A new study published in the journal Scientific Reports states global warming increases the salinity of beaches or their salt content.  The research team found that sediments from the Slaughter Beach in Delaware, US contain four times more salt content than ocean water.

According to the study’s lead author Xiaolong Geng, a postdoctoral fellow at the New Jersey Institute of Technology’s Center for Natural Resources Development (CNRDP), the increased salinity is caused by evaporation along the shore. They gathered 400 sediment samples at the beach for seven days.

The researchers were expecting to record 25 grams per liter (g/L) of salt but they found that the salinity in the upper intertidal zone or the high tide line of the seashore, which gets covered during high tide and uncovered during low tide, measured 60 g/L. Some even reached up to 100 g/L.

This increased salt content can negatively affect invertebrates like mussels, sea anemones and crabs. Animals like birds and sea mammals that feed on these as well as planets like kelp will also be affected.

The research team’s models demonstrate that increasing temperature associated with global warming will also alter the pattern of pore water salinity apart from increasing the salinity. This will cause the species that thrive in the area to migrate to other locations.

“Evaporation is an important driver of underground water flow and salinity gradients, and animals such as mussels and crabs are affected by changes in salinity. If the concentrations are too high or too low, they will move away,” says Geng.

This study is the first major one  to investigate the effects of evaporation on the flow of subsurface water and salinity in the beach intertidal zone. Michel Boufadel, director of the CNRDP, hopes that their study could improve how authorities conduct water management in coastal areas.