Microplastic pollution reduces the energy production of tiny organisms found in freshwater around the world, new research shows.
Paramecium contains algae that live inside their cells and provide energy through photosynthesis.
A new study by the University of Exeter tested whether severe microplastic pollution in water affects this symbiotic relationship.
The results showed a 50% decrease in net photosynthesis. This had a significant impact on the algae’s ability to produce energy and release oxygen.
“The relationship I have explored, known as photosymbiosis, is commonly found in both freshwater and marine waters,” says lead author and director of the Institute for Environment and Sustainability, Penrhyn Campus, Exeter, Cornwall. Assistant Researcher Ben Makin, Ph.D.
“We know that climate change can impair photosymbiotic relationships involving corals (leading to ‘bleaching’ events).
“Recent research has shown that microplastics (plastic particles smaller than 5 mm) can also interfere with photosymbiosis, but more research is needed, especially in freshwater habitats.
“For this study, we chose a ‘classic’ example of photosymbiosis. Paramecium is found in freshwaters around the world, and similar symbiotic relationships exist in the ocean.”
In this study, we placed paramecium in water contaminated with microplastics in the laboratory.
Contamination levels were higher than normally found in nature, but were found in some locations.
“At this stage, the question I wanted to answer was whether severe contamination could affect this important relationship and what those effects would be,” Dr. Makin explains. Did.
“This is a pilot experiment, and more research is needed to test the effects on different microplastic concentrations, different types of plastics, and different species.”
The findings do not reveal how microplastics caused the observed effects on photosymbiosis. Possibly, Paramecium bursaria ingests plastic particles, or chemicals from the plastic affect biological processes.
In this study, we compared the effects of microplastics on growth rate, symbiont density (number of algae contained in each paramecium), metabolic rate, feeding rate, and net photosynthesis (compared to control water samples without microplastics). ) I tracked it down.
Only net photosynthesis was significantly affected, but this may be important as it provides the organism with energy and underpins the nutrient “trading” that sustains photosymbiosis.
Surprisingly, associations of this type are involved in many photosyntheses around the world. About half of all photosynthesis in the ocean is supported by photosymbiosis.
“This finding may raise concerns about the important contribution of photosymbiosis to primary production at the global level,” Dr. Makin explained.
“Microplastics are pervasive pollutants, and their effects on photosymbiosis, especially in freshwater, are still poorly understood.”
Original: Microplastics limit energy production in small freshwater species
Than: University of Exeter
