posted on 2023-11-29, 20:34authored byZipei Dong, Wen-Xiong Wang
Nano-
and microplastics (NMPs) are now prevalent in the marine
environment. This study quantified the uptake and depuration kinetics
of spherical polystyrene NMPs of different particle sizes (200 nm/30
μm) and functional groups (−NH2/–COOH)
in a temperate calanoid copepod Calanus sinicus (C. sinicus), which exhibited rhythmic
feeding patterns in natural environments. Aggregated-induced emission
(AIE) fluorescent probes were employed to track and quantify the kinetics
of NMPs with excellent photostability and biocompatibility. The results
showed that C. sinicus consumed all
NMPs types, with preference of NMPs to small size and amino group.
Increased diatom concentrations also inhibited the bioaccumulation
of NMPs. Influenced by rhythmic behavior, the bioaccumulation of NMPs
by C. sinicus was nonstationary during
the 6 h uptake phase. After 1–3 h of rapid uptake, the body
burden peaked and then slowly declined. During the 3 h depuration
phase, C. sinicus rapidly and efficiently
removed NMPs with a mean half-life of only 0.23 h. To further quantify
the body burden of C. sinicus under
the influence of rhythmic feeding behavior, a biokinetic model was
established, and the Markov chain Monte Carlo method was used to estimate
the parameter distribution. Our results highlighted that copepods
exhibited unique rhythmic feeding behavior under environmentally relevant
concentrations of NMPs exposure, which may influence the bioaccumulation,
trophic transfer, and environmental fate of NMPs.