Sticky with sediment, the bottom waters of lakes are more than their deepest, darkest layer.
Sticky with sediment, the bottom waters of lakes are more than their deepest, darkest layer. They bury massive portions of the carbon, nitrogen, and phosphorus found in runoff rolling in from the land. As one of nature’s critical nutrient sinks, lakes earn their recognition as “sentinels” of their surroundings, said freshwater scientist Cayelan Carey.
“We think of lakes as sentinels because they truly integrate all of the changes that happen on land,” said Carey, an associate professor of biological sciences in the Virginia Tech College of Science and an affiliated scientist with the Fralin Life Sciences Institute. “Lakes do this really great job of receiving and processing all of this carbon, nitrogen, and phosphorus, preventing them from going downstream and reaching the ocean.”
But that work could be dismantled by anoxia, the loss of oxygen availability, Carey’s team found in a study published this week in Global Change Biology. Dreaded by scientists for years and recently confirmed as widespread by data from hundreds of lakes, anoxia is sucking oxygen from the world’s fresh waters.
It’s a phenomenon linked to the warming of waters brought on by climate change and to excess pollutant runoff from land use. Warming waters diminish fresh water’s capacity to hold oxygen, while the breakdown of nutrients in runoff by freshwater microbes gobbles up oxygen.
Read more at Virginia Tech
Image: Cayelan Carey, an assistant professor of biological sciences in the College of Science (at center) works with graduate students Jonathan Doubek (at left) and Ryan McClure to filter water samples at Falling Creek Reservoir for analysis of iron and manganese concentrations. (Credit: Virginia Tech)
