Satellites can now reveal why the water in Lake Peipus has turned cloudy, or why Lake Võrtsjärv suddenly turns a suspicious green, and the latest technology is helping scientists determine what caused the changes, writes ERR News.
A study published in the journal Applied Sciences has confirmed that the latest generation of satellites can assess water quality in Estonia’s largest lakes much more accurately than before.
The study was conducted by scientists from the University of Tartu in collaboration with colleagues from Italy and France. Data from two European satellites, PRISMA and EnMAP, were used to analyze 12 satellite images of Lake Peipus and Lake Võrtsjärv. To ensure accuracy, the satellite data was compared with measurements physically taken on the lakes.
PRISMA and EnMAP are distinguished from other satellites by their so-called hypersensitive “vision”. While older satellites only recorded simplified shades of brown or green, newer technologies allow us to detect even the most subtle changes in color. This is important because different organisms produce specific, characteristic shades of color in the water. For example, satellites can detect the presence of a pigment produced by blue-green algae in Lake Peipus, which the old Sentinel satellite missed. Laboratory analyses confirmed that blue-green algae were indeed present in the lake at that time.
The satellite’s advantages allow to assess possible algal blooms in water bodies more quickly and comprehensively.
Satellite data can also be used to observe how rivers affect lake ecosystems. The brownish waters of the nutrient-rich Emajõgi River in Lake Peipus were visible as a fan-shaped coloration that slowly mixed with the lake water. Images taken after heavy rain and wind showed that much more sediment had entered the lake.
Satellite hypervision shows even subtle “footprints” left by organisms and substances in lakes, which until now could only be detected by performing analyses in a laboratory.
The study also concluded that the latest generation of satellites helps to better monitor the distribution of aquatic plants in lake waters.
Read also: Italy plans to give green light to Messina Strait bridge project