According to recent research, microplastic pollution causes a microscopic species that lives in freshwater all over the world to produce less energy.
Algae that reside inside Paramecium bursaria’s cells and produce energy through photosynthesis.
The University of Exeter’s latest study investigated how this symbiotic relationship can be impacted by severe water contamination with microplastics.
The findings revealed a 50% decrease in net photosynthesis, which had a significant effect on the algae’s capacity to release oxygen and produce energy.
According to Dr. Ben Makin, principal author and associate researcher at the Environment and Sustainability Institute on Exeter’s Penryn Campus in Cornwall, “the association I explored, known as photosymbiosis, is often found both in freshwater and the oceans.”
“We are aware that corals’ photosymbiotic interactions can be harmed by climate change, which can result in ‘bleaching’ events.
Further research is required, particularly in freshwater ecosystems, however recent studies have revealed that microplastics (plastic particles smaller than 5 mm) may also interfere with photosymbiosis.
In this work, I focused on a ‘classic’ case of photosymbiosis: Paramecium bursaria, which is prevalent in freshwater all over the world and shares symbiotic connections with other organisms in the ocean.
The experiment submerged Paramecium bursaria in water tainted with microplastics.
It has been discovered in some locations, though the level of contamination was higher than what is often observed in the natural environment.
“At this stage, the question I wanted to answer was whether severe contamination could affect this important relationship – and what those effects might be,” Dr Makin explained.
“This is a pilot experiment, and more research is needed to test different microplastic concentrations, different kinds of plastic and the effects on different species.”
The findings do not explain how microplastics contributed to the effects on photosymbiosis that were noticed. It’s possible that Paramecium bursaria ingested plastic debris or that compounds from plastics affected biological functions.
The study monitored the effects of microplastics on growth rate, symbiont density (how many algae were in each Paramecium bursaria), metabolic rate, feeding rate, and net photosynthesis in comparison to control water samples with no microplastics.
Only net photosynthesis was considerably impacted, but this could be crucial because it fuels the organism and supports the “trade” in nutrients that ensures the longevity of the photosymbiosis.
Surprisingly, this kind of relationship underlies a significant portion of photosynthesis in all of nature—roughly half of all photosynthesis in the ocean is supported by photosymbiosis.
“The findings could raise concern for the important contributions of photosymbiosis to primary production at a global level,” Dr Makin explained.
“Microplastics are a widespread contaminant, and their impacts on photosymbiosis – especially in freshwater – remain quite poorly characterised.”
The article, titled “Microplastic contamination decreases productivity in a common freshwater photosymbiosis,” was published in the journal Aquatic Biology.
Source:University of Exeter
