Microplastics are believed to disrupt photosynthesis — the biological process central to life on earth that provides the basis for global food chains as well as the oxygen we breathe. The tiny shreds of plastics — often originating from the disintegration of larger plastic items — have found their way into the most remote corners of the planet and even human organs. Now there is growing concern that these particles, once inside plant cells, can interfere with photosynthesis — the process by which plants convert sunlight, water, and carbon dioxide into energy in the form of sugars. This may impede plant growth, with potentially serious consequences for food production and climate change. Tractor on an agricultural fieldTractor on an agricultural field Microplastics could harm food productionImage: Frank Hoermann/SVEN SIMON/picture alliance What impact could microplastics be having on food production? Microplastics can reduce photosynthesis by up to 12%, according to an assessment led by a team of mostly China-based researchers. The study, published earlier this year in the Proceedings of the National Academy of Sciences, analyzed terrestrial crops, marine algae and freshwater algae. Seafood yields could plunge 7%, and staple crops could see a loss of up to 13.5%, according to the study. The scientists behind the paper warned this could leave hundreds of millions of people without reliable access to food. But cutting microplastic levels by just 13% could prevent nearly a third of photosynthesis loss, they found. Still, Peter Fiener, a soil and water expert, warned that there isn't enough data to reliably project the paper's findings on a global scale when it comes to photosynthesis loss and the resulting impact on food production. 9 images 1 | 99 images Microplastics are usually absorbed through soil when a plant sucks up water and other nutrients through its roots, Fiener told DW, adding if the particles are small enough they can pass into its cells. To understand the impact microplastics are having on food production around the world you would "need to have a global map of the plastic contamination of our soils and we just don't have such a map," said Fiener, who is a professor at Augsburg University in Germany. One of the biggest problems is the lack of data for the Global South, said Victoria Fulfer, a microplastics scientist at 5 Gyres, a US nonprofit tackling plastic pollution. "The other issue is that microplastics are made up of hundreds of different polymers and thousands of chemical additives and so we obviously haven't been able to test as scientists the impact that all of these have on plants," said Fulfer. While research into the impact of microplastics on plant growth is a very new field, it's "definitely something that we need to be concerned about and need to be focusing on," Fulfer told DW. Plants growing in soilPlants growing in soil There is a lack of data on the presence of microplastics in soil around the worldImage: MISEREOR/Achim Pohl Where does microplastic pollution come from? Microplastics absorbed by plants often come from tarps used to cover crops in agriculture and the spreading of fertilizers, said Fulfer. "But also microplastics are in our air and in our water." Agricultural mulch films are often used to cover crops and boost growth. While they're meant to be biodegradable, many still contain chemical additives and microplastics. As they break down, these substances seep into the soil, said Winnie Courtene-Jones, marine biologist and plastic pollution expert at Bangor University in Wales. Other sources include tiny fragments from car tires and fibers from clothing, which end up in sewage sludge later used as fertilizers. "So we're adding them directly to these ecosystems where the plants and the crops are growing and once they're at that small level of microplastics and nanoplastics, it's very difficult to get rid of them," said microplastics scientist Fulfer. Microplastics are usually defined as plastic pieces measuring between 1-5 millimeters, while nanoplastics are even smaller. Once in the soil, they can disrupt water movement and nutrient breakdown, affecting the growth of plants and other small organisms, said Courtene-Jones. Microplastics have been found throughout the human body and linked to a range of potential health problems, including strokes and heart attacks. Why recycled ocean plastic is (often) a lie