Global Warming Is Invading Our Lakes, and Only Satellites Can Stop It

Image: TUM

Global warming is slowly heating up freshwater lakes around the world. As it does, the wrong kind of organisms can thrive—then you get what you have here today. That’s an aerial map of vegetation in and around a lake in Germany that shows the rise of invasive aquatic plant life. Gross, slippery stuff like the western waterweed and the spiny naiad have been multiplying like mad in German lakes. 

The problem is, detecting all that invasive plant life is difficult to do—divers typically have to check out lake beds by hand. But the water-weeds are on the march, they’re grossing out lake-goers and strangling the native species, and by the time they’re properly accounted for, they’ve spilled out across the waterways. 

So, researchers with the Technische Universität München developed a new way to detect spreading invasive, global warming-fed aquatic plants. They use aerial images taken by satellites that hone in on how much light underwater plants are reflecting. 

“In order to draw conclusions on plant growth from the imagery produced, we measure reflectance,” Dr. Thomas Schneider, the project’s supervisor, said in an announcement. “Each plant species reflects the incident light in a specific way, depending on its pigmentation and structure.”

They collected images, and, according to the study’s release, the “researchers developed a digital library with the spectral characteristics of plants to help them evaluate the aerial and satellite images.”

As seen above, the bare sediment is blue, sparsely plant-covered areas are green and yellow, and the dense vegetation is dark red. 

This may seem like a small step in understanding and combating climate change, but warming waters are already rapidly transforming underwater ecosystems. From Cuba to Singapore, climate change is speeding the rise of invasive aquatic plants. And this is serious stuff: Based on already observed trends, invasive species are estimated to do about $1.4 trillion in damages annually. 

This new technique may help us better understand the spread of underwater plants on the prowl—in the meantime, watch your step while you’re wading in. 

Global Warming Is Invading Our Lakes, and Only Satellites Can Stop It