Wet, Again

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We’ve had a bit of a dry spell in southern Iowa; in fact the most recent data indicated a drought condition (D3, Extreme Drought, according to the US Drought Monitor for Oct 3). Wetlands that would normally be covered in water were left with dry, cracked mud.

And then, Friday, the rain finally came. It made the wetlands wet again.

I was reminded of the changing fortunes of a wetland when I visited Blue Flag Marsh in Warren County on Sunday. Much like other sites in our area, there was cracked mud, but after the rain it was covered with water. But a close look showed something else.

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The animals were moving all over this reflooded habitat: frogs, snails, insects. The algae was busy photosynthesizing (bubbles all over the “green snot,” filamentous algae). The flowers were perked right back up and green and some even bloomed. In short, the wetland was very much alive and well despite what a visitor three days before may have wondered: is this dry, cracked mud even a wetland?

 

I am reminded of two important lessons. First, living things adapt to their environments. They move, they  pause and rest, they revive. At another extremely dry wetland recently, my students and I collected a bucket of really dry, cracked mud. We added (filtered) water and the next day we had numerous small animals swimming around in the water above the flooded mud. The animals must have been there resting in the substrate, dormant but alive: and they responded literally overnight to the availability of water. Life is resilient and dynamic.

Second, wetlands aren’t always wet. Indeed, this is a difficult point for many people to grasp, but it is actually a defining characteristic of a wetland.  As opposed to a truly aquatic system like a pond, wetland hydrology is  highly variable—water depths fluctuate, and the occasional absence of water is quite normal for many wetlands. So don’t fear the drawdown; embrace the dry with the wet. Let the water rise and fall.  It will return. It’s the way of the water cycle.

If you visit Blue Flag marsh sometime, leave a comment about the water you find…and of course, reports of pretty Blue Flag Irises in bloom are most welcome too.

Author: Paul Weihe

Associate Professor of Biology at Central College, traditional author (Textbook of Limnology, Cole & Weihe, 5th ed.; Waveland Press), and now...blogger!

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