Abstract:
Microplastics (MPs) are an emerging issue in the modern marine environment. Plastic waste with different sizes, shapes and chemical components are accumulating in marine habitats. An ecological experiment was conducted to evaluate the impacts of increasing concentrations of micro-polyethylene terephthalate (mPETs) on the bioturbator Macomona liliana, primary productivity and nitrogen cycling. A 31-day laboratory experiment was conducted to assess the potential effects of mPETs at five concentrations (0%, 1%, 3%, 6%,and 8% based on wet weight of top 1cm sediment). The deposit feeder M. liliana incubated with the different concentration of mPETs for 31 days had slower reburial rates. The experiment revealed that the accumulation of mPETs could have adverse impacts on the ecosystem functioning through the feedback of interactions among deposit feeder, microphytobenthos and mPETs. The less reworking of the sediment by M. liliana reduced sediment oxygen consumption. When concentration of mPETs increased to 3%, nitrogen cycling was decoupled and the system lost the functionality of nitrogen regeneration, the high concentration of mPETs (8%) post the highest stress on the functional species and might lead to an alternative regime. Key words: polyethylene terephthalate (PET); microplastic; bioturbation; deposit feeder microphytobenthos; ecosystem function; marine sediments.
