TY - JOUR

T1 - Microplastic ingestion affects hydrogen production and microbiomes in the gut of the terrestrial isopod Porcellio scaber

AU - Hink, Linda

AU - Holzinger, Anja

AU - Sandfeld, Tobias

AU - Weig, Alfons R

AU - Schramm, Andreas

AU - Feldhaar, Heike

AU - Horn, Marcus A.

N1 - This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation); Project Number 391977956; SFB 1357 Microplastic subproject A02. We thank Peter Strohriegl and Lisa Weber for processing polymer granules, Lars Borregard Pedersen for microsensor construction and assistance during measurements, and the Poul Due Jensen Foundation for funding the sensor work. Alina Bernstein and Sabrina Kaupp helped to perform the isopod feeding experiments. We are also grateful to Anja Poehlein for library preparation and sequencing. Open Access funding enabled and organized by Projekt DEAL.

PY - 2023/12/19

Y1 - 2023/12/19

N2 - Microplastic (MP) is an environmental burden and enters food webs via ingestion by macrofauna, including isopods (Porcellio scaber) in terrestrial ecosystems. Isopods represent ubiquitously abundant, ecologically important detritivores. However, MP-polymer specific effects on the host and its gut microbiota are unknown. We tested the hypothesis that biodegradable (polylactic acid [PLA]) and non-biodegradable (polyethylene terephthalate [PET]; polystyrene [PS]) MPs have contrasting effects on P. scaber mediated by changes of the gut microbiota. The isopod fitness after an 8-week MP-exposure was generally unaffected, although the isopods showed avoidance behaviour to PS-food. MP-polymer specific effects on gut microbes were detected, including a stimulation of microbial activity by PLA compared with MP-free controls. PLA stimulated hydrogen emission from isopod guts, while PET and PS were inhibitory. We roughly estimated 10 7  kg year -1 hydrogen emitted from the isopods globally and identified their guts as anoxic, significant mobile sources of reductant for soil microbes despite the absence of classical obligate anaerobes, likely due to Enterobacteriaceae-related fermentation activities that were stimulated by lactate generated during PLA-degradation. The findings suggest negative effects of PET and PS on gut fermentation, modulation of important isopod hydrogen emissions by MP pollution and the potential of MP to affect terrestrial food webs.

AB - Microplastic (MP) is an environmental burden and enters food webs via ingestion by macrofauna, including isopods (Porcellio scaber) in terrestrial ecosystems. Isopods represent ubiquitously abundant, ecologically important detritivores. However, MP-polymer specific effects on the host and its gut microbiota are unknown. We tested the hypothesis that biodegradable (polylactic acid [PLA]) and non-biodegradable (polyethylene terephthalate [PET]; polystyrene [PS]) MPs have contrasting effects on P. scaber mediated by changes of the gut microbiota. The isopod fitness after an 8-week MP-exposure was generally unaffected, although the isopods showed avoidance behaviour to PS-food. MP-polymer specific effects on gut microbes were detected, including a stimulation of microbial activity by PLA compared with MP-free controls. PLA stimulated hydrogen emission from isopod guts, while PET and PS were inhibitory. We roughly estimated 10 7  kg year -1 hydrogen emitted from the isopods globally and identified their guts as anoxic, significant mobile sources of reductant for soil microbes despite the absence of classical obligate anaerobes, likely due to Enterobacteriaceae-related fermentation activities that were stimulated by lactate generated during PLA-degradation. The findings suggest negative effects of PET and PS on gut fermentation, modulation of important isopod hydrogen emissions by MP pollution and the potential of MP to affect terrestrial food webs.

UR - http://www.scopus.com/inward/record.url?scp=85152783306&partnerID=8YFLogxK

U2 - 10.1111/1462-2920.16386

DO - 10.1111/1462-2920.16386

M3 - Article

C2 - 37041018

VL - 25

SP - 2776

EP - 2791

JO - Environmental microbiology

JF - Environmental microbiology

SN - 1462-2912

IS - 12

ER -