles (<5 mm) are ubiquitous throughout global marine ecosystems, including the deep sea. Ingestion of microplastics and other anthropogenic microparticles is reported in diverse marine taxa across trophic levels. Trophic transfer, or the movement of microplastics across trophic levels, is reported in laboratory studies but not yet widely measured in marine food webs. The Monterey Bay submarine canyon ecosystem contains a well-studied, known deep-sea food web in which to examine the trophic fate of microplastics. We measured microplastic abundance across 17 genera spanning approximately 5 trophic levels and a diversity of feeding behaviors. Samples were collected using remotely operated vehicles and oblique midwater trawls, and gut contents of all individuals examined (n = 157) were analyzed for microplastic abundance and other anthropogenic particles greater than 100 µm using stereo microscopy. Microparticles were analyzed with Raman spectroscopy to confirm material type. Anthropogenic particles were found in all genera examined, across crustacean, fish, mollusk, and gelatinous organisms, in amounts ranging from 0 to 24 particles per individual. There was no significant relationship between microplastic amount and fish trophic level, suggesting that the trophic transfer of microparticles is not occurring. Body size was positively correlated with microplastic abundance across all taxa. The fish genus Scomber sp. drove this relationship, suggesting higher microparticle abundance in mobile individuals with broad horizontal distributions. Future work should examine physiological pathways for microplastic transport within organisms (e.g. excretion, accumulation on gills, internal translocation of particles) and between organisms within shared habitats to more fully understand the fate of microplastics within aquatic food webs.

Highlights

Large-scale plastic production was introduced to the global economy in the mid-20th century (Geyer et al 2017)
Microplastics and other suspected anthropogenic microparticles were found in 96.4% of all samples, confirming that microparticles are widely ingested by organisms from diverse habitats, including the deep sea (Bergmann et al 2017, Choy et al 2019, Courtene-Jones et al 2019, Martinelli et al 2020)
We determined that microplastics and other anthropogenic particles are ubiquitous within a well-defined deep-pelagic marine food web, in congruence with studies that document microplastic ingestion across a wide variety of taxa and trophic levels elsewhere

Summary

Introduction

Large-scale plastic production was introduced to the global economy in the mid-20th century (Geyer et al 2017). Lusher et al 2015, Bergmann et al 2017) and the deep sea (e.g. Chiba et al 2018, Choy et al 2019) This environmental ubiquity necessitates ecological and environmental understanding of how plastic pollution interacts with and affects diverse organisms across varying ecosystems. Microplastic particles are readily transported within and between ecosystems by myriad physical and biological processes (Cozar et al 2014, Eriksen et al 2014), including long-range atmospheric transport (Dris et al 2016, Zhang et al 2019, Brahney et al 2020) and deep-ocean circulation (Kane et al 2020), and direct ingestion by animals or indirect ingestion via prey (Watts et al 2016, Chagnon et al 2018, Nelms et al 2018)

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