Effect of ABS secondary microplastics on survival, mortality rate, life expectancy and fecundity of the freshwater cladocerans Moina macrocopa

Abstract

Microplastics are a ubiquitous pollutant and ingested by living beings, mainly aquatic organisms. Among freshwater organisms, zooplankton is susceptible to the ingestion of microplastics. The cladoceran Daphnia magna is used in most experiments with freshwater zooplankton, and other genera, such as the genus Moina, receive scarce attention. Likewise, are used primary polystyrene and polyethylene microplastics with the same shape, and other types of plastics are rarely used, such as secondary ones, which arise by fragmentation of larger ones. The objective was to determine the possible effects on survival, mortality, life expectancy, and fecundity of Moina macrocopa at different concentrations of secondary microplastics of the Acrylonitrile Butadiene Styrene type. We exposed groups of 10 neonates to a diet of microalgae and microplastics. There were four groups of cladocerans, each with a different concentration of microplastics (5, 10, and 20 mg/L) and a control. Daily we count individuals alive, dead, and their offspring until the last individual of the original cohort died. We demonstrated that microplastics may block the digestive tract and adhere to the carapace of M. macrocopa, thereby disrupting swimming activity. In addition, survival, mortality, life expectancy, and fecundity were negatively affected when exposed to the minimum concentration of microplastics; conversely, there are no significant changes in medium and high concentrations. The decline in neonates could alter the dynamics of M. macropa populations in the long term. Microplastics may be an emerging cause of the alteration of the zooplankton community and violate the base of the trophic webs.