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IESA research uses satellites to map algal blooms

Dr. Amber Ignatius knows that too much of a good thing can be bad. A prime example is the algae that grows in Lake Lanier and its tributaries in northeast Georgia.

“Algae are excellent for photosynthesis, which generates oxygen for the Earth and its inhabitants. Algae also provide food for fish and other organisms in the water,” said the assistant professor of geography and geospatial science at the Lewis F. Rogers Institute for Environmental and Spatial Analysis at the University of North Georgia (UNG).

But when algae contain too many nutrients, they can develop a harmful bloom. This explosion of algae or cyanobacteria can be detrimental to wildlife, animals and humans. Cyanobacteria blooms occur annually in Georgia and occur in agricultural ponds, large reservoirs, and tributaries.

“When a cyanobacterial bloom occurs, it can lead to fish kills and increased exposure to cyanotoxins,” Ignatius said. “The deaths of dogs, cattle, and waterfowl have been directly linked to exposure to cyanobacteria in the state. Symptoms in humans of exposure may include headache, fever, muscle and joint pain, stomach cramps, diarrhea and vomiting.”

Ignatius said she is monitoring Lake Lanier to better understand the patterns of cyanobacteria in this ecosystem and to see if there are any high-risk spots in the lake.

To determine where algae and cyanobacteria are forming in Lake Lanier, Ignatius uses remote sensing technology to scan thousands of satellite images over an eight-year period to determine the location and frequency of blooms.

“I wrote code that extracts information from EPA CyAN data and thousands of satellite images and shows the amount of algae and cyanobacteria that may be in the water through color variations,” Ignatius said. , who received a presidential incentive award for conducting this research. “Thanks to Google Earth Engine and satellite images stored in the cloud, I can observe bodies of water from all over Georgia and the United States.”

The data that Ignatius collected and analyzed has some practical applications. First, it can map the locations of cyanobacterial blooms and share them with local authorities who manage waterways.

Chattahoochee Riverkeeper (CRK) is a non-profit organization that plans to listen to Ignatius’ research. She monitors algae levels and water quality according to state standards at five different locations on Lake Lanier.

“The same ingredients that cause high levels of algae, such as nutrient pollution and stormwater runoff, are also the same ingredients that cause cyanobacterial blooms,” said Dale Caldwell, director of CRK’s Headwaters office. in Gainesville, Georgia. “Any information we can glean from Amber Ignatius’ type of research will help us. We can refer to it and help meet water quality standards.”

A second application is that the computer program can create interactive maps to view the geography and topography of the land in the past and present.

Ignatius also plans to use the data and information in an introductory science class and lab to expose students to habitat in their area.

“We’re going to look at Lake Lanier and study how scientists study it,” she said. “Some scientists look at land use while others look at historical changes in water quality over time. Students can see the broad spectrum of science while gaining a better understanding of our region. “