America's Lakes Are Losing Their Blue Hue as Waters Shift to Murky Greenish-Brown
Over five-year period, the country’s number of blue lakes declined by 18 percent, while murky lakes increased by 12 percent
Murky lakes contain high quantities of both algae and organic matter. Lakes bearing such greenish-brown or brownish-green tints tend to be of low water quality (Wikimedia Commons)
By Meilan Solly
smithsonian.com
August 31, 2018 11:32AM
Between 2007 and 2012, lakes tinted with a greenish-brown hue—officially classified as “murky”—stealthily overtook blue lakes to become the country’s dominant lake type, Cara Giaimo reports for Atlas Obscura.
At the start of this five-year period, blue lakes represented 46 percent of the freshwater bodies included in the Environmental Protection Agency’s National Lakes Assessment (NLA). By 2012, this figure had dropped to 28 percent; at the other end of the spectrum, the percentage of murky lakes skyrocketed from 24 percent to 35.4 percent.
Researchers from the EPA, Virginia’s Longwood University and Washington State University relied on NLA data to evaluate the current state of America’s lakes and, according to a press release, assess encroaching murkiness’ “potential negative consequences for water quality and aquatic life.” The team’s findings are newly published in Limnology and Oceanography.
Color can reveal information about a lake’s nutrient load, algal growth, water quality and surrounding landscape, explains Kevin Rose, an environmental biologist at New York’s Rensselaer Polytechnic Institute, in a separate article published in online journal Lake Scientist.
Read more: https://www.smithsonianmag.com/smart-news/americas-lakes-are-losing-their-blue-hue-waters-shift-murky-greenish-brown-180970180/#mvbuLVBMybWPy35c.99
