This summer as I flew over Minneapolis, I looked down fondly at the chain of lakes that beautifies this tidy, progressive city. My second hometown.

I noticed the surrounding land was lush and green. And so were many of the lakes. Wait a minute: The lakes themselves were more green than blue, ringed in pea-soup of algae that was closing in fast on the open water at the middle. This algae-green, sickly green mess set off alarm bells.

I suspected that all those lake-dwellers residing on their hard-fought real estate were sullying the waters by collectively dumping tons of fertilizer on their neat green lawns, which created a super-rich, even toxic runoff. This was hugely ironic, because these striving homeowners had moved there so they could boat, swim and engage in the state sport, fishing fer walleye. Yet their pursuit of the picture-perfect lake house retreat was poisoning the natural environment.

This is not hard science.  Think of steroids. They can make muscles grow, but trigger disease in the host organism. Same with fertilizer. Add too much nitrogen or phosphorus to the environment and you may trigger some awesome growth — and throw the ecosystem out of whack. This is why organic gardeners advocate using natural compost, but I digress.

This whole algae issue popped up this week in  a story by the Associated Press, reporting that, indeed, many lakes in the Upper Midwest are suffering from fertilizer overload. Fertilizer runoff (which is worse with synthetic soluble products) is causing a serious overgrowth of algae in some bodies of water. It chokes the life out of the lakes, and doesn’t make them smell so great either.

While lakes sometimes get overly ripe on their own, the AP article quotes a Wisconsin Department of Natural Resources expert saying that lakes tend to develop serious problems when humans introduce nutrients like phosphorus. (Nitrogen to a lesser extent.)

Aside from what the algae do within the lake — depleting the oxygen available for higher life forms, like walleye — the toxins released in the water and air can be lethal. Dogs have died. Humans have been sickened.

In some areas people have been advised to not walk their dogs along the lake and to stop the animals from drinking from it.

When will we get a clue?

Copyright © 2009 Green Right Now | Distributed by Noofangle Media

The dead zone in the Gulf of Mexico is expected to grow this year to between 7,400 and 8,400 square miles, a size roughly equivalent to the state of New Jersey, according to researchers at the University of Michigan.

That means the zone will be among the top three largest on record; the largest oxygen-starved zone reached 8,484 square miles in 2002.

The dead zones are inadvertently man made: In a sort of reverse circle of life, fertilizer and livestock waste runoff from farms and lawns across the United States overfeeds the Mississippi and other rivers with nitrogen, which prompts massive algae growth in the Gulf of Mexico. The algae sinks and is consumed by bacteria, a process that depletes oxygen supplies along the bottom and lower water levels, choking off aquatic plants and animals. Fish, shellfish and other plants die for lack of oxygen (hypoxia).

The phenomenon has been underway for decades, but has reached its largest proportions in recent years.
“The growth of these dead zones is an ecological time bomb,” said Donald Scavia, a professor at the U-M School of Natural Resources and Environment and director of the U-M Graham Environmental Sustainability Institute. “Without determined local, regional and national efforts to control them, we are putting major fisheries at risk.”

Scavia’s forecasts also include annual dead zone predictions for the Chesapeake Bay, which this year is expected to see a decrease in the size of the dead zone, though it is due to declining runoff resulting from less area precipitation and not pollution reduction.

The Gulf hypoxia research team is supported by the U.S. National Oceanic and Atmospheric Administration’s Center for Sponsored Coastal Ocean Research and includes scientists from Louisiana State University and the Louisiana Universities Marine Consortium.

See an animation of how dead zones are created at National Oceanic and Atmospheric Administration website.

Copyright © 2009 Green Right Now | Distributed by Noofangle Media