Food web transfer of plastics to an apex riverine predator

Abstract

As a rapidly accelerating expression of global change, plastics now occur extensively in freshwater ecosystems, yet there is barely any evidence of their transfer through food webs. Following previous observations that plastics occur widely in their prey, we used a field study of free‐living Eurasian dippers (Cinclus cinclus), to test the hypotheses that (1) plastics are transferred from prey to predators in rivers, (2) plastics contained in prey are transferred by adults to altricial offspring during provisioning and (3) plastic concentrations in faecal and regurgitated pellets from dippers increase with urbanization. Plastic occurred in 50% of regurgitates (n = 74) and 45% of faecal samples (n = 92) collected non‐invasively from adult and nestling dippers at 15 sites across South Wales (UK). Over 95% of particles were fibres, and concentrations in samples increased with urban land cover. Fourier transform infrared spectroscopy identified multiple polymers, including polyester, polypropylene, polyvinyl chloride and vinyl chloride copolymers. Although characterized by uncertainty, steady‐state models using energetic data along with plastic concentration in prey and excreta suggest that around 200 plastic particles are ingested daily by dippers, but also excreted at rates that suggest transitory throughput. As some of the first evidence revealing that plastic is now being transferred through freshwater food webs, and between adult passerines and their offspring, these data emphasize the need to appraise the potential ecotoxicological consequences of increasing plastic pollution.

Plastic ingestion by freshwater turtles: a review and call to action

“…Some ingested plastic that we documented in our T. s. elegans field sample may also have been attributable to trophic transfer (i.e., turtles eating prey that had itself ingested or become entangled in plastic). Trophic transfer was recently reported in a riverine bird 9 and potentially in some freshwater fishes 75 . For certain sea turtle species, eating jellyfish or seagrass with ingested/entangled plastic could facilitate trophic transfer 35 , 76 , as could eating benthic bivalve mollusks in marine and freshwater systems.…”

“…Given the well-documented negative individual-level impacts of plastic pollution on marine organisms, freshwater organisms are likely to be similarly affected—assuming that similar amounts of plastic exist in marine and freshwater habitats. However, both plastic volume and impacts to wildlife in freshwater systems remain comparatively understudied 6 – 9 .…”

Microplastics in terrestrial ecosystems: Moving beyond the state of the art to minimize the risk of ecological surprise

“…While studies of the transfer of microplastics across trophic levels in terrestrial system are scarce, microplastics have been found in the digestive tracts of carnivorous terrestrial birds, which suggests that they can be transferred up the food chain (Carlin et al, 2020; D'Souza et al, 2020; Zhao et al, 2016). Bioaccumulation of microplastics in terrestrial organisms was first reported by Huerta Lwanga, Gertsen, et al (2017) and Huerta Lwanga, Mendoza, et al (2017).…”

“…Terrestrial and aquatic food webs are generally intertwined by organisms, which are mobile and occupy large spatial area (e.g., birds and winged insects), and can seamlessly transit ecotones (Knight et al, 2005). A recent study (D’Souza et al, 2020) showed that microplastics can be transferred from aquatic to terrestrial ecosystems, when aquatic insects (Ephemeroptera and Trichoptera; 26 ± 3 particles/g) are consumed by passerines ( Cinclus cinclus ; regurgitated pellets 16 ± 3 particles/g, feces 8 ± 2 particles/g).…”

Impact of Plastic Debris on the Gut Microbiota of Caretta caretta From Northwestern Adriatic Sea

“…Up to now, it has been estimated that around 260 species, including marine mammals, birds and sea turtles, are threatened by PD, via entanglement and/or ingestion (Caron et al, 2018;Isangedighi et al, 2018). Moreover, breaking down into smaller fragments and filaments (Rocha- Santos and Duarte, 2015;Peng et al, 2017), plastics enter the marine food webs through ingestion by a large number of fish and shellfish species (Barboza et al, 2018), progressively accumulating across the food chain up to the top predators, including humans (Rochman et al, 2015;Nelms et al, 2018;D'Souza et al, 2020).…”