Ingestion and Depuration of Microplastics by a Planktivorous Coral Reef Fish, Pomacentrus amboinensis

Abstract

Microplastics are ubiquitous contaminants in marine environments and organisms. Concerns about potential impacts on marine organisms are usually associated with uptake of microplastics, especially via ingestion. This study used environmentally relevant exposure conditions to investigate microplastic ingestion and depuration kinetics of the planktivorous damselfish, Pomacentrus amboinensis. Irregular shaped blue polypropylene (PP) particles (longest length 125–250 μm), and regular shaped blue polyester (PET) fibers (length 600–700 μm) were selected based on physical and chemical characteristics of microplastics commonly reported in the marine environment, including in coral reef ecosystems. Individual adult damselfish were exposed to a single dose of PP particles and PET fibers at concentrations reported for waters of the Great Barrier Reef (i.e., environmentally relevant concentrations, ERC), or future projected higher concentrations (10x ERC, 100x ERC). Measured microplastic concentrations were similar to their nominal values, confirming that PP particles and PET fibers were present at the desired concentrations and available for ingestion by individual damselfish. Throughout the 128-h depuration period, the 88 experimental fish were sampled 2, 4, 8, 16, 32, 64, and 128-h post microplastic exposure and their gastrointestinal tracts (GIT) analyzed for ingested microplastics. While damselfish ingested both experimental microplastics at all concentrations, body burden, and depuration rates of PET fibers were significantly larger and longer, respectively, compared to PP particles. For both microplastic types, exposure to higher concentrations led to an increase in body burden and lower depuration rates. These findings confirm ingestion of PP particles and PET fibers by P. amboinensis and demonstrate for the first time the influence of microplastic characteristics and concentrations on body burden and depuration rates. Finally, despite measures put in place to prevent contamination, extraneous microplastics were recovered from experimental fish, highlighting the challenge to completely eliminate contamination in microplastic exposure studies. These results are critical to inform and continuously improve protocols for future microplastics research, and to elucidate patterns of microplastic contamination and associated risks in marine organisms.

Evaluating the Effect of Chemical Digestion Treatments on Polystyrene Microplastics: Recommended Updates to Chemical Digestion Protocols

“…[29][30][31] PS frequently interacts with wildlife and ecotoxicity studies have revealed they adversely impact many marine species. [32][33][34][35] Additionally, PS is highly susceptible to chemical reaction. Treated PS MPs will be analyzed using both qualitative (microscopy) and quantitative (FT-IR, PL, NMR, and GPC) methods to accurately evaluate the effect these digestion methods have on the physical and chemical properties of the MP, which may impact accurate characterization and recovery.…”

Bottom-Up Evaluation of the Uncertainty of the Quantification of Microplastics Contamination in Sediment Samples

“…The instrumental conditions of the FTIR analysis are described following guidelines proposed by Andrade et al . The spectra obtained by the micro-FTIR were acquired in reflectance mode from 4000 to 600 cm –1 using eight scans or in micro-ATR mode from 4000 to 500 cm –1 using four scans to reduce analysis time. , For 94% of the particles, a 100 × 100 μm 2 aperture was used for spectrum acquisition, but the remaining smaller particles were identified using reduced apertures. The four spectra from microparticles with sizes larger than 1000 μm, obtained by the Spectrum Two FTIR, were acquired in universal ATR mode from 4000 to 600 cm –1 using eight or four scans. , A strong Norton–Beer apodization with 1 and 4 cm –1 wavenumber and resolution intervals, respectively, were used in all operational modes.…”

“…The four spectra from microparticles with sizes larger than 1000 μm, obtained by the Spectrum Two FTIR, were acquired in universal ATR mode from 4000 to 600 cm –1 using eight or four scans. 26 , 27 A strong Norton–Beer apodization with 1 and 4 cm –1 wavenumber and resolution intervals, respectively, were used in all operational modes. The instrumental signal was acquired in transmittance units (% T ).…”

Evolution, Development and Ecology of Anemonefishes

“…Lastly, microplastics are now widely distributed in marine ecosystems. Ingestion of microplastics has been shown to be an important pollutant in other fish due to its increased presence in the intestinal tract and the limited capacity of fish to expel the plastic pieces (Santana et al 2021).…”