Wednesday, August 15, 2012

Summer's Wane

The “dog days” of August.  Everyone’s heard the phrase, but what does it really mean?  After a bit of internet investigating, I was able to determine that the term refers to the 20 days both before and after the conjunction of Sirius, the dog star, and the sun.  During the summer, Sirius rises and sets with the sun.  Ancient civilizations believed that Sirius’ heat, added to the heat of the sun, produced the stretch of hot and humid weather found from late July till early September.

Now that’s a neat explanation, but it doesn’t explain “why” bodies of water look so incredibly cruddy this time of year.   The quick answer is dog days’ heat has caused an algae bloom explosion.

Actually, though, late summer’s accelerated aquatic vegetation growth is only part of the annual turnover cycle of a lake's water mass.  At this time of year, thanks to the sun’s beating summer rays,  the lake strata  has stabilized  with warm water on the top and cold water on the bottom.  Since cold is attracted to heat, when there becomes enough warm water on top the cold water will rise and the warm will gradually sink to the bottom where it will cool off.  By the time the cycle completes in autumn, the lake will have “turned over” and will appear clear and pristine. 

What an amazing process for these living, breathing entities!  Mother Nature, in all her wisdom, refreshing and renewing the jewels of her creation before putting them to sleep for the winter.
                                                                                                                               Lovely Long Lake in May Township, looking, like most mid-sized and small bodies of water at this time of year, a little worse for wear.  Check back in autumn for a photo when she has morphed back to her true beauty,

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