Dados do Trabalho

Título

MICROPLASTICS CAN AFFECT SOIL MICROBIAL RESPIRATION OF AN ANTARCTIC MARINE TERRACE

Resumo

Evidence of microplastic (MP) contamination in terrestrial environments of Antarctica reinforces concerns about potential impacts on soil, which plays a critical role in ecological processes of ice-free areas. This study investigated the effects of two types of MPs on CO2 fluxes – as an estimate of microbial activity – and on temperature of a marine terrace soil from Fildes Peninsula (King George Island, Antarctica). Soils treated with polypropylene fragments [FR; 0.01% (1), 0.1% (2) and 1.0% (3) w w-1] and polyacrylic fibers [FB; 0.001% (1), 0.01% (2) and 0.1% (3) w w-1], in addition to a control treatment (C), were placed in plastic pots (Ø = 10 cm; h ≈ 10 cm) at the same sampling site, experiencing natural field conditions for 22 days. CO2 fluxes were measured every 2 days with an Infrared Gas Analyzer LI8100a, recording the soil temperature with a digital thermometer (±0.1 ºC). Treatments differed in mean CO2 flux but did not induce significant effects on soil temperature. There is an increase trend for CO2 fluxes by increasing fibers concentration, with FB3 showing a mean higher than FB1 and C. For fragments, only FR2 presented a mean higher than C. From the 5th to the 19th day, the evolution of the cumulative fluxes shows a logarithmic behavior for all samples except for FR2 and FR3, which were closer to a linear response, resulting in final cumulative flux value up to 1.4 times greater than C. Impacts on CO2 fluxes induced by fibers are proportional to the dose and possibly influenced by soil physical conditioning, while those induced by fragments had a more complex behavior, with an optimum point at an intermediate concentration. No significant correlation between CO2 fluxes and soil temperature suggests that the stimuli in soil microbial respiration were not able to promote nor were promoted by changes in temperature. MP contamination can impact Antarctic soil microbial functions and raises concerns about ecological processes in this sensitive environment.

Palavras-chave

CO2 fluxes; Fildes Peninsula; polyacrylic; polypropylene.

Instituição financiadora

CNPq

Agradecimentos

Projetos Terrantar/Permaclima; PROANTAR; Marinha do Brasil; UFV.