Ozone pollution is damaging plant health, obstructing pollinators

Rising ozone pollution is having a detrimental impact on the natural world, damaging flora and making it harder for insects to find flowers.

There has long been an understanding that pollinators such as bees perform an invaluable role in the global ecosystem, and without them biodiversity and the food chain would collapse. Now scientists believe that – in addition to falling numbers of insect species linked to agricultural practices and rising temperatures damaging plants – ozone pollution is also impeding this life-giving process. 

Research first published in the journal Trends in Ecology and Evolution has pointed to a strong link between the presence and rising levels of ozone, damage to plant foliage and a change to flowering patterns. The latter makes it much more difficult for pollinators to locate blooms.

While ozone in the atmosphere at an altitude of 12km or higher naturally helps protect the Earth from the sun’s dangerous radiation, when the gas forms closer to the planet’s surface it acts as a harmful pollutant. This new evidence adds to a growing list of ways in which ozone damages the world and life therein. 

‘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,’ said lead author Evgenios Agathokleous, an ecologist at Nanjing University of Information Science & Technology. ‘These impacts of ozone have long been missed.

‘Ozone pollution can affect the timing and duration of flowering in such a way that the occurrence of flowering is asynchronous to the activities of pollinators,’ Agathokleous continued. ‘It can also change the color of flowers, disrupting the visual signals to pollinators. Ozone pollution can also directly react with pollen, decreasing its quality, but also indirectly changing the amount of pollen.’

In addition to the flowering effect, ozone has also been found to damage plant leaves, leaving them injured. Tell-tale signs include altered shape and discolouration. When in this state, it is more difficult to photosynthesise, and therefore it becomes a challenge to produce the amount of energy they need to grow. Volatile organic compounds that create the chemical signals plants use as a form of communication with each other, are also being disrupted.

Ozone pollution isn’t just effecting flowers and plants. Recent research shows the gas is responsible for the majority of Antarctic sea warming since 1950. 

Image: David Clode