Study at the University of Giessen shows negative effects of microplastic particles on corals – part of the research project “Ocean 2100” at the German-Colombian Center of Excellence in Marine Sciences CEMarin.
Coral reefs belong to the most diverse habitats on our planet. Thousands of species of fish use corals as shelter, food source and nursery. However, coral reefs are increasingly suffering from the effects of global change. Alongside rising temperatures, it is the increase in pollution from plastic waste that is having a detrimental impact. Plastic bottles, bags and packaging are present in nearly every reef today. What is not immediately obvious, but is just as prevalent and potentially dangerous, is microplastics – tiny plastic fragments measuring less than five millimetres. Scientists at Justus Liebig University Giessen (JLU) have now examined the effects of these particles on six widespread species of coral for the first time. Their results have been published in the journal “Environmental Pollution”.
For this study, the scientists exposed corals to increased concentrations of microplastics
under laboratory conditions and documented the reactions shown by the corals. It was
observed that corals often interacted with the plastic particles and some even confused
them with food. Other corals responded by more frequently producing mucus and showing
other forms of rejection. After four weeks, five of the six species examined displayed initial
signs of impaired health such as bleaching and tissue necrosis. Further studies must now
show whether negative effects can be registered even under low microplastic concentrations
and what longterm effects microplastics have on corals.
“Our study clearly indicates that microplastics are yet another human-made stress factor for
corals and that they are very likely to contribute to further deterioration of coral reefs on our
planet”, reports Jessica Reichert, the lead author. The study forms part of the “Ocean 2100”
project located in Giessen, in which doctoral students from the German-Colombian Center of
Excellence in Marine Sciences CEMarin are examining the effects of climate change on reef
building stony corals. Conditions for the year 2100 are simulated in experiment tanks at the
Interdisciplinary Research Centre (iFZ) by gradually setting different parameters such as
temperature and acidic content of the water to the levels to be expected.
Jessica Reichert, Johannes Schellenberg, Patrick Schubert and Thomas Wilke: Responses of
reef building corals to microplastic exposure. Environmental Pollution, Volume 237, June