Rising ozone pollution levels have disrupted pollination over the past few decades, affecting both the survival of plants and the animals that pollinate them. In a review article that appeared in the September 29 issue of the journal Trends in Ecology and Evolution, scientists describe how too much ground-level ozone can harm plant foliage, alter plants’ flowering cycles, and make it harder for pollinators to locate blooms.
Evgenios Agathokleous, the lead author and an ecologist at Nanjing University of Information Science & Technology, says, “There is much noise about the direct effects of agrochemicals on pollinators, a subject of profound societal attention, but it now emerges that ozone is a silent threat to pollinators and thus pollination.” “These ozone effects have long gone unnoticed.”
Both allies and enemies of the planet can exist in ozone gas. Ozone naturally forms in the stratosphere, 12 kilometers above sea level, and aids in shielding the Earth from damaging solar radiation. However, ozone is a harmful pollutant below that zone. Volatile organic compounds, which are emitted by vegetation and are frequently present in products like paint and aerosols, and nitrogen oxides, which are released when fossil fuels burn, interact photochemically to produce ozone gas at the troposphere-level. Because climate change has made it easier for ozone to form, the amount of ozone in the atmosphere has been going up.
According to Agathokleous, ozone pollution can have an impact on flowering’s timing and duration in a way that makes it happen at a different time from when pollinators are active. “Additionally, it can alter the appearance of flowers, confusing pollinators’ visual cues. “Pollen quality can be directly lowered by ozone pollution’s reaction with it, while pollen quantity can be indirectly altered.
Ozone pollution can also quickly discolor and injure plant leaves, leaving behind injury signs in a variety of colors and shapes. When harmed, leaves struggle to photosynthesize and give the plant the energy it needs to grow. As chemical signals that facilitate communication between plants and alert pollinators to the presence of a waiting flower, plants release their own organic volatile compounds. These chemical signatures seem to be being disrupted by ozone pollution.
According to Agathokleous, “Changes in the volatile blends’ composition could also have serious effects on pollinators because they might not recognize host plants and their characteristics the same way they did in the past.” “Ozone pollution in plant tissues could lower the amount of nutrients that insects need, increase the amount of chemicals that are bad for insects to eat, and make the condition of plant tissues worse as a whole.”
