DOI: 10.5061/dryad.4vs36
title: Data from: The effects of natural and anthropogenic microparticles on individual fitness in Daphnia magna

description: Concerns are being raised that microplastic pollution can have detrimental
 effects on the feeding of aquatic invertebrates, including zooplankton.
 Both small plastic fragments (microplastics, MPs) produced by degradation
 of larger plastic waste (secondary MPs; SMPs) and microscopic plastic
 spheres used in cosmetic products and industry (primary MPs; PMPs) are
 ubiquitously present in the environment. However, despite the fact that
 most environmental MPs consist of weathered plastic debris with irregular
 shape and broad size distribution, experimental studies of organism
 responses to MP exposure have largely used uniformly sized spherical PMPs.
 Therefore, effects observed for PMPs in such experiments may not be
 representative for MP-effects in situ. Moreover, invertebrate
 filter-feeders are generally well adapted to the presence of refractory
 material in seston, which questions the potential of MPs at
 environmentally relevant concentrations to measurably affect digestion in
 these organisms. Here, we compared responses to MPs (PMPs and SMPs) and
 naturally occurring particles (kaolin clay) using the cladoceran Daphnia
 magna as a model organism. We manipulated food levels (0.4 and 9 μg C
 mL-1) and MP or kaolin contribution to the feeding suspension (&lt;1
 to 74%) and evaluated effects of MPs and kaolin on food uptake, growth,
 reproductive capacity of the daphnids, and maternal effects on offspring
 survival and feeding. Exposure to SMPs caused elevated mortality,
 increased inter-brood period and decreased reproduction albeit only at
 high MP levels in the feeding suspension (74% by particle count). No such
 effects were observed in either PMP or kaolin treatments. In daphnids
 exposed to any particle type at the low algal concentration, individual
 growth decreased by ~15%. By contrast, positive growth response to all
 particle types was observed at the high algal concentration with 17%, 54%
 and 40% increase for kaolin, PMP and SMP, respectively. When test
 particles comprised 22% in the feeding suspension, both MP types decreased
 food intake by 30%, while kaolin had no effect. Moreover, SMPs were found
 to homoaggregate in a concentration-dependent manner, which resulted in a
 77% decrease of the ingested SMPs compared to PMPs. To better understand
 MP-processing in the gut, gut passage time (GPT) and evacuation rate of
 MPs were also assayed. SMPs and PMPs differed in their effects on
 daphnids; moreover, the particle effects were dependent on the MP: algae
 ratio in the suspension. When the MP contribution to the particle
 abundance in the medium changed from 1 to 4%, GPT for daphnids exposed to
 SMPs increased 2-fold. Our results suggest that MPs and, in particular,
 SMPs, have a greater capacity to negatively affect feeding in D. magna
 compared to naturally occurring mineral particles of similar size.
 Moreover, grazer responses observed in experiments with PMPs cannot be
 extrapolated to the field where SMPs dominate, because of the greater
 effects caused by the latter.
description: Exp_I_reproduction_dataRaw data from a 21 day reproduction test using D.magna exposed to kaolin, and primary and secondary microplastics.Exp_II_DW_comparisonDry weights of daphnids used in statistical evaluation of experiment II.Exp_III_food_consumptionData from experiment III on consumption of algae in the presence of inert particles (kaolin, primary or secondary microplastics).Exp_IV_aggregatesData for evaluation of MP-aggregates in the gut of D. magna from experiment IV.Exp_IV_gutevacGut evacuation data from Experiment IV.Exp_V_maternal_effectsMaternal effects data from experiment V.