When autumn’s first chill arrives, the first word that comes to my mind is “Turnover.” It’s a word used by fishermen and lake scientists. A word that represents opportunity and confusion. A phenomenon that makes both trophy hunting and deep study possible. A condition when things that seemed in equilibrium all at once become chaotic.
Turnover occurs when the surface of a lake cools to a temperature lower than the water resting beneath it. The no-longer-warm summer layers start to sink. It’s at this point that the lake quite literally “turns over.” The once-colder, deep water, filled with nutrients stored up over the course of a summer of sinking detritus, rises to the top and takes the summer water’s place. Poof, the lake becomes an inverse of itself.
For us fishermen, this is a temporary moment of paradise. In summer, cold, deep water acts as a refuge for heat-intolerant species like lake trout and landlocked salmon. Those beautiful fish spend their Julys and Augusts hiding in a near-freezing bubble at lake’s bottom, patiently waiting to escape their thermal jail. In fall they are suddenly sprung. Fish find themselves with a whole lake to explore, not just a thin, compressed slice. When turnover occurs the fish that anglers most want suddenly come within range of a shoreside cast.
Researchers also love a good turnover. Lakes present themselves with all their biology exposed and on the move. Things are dynamic and interesting. What’s not to love?
I wonder if we all could take a lesson from lakes here. There’s something to be said for the moment in our lives when hot passions dim enough to allow cooler, more complex thoughts to rise up. On a societal level there’s also a metaphorical reflection — especially for a relatively young country like the United States. Our nation spent its first centuries burning up its forests and mowing down its wildlife. Our forebears blazed with passion for industry and development before a cooler, environmentally focused ethos began to emerge from below.
Could it be possible that one day we’ll experience a global turnover? Could the things that threaten our planet have reached a point where they’ve flamed themselves out? Is it time for destructive ways of thinking to die and sink and allow different kinds of rationales to rise and take their place?
It’s something to ponder this autumn when the wind starts to blow and the heat finally breaks.
Turnover is good for any system whether it’s a lake, a person or a planet.