As wildfire activity and severity increase globally, so too does the pervasiveness of wildfire smoke.
Researchers in the U.S. are working to find out how growing amounts of wildfire smoke nationwide affect ecosystems including aquatic habitats. A recent study published in the Global Change Biology research journal found that even smoke impacts lake ecology.
“An incredible 98.9 percent of lakes experienced at least 10 smoke-days a year, with 89.6 percent of lakes receiving over 30 lake smoke-days, and lakes in some regions experiencing up to 4 months of cumulative smoke-days,” the study said.
The term “smoke-days” describes the number of days on which any portion of a lake’s boundary intersected with smoke as defined by NOAA’s hazard mapping system daily smoke product. The smoke-days concept has been used previously to demonstrate smoke exposure by ecoregion, but was used specifically for lakes for the first time in this study.
Smoke and ash from wildfires lower the solar radiation that enters lake habitats, affecting organisms in numerous ways from physiology to behavior, according to the research. Particles from the smoke deposited within lake ecosystems can also affect several biological and geological processes, including the availability and cycling of various nutrients.
Less than 0.01 percent of land in North America burned between 2019 and 2021, but the area covered in smoke was 75 percent of the continent’s total land. The year 2021 marked the largest number of high-density lake smoke-days and is the year with the largest portion of the country burned and largest area covered with smoke, while 2020 had the lowest number of high-density smoke-days and the smallest area burned and smallest area covered with smoke.
“Large knowledge gaps impede our ability to predict and manage the responses of lakes to smoke and ash,” the researchers concluded. “Measuring the extent and effects of smoke and ash deposition remains challenging. Larger-scale studies are necessary to disentangle the mediating effects of scale and watershed context on the responses of lakes to smoke and ash deposition.”
Read the entire study here.
