Photo: NASA//OB.DAAC
El Niño may not be new to the world but the event is teaching scientists new things about our oceans. As things are starting to wind down from this most recent El Niño winter, NASA has spotted the climate phenomenon actively changing the salinity of coastal waters.
A team at NASA’s Jet Propulsion Laboratory in Southern California observed satellite images taken from 2011 to 2022. They noted marks of sediment at the surface and tracked the dissolved salt content, which helped them better understand the water cycle in which freshwater falls, flows, and evaporates between the land, ocean, and atmosphere.
In places where El Niño creates less rain and snowfall during the winter months, they found less water discharging from rivers into the ocean. Naturally, less freshwater flowing from rivers into the ocean is going to lead to a higher salt content at those river mouths. What’s noteworthy is that higher salinity levels can be found as far as 125 miles from shore. The inverse is obviously seen in areas that see more rain and snowfall during El Niño.
“Given the sensitivity to rainfall and runoff, coastal salinity could serve as a kind of bellwether, indicating other changes unfolding in the water cycle,” said lead author Severine Fournier, an ocean physicist at the JPL.
In their published report, the researchers pointed out that this relationship between El Niño/La Niña weather cycles and the coastal water cycle will have impacts on anything living in those environments, especially as the global climate changes and weather events intensify.
“For example, consequences of changes in supply of freshwater to the coastal ocean and beyond can have impacts on air-sea interactions such as convection and rainfall, intensification of hurricanes, and global ocean circulation,” they wrote. “Also, the supply of nutrients, sediments, organic and inorganic matter into the coastal ocean by discharge has been associated with altering biogeochemistry, and ecological and biological activities with subsequent impacts on fisheries and ecosystems and on carbon cycle fluxes in the greater regional ocean.”
