Lake Erie ‘pond scum’ may become the norm
From Discover Magazine comes the disturbing news that a record-breaking algae bloom in Lake Erie in 2011 could repeat itself this year and in years to come. Before you dismiss something as mundane-sounding as an algae bloom, as I was tempted to do, take a look at the photos from NASA’s Earth Observatory:
At its worst in October 2011, this lovely green ooze was 4″ thick and covered some 2,000 square miles (three times more than any previous bloom). You wouldn’t want to run your prized fishing boat through this goop, and you certainly wouldn’t want to swim or wade in it. Drink it? No way. Especially since it’s more than yucky; much of it is toxic. Toxicity levels reached 225 times the World Health Organization’s maximum level for safe swimming and boating.
When the algae gets thick enough, it blocks needed sunlight to other lake flora. Then as the algae dies, it decomposes with the aid of bacteria which consume huge amounts of oxygen, killing fish and other organisms. If the situation gets bad enough, an ecological dead zone will develop.
The primary cause of this nasty muck is fertilizer (nitrogen and phosphorus) run-off from farmland in the lake’s watershed. In the ’60s and ’70s, such nutrient loading in the Great Lakes got so bad that the US and Canadian governments implemented the Great Lakes Water Quality Agreement. It helped for several decades, but nutrient levels began rising again in the ’90s, not so much from more farms as from changing agriculture techniques.
The record bloom in 2011 resulted from a combination of when and how farmers spread their fertilizer and changing climate conditions — heavy rains, warm summers, and a lack of circulation in the lake. Researchers fear that the increasing use of biofuels will result in more farming acres and that our changing climate means warmer weather and larger, more frequent rainstorms. All of which favors more giant algae blooms like that seen two years ago.
If photos like these had existed in the early ’70s, I might not have complained quite so much when phosphates were removed from my favorite laundry detergent just when I most needed heavy duty cleaning for a young son’s clothes.