Forest fires worsen mercury contamination in fish
December 4, 2006
Forest fires can worsen mercury accumulation in fish according to a paper published in the early online edition of the Proceedings of the National Academy of Sciences (PNAS) for the week of December 4-8, 2006.
Erin Kelly, a biologist from the University of Alberta, Edmonton, and colleagues examined a mountain lake affected by a fire and found that mercury in rainbow trout and other top-level fish species was up to five times higher than before the fire. Kelly says the primary contributor to the contamination was a restructuring of the food web. A news release from PNAS explains:
The nutrient influx from the burned area increased lake productivity, which altered the fish’s diet. Post-fire, trout began to eat smaller fish rather than invertebrates. This feeding change added another layer to the food web, causing fish at the top of the web to ingest more mercury than before the fire.
The researchers say that the findings are significant given the projected increase in forest fires due to climate change. Mercury contamination could worsen as forest fires become more frequent.
Citation: Kelly, et al. “Forest fire increases mercury accumulation by fishes via food web restructuring and increased mercury inputs.” PNAS Early Edition. December 4-8, 2006.
This article is based on a news release from PNAS.