When it comes to the natural world, even the smallest species can make a big impact. To that tune, a new study published in the journal iScience identifies a species of phytoplankton that can influence our global climate.
Phytoplankton, also known as microalgae, are microscopic plant-like organisms that float through the water column. When infected with a closely associated virus (EhV), one species called Emiliania huxleyi releases a chalky shell made of calcium carbonate into the air. These little bits of shells act as sea spray aerosols (SSA) that can reflect sunlight and affect cloud creation and movement.
"SSAs are particles emitted into the atmosphere when bubbles in the ocean burst," said Ilan Koren, an atmospheric scientist, in a statement. "They cover 70% of the atmosphere and can serve as cloud condensation nuclei, be surfaces for chemical reactions, and significantly contribute to the Earth radiation budget (the balance of how much solar energy Earth absorbs and how much it emits back into space) because they are very reflective."
The relationship between Earth’s oceans, atmosphere, and climate are interconnected by chemicals that are released and deposited in a loop cycle that controls the composition of our atmosphere, and thus climate. Previous research suggests SSAs impact the climate depending on their size and chemical composition, but how individual particles interact and respond with ocean biology remains a bit of a mystery.
In the lab, researchers took seawater samples and measured rates of emissions in infected and non-infected populations, controlling for environmental conditions present in the ocean.
The amount and size of these emissions far surpassed predictions by the scientists and, because E. huxleyi is one of the most dominant bloom-forming species of phytoplankton in the world, these infections could have a much bigger impact on processes that depend on SSA interaction, like light scattering and cloud droplet formation, than previously thought. Paired with their parachute-like shape, which allows the SSAs to stay in the atmosphere much longer, the scientists say more research is needed to see how their dispersal could further affect the environment.
“This study focuses on one species and its virus, but in a broader context it can show that the state of the atmosphere actually depends on the daily interactions in the seawater," said study author Miri Trainic. "Now we must do our best to further understand that relationship."
Like terrestrial plants, phytoplankton contains chlorophyll and uses photosynthesis to live and grow. Photosynthesis by phytoplankton accounts for as much as half of global primary production and plays a crucial role in carbon sequestration, according to the National Oceanic and Atmospheric Administration (NOAA). These tiny plants provide food for zooplankton (microscopic floating animals), who then feed larger and larger marine mammals.