|Microplastic pollution in Belgian coastal waters: realistic assessment of the effects of microplastics on zooplankton|
Vlaeminck, K. (2016). Microplastic pollution in Belgian coastal waters: realistic assessment of the effects of microplastics on zooplankton. MSc Thesis. Universiteit Gent - Faculteit Bio-ingenieurswetenschappen: 2016. 76 pp.
Temora longicornis (Müller O.F., 1785) [WoRMS]
ANE, Noordzee [Marine Regions]
Contamination of the marine environment with microplastics is a growing, world-wide problem with possible consequences for numerous species and ecosystems. Although there is a large amount of data and literature available on the presence and distribution of microplastics in our oceans, little is known about their possible adverse effects on organisms. Because of their small – microscopic (<1mm) – size microplastics can be ingested by different groups of organisms and it is assumed that this ingestion leads to adverse effects. However, to date, there is little evidence to support this assumption. In this master thesis the effects of microplastics on the filtration rate of copepods was studied in a series of laboratory experiments. Particular attention was given, in contrast to all previous studies available in literature, to the use of environmentally realistic microplastic concentrations. These results were subsequently integrated in a new Individual Based Model (IBM) developed for the test organism Temora longicornis which was then used to predict the potential effect at the population and community level. The experiments showed that there is a significant decrease in filtration rate when T. longicornis is exposed to microplastic concentrations >100 microplastics per liter. Based on the developed concentration-response (filtration) curves, the following effect concentrations were derived: 48h-EC50 = 2000 partikels per liter, 48h-EC20 = 500 particles per liter, and 48h- EC10 = 230 particles per liter. The IBM simulations showed that the carrying capacity of T. longicornis populations – depending on the season – was reduced by 11.8% (based on number of individuals) after exposure to a microplastic concentration of 130 microplastics per liter, i.e. an environmental concentration which is currently already exceeded in some marine environments. This is the first study to demonstrate adverse effects on the filtration rate of copepods exposed to environmentally realistic microplastic concentrations and which links these effects to population level consequences.