How plankton create clouds and keep us cool in the summer

A new study has shown that plankton in the Southern Ocean are responsible for creating nearly half of the water droplets in the clouds during the summer.

Tiny marine organisms called phytoplankton are found all throughout the world’s oceans, coalescing to form free-floating green blobs. And according to a report from Live Science, new research has shown just how important these little organisms are – they are responsible for half of the cloud droplets that cover the Southern Ocean in the summer months.

The study’s findings could help scientists more accurately predict the global effects of climate change by taking the cloud-creating capabilities of plankton into consideration. The phytoplankton rely on light to grow and populate the sea with blobs. In the summer when the water temperature is higher, massive phytoplankton blooms seem to influence how clouds form.

Researchers found that the number of cloud droplets nearly doubles in the summer over the Southern Ocean, when the phytoplankton are most abundant. The heavy cloud cover reflects more sunlight away from the atmosphere, which keeps the surface of the Earth cool.

Clouds may seem inconsequential, but they actually regulate the temperature to a large degree. Brighter clouds have more water droplets, which reflect most of the sun’s heat back into space.

Phytoplankton come into the picture by creating tiny particles called aerosols, which bind with water droplets and join together to make clouds. Aerosols can come from a wide range of sources, both natural and manmade. The study used sensitive satellite imaging tools to distinguish between the different types of aerosols in the atmosphere, and quantify the effects the plankton had on cloud formation.

When plankton absorb sunlight, they release a chemical called dimethyl sulfide, which then turns into a sulfate aerosol when it reaches the atmosphere. Found in the spray of crashing waves, researchers were able to track this compound from the algae all the way up to the clouds.

The study shows just how important phytoplankton are – they regulate many aspects of life, from the food chain, to the oxygen levels in the air, and according to the new study, perhaps even the climate.